This document summarizes an experimental study on two-phase air-water flow in a horizontal rectangular minichannel with a Y-junction. The study investigated flow patterns, bubble velocity, bubble length, void fraction, and pressure profiles upstream and downstream of the junction. Two flow patterns (slug flow and annular flow) were observed. Pressure loss coefficients were proposed for the pressure drop at the junction. Results were compared to existing correlations from literature to analyze frictional pressure drops, void fractions, and other two-phase flow parameters.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The two-phase flow through vertical transparent pipe is investigated
experimentally. The experimental rig designed to achieve the measurements of
pressure drop for various combinations of phases, flow pattern regimes such as
bubbly, slug and annular, with various range of water and air volumetric high speed
camera . The air volumetric ranged from 8.3334 L/min to 25 l/min, while the water
volumetric ranged from 5 l/min to 20 l/min and of 50 mm internal diameter along 1 m
length. The measured of the pressure will be done using four pressure sensors along
test pipe. The measured pressure values were used for different air volumetric and
different water volumetric. It has been found that the measuring of pressure gradient
through the distance of rig pipe are inversely changed with air volumetric. In
addition, it has been analyzed the flow pattern through obstruction, it has showed one
phase flow, bubbly and slug flow.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
A Computational Investigation of Flow Structure Within a Sinuous DuctIJERA Editor
In the present investigation the distribution of mean velocity are experimentally studied on three constant area
rectangular curved ducts with an aspect ratio of 2.4. First one is C-shape, second one is S-shape and third one
is a DS-shape duct. The experiment is carried out at mass averaged mean velocity of 40m/s for all the ducts.
The velocity distribution shows for C-duct, the bulk flow shifting from outer wall to the inner wall along the
flow passage and for S-duct, the bulk flow shifting from outer wall to the inner wall in the first half and from
inner wall to the outer wall in the second half along the flow passage of curved ducts are very instinct. Due to
the imbalance of centrifugal force and radial pressure gradient, secondary motions in the forms of counter
rotating vortices have been generated within both the curved duct. For DS-duct the velocity distributions shows
the Bulk of flow shifting from inner watt to outer wall in the first bend and third bend of the duct and outer wall
to inner wall in the second bend and forth bend of the duct along the flow passage is very instinct. Flow at end
of the DS-duct is purely uniform in nature due to non existence of secondary motion. The experimental results
then were numerically validated with the help of Fluent, which shows a good agreement between the
experimental and predicted results for all the ducts
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Diffusers are extensively used in centrifugal
compressors, axial flow compressors, ram jets, combustion
chambers, inlet portions of jet engines and etc. A small change in
pressure recovery can increases the efficiency significantly.
Therefore diffusers are absolutely essential for good turbo
machinery performance. The geometric limitations in aircraft
applications where the diffusers need to be specially designed so
as to achieve maximum pressure recovery and avoiding flow
separation.
The study behind the investigation of flow separation in a planar
diffuser by varying the diffuser taper angle for axisymmetric
expansion. Numerical solution of 2D axisymmetric diffuser model
is validated for skin friction coefficient and pressure coefficient
along upper and bottom wall surfaces with the experimental
results of planar diffuser predicted by Vance Dippold and
Nicholas J. Georgiadis in NASA research center [2]
.
Further the diffuser taper angle is varied for other different
angles and results shows the effect of flow separation were it is
reduces i.e., for what angle and at which angle it is just avoided.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The two-phase flow through vertical transparent pipe is investigated
experimentally. The experimental rig designed to achieve the measurements of
pressure drop for various combinations of phases, flow pattern regimes such as
bubbly, slug and annular, with various range of water and air volumetric high speed
camera . The air volumetric ranged from 8.3334 L/min to 25 l/min, while the water
volumetric ranged from 5 l/min to 20 l/min and of 50 mm internal diameter along 1 m
length. The measured of the pressure will be done using four pressure sensors along
test pipe. The measured pressure values were used for different air volumetric and
different water volumetric. It has been found that the measuring of pressure gradient
through the distance of rig pipe are inversely changed with air volumetric. In
addition, it has been analyzed the flow pattern through obstruction, it has showed one
phase flow, bubbly and slug flow.
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
A Computational Investigation of Flow Structure Within a Sinuous DuctIJERA Editor
In the present investigation the distribution of mean velocity are experimentally studied on three constant area
rectangular curved ducts with an aspect ratio of 2.4. First one is C-shape, second one is S-shape and third one
is a DS-shape duct. The experiment is carried out at mass averaged mean velocity of 40m/s for all the ducts.
The velocity distribution shows for C-duct, the bulk flow shifting from outer wall to the inner wall along the
flow passage and for S-duct, the bulk flow shifting from outer wall to the inner wall in the first half and from
inner wall to the outer wall in the second half along the flow passage of curved ducts are very instinct. Due to
the imbalance of centrifugal force and radial pressure gradient, secondary motions in the forms of counter
rotating vortices have been generated within both the curved duct. For DS-duct the velocity distributions shows
the Bulk of flow shifting from inner watt to outer wall in the first bend and third bend of the duct and outer wall
to inner wall in the second bend and forth bend of the duct along the flow passage is very instinct. Flow at end
of the DS-duct is purely uniform in nature due to non existence of secondary motion. The experimental results
then were numerically validated with the help of Fluent, which shows a good agreement between the
experimental and predicted results for all the ducts
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Diffusers are extensively used in centrifugal
compressors, axial flow compressors, ram jets, combustion
chambers, inlet portions of jet engines and etc. A small change in
pressure recovery can increases the efficiency significantly.
Therefore diffusers are absolutely essential for good turbo
machinery performance. The geometric limitations in aircraft
applications where the diffusers need to be specially designed so
as to achieve maximum pressure recovery and avoiding flow
separation.
The study behind the investigation of flow separation in a planar
diffuser by varying the diffuser taper angle for axisymmetric
expansion. Numerical solution of 2D axisymmetric diffuser model
is validated for skin friction coefficient and pressure coefficient
along upper and bottom wall surfaces with the experimental
results of planar diffuser predicted by Vance Dippold and
Nicholas J. Georgiadis in NASA research center [2]
.
Further the diffuser taper angle is varied for other different
angles and results shows the effect of flow separation were it is
reduces i.e., for what angle and at which angle it is just avoided.
Transient Three-dimensional Numerical Analysis of Forced Convection Flow and ...IOSR Journals
A three-dimensional transient numerical study of a constant property Newtonian fluid in curved pipe under laminar flow conditions is presented for a uniform wall temperature boundary condition. Numerical solutions were obtained using the control volume method described by Patankar for the range of. The working fluid was water. The transient flow pattern and the temperature distribution on the tube section were derived for different values of the Reynolds number. Graphical results for velocity and temperature are presented and analyzed. Results have shown that the maximum velocity in center of velocity profile increase with increasing of Reynolds number. In curved pipes, time averaged results exhibited Dean circulation and a strong velocity and temperature stratification in the radial direction. Flow and heat transfer were strongly asymmetric, with higher values near the outer pipe bend.
NUMERICAL INVESTIGATION OF LAMINAR NANOFLUID FLOW IN MICRO CHANNEL HEAT SINKS IAEME Publication
The effect of using nanofluids on heat transfer and aerodynamics characteristics in rectangular shaped micro channel heat sink (MCHS) is numerically investigated for Reynolds number range of (100-400 ) and different value of heat flux (50 , 100, 150 ) / . In this study,the MCHS performance using tow type of nanofluid with volume
fraction 10% was used as a coolant is examined. The three-dimensional steady, laminar flow and heat transfer governing equations are solved using The computational fluid dynamics code (FLUENT). The MCHS performance is evaluated in terms of temperature profile, heat transfer,velocity profile, pressure drop and friction factor.
Basics of two phase flow (gas-liquid) line sizingVikram Sharma
This article was produced with the objective to provide a condensed fundamental insight in gas-liquid line sizing using Lockhart-Martinelli correlation. The content of this article is purely academic by nature.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
HEAT TRANSFER CORRELATION FOR NON-BOILING STRATIFIED FLOW PATTERN | J4RV3I11006Journal For Research
In chemical industries two phase flow is a process necessity. A better understanding of the rates of momentum and heat transfer in multi-phase flow conditions is important for the optimal design of the heat exchanger. To simplify the complexities in design, heat transfer coefficient correlations are useful. In this work a heat transfer correlation for non- boiling air-water flow with stratified flow pattern in horizontal circular pipe is proposed. To verify the correlation, heat transfer coefficients and flow parameters were measured at different combinations of air and water flow rates. The superficial Reynolds numbers ranged from about 2720 to 5740 for water and from about 563 to 1120 for air. These experimental data were successfully correlated by the proposed two-phase heat transfer correlation. It is observed that superficial.
The dependencies of total pressure, velocity, vorticity, turbulent length, turbulent dissipation, turbulent viscosity, turbulent energy and turbulent time of moving fluid from a straight pipe length of a circular cross section are presented in graphical and mathematical forms. Changing analysis of considered parameters was performed at mass flow rates of 0.45, 1.0 and 1.5 kg/s. A transition boundary of laminar flow of fluid to turbulent flow is at the distance of 2/5 of length from the inlet of the pipe (at accepted total length of the pipe of 1000 mm).
Experimental Investigation on Heat Transfer Analysis in a Cross flow Heat Ex...IJMER
Heat exchanger is devices used to exchange the heat between two liquids that are at different
temperature .These are used as a reheated in many industries and auto mobile sector and power
plants. The main aim of our project is thermal analysis of heat exchanger with waved baffles for
different types of materials at different mass flow rates and different tube diameters using FLOEFD
software and comparing the results that are obtained. The work is a simplified model for the study of
thermal analysis of shell-and-tubes heat exchangers having water as cold and hot fluid. Shell and
Tube heat exchangers are having special importance in boilers, oil coolers, condensers, pre-heaters.
They are also widely used in process applications as well as the refrigeration and air conditioning
industry. The robustness and medium weighted shape of Shell and Tube heat exchangers make them
well suited for high pressure operations. The project shows the best material, best boundary conditions
and parameters of materials we have to use for better heat conduction. For this we are chosen a
practical problem of counter flow shell and tube heat exchanger having water, by using the data that
come from cfd analysis. A design of sample model of shell and tube heat exchanger with waved baffles
is using Pro-e and done the thermal analysis by using FLOEFD software by assigning different
materials to tubes with different diameters having different mass flow rates and comparing the result
that obtained from FLOEFD software.
THE EFFECT OF GEOMETRICAL PARAMETERS ON HEAT TRANSFER AND HYDRO DYNAMICAL CHA...ijmech
Compact size and high heat transfer coefficient of helical coil heat exchangers causes them to have an
important role in various industrial applications. This paper investigate numerically on the influence of
different parameters such as coil radius, coil pitch and diameter of tube on the hydrodynamic and
heat transfer characteristics of helical double tube heat exchangers using the CFD software which is
based on the principles of heat transfer, fluid mechanics and thermodynamics. The results indicated that
heat transfer augmentation occurs by increasing of the inner Dean Number, inner tube diameter, curvature
ratio and by the reduction of the pitch of heat exchanger coil. By increasing the radius of coils, the
secondary flow effects due to centrifugal forces diminishes and flow of fluid through the coils tends to flow
in a straight path and as a result, the friction coefficient decreases consequently.
Control of Suddenly Expanded Flow at Low Supersonic Mach NumbersIJERA Editor
In the present study the experiments were conducted to control the base pressure from a convergent-divergent
nozzle at low supersonic Mach numbers to assess the effectiveness of active control mechanism in the form of
micro jets at different expansion level. The parameters considered in the present study are the diameter ratio,
length to diameter ratio (L/D), Nozzle Pressure Ratio (NPR), and the Mach number. The diameter ratio selected
for the present study are 1.6, 1.8, 2.2, and 2.5. Experiments were conducted for nozzle pressure ratio (NPR)
from 3 to 11. The L/D ratio of the enlarged duct was varied from 10 to 1, and results are presented for L/D 4, 3,
2, and 1. The Mach numbers of the present studies are 1.1, 1.2, 1.4, and 1.5. The results show that the Micro jets
are very effective and are able to raise the base pressure value to a considerable level under the influence of
favorable pressure gradient except at lower NPR 3. At NPRs 5 and 7 for some cases the trends differ due to the
level of expansion, nature of waves present in the base region, relief available to the flow, L/D ratio of the
enlarged duct and the Mach numbers. It is seen that most of the cases exhibit similar behavior for the L/Ds in
the range 4 and 3, which means; that the back pressure has not adversely influenced the flow field in the base
region as well as in the duct. The minimum duct length required for the flow to be attached is L/D = 2, even
though in some cases flow is attached with duct wall. With this it can be stated that the micro jets can be an
alternative for the for base pressure control.
Climatic variability and spatial distribution of herbaceous fodders in the Su...IJERA Editor
This study focused on future spatial distributions of Andropogon gayanus, Loxodera ledermanii and Alysicarpus
ovalifolius regarding bioclimatic variables in the Sudanian zone of Benin, particularly in the W Biosphere
Reserve (WBR). These species were selected according to their importance for animals feed and the
intensification of exploitation pressure induced change in their natural spatial distribution. Twenty (20)
bioclimatic variables were tested and variables with high auto-correlation values were eliminated. Then, we
retained seven climatic variables for the model. A MaxEnt (Maximum Entropy) method was used to identify all
climatic factors which determined the spatial distribution of the three species. Spatial distribution showed for
Andropogon gayanus, a regression of high area distribution in detriment of low and moderate areas. The same
trend was observed for Loxodera ledermannii spatial distribution. For Alysicarpus ovalifolius, currently area
with moderate and low distribution were the most represented but map showed in 2050 that area with high
distribution increased. We can deduce that without bioclimatic variables, others factors such as: biotic
interactions, dispersion constraints, anthropic pressure, human activities and another historic factor determined
spatial distribution of species. Modeling techniques that require only presence data are therefore extremely
valuable.
Effect of Grain Size and Reaction Time in Characterisation of Aggregates for ...IJERA Editor
Concrete can deteriorate as a result of alkali aggregate reaction, an interaction between alkalis present in
alkaline pore solution originating from the Portland cement and reactive minerals in certain types of aggregates.
Potential reactivity of aggregates with regard to alkalis present in concrete mix can be determined by Mortar Bar
method, Chemical Method and Petrographic analysis. Of these the chemical method though is quick and does
not require a large quantity of material for testing yet have its own inherent limitations. It does not ensure
completion of reaction as the observations are limited to 24hour only and also does not assess the effect of
varying the combination of coarse and fine aggregates. A study on chemical method by allowing the reaction for
a prolonged time up to 96 hours and also on different grain size ranged matrix was carried at Central Soil and
Materials Research Station, New Delhi. Simultaneously the test results of the modified method are compared to
the existing Mortar Bar method, Chemical Method and Petrographic analysis The outcome of the studies clearly
reflects that the grain size play an important role in the reaction, the reaction time has a demarked impact on
reactivity, in the cases having a high value of silica release the choice of reduction in alkalinity as an indicator
of degree of reaction is not reliable, instead measuring remaining Na2O concentration in Sodium hydroxide
solution after the reaction seems to be much more meaningful in justifying the silica release.
An Overview of the Entrepreneurial Process in Distance Education (DE) of UNESAIJERA Editor
This article presents a panoramic view of entrepreneurship of Distance Education (DE) at UniversityEstácio de
Sá (UNESA) of Brazil. It is based on field research, interviews and bibliographical research on the processes of
teaching and learning in Distance Education (DE), especially those used in academic education. The aim of this
article is to show the existence of the entrepreneur process in the Distance Education of University Estácio de Sá
(DE-UNESA). To this end, the article takes a qualitative approach denoting interpretative grounds and connects
the entrepreneurial process with the DE-UNESA. It presents a graphic illustrating the entrepreneurial process
model by adding the factor-educator or educational. In addition, describes information about DE-UNESA
backdrop developer of a continuous educational entrepreneurship.
Analysis of Waste Water Treatment in Kaduna Refining and Petrochemicals Corpo...IJERA Editor
Scientific data and results have to be accurate, precise and reliable and are subject to ever increasing scrutiny by
regulators in industry, the environment and medicine, in validation and also in research and development. Given
our numerous environmental problems, the need for accurate, precise and reliable results cannot be
overemphasized in environmental pollution control. This research was undertaken by visiting the analytical
laboratory involved in environmental pollution control in Nigerian National Petroleum Corporation (NNPC)
Kaduna which is known as Kaduna Refining and Petrochemicals (KRPC). Results were taken within a span of
three years at different times of the year. End of month results were also taken for the two receiving rivers
(River Kaduna & Romi River) and effluent from the refinery. The waste water was analyzed using available
instruments in the Refinery such as PH meter, Dissolved Oxygen (DO) Meter, Conductivity Meter, Gas
chromatography, burette, pipette, Double beam Spectrometer, and Thermometer. The results showed that many
parameters meet the standard of limit set by the Nigerian Standard Organization but there are many vital
parameters whose limits are very low but not measured for lack of instruments. The point of concern here
becomes the availability of suitable analytical instruments for quality control in the waste water treatment.
A Hybrid method of face detection based on Feature Extraction using PIFR and ...IJERA Editor
In this paper we proposed a face detection method based on feature selection and feature optimization. Now in
current research trend of biometric security used the process of feature optimization for better improvement of
face detection technique. Basically our face consists of three types of feature such as skin color, texture and
shape and size of face. The most important feature of face is skin color and texture of face. In this detection
technique used texture feature of face image. For the texture extraction of image face used partial feature
extraction function, these function is most promising shape feature analysis. For the selection of feature and
optimization of feature used multi-objective TLBO. TLBO algorithm is population based searching technique
and defines two constraints function for the process of selection and optimization. The proposed algorithm of
face detection based on feature selection and feature optimization process. Initially used face image data base
and passes through partial feature extractor function and these transform function gives a texture feature of face
image. For the evaluation of performance our proposed algorithm implemented in MATLAB 7.8.0 software and
face image used provided by Google face image database. For numerical analysis of result used hit and miss
ratio. Our empirical evaluation of result shows better prediction result in compression of PIFR method of face
detection.
From Hearing Aids, Prostheses and Cochlear Implants to "Bionic" Feedback Phon...IJERA Editor
In Otorhinolaryngological medical practice therapeutic devices are used that are highly invasive and immersive.
For aural and oral communication these could be hearing aids, prosthetics, implants or radio-electronic
appliances that build up a bionic environment with apparent tendencies for virtualization. The popularization of
such devices promotes the extensive use of Brain Computer Interfaces to both the scientific community and the
consumer market. The use of bionic devices clinched with synapses of the nerves does not merely mingle input
activity to brain activity, but also it provides a virtual channel for augmenting and manipulating speech
communication, language communication and even further musical communication. The effects of bionic aural
and oral communication when learning practices for the impaired in hearing are applied is encountered in terms
of ability for speech perception and linguistic competence.
Transient Three-dimensional Numerical Analysis of Forced Convection Flow and ...IOSR Journals
A three-dimensional transient numerical study of a constant property Newtonian fluid in curved pipe under laminar flow conditions is presented for a uniform wall temperature boundary condition. Numerical solutions were obtained using the control volume method described by Patankar for the range of. The working fluid was water. The transient flow pattern and the temperature distribution on the tube section were derived for different values of the Reynolds number. Graphical results for velocity and temperature are presented and analyzed. Results have shown that the maximum velocity in center of velocity profile increase with increasing of Reynolds number. In curved pipes, time averaged results exhibited Dean circulation and a strong velocity and temperature stratification in the radial direction. Flow and heat transfer were strongly asymmetric, with higher values near the outer pipe bend.
NUMERICAL INVESTIGATION OF LAMINAR NANOFLUID FLOW IN MICRO CHANNEL HEAT SINKS IAEME Publication
The effect of using nanofluids on heat transfer and aerodynamics characteristics in rectangular shaped micro channel heat sink (MCHS) is numerically investigated for Reynolds number range of (100-400 ) and different value of heat flux (50 , 100, 150 ) / . In this study,the MCHS performance using tow type of nanofluid with volume
fraction 10% was used as a coolant is examined. The three-dimensional steady, laminar flow and heat transfer governing equations are solved using The computational fluid dynamics code (FLUENT). The MCHS performance is evaluated in terms of temperature profile, heat transfer,velocity profile, pressure drop and friction factor.
Basics of two phase flow (gas-liquid) line sizingVikram Sharma
This article was produced with the objective to provide a condensed fundamental insight in gas-liquid line sizing using Lockhart-Martinelli correlation. The content of this article is purely academic by nature.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
HEAT TRANSFER CORRELATION FOR NON-BOILING STRATIFIED FLOW PATTERN | J4RV3I11006Journal For Research
In chemical industries two phase flow is a process necessity. A better understanding of the rates of momentum and heat transfer in multi-phase flow conditions is important for the optimal design of the heat exchanger. To simplify the complexities in design, heat transfer coefficient correlations are useful. In this work a heat transfer correlation for non- boiling air-water flow with stratified flow pattern in horizontal circular pipe is proposed. To verify the correlation, heat transfer coefficients and flow parameters were measured at different combinations of air and water flow rates. The superficial Reynolds numbers ranged from about 2720 to 5740 for water and from about 563 to 1120 for air. These experimental data were successfully correlated by the proposed two-phase heat transfer correlation. It is observed that superficial.
The dependencies of total pressure, velocity, vorticity, turbulent length, turbulent dissipation, turbulent viscosity, turbulent energy and turbulent time of moving fluid from a straight pipe length of a circular cross section are presented in graphical and mathematical forms. Changing analysis of considered parameters was performed at mass flow rates of 0.45, 1.0 and 1.5 kg/s. A transition boundary of laminar flow of fluid to turbulent flow is at the distance of 2/5 of length from the inlet of the pipe (at accepted total length of the pipe of 1000 mm).
Experimental Investigation on Heat Transfer Analysis in a Cross flow Heat Ex...IJMER
Heat exchanger is devices used to exchange the heat between two liquids that are at different
temperature .These are used as a reheated in many industries and auto mobile sector and power
plants. The main aim of our project is thermal analysis of heat exchanger with waved baffles for
different types of materials at different mass flow rates and different tube diameters using FLOEFD
software and comparing the results that are obtained. The work is a simplified model for the study of
thermal analysis of shell-and-tubes heat exchangers having water as cold and hot fluid. Shell and
Tube heat exchangers are having special importance in boilers, oil coolers, condensers, pre-heaters.
They are also widely used in process applications as well as the refrigeration and air conditioning
industry. The robustness and medium weighted shape of Shell and Tube heat exchangers make them
well suited for high pressure operations. The project shows the best material, best boundary conditions
and parameters of materials we have to use for better heat conduction. For this we are chosen a
practical problem of counter flow shell and tube heat exchanger having water, by using the data that
come from cfd analysis. A design of sample model of shell and tube heat exchanger with waved baffles
is using Pro-e and done the thermal analysis by using FLOEFD software by assigning different
materials to tubes with different diameters having different mass flow rates and comparing the result
that obtained from FLOEFD software.
THE EFFECT OF GEOMETRICAL PARAMETERS ON HEAT TRANSFER AND HYDRO DYNAMICAL CHA...ijmech
Compact size and high heat transfer coefficient of helical coil heat exchangers causes them to have an
important role in various industrial applications. This paper investigate numerically on the influence of
different parameters such as coil radius, coil pitch and diameter of tube on the hydrodynamic and
heat transfer characteristics of helical double tube heat exchangers using the CFD software which is
based on the principles of heat transfer, fluid mechanics and thermodynamics. The results indicated that
heat transfer augmentation occurs by increasing of the inner Dean Number, inner tube diameter, curvature
ratio and by the reduction of the pitch of heat exchanger coil. By increasing the radius of coils, the
secondary flow effects due to centrifugal forces diminishes and flow of fluid through the coils tends to flow
in a straight path and as a result, the friction coefficient decreases consequently.
Control of Suddenly Expanded Flow at Low Supersonic Mach NumbersIJERA Editor
In the present study the experiments were conducted to control the base pressure from a convergent-divergent
nozzle at low supersonic Mach numbers to assess the effectiveness of active control mechanism in the form of
micro jets at different expansion level. The parameters considered in the present study are the diameter ratio,
length to diameter ratio (L/D), Nozzle Pressure Ratio (NPR), and the Mach number. The diameter ratio selected
for the present study are 1.6, 1.8, 2.2, and 2.5. Experiments were conducted for nozzle pressure ratio (NPR)
from 3 to 11. The L/D ratio of the enlarged duct was varied from 10 to 1, and results are presented for L/D 4, 3,
2, and 1. The Mach numbers of the present studies are 1.1, 1.2, 1.4, and 1.5. The results show that the Micro jets
are very effective and are able to raise the base pressure value to a considerable level under the influence of
favorable pressure gradient except at lower NPR 3. At NPRs 5 and 7 for some cases the trends differ due to the
level of expansion, nature of waves present in the base region, relief available to the flow, L/D ratio of the
enlarged duct and the Mach numbers. It is seen that most of the cases exhibit similar behavior for the L/Ds in
the range 4 and 3, which means; that the back pressure has not adversely influenced the flow field in the base
region as well as in the duct. The minimum duct length required for the flow to be attached is L/D = 2, even
though in some cases flow is attached with duct wall. With this it can be stated that the micro jets can be an
alternative for the for base pressure control.
Climatic variability and spatial distribution of herbaceous fodders in the Su...IJERA Editor
This study focused on future spatial distributions of Andropogon gayanus, Loxodera ledermanii and Alysicarpus
ovalifolius regarding bioclimatic variables in the Sudanian zone of Benin, particularly in the W Biosphere
Reserve (WBR). These species were selected according to their importance for animals feed and the
intensification of exploitation pressure induced change in their natural spatial distribution. Twenty (20)
bioclimatic variables were tested and variables with high auto-correlation values were eliminated. Then, we
retained seven climatic variables for the model. A MaxEnt (Maximum Entropy) method was used to identify all
climatic factors which determined the spatial distribution of the three species. Spatial distribution showed for
Andropogon gayanus, a regression of high area distribution in detriment of low and moderate areas. The same
trend was observed for Loxodera ledermannii spatial distribution. For Alysicarpus ovalifolius, currently area
with moderate and low distribution were the most represented but map showed in 2050 that area with high
distribution increased. We can deduce that without bioclimatic variables, others factors such as: biotic
interactions, dispersion constraints, anthropic pressure, human activities and another historic factor determined
spatial distribution of species. Modeling techniques that require only presence data are therefore extremely
valuable.
Effect of Grain Size and Reaction Time in Characterisation of Aggregates for ...IJERA Editor
Concrete can deteriorate as a result of alkali aggregate reaction, an interaction between alkalis present in
alkaline pore solution originating from the Portland cement and reactive minerals in certain types of aggregates.
Potential reactivity of aggregates with regard to alkalis present in concrete mix can be determined by Mortar Bar
method, Chemical Method and Petrographic analysis. Of these the chemical method though is quick and does
not require a large quantity of material for testing yet have its own inherent limitations. It does not ensure
completion of reaction as the observations are limited to 24hour only and also does not assess the effect of
varying the combination of coarse and fine aggregates. A study on chemical method by allowing the reaction for
a prolonged time up to 96 hours and also on different grain size ranged matrix was carried at Central Soil and
Materials Research Station, New Delhi. Simultaneously the test results of the modified method are compared to
the existing Mortar Bar method, Chemical Method and Petrographic analysis The outcome of the studies clearly
reflects that the grain size play an important role in the reaction, the reaction time has a demarked impact on
reactivity, in the cases having a high value of silica release the choice of reduction in alkalinity as an indicator
of degree of reaction is not reliable, instead measuring remaining Na2O concentration in Sodium hydroxide
solution after the reaction seems to be much more meaningful in justifying the silica release.
An Overview of the Entrepreneurial Process in Distance Education (DE) of UNESAIJERA Editor
This article presents a panoramic view of entrepreneurship of Distance Education (DE) at UniversityEstácio de
Sá (UNESA) of Brazil. It is based on field research, interviews and bibliographical research on the processes of
teaching and learning in Distance Education (DE), especially those used in academic education. The aim of this
article is to show the existence of the entrepreneur process in the Distance Education of University Estácio de Sá
(DE-UNESA). To this end, the article takes a qualitative approach denoting interpretative grounds and connects
the entrepreneurial process with the DE-UNESA. It presents a graphic illustrating the entrepreneurial process
model by adding the factor-educator or educational. In addition, describes information about DE-UNESA
backdrop developer of a continuous educational entrepreneurship.
Analysis of Waste Water Treatment in Kaduna Refining and Petrochemicals Corpo...IJERA Editor
Scientific data and results have to be accurate, precise and reliable and are subject to ever increasing scrutiny by
regulators in industry, the environment and medicine, in validation and also in research and development. Given
our numerous environmental problems, the need for accurate, precise and reliable results cannot be
overemphasized in environmental pollution control. This research was undertaken by visiting the analytical
laboratory involved in environmental pollution control in Nigerian National Petroleum Corporation (NNPC)
Kaduna which is known as Kaduna Refining and Petrochemicals (KRPC). Results were taken within a span of
three years at different times of the year. End of month results were also taken for the two receiving rivers
(River Kaduna & Romi River) and effluent from the refinery. The waste water was analyzed using available
instruments in the Refinery such as PH meter, Dissolved Oxygen (DO) Meter, Conductivity Meter, Gas
chromatography, burette, pipette, Double beam Spectrometer, and Thermometer. The results showed that many
parameters meet the standard of limit set by the Nigerian Standard Organization but there are many vital
parameters whose limits are very low but not measured for lack of instruments. The point of concern here
becomes the availability of suitable analytical instruments for quality control in the waste water treatment.
A Hybrid method of face detection based on Feature Extraction using PIFR and ...IJERA Editor
In this paper we proposed a face detection method based on feature selection and feature optimization. Now in
current research trend of biometric security used the process of feature optimization for better improvement of
face detection technique. Basically our face consists of three types of feature such as skin color, texture and
shape and size of face. The most important feature of face is skin color and texture of face. In this detection
technique used texture feature of face image. For the texture extraction of image face used partial feature
extraction function, these function is most promising shape feature analysis. For the selection of feature and
optimization of feature used multi-objective TLBO. TLBO algorithm is population based searching technique
and defines two constraints function for the process of selection and optimization. The proposed algorithm of
face detection based on feature selection and feature optimization process. Initially used face image data base
and passes through partial feature extractor function and these transform function gives a texture feature of face
image. For the evaluation of performance our proposed algorithm implemented in MATLAB 7.8.0 software and
face image used provided by Google face image database. For numerical analysis of result used hit and miss
ratio. Our empirical evaluation of result shows better prediction result in compression of PIFR method of face
detection.
From Hearing Aids, Prostheses and Cochlear Implants to "Bionic" Feedback Phon...IJERA Editor
In Otorhinolaryngological medical practice therapeutic devices are used that are highly invasive and immersive.
For aural and oral communication these could be hearing aids, prosthetics, implants or radio-electronic
appliances that build up a bionic environment with apparent tendencies for virtualization. The popularization of
such devices promotes the extensive use of Brain Computer Interfaces to both the scientific community and the
consumer market. The use of bionic devices clinched with synapses of the nerves does not merely mingle input
activity to brain activity, but also it provides a virtual channel for augmenting and manipulating speech
communication, language communication and even further musical communication. The effects of bionic aural
and oral communication when learning practices for the impaired in hearing are applied is encountered in terms
of ability for speech perception and linguistic competence.
Data Leakage Detection and Security Using Cloud ComputingIJERA Editor
The data owner will store the data in the cloud. Every user must registered in the cloud. Cloud provider must
verify the authorized user. If someone try to access the account, data will get leaked. This leaked data will
present in an unauthorized place (e.g., on the internet or someone’s laptop). In this paper, we propose Division
and Replication of Data in the Cloud for Optimal Performance and Security (DROPS) that collectively
approaches the security and performance issues. In DROPS methodology, we have to select the file and then
store the particular file in the cloud account. In order to provide security we are going to implement DROPS
concepts. Now we divide the file into various fragments based on the threshold value. Each and every fragments
are stored in the node using T-Coloring. After the placement of fragments in node, it is necessary to replicate
each fragments for one time in cloud.
A Framework for Predicate Based Access Control Policies in Infrastructure as ...IJERA Editor
Infrastructure as a Service (IaaS) is the service with which IT of enterprises integrated for on-demand services.
Different deployment models of cloud further makes it flexible so as to meet the requirements of users. As the
customers’ policies are not same, Cloud Service Provider (CSP) needs a flexible architecture to accommodate
the varied requirements of customers with respect to access control. The existing access control models such as
Role Based Access Control (RBAC) and Attribute Based Access Control (ABAC) have limitations. The
combination of RBAC and ABAC also could not offer fine grained access control. We also studied the RBAC
model offered by Open Stack and came to know its limitations in catering to diversified needs of customers. The
One Size Fits for All policy cannot provide flexible access control due to the aforementioned reason. Therefore
a more flexible access control model is required. In this paper we proposed a framework with Predicate Based
Access Control (PBAC) in general and then implemented it in Open Stack. Our empirical results revealed that
the proposed framework can improve the granularity with fine grained access control mechanism. Though our
framework is at primitive stage, it shows significant step forward in access control policies for IaaS clouds.
Periodic material-based vibration isolation for satellitesIJERA Editor
The vibration environment of a satellite is very severe during launch. Isolating the satellitevibrations during
launch will significantly enhance reliability and lifespan, and reduce the weight of satellite structure and
manufacturing cost. Guided by the recent advances in solid-state physics research, a new type of satellite
vibration isolator is proposed by usingperiodic material that is hence called periodic isolator. The periodic
isolator possesses a unique dynamic property, i.e., frequency band gaps. External vibrations with frequencies
falling in the frequency band gaps of the periodic isolator are to be isolated. Using the elastodynamics and the
Bloch-Floquet theorem, the frequency band gaps of periodic isolators are determined. A parametric study is
conducted to provide guidelines for the design of periodic isolators. Based on these analytical results, a finite
element model of a micro-satellite with a set of designed periodic isolators is built to show the feasibility of
vibration isolation. The periodic isolator is found to be a multi-directional isolator that provides vibration
isolation in the three directions.
Efficient Detection Of Selfish Node In Manet Using A Colloborative WatchdogIJERA Editor
Mobile ad-hoc networks(MANET) are collected many number of nodes.In a mobile ad-hoc network(MANET)
undertakes that all the mobile nodes unitewillingly in order to work accurately.This is a cost –intensive action
for the collaboration and particular nodes can decline to cooperate then it will prominent to a selfish node
behaviour.Thus, it will utterly affect the global network performance.The watchdogs are a well-known device
used for identifying a selfish node.Theprocedure performed by watchdogs can fail,generating false positives
and false negatives this may convince to wrong operation.Whenidentifying selfish node trusting on local
watchdogs only can prime to poor performance,in terms of precision and speed.Thus we propose collaborative
contact based watchdog(COCOWA) as a collaborative method based on the dispersion of selfish nodes
responsiveness when a contact occurs,so the evidence will quickly circulated about selfish nodes. As shown in
the paper,whenidentifying a selfish nodes this collaborative approach decreases the time and rises the precision
E-Mail Systems In Cloud Computing Environment Privacy,Trust And Security Chal...IJERA Editor
In this paper, SMCSaaS is proposed to secure email system based on Web Service and Cloud Computing
Model. The model offers end-to-end security, privacy, and non-repudiation of PKI without the associated
infrastructure complexity. The Proposed Model control risks in Cloud Computing like Insecure Application
Programming Interfaces, Malicious Insiders, Data Loss Shared Technology Vulnerabilities, or Leakage,
Account, Service, Traffic Hijacking and Unknown Risk Profile
Design and Experimentation of Collector based Solar Dryer with Recirculation ...IJERA Editor
Sun drying system is very common method of preserving agricultural product. Solar energy is used for heating
of air and to dry food substance. In open sun drying food is unprotected from rain, wind-borne dirt and dust,
infestation by insects, rodents and other animal. This process is practically attractive and environmentally sound.
Shell life of agricultural product is improve by drying. This paper present design and construction of active solar
dryer with recirculation technique. It consists of solar collector, drying chamber with netted trays and
recirculation arrangement. Air is allowed through inlet and it is heated up in collector. Then it is circulated in
drying chamber where it is utilize for drying. The design based on geographical location Wardha and
meteorological data were obtained for proper design specification. Locally available materials were used for
construction such as polyurethane glass, mild steel metal sheet, plywood sheet and insulating material.
Framework for Bridges Maintenance in EgyptIJERA Editor
The traditional approaches for bridges maintenance is proven to be inefficient as they lead to random way of
spending maintenance budget and deteriorating bridge conditions. In many cases, maintenance activities are
performed due to user complaints. The objective of this paper is to develop a practical and reliable framework to
manage the maintenance and repair activities of Bridges network in Egypt considering performance and budget
limits. The model solves an optimization problem that maximizes the average condition of the network given the
limited budget using Genetic Algorithm (GA).
The main tasks of the system are bridge inventory, condition assessment, deterioration using markov model, and
maintenance optimization. The developed model takes into account multiple parameters including serviceability
requirements, budget allocation, element importance on structural safety and serviceability, bridge impact on
network, and traffic. A questionnaire is conducted to complete the research scope. The proposed model is
implemented in software, which provides a friendly user interface. The results of the framework are multi – year
maintenance plan for the entire network for up to five years. A case study is presented for validating and testing
the model with Data collected from “General Authority for Roads, Bridges and Land Transport” in Egypt.
Query Image Searching With Integrated Textual and Visual Relevance Feedback f...IJERA Editor
There are many researchers who have studied the relevance feedback in the literature of content based image
retrieval (CBIR) community, but none of CBIR search engines support it because of scalability, effectiveness
and efficiency issues. In this, we had implemented an integrated relevance feedback for retrieving of web
images. Here, we had concentrated on integration of both textual features (TF) and visual features (VF) based
relevance feedback (RF), simultaneously we also tested them individually. The TFRF employs and effective
search result clustering (SRC) algorithm to get salient phrases. Then a new user interface (UI) is proposed to
support RF. Experimental results show that the proposed algorithm is scalable, effective and accurated
The Case Study of an Early Warning Models for the Telecare Patients in TaiwanIJERA Editor
To propose a practical early warning analysis model for the telecare patients, this study applied data mining
technology as a basis to investigate the classification of patient groups by disease severity and incidence using
data contained in a telecare database regarding the number of a clinic. The ultimate purpose of this study was to
provide a new direction for telecare system planning and developing strategies.
The subject of this case study was a private clinic which is providing telecare system to patients in Taiwan, and
we used three data mining techniques including discriminant analysis, logistic regression and artificial neural
network to construct an early warning analysis model based on several factors such as: Demographic variables,
pathological signals, health management index, diagnosis and treatment records, emergency notification signal.
According the results, the telecare system can build stronger physician-patient relationship in advance through
previously paying attention to patients’ physiological conditions, reminding them to do self-management, even
taking them to the hospital for observation. A comparison of discriminative rates showed that the artificial neural
network model had the highest overall correct classification rate, 85.52%, and thus is a tool worthy of
recommendation
Micro Extended[X] Enterprises & An Ea Framework Best Suited For Them.IJERA Editor
“SMiXE’s – Small & Micro Extended Enterprises”, in automobile industry, though referred as Small & Micro,
but forms a bulk or a huge base of the automobile Cluster/ Pyramid (see Fig 1 below) in terms of people
employed, work done by them in tot up. It compliments the auto industry in absorbing the cost pressure and at
the same time facilitates the auto industry in segregating the less efficient routine as well as menial work
towards the bottom of the pyramid. Freeing the OEM to focus on their core activities. By their very “Nature &
Need”, SMiXE have to be very “Agile, Cost Competitive and Adaptive” by their “Nature”, as all OEM’s
(Global & Local) are being forced to adapt new, improved, environment friendly and fuel efficient standards.
The environment in which they (SMiXE) exist and to the very market (“Need”) that they cater is very dynamic.
Keeping the above mentioned points and the constraints mentioned below, in this paper we will be evaluating
the best suited EA framework which will enable us in providing a viable EA solution for SMiXE’s.
Calculating Wind Farm Production in Al-Shihabi (South Of Iraq) Using WASPIJERA Editor
The Wind Turbine farms are becoming popular in the renewable energy world. In this research, the Wind Atlas
Analysis and Application Program (WAsP) has been used to estimate wind power density in Al-Shihabi (south
of Iraq). All statistical operations on data series are obtained from Field data collected from the wind
measurement towers which installed by the Science and Technology Ministry at Kut city south of IRAQ at three
heights (10, 30, 50 m). The wind turbine selected for this study to be installed in the wind farm are Bonus-
300kw, 600kw The Annual Energy Production (AEP) has been calculate which varies between (746.990 -
759.446 MWH) at 30 m and it s varies between produced AEP (1.576 - 1.600 GWh) at 50 m ,this site classified
as ( class-1).
A Critical View on Pedagogical Dimension of Architectural Education in IndiaIJERA Editor
The built environment is becoming more complex in terms of its quality and structure. In such circumstances
architectural education pedagogical strategies has to be modified to address social, political, economical and
environmental issues and challenges. Innovative interdisciplinary strategies in architecture education have to be
organized in a way which leads to better architecture and urban environments. Pure theoretical approaches are to
be related to practice which can be done with pedagogy comprising real-life examples in respect to new models
and collaboration between architecture education and non-academic partners. This paper discusses the status of
current architectural education in India.It examine the student‟s perception regarding teaching and learning in
schools of architecture from the state of Maharashtra It is aimed to highlight the need for paradigm shift in
pedagogy in schools imparting architectural education in India to enhance learning in architecture education.
A case study on Machine scheduling and sequencing using Meta heuristicsIJERA Editor
Modern manufacturing systems are constantly increasing in complexity and become more agile in nature such
system has become more crucial to check feasibility of machine scheduling and sequencing because effective
scheduling and sequencing can yield increase in productivity due to maximum utilization of available resources
but when number of machine increases traditional scheduling methods e.g. Johnson‟s ,rule is becomes in
effective Due to the limitations involved in exhaustive enumeration, for such problems meta-heuristics has
become greater choice for solving NP hard problems because of their multi solution and strong neighbourhood
search capability in a reasonable time.
Flow Investigation inside A Curved Square DuctIJERA Editor
This paper presents the results of an experimental work with measurement of wall static pressure of 90°C shaped Curved duct. The test duct is made up of transparent perspex sheets to facilitate the flow visualization study. The duct has an inlet to exit area ratio of 1.0 with centerline distance of 750 mm. The inlet aspect ratio of the test duct has been fixed at 1.0. The velocities for the proposed investigations are to be measured by using a Pitot tube.Wall pressures are measured with the help of an inclinedmanometer with the inclination of 35°. The manometer had two tubes emanating from it: one left open to the atmosphere and the other connected to the steel pipes attached to the four walls of the curved duct. The difference in the readings helped us calculate the static pressure and thereby the normalized pressure. Wall pressure distribution along the curved and parallel walls of the duct at 0°, 22.5°, 45°, 67.5° and 90° measuring sections was measured. All the experimental data has been processed by an Intel i3 CPU, 3 GB RAM PC and analyzed to give the distribution of static pressure in the square duct.The main purpose of this investigation is to show the development of secondary flow which happens when the flow takes place through the bend in the curvature. This secondary flow arises as a result of a centrifugal force acting when the flow moves through the bend. The investigation is carried out at three different velocities 20 m/s, 40 m/s and 60 m/s. The distribution of normalized pressure which is the ratio of static pressure to the dynamic pressure is mapped and shown in the form of contours by using the software package SURFER.The trend of wall static pressure development on the walls of C shaped duct shows that as the flow proceeds towards the curvature, there exists a high pressure gradient between the outside face and inside face due the centrifugal force acting along the curvature. This shows the bulk shifting of flow towards the inside face. This is due to the generation of secondary motion in a plane perpendicular to the primary flow.
CFD Simulation and Analysis of Fluid Flow Parameters within a Y-Shaped Branch...IOSR Journals
Plumbing system use pipe fittings to connect straight pipe or tubing section for regulating or measuring fluid flow. Y (wye)-shape fitting is one of the important component in the plumbing system. A wye branch allows splitting a branch line equally in two directions. The opening sizes can vary for different situations for instance in situation where a large main line needs to be split into two smaller branches. The wye shape fitting will convert into T shape fitting when the included angle between two pipe branches is 180°. In the present work, effect of angle of turn/bend for a Y-shape pipe will be studied computationally using ANSYS CFX software. For the analysis, all the three pipe branches of 1 inch internal diameter are selected along with equal length so that only the effect of bend angle at 450, 600, 900 and 1800 can be studied. Water as a fluid is selected which flows through the plumbing system. The effect of bend angle, pipe diameter, pipe length, Reynolds number on the resistance coefficient is studied. It was observed that resistance coefficient vary with the change in flow
A Review on Comparison between Shell And Tube Heat Exchanger And Helical Coil...ijiert bestjournal
The curved shape of the tube causes the flowing fluid to experience centrifugal force. The
extent of centrifugal force experienced depends on the local axial velocity of the fluid particle
and radius of curvature of the coil. The fluid particles flowing at the core of the pipe have
higher velocities than those flowing near to the pipe wall. Thus the fluid particles flowing
close to the tube wall experience a lower centrifugal force than the fluid particles flowing in
the tube core. This causes the fluid from the core region to be pushed towards the outer wall.
This stream bifurcates at the wall and drives the fluid towards the inner wall along the tube
periphery, causing generation of counter-rotating vortices called secondary flows which
produce additional transport of the fluid over the cross section of the pipe. This additional
convective transport increases heat transfer and the pressure drop when compared to that in a
straight tube.
FLOW DISTRIBUTION NETWORK ANALYSIS FOR DISCHARGE SIDE OF CENTRIFUGAL PUMPijiert bestjournal
A computational fluid dynamics (CFD) analysis has been conducted to f ind the pressure losses for dividing and combining fluid flow through a junction of discharge system. Si mulations are performed for a range of flow ratios and equations are developed for pressure loss coeff icients at junctions. A mathematical model based on successive approximations then would be employed to estim ate the pressure losses. The proposed CFD based strategy can be used for the analysis of all the thr ee pipe branches of some diameter are selected along with equal length so that only the effect of bend angle can be studied. The effect of bend angle,pipe diameter,pipe length,Reynolds number on the resistance coeffi cient is studied. The software used is CATIA for modeling and ANSYS fluent for analysis purpose.
Flow Development through a Duct and a Diffuser Using CFDIJERA Editor
In the present paper an extensive study of rectangular cross-sectioned C-duct and C-diffuser is made by the help of 2-D mean velocity contours. Study of flow characteristics through constant area duct is a fundamental research area of basic fluid mechanics since the concepts of potential flow and frictional losses in conduit flow were established. C-ducts are used in aircraft intakes, combustors, internal cooling systems of gas turbines, ventilation ducts, wind tunnels etc., while diffuser is mechanical device usually made in the form of a gradual conical expander intended to raise the static pressure of the fluid flowing through it. Flow through curved ducts is more complex compared to straight duct due to the curvature of the duct axis and centrifugal forces are induced on the flowing fluid resulting in the development of secondary motion (normal to the primary flow direction) which is manifested in the form of a pair of contra-rotating vortices. For a diffuser in addition to the secondary flow, the diverging flow passage, which causes an adverse stream wise pressure gradient, can lead to flow separation. The combined effect may result n non uniformity of total pressure and total pressure loss at the exit. A comparative study of different turbulent models available in the Fluent using y as guidance in selecting the appropriate grid configuration and turbulence models are done. Standard k-ε model and RSM models are used to solve the closure problem for both the constant area duct and the diffuser. It has been observed that the Standard k-e model predicts the flow through the constant area duct and the diffuser within a reasonable domain ofthe y range.
3 ijaems jun-2015-17-comparative pressure drop in laminar and turbulent flowsINFOGAIN PUBLICATION
The study of Turbulent flow characteristics in complex geometries receives considerable attention due to its Importance in many engineering applications and has been the subject of interest for researchers. Some of these include the energy conversion systems found in same design of heat exchangers, nuclear reactor, solar collectors & cooling of industrial machines and electronic components. Flow in channels with baffle plates occurs in many industrial applications such as heat exchangers, filtration, chemical reactors, and desalination. These baffles cause turbulence which leads to increases friction within the pipe or duct and leads significant pressure drop.
This work is concern with the comparative flow and pressure distribution analysis of a smooth and segmented Baffles pipe. In which pressure drop during the flow is examined and with the help of hydrodynamic characteristics performance is predicted with the help of Finite element volume tool ANSYS- Fluent, where simulation is been done. The goal is to carry out evaluating pressure drop across the pipe using different turbulent model and at simulation is done for wide range of Reynolds number in both laminar and turbulent flow regimes. The FEV results are validated with well published results in literature and furthermore with experimentation. The FEV and experimental results show good agreement.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Vaccine management system project report documentation..pdfKamal Acharya
The Division of Vaccine and Immunization is facing increasing difficulty monitoring vaccines and other commodities distribution once they have been distributed from the national stores. With the introduction of new vaccines, more challenges have been anticipated with this additions posing serious threat to the already over strained vaccine supply chain system in Kenya.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
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Experimental Study on Two-Phase Flow in Horizontal Rectangular Minichannel with Y-Junction
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Experimental Study on Two-Phase Flow in Horizontal
Rectangular Minichannel with Y-Junction
Agus Santoso*, Rintaro Nagai*, Akifumi Mori*, Akimaro Kawahara*, Michio
Sadatomi *
*(Department of Advanced Mechanical Systems, Graduate School of Science and Technology, Kumamoto
University, Kurokami 2-39-1 Chuo-ku, Kumamoto City 860-8555, Japan)
ABSTRACT
An experimental study was conducted to investigate two-phase air-water flow characteristics, in horizontal
rectangular minichannel with Y-junction. The width (W), the height (H) and the hydraulic diameter (DH) of the
rectangular cross section for the upstream side of the junction are 4.60 mm, 2.50 mm and 3.24 mm, while those
for the downstream side are 2.36 mm, 2.50 mm and 2.43 mm. The entire test section was machined from
transparent acrylic block, so that the flow structure could be visualized. Liquid single-phase and air-liquid two-
phase flow experiments were conducted at room temperature. The flow pattern, the bubble velocity, the bubble
length, and the void fraction were measured with a high-speed video camera. Pressure profile upstream and
downstream from the junction was also measured for the respective flows, and the pressure loss due to the
contraction at the junction was determined from the pressure profiles. Two flow patterns, i.e., slug and annular
flows, were observed in the fully-developed region apart from the junction. In the analysis, the frictional pressure
drop data, the two-phase frictional multiplier data, bubble velocity data, bubble length data and void fraction data
were compared with calculations by some correlations in literatures. In addition, new pressure loss coefficient
correlations for the pressure drop at the junction has been proposed. Results of such experiment and analysis are
described in the present paper.
Keywords- Minichannel, two-phase flow, Y-junction, bubble velocity, bubble length
I. INTRODUCTION
Gas-liquid two-phase flow in mini-channels is a
phenomenon seen in compact heat exchanger with
phase changes, e.g., air conditioners, cooling devices
in electronic equipments. In many arrangements it is
necessary to divide the flow into two or more
channel motivated by area restrictions or process
requirements. There has been considerable interest
recently in compact heat exchangers with mini- and
micro-sized flow channels. These heat exchangers
contain flow passages of various cross-sections (e.g.,
circular and rectangular), as well as various types of
dividing tee junctions (e.g., branching and
impacting) [1, 2]. Under two-phase flow conditions
the behavior of the junction is complicated
considerably by the structure of the gas-liquid
mixture and, in particular, by its influence on the
relative division of the two phases to the main and
branch outlets, which becomes a parameter of great
significance in the overall design of two-phase flow
systems [3]. Flow distribution through the branches
has to be investigated in order to design the system
optimally.
Several investigations have been reported on
two-phase flows in dividing tee junctions. For the
case of impacting tees, a few studies have been
reported in literatures (e.g., [1, 4, 5, 6, 7]). Elazhary
and Soliman [2] investigated the single- and two-
phase pressure drops in a mini-size, horizontal,
impacting tee junction with a rectangular cross-
section (1.87-mm height x 20-mm width). The
single-phase experiments were conducted using air
or water in a wide range of Reynolds number, and
the two-phase experiments using air and water at
200 kPa (abs) and room temperature for various inlet
flow regimes. They reported the pressure loss
coefficient for the single-phase flows was found to
be dependent on Reynolds number in laminar flows
( ≤ 2000), but independent of Reynolds
number in turbulent flows ( ≥ 5000). Four
flow regimes were observed : bubbly, plug, churn,
and annular flows. El-Shaboury et al. [8] conducted
experiments for air-water flows in a horizontal
impacting tee junction (37.8-mm i.d.) with equal-
diameter sides at a system pressure of 1.5 bar
nominally. They obtained phase-distribution and
pressure drop and found that the phases did not
distribute themselves evenly between the two outlets
unless the mass split is equal.
For the case of branching tees, more than ten
studies were reported by [9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19]. They studied the two-phase flow
through a dividing T with 90 degree branch arms.
However, there are few studies about the two-phase
flows through a Y-junction. Ishiguro et al. [20]
carried out experiments to separate gas from
downward gas-liquid two-phase flows using a Y-
RESEARCH ARTICLE OPEN ACCESS
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junction of poor wettability. The branch angle was
90 degree, and the inner diameters of the main pipe
and two branches were 10 mm. One side of the
channels downstream from the Y-junction was
coated with repellent to change its wettability. Air
and water were used as the working fluids.
Guangbin et al. [21] reported the characteristics of
gas–solid two-phase flows through a Y-shaped
branch pipes (0.032-m i.d) with a fixed branch angle
and the other adjustable branch angle. Micro-glass
bead and millet particles with similar diameter but
different density were used in this experimental
system. As a result, the trend of solids mass ratio
flowing in the adjustable branch and pressure drop
on each branch pipe were analyzed to study flow
distribution characteristics and resistance properties.
It was found that the solids flow distribution and
pressure drop for the two materials have similar
trend and were significantly affected by the branch
angle and gas velocity. Chen et al. [22] performed an
experimental study of nitrogen-pure water two-phase
flow splitting at microchannel junctions with the
square cross-section of 0.5 x 0.5 mm2
, and with five
different branch angles varying from 30 to 150
degree. The inlet superficial velocities were varied
from 0.8 to 21.3 m/s for the gas phase, and from
0.019 to 0.356 m/s for the liquid phase. Data
analysis shows that the phase split at microchannel
junctions depends strongly on inlet flow patterns.
The liquid taken off from the branch did not
decrease with increasing of the branch angle for all
inlet flow patterns. Likewise, some researcher have
studied computationally the flow through Y-junction
such as, [23, 24, 25, 26].
The literature survey indicates that the research
on two-phase flow in rectangular minichannel with
Y-junction is limited. Therefore, the purpose of the
present work is to investigate experimentally the
two-phase flow in horizontal rectangular
minichannel with the hydraulic diameter (DH) for the
channel upstream from the junction 3.24 mm, and
that for the downstream channel 2.43 mm. The high
speed video technique was used to analyze the fluid
dynamics of two-phase distribution at the junction.
The experimental and the analytical results are
compared with the data from previous studies and
are presented in the present paper.
II. EXPERIMENTS
A schematic diagram of the test facility used in
the present study is shown in Fig. 1. As the test
fluids, water was used for the liquid phase, and air
for the gas phase. Pressurized air from a compressor
pushed the water in a tank and supplies it to the test
channel. Thus, no mechanical pump was used in the
present experiment to avoid pulsation by the pump
and also to avoid contamination by the pump. Figure
2 shows a schematic diagram of test channel with
branch placed on a horizontal plane. The branch
angle was 60o
. The test channel had a rectangular
cross-section and made of transparent acrylic resin
for visual observation. Table 1 shows the cross-
sectional dimensions of the test channel on the width
(W), the height (H) and the hydraulic diameter (DH).
Those for the channel upstream from the junction
(Upstream I) were 4.60 mm, 2.50 mm and 3.24 mm,
while those for the channel downstream
(Downstream II and Downstream III) were 2.36 mm,
2.50 mm and 2.43 mm. In Fig. 2, the port #1 was the
liquid inlet port, while the port #2 and #3 were the
gas inlet ports. Therefore, two phases were supplied
through the section 1 as a gas-liquid mixer. The port
#4 and #5 were the gas-liquid mixture outlet to
individual separator tanks. Volume flow rate of air
was measured with a flow meter (KEYENCE, FD-
A10 AND FD-A1 depending on the flow rate range)
within 2 %, while that of water with a flow meter
(KEYENCE, FD-S) within 1 %.
In order to obtain accurate time averaged values
of air and water flow rates and pressures, the output
signals from the respective sensors were fed to a
personal computer via A/D converter over 10 sec. at
nominally 1 kHz. P1 to P15 are the pressure taps, and
the pressure at P4 in Fig. 2 was measured with a
gauge type pressure transducer (Yokogawa, FP101-
L31-L20). The pressures at other pressure taps were
determined from the difference in pressure between
there and P4 tap measured with a differential
pressure transducer (Validyne, DP15-32 and DP15-
26 depending on the pressure range). The accuracy
of the pressure measurement was within 4 Pa from a
calibration test. The gas-liquid mixture discharged to
each separator was separated. The air from the top of
each separator was metered by a gas flow meter
(SINAGAWA, DC-1C, 10 ~ 1100 L/h) before
exhausting to the atmosphere. During the flow rate
measurement, the water levels in the separator tanks
were monitored to be in the respective constant
levels. The water flow rate from the bottom of each
separator tank was calculated by measuring the mass
of water discharged per a enough measurement time.
In the present experiment, the water flow rates of the
two branch channels were adjusted to be equal each
other as possible by changing the openings of two
valves between the channel exit and the separator
tank.
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GF GF
Compressor
Regulator
Tank
Air
Mini-channel
with Y-junction
Gas flowmeter
Valve
ΔP
Pg
Air
T
GF
GF
LF
Liquid
flowmeter
Differential pressure
transducer
Pressure gauge
Separator
Thermoelectric
couple
Fig. 1 : Test apparatus
Flow pattern was observed with a high-speed
video camera (KEYENCE, VH-Z00R, frame rate :
1000 ~ 8000 frame/s, shutter speed 1/1000 ~
1/8000s) in four observation area marked with
broken circles in Fig. 2, and bubble velocity, uG, in
slug flow in the test channel was also measured.
Furthermore, void fraction, α, data was obtained by
substituting the measured uG and the gas volumetric
flux, jG, into = ⁄ . For single-phase water
flow experiments, the ranges of Reynolds number
(= , where is the mean velocity of water,
and the density and viscosity of water) in the
upstream channel was from 762 to 4661. For two-
phase air-water flow experiments, the ranges of
volumetric fluxes of the liquid and the gas were 0.2
< jL < 1.5 m/s and 0.2 < jG < 5.0 m/s.
Fig. 2 : Test channel with Y-junction
Table 1 : Dimension of test channel cross section
W
[mm]
H
[mm]
DH
[mm]
Upstream I 4.60 2.50 3.24
Downstream II, III 2.36 2.50 2.43
III. RESULTS AND DISCUSSION
3.1 Flow pattern
Figure 3 shows the flow pattern map in the
present two-phase flow experiment. The ordinate
and abscissa are the volumetric fluxes of water and
air. The flow regimes observed with a high-speed
video camera covered in a range of 0.2 ≤ jG ≤ 5.0
m/s and 0.2 ≤ jL ≤ 1.5 m/s. Two flow regimes were
observed, i.e., slug flow and annular flow under the
present flow conditions.
Fig. 3 : Flow pattern map in the present experiment
Figures 4 (a) and (b) show typical flows in the
test channel, respectively for a slug flow at jG, I = 0.5
m/s, jL, I = 0.5 m/s and an annular at jG, I = 5.0 m/s,
jL, I = 0.5 m/s. The flow regimes among upstream I,
and downstream II and III are similar at all the
experimental conditions.
(a) Slug flow (jG, I = 0.5 m/s, jL, I = 0.5 m/s)
(b) Annular flow (jG, I = 5.0 m/s, jL, I = 0.5 m/s)
Fig. 4: Typical flows in the test channel
3.2 Data reduction in pressure drop
Figures 5 (a) and (b) show typical pressure
distributions for water single- and air-water two-
phase flows upstream and downstream of Y-
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junction. The ordinat is the gauge pressure, while the
abscissa is the distance from the junction. There are
five pressure taps, tap #1 to tap #5, for the upstream
channel from the junction and the another ten taps,
tap #6 to tap #15, for the downstream channel. The
total pressure drop across the Y-junction, ∆pb, was
determined by the extrapolations of the axial
pressure profiles upstream and downstream from the
junction, as shown in Figs. 5 (a) and (b).
(a) Single-phase flow (Re = 4700)
(b) Two-phase flow (JG = 1.0 m/s, JL = 1.5 m/s)
Fig. 5 : Pressure distribution along the channel
with Y-junction
In order to check the pressure measurement
accuracy, the single-phase friction factors were
determined from the fully developed pressure
gradients upstream and downstream from the
junction. Figs. 6 (a) and (b) show the Darcy friction
factor data respectively for the channels upstream
and downstream from the junction. The data are
plotted against the Reynolds number, based on the
hydraulic diameter. The present data in laminar flow
region are compared with calculated curve by Shah
and London [27] which is a function of aspect ratio,
∗(= ⁄ ), for a rectangular channel :
= 96(1 − 1.3553 ∗
+ 1.9467 ∗
1.7012 ∗
+
0.9564 ∗
− 0.2537 ∗ ). (1)
In addition, the data in turbulent flow are compared
with familiar calculated curves by Blasius,
= 0.316 .
, (2)
and Nikuradse :
= 0.0032 + 0.221 .
. (3)
(a) λ vs. Re (Upstream I)
(b) λ vs. Re (Downstream II, III)
Fig. 6 : Single-phase friction factors in channels
upstream and downstream from the junction
3.3 Pressure drop at Y-junction
The pressure drop at the Y-junction can be
evaluated by the change in dynamic pressure
between the flows in channels upstream and
downstream from the junction. Since the two-phase
flow energy per unit time is composed of two
components as follows :
= 2 +⁄ 2⁄ . (4)
Thus, the dynamic pressure, i.e., the flow energy/the
total volume flow rate, is given by
, = 2⁄ + (1 − ) 2.⁄ (5)
Here ρ, Q and u are the density, the volume flow rate
and the mean velocity, and the homogeneous void
fraction defined as = (⁄ + ). Since the first
term in the right hand side of Eq. (5) is much smaller
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than the second term in bubble and slug flow
regimes. , can be approximated as :
, = (1 − ) 2⁄ (6)
Here, (= (1 − )⁄ ) is the mean liquid velocity
and can be approximated as (1 − )⁄ because
≈ in the present experimental range as shown in
Fig. 14, the last figure of the present paper. And
then, Y-junction loss coefficients for single- and
two-phase flows are defined as follows :
kSP,ⅠⅡ =
∆PbSP,ⅠⅡ
ρLuL,Ⅰ
2 2⁄
(7)
kSP,ⅠⅢ =
∆PbSP,ⅠⅢ
ρLuL,Ⅰ
2 2⁄
(8)
kTP,ⅠⅡ =
∆PbTP,ⅠⅡ
( ) , ⁄
(9)
kTP,ⅠⅢ =
∆PbTP,ⅠⅢ
( ) , ⁄
(10)
Figures 7 (a) and (b) show the junction loss
coefficient for single- and two-phase flows,
respectively. In Figure 7 (a) both , and
, data are simultaneously plotted. The
abscissa is the Reynold number of the channel
upstream from the junction. The vertical doted line
on the figure is the critical Reynold number ( =
2300), between laminar flow and turbulent flow.
The junction loss coefficient in laminar flow region
( < 2300) is nearly constant, and it decreases
with increasing of ReI in turbulent flow region
( > 2300). Thus, the data for the single-phase
flow in this study is correlated with
Laminar flow region (Re < 2300) = 0.67, (11)
Turbulent flow region (Re > 2300) = 291 ×
10 .
. (12)
Figure 7 (b) shows the junction loss coefficient for
two-phase flow, , against the volumetric flux of
gas in the channel upstream from the junction, , . It
can be seen that the loss coefficient for two-phase
flow is nearly constant at 0.0001, independent of ,
and , except for in annular flows. The data
at , = 0.2 m/s seem to be inaccurate because ,
data become quite small with decreasing of , .
(a) Single-phase flow
(b) Two-phase flow
Fig. 7: Y-junction loss coefficient
Figures 8 (a) and (b) show the present two-
phase frictional pressure drop data for the channels
upstream and downstream from the junction,
⁄ , against the mass quality, x. In general,
the pressure gradient increase with the quality, x, and
total mass flow flux, (= + ).
(a) Upstream I
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(b) Downstream II, III
Fig. 8 : Frictional pressure drop for two-phase flow
The frictional pressure drop data are commonly
correlated with the following two-phase friction
multiplier, (Lochhart & Martinelli, [28]) :
= , (13)
where ⁄ is the frictional pressure drop
when the liquid flows alone in the same channel. A
widely used correlation for the friction multiplier is
that proposed by Chisholm and Laird (1958) :
= 1 + + , (14)
where X is the Lockhart-Martinelli parameter given
by
=
⁄
⁄
, (15)
where ⁄ is the frictional pressure drop
when the gas flows alone in the same channel.
Figures 9 (a) and (b) show the two-phase friction
multiplier data against the Lockhart-Martinelli
parameter, X, for the channels upstream and
downstream from the junction. The dot-dashed line
is the calculated curve by Mishima-Hibiki [29], who
proposed the C correlation as follows :
C = 21(1 -e-0.319DH ). (16)
where DH is the hydraulic diameter of the channel.
Here, the unit of DH should be in millimeter. The
data are well correlated with the Lockhart-Martinelli
parameter, and is a little bit lower than the
calculation by Mishima-Hibiki [29].
(a) Upstream I
(b) Downstream II, III
Fig. 9 : Two-phase frictional multiplier data against
Lockhart & Martinelli parameter
3.4. Bubble velocity
Figure 10 shows the bubble velocity data, uG,
for the respective channels in the present experiment
against the total volumetric flux of gas and liquid,
+ . The solid line of = is applicable to
homogenous flows. It can be seen the data agree
reasonably with = . Figure 11 shows a
comparison of the bubble velocity between
experiment and calculation by the drift flux model of
Zuber and Findlay [30] :
= + (17)
Here, VGj, is the drift velocity, was taken as zero
because of horizontal flow. The distribution
parameter, , was determined by Kawahara et al.’s
correlation [31] :
C = αB 0.19
ReL
-0.01
WeG
0.01
(18)
and the distribution parameter, C , in this study are
proposed :
C = 1.02B 0.19
ReL
-0.01
WeG
0.01
for upstream I (DH =
3.24 mm) (19)
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C = 1.82B 0.19
ReL
-0.01
WeG
0.01
for downstream II and
III (DH = 2.43 mm) (20)
In Eqs. (19) and (20), B is the Bond number, ReL
the liquid Reynolds number and WeG the gas Weber
number. As seen in Fig. 11, the calculations agree
well with the data within root mean square errors of
15% for both the upstream and the downstream
channels.
Fig. 10 : Bubble velocity data
Fig. 11 : Comparison of bubble velocity between
experiment and calculation
3.5. Bubble length
Figure 12 shows the bubble length data divided
by the channel width, .⁄ The abscissa is the ratio
of the gas volume flow rate to the liquid one,
⁄ . The solid curve represents calculation by
Garstecki et al.’s correlation [32] :
= 1 + (21)
whereas the dashed lines represents the calculation
by Miyagawa’s correlation [33] :
= 1 + × 5 (22)
The data for both the upstream and the
downstream channels have a similar trend to both
the solid curve and the dashed curve, however it
approaches to the value calculated by Miyagawa’s
correlation as ⁄ increases.
Fig. 12 : Dimensionless bubble length data against
gas-liquid volume flow rate ratio in the upstream
and the downstream channels
Figure 13 shows the ratio of bubble length, LG,
to unit cell length, L (= + ; is the liquid slug
length) against homogeneous void fraction =
/( + ) in the upstream and the downstream
channels. The solid curve shows the calculation by
Kawahara et al.’s correlation [34] :
=
. .
. . ≅ .
(23)
Eq. (23) was proposed based on the data for
horizontal straight microchannels with square and
circular cross-sections. The ⁄ data for both the
upstream and downstream channels distribute
around the curve. Therefore the junction does not
affect ⁄ data, the Kawahara et al.’s correlation
can be applied, irrespective of the channel geometry.
Fig. 13 : Length ratio of large gas bubble to unit
cell against homogenous void fraction
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3.6 Void fraction
Figure 14 shows the void fraction data, α, in the
present experiment against the homogeneous void
fraction, = ( + )⁄ . The solid line of α = β is
applicable to homogeneous flow, and the dashed
lines represents the Armand’s correlation [35],
= 0.833 . The void fraction, α, data especially for
downstream III case, agree reasonably with the
homogeneous flow. Almost all the data are higher
than Armand’s correlation.
Fig. 14 : Void fraction against homogeneous void
fraction
IV. CONCLUSIONS
Water single-phase flow and air-water two-
phase flow experiments were conducted at room
temperature and at near atmospheric pressure using a
horizontal rectangular minichannel with Y-junction.
The width (W), the height (H) and the hydraulic
diameter (DH) for the upstream channel from the
junction were 4.60 mm, 2.50 mm and 3.24 mm,
while those for the downstream channel were 2.36
mm, 2.50 mm, 2.43 mm. The main findings can be
summarized as follows:
1. Two type of flow patterns, i.e., slug flow and
annular flow are observed under the present
flow conditions.
2. The junction pressure loss coefficient in the
single-phase laminar is constant independent of
Reynolds number, but decreases with increasing
of it in turbulent flow. The coefficient in two-
phase flow is nearly constant, independent of jL
and jG except for in annular flows.
3. Frictional pressure drop for two-phase flows,
⁄ , increases with the mass quality at
a fixed mass flow flux, G, for both the upstream
and the downstream channels from the junction.
In addition, ⁄ increases with G at a
fixed mass quality.
4. Two-phase frictional pressure drop data are a
little bit lower than the calculation by the
Chisholm and Laird correlation with Mishima-
Hibiki’s correlation.
5. The bubble velocity data, uG, for both the
upstream and the downstream channels agree
reasonably with that calculated by homogenous
flow model. The data were well correlated with
the drift flux model with Kawahara et al.’s
modified parameter correlation.
6. The bubble length data, LG, for both the
upstream and the downstream channels have a
similar trend to both the Garstecki et al.’s
correlation and Miyagawa’s correlation,
however it approaches to a value calculated by
Miyagawa’s correlation as ⁄ increases.
7. The ratio of bubble length to unit cell length
data, ⁄ , can be predicted by the Kawahara et
al.’s correlation, irrespective of channel aspect
ratio.
8. The void fraction data, α, especially for
downstream III case, agree reasonably with
those for homogeneous flow.
Acknowledgements
The authors deeply appreciate DIKTI of
Indonesian government and State Polytechnic of
Cilacap for the fellowship and the permission to Mr.
Agus Santoso to study in Kumamoto University.
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