Abstract The backward facing steps nozzle (BFSN) is a flow adjustable exit area nozzle for large rocket engines. It consists of two parts, the first is a base nozzle with small area ratio and the second part is a nozzle extension with surface consists of backward facing steps. The number of steps and their heights are carefully chosen to produce controlled flow separation at steps edges that adjust the nozzle exit area at all altitudes (pressure ratios). The BFSN performance parameters are assessed in terms of thrust and side loads against the dual-bell nozzle (DBN) with the same pressure ratios and cross sectional areas. The DBN is a two-mode flow adjustable exit area nozzle for low and high altitude. Three-dimensional turbulent flow solutions are obtained for the BFSN indicating that the flow is axi-symmetric and does not generate significant side loads. Further confirmation of the axi-symmetric flow is obtained by comparing the three-dimensional flow with the two-dimensional axi-symmetric solutions. The comparison of the thrust generated over the PR range from 50 to 1500 shows that BFSN generates more uniform and higher thrust than the DBN in the intermediate pressure ratios. At PR 1500 (high altitude), the BFSN thrust is 0.28% less than the DBN. All numerical solutions are obtained using the Fluent code. Keywords: Backward facing steps nozzle, Turbulent flow in supersonic nozzle, Side load in supersonic nozzle.
Analysis of dual bell rocket nozzle using computational fluid dynamicseSAT Journals
Abstract Concept of Altitude adaptive rocket nozzles recently received greater importance and interest in the space explorations and other such applications in space and rocket technology. The operations reliability of rocket launcher and the earth to orbit rocket launch are the crucial for the space transportation in the future. The performance of the engine components such as the power plant and the thrust delivery of the engine such as nozzles are in renovation for the greater performance and applicability for complex space applications. In the recent progress of the combustion expansion system the rocket nozzles are greatly revised from both application and design perspectives. One of such development is the dual bell nozzle. The publications indicate that the research on the concept of dual bell nozzle is tardy and there is no much progress from the inception of the idea. The specific application purpose designs are tested experimentally and implemented but the large scale development can only be possible if the generalized design parameters can be suggested. In the present paper one of such nozzle is selected and studied using computational fluid dynamics (CFD) and the results are synthesized for bench marking the general approach to study the Dual Bell nozzles. The result shows the variation in the Mach number, pressure, temperature distribution and turbulence intensity. Keywords: Altitude adaptation, Dual bell nozzle, Nozzle pressure ratio, Over-expansion factor.
Numerical simulation and optimization of high performance supersonic nozzle a...eSAT Journals
Abstract The Principle purpose of a nozzle is to accelerate the flow to higher exit velocities. The fluid acceleration is based on the design criteria and characteristics. To achieve good performance characteristics with minimum energy losses a nozzle must satisfy all the design requirements at all operating conditions. This is possible only when the nozzle theory is assumed to be isentropic irrespective of the changes in pressure, temperature and density which is generally caused due to formation of a Shock Wave. The thesis focuses on the design, development and optimization of a Supersonic Convergent-Divergent Nozzle where the analytical results are validated using theory calculations. The simulation work is carried out for CD Nozzles with different angles of divergence keeping the other inputs fixed. The objective of the proposed thesis is to show the best Expansion ratio, Nozzle Pressure ratio (NPR) and Nozzle Area Ratio(NAR) where the thrust obtained by the supersonic nozzle is maximum. The simulation is then repeated for expansion gas the results of which are later compared with standard air to show which possesses better performance characteristics. The Nozzle design chosen is based upon existing literature studies. Key Words: CD Nozzle, Expansion Ratio, Nozzle Pressure Ratio (NPR), Nozzle Area Ratio(NAR),Divergence Angle etc…
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.
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.
Design and Development of Transonic Axial Flow Compressor Rotor BladeIJERDJOURNAL
Abstract:- This paper is about a new computational fluid dynamics developed for the transonic flow in a compressor rotor. Due to 3-Dimensional blade modification the arrangements satisfying the required boundary condition. Engine compressor towards distorted inflow has to be taken in account which is already in the design phase. Flow separation over the blade surface reduction and elimination can improve better aerodynamic, performance, efficiency and stall margin. NASA transonic rotor tip critical in baseline blade rotor performance energizing the low momentum boundary layer, controlling the inception of stall. A Profile generator are attached on the inner casing of the rotor ahead to the loading edge of the rotor and it is influenced on the overall performance which has been studied.
Analysis of dual bell rocket nozzle using computational fluid dynamicseSAT Journals
Abstract Concept of Altitude adaptive rocket nozzles recently received greater importance and interest in the space explorations and other such applications in space and rocket technology. The operations reliability of rocket launcher and the earth to orbit rocket launch are the crucial for the space transportation in the future. The performance of the engine components such as the power plant and the thrust delivery of the engine such as nozzles are in renovation for the greater performance and applicability for complex space applications. In the recent progress of the combustion expansion system the rocket nozzles are greatly revised from both application and design perspectives. One of such development is the dual bell nozzle. The publications indicate that the research on the concept of dual bell nozzle is tardy and there is no much progress from the inception of the idea. The specific application purpose designs are tested experimentally and implemented but the large scale development can only be possible if the generalized design parameters can be suggested. In the present paper one of such nozzle is selected and studied using computational fluid dynamics (CFD) and the results are synthesized for bench marking the general approach to study the Dual Bell nozzles. The result shows the variation in the Mach number, pressure, temperature distribution and turbulence intensity. Keywords: Altitude adaptation, Dual bell nozzle, Nozzle pressure ratio, Over-expansion factor.
Numerical simulation and optimization of high performance supersonic nozzle a...eSAT Journals
Abstract The Principle purpose of a nozzle is to accelerate the flow to higher exit velocities. The fluid acceleration is based on the design criteria and characteristics. To achieve good performance characteristics with minimum energy losses a nozzle must satisfy all the design requirements at all operating conditions. This is possible only when the nozzle theory is assumed to be isentropic irrespective of the changes in pressure, temperature and density which is generally caused due to formation of a Shock Wave. The thesis focuses on the design, development and optimization of a Supersonic Convergent-Divergent Nozzle where the analytical results are validated using theory calculations. The simulation work is carried out for CD Nozzles with different angles of divergence keeping the other inputs fixed. The objective of the proposed thesis is to show the best Expansion ratio, Nozzle Pressure ratio (NPR) and Nozzle Area Ratio(NAR) where the thrust obtained by the supersonic nozzle is maximum. The simulation is then repeated for expansion gas the results of which are later compared with standard air to show which possesses better performance characteristics. The Nozzle design chosen is based upon existing literature studies. Key Words: CD Nozzle, Expansion Ratio, Nozzle Pressure Ratio (NPR), Nozzle Area Ratio(NAR),Divergence Angle etc…
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.
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.
Design and Development of Transonic Axial Flow Compressor Rotor BladeIJERDJOURNAL
Abstract:- This paper is about a new computational fluid dynamics developed for the transonic flow in a compressor rotor. Due to 3-Dimensional blade modification the arrangements satisfying the required boundary condition. Engine compressor towards distorted inflow has to be taken in account which is already in the design phase. Flow separation over the blade surface reduction and elimination can improve better aerodynamic, performance, efficiency and stall margin. NASA transonic rotor tip critical in baseline blade rotor performance energizing the low momentum boundary layer, controlling the inception of stall. A Profile generator are attached on the inner casing of the rotor ahead to the loading edge of the rotor and it is influenced on the overall performance which has been studied.
Atmospheric turbulent layer simulation for cfd unsteady inlet conditionsStephane Meteodyn
The aim of this work is to bridge the gap between experimental approaches in wind tunnel testing and numerical computations, in the field of structural design against strong winds. This paper focuses on the generation of an unsteady flow field, representative of a natural wind field, but still compatible with CFD inlet requirements. A simple and “naïve” procedure is explained, and the results are successfully compared to some standards.
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
An Investigation on the Performance Characteristics of a Centrifugal CompressorIJERD Editor
The design and off-design performance characteristics of single stage centrifugal compressor
consisting of 12 vanes impeller interfacing with 11 vanes diffuser have been studied experimentally and
numerically. The impeller has been designed and developed with radial exit, 30o inlet blade angle (with
tangent), 77 mm diameter and the discharge volute considering constant mean flow velocity. The performance
of the compressor at varying capacity (60 to 120 % of design) by controlling the discharge valve and with the
variation of rotating speed (15000 to 35000 rpm) by regulating speed of the coupled gas turbine has been
conducted at the recently developed test rig. The numerical simulation has been done by adopting viscous
Reynolds Average Navier-Stokes (RANS) equations with and without Coriolis Force & Centrifugal Force in
rotating reference frame (impeller) and stationary reference frame (casing) respectively utilizing CFD software
Fluent 14. The flow around a single vane of impeller interfacing with single vane of diffuser, the rotational
periodicity and sliding mesh at the interfacing zone between rotating impeller and stationery diffuser are
considered. Non dimensional performance curves derived from experimental and numerical results are
presented and compared. The numerical results are found to match very closely with the experimented data near
the design point and deviation is observed at the both side of the designed operating point. Non-uniform
pressure profiles towards the impeller exit and strong cross flow from blade to blade are detected at low flow
operating conditions. Total pressure, static pressure and velocity distributions at design and off design
operation obtained from the CFD results are analysed and presented here.
Numerical analysis for two phase flow distribution headers in heat exchangerseSAT Journals
Abstract A flow header having number of multiple small branch pipes are commonly used in heat exchangers and boilers. In beginning the headers were designed based on the assumption that the fluid distribute equally to all lateral pipes. In practical situation the flow is not uniform and equal in all lateral pipes. Mal distribution of flow in heat exchangers significantly affects their performance. Non-uniform flow distribution from header to the branch pipes in a flow system will lead to 25% decrease in effectiveness of a cross flow heat exchanger. Mal distribution of flow in the header is influenced by the geometric parameters and operating conditions of the header. In this work the flow distribution among the branch pipes of dividing flow header system is analyzed for two phase flow condition. In the two phase flow condition, the effect of change in geometric cross sectional shape of the header (circular, square), inlet flow velocities are varied to find the flow mal distribution through the lateral pipes are investigated with the use of Computational Fluid Dynamics software. Keywords: circular, square headers and Computational Fluid Dynamics software. (CFD)
Cfd simulation of single stage axial flow compressor for varying blade aspect...eSAT Journals
Abstract The aspect ratio of blade is an important parameter and has a strong influence on the performance of axial flow compressor. The performance of axial flow compressors is known to be affected by the choice of aspect ratio (the ratio of blade height to axial chord length). A study has been carried out to verify the effect of aspect ratio on the performance of 1.2 pressure ratio single stage subsonic compressor through AxStream analysis using Axial flow compressor design. The analysis has been carried out for the constant tip diameter of the compressor rotor blade having an aspect ratio 1, 2 and 3 and obtained the pressure loss and flow parameters of the compressor stage. This paper shows that the best operating conditions occur for the aspect ratio between 2 and 3. Keywords: Axial flow compressor, Aspect ratio, Computational Fluid Dynamic, AxStream
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
Atmospheric turbulent layer simulation for cfd unsteady inlet conditionsStephane Meteodyn
The aim of this work is to bridge the gap between experimental approaches in wind tunnel testing and numerical computations, in the field of structural design against strong winds. This paper focuses on the generation of an unsteady flow field, representative of a natural wind field, but still compatible with CFD inlet requirements. A simple and “naïve” procedure is explained, and the results are successfully compared to some standards.
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
An Investigation on the Performance Characteristics of a Centrifugal CompressorIJERD Editor
The design and off-design performance characteristics of single stage centrifugal compressor
consisting of 12 vanes impeller interfacing with 11 vanes diffuser have been studied experimentally and
numerically. The impeller has been designed and developed with radial exit, 30o inlet blade angle (with
tangent), 77 mm diameter and the discharge volute considering constant mean flow velocity. The performance
of the compressor at varying capacity (60 to 120 % of design) by controlling the discharge valve and with the
variation of rotating speed (15000 to 35000 rpm) by regulating speed of the coupled gas turbine has been
conducted at the recently developed test rig. The numerical simulation has been done by adopting viscous
Reynolds Average Navier-Stokes (RANS) equations with and without Coriolis Force & Centrifugal Force in
rotating reference frame (impeller) and stationary reference frame (casing) respectively utilizing CFD software
Fluent 14. The flow around a single vane of impeller interfacing with single vane of diffuser, the rotational
periodicity and sliding mesh at the interfacing zone between rotating impeller and stationery diffuser are
considered. Non dimensional performance curves derived from experimental and numerical results are
presented and compared. The numerical results are found to match very closely with the experimented data near
the design point and deviation is observed at the both side of the designed operating point. Non-uniform
pressure profiles towards the impeller exit and strong cross flow from blade to blade are detected at low flow
operating conditions. Total pressure, static pressure and velocity distributions at design and off design
operation obtained from the CFD results are analysed and presented here.
Numerical analysis for two phase flow distribution headers in heat exchangerseSAT Journals
Abstract A flow header having number of multiple small branch pipes are commonly used in heat exchangers and boilers. In beginning the headers were designed based on the assumption that the fluid distribute equally to all lateral pipes. In practical situation the flow is not uniform and equal in all lateral pipes. Mal distribution of flow in heat exchangers significantly affects their performance. Non-uniform flow distribution from header to the branch pipes in a flow system will lead to 25% decrease in effectiveness of a cross flow heat exchanger. Mal distribution of flow in the header is influenced by the geometric parameters and operating conditions of the header. In this work the flow distribution among the branch pipes of dividing flow header system is analyzed for two phase flow condition. In the two phase flow condition, the effect of change in geometric cross sectional shape of the header (circular, square), inlet flow velocities are varied to find the flow mal distribution through the lateral pipes are investigated with the use of Computational Fluid Dynamics software. Keywords: circular, square headers and Computational Fluid Dynamics software. (CFD)
Cfd simulation of single stage axial flow compressor for varying blade aspect...eSAT Journals
Abstract The aspect ratio of blade is an important parameter and has a strong influence on the performance of axial flow compressor. The performance of axial flow compressors is known to be affected by the choice of aspect ratio (the ratio of blade height to axial chord length). A study has been carried out to verify the effect of aspect ratio on the performance of 1.2 pressure ratio single stage subsonic compressor through AxStream analysis using Axial flow compressor design. The analysis has been carried out for the constant tip diameter of the compressor rotor blade having an aspect ratio 1, 2 and 3 and obtained the pressure loss and flow parameters of the compressor stage. This paper shows that the best operating conditions occur for the aspect ratio between 2 and 3. Keywords: Axial flow compressor, Aspect ratio, Computational Fluid Dynamic, AxStream
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
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
Analysis of aerodynamic characteristics of a supercritical airfoil for low sp...eSAT Publishing House
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.
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
Experimental Investigations and Computational Analysis on Subsonic Wind Tunnelijtsrd
This paper disclose the entire approach to design an open circuit subsonic wind tunnel which will be used to consider the wind impact on the airfoil. The current rules and discoveries of the past research works were sought after for plan figuring of different segments of the wind tunnel. Wind speed of 26 m s have been practiced at the test territory. The wind qualities over a symmetrical airfoil are viewed as probably in a low speed wind tunnel. Tests were finished by moving the approach, from 0 to 5 degree. The stream attributes over a symmetrical airfoil are examined tentatively. The pressure distribution on the airfoil area was estimated, lift and drag force were estimated and velocity profiles were acquired. Rishabh Kumar Sahu | Saurabh Sharma | Vivek Swaroop | Vishal Kumar ""Experimental Investigations and Computational Analysis on Subsonic Wind Tunnel"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-3 , April 2019, URL: https://www.ijtsrd.com/papers/ijtsrd23511.pdf
Paper URL: https://www.ijtsrd.com/engineering/mechanical-engineering/23511/experimental-investigations-and-computational-analysis-on-subsonic-wind-tunnel/rishabh-kumar-sahu
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
Effect of spikes integrated to airfoil at supersonic speedeSAT Journals
Abstract
The objective of this is to analyse the flow field over an aerofoil section integrated with spikes at supersonic speed (Mach number
greater than 1). Use of spike integrated with aerofoil changes the flow characteristics over aerofoil and hence aerodynamic lift
and drag. The experiment consists of flow visualization graphs and measurement of coefficient of aerodynamic drag and lift.
Here we are using different shapes of spike like sharp edge and hemi spherical edge. In this we will compare the flow over
aerofoil with spike and without spike. The flow analysis is done by using Computational fluid dynamics (CFD). CFD is the study
of external flow over a body or internal flow through the body. CFD is aiding aero-dynamist to better understand the flow physics
and in turn to design efficient models. In short, CFD is playing a strong role as a design tool as well as a research tool.
Keywords: NACA 651-412 airfoil, spike, Ansys Fluent, Ansys ICEM CFD, Pressure Coefficient
Optimization of design of mixed flow centrifugal pump impeller using cfdeSAT Journals
Abstract
Centrifugal pumps are widely used hydraulic machines, irrespective of the fact that their performance is generally not very good. So, turning them into more efficient machines is quite a challenge. The performance of a centrifugal pump is highly dependent on its geometrical parameters and its vane profile. In order to analyze the flow through complex systems like centrifugal pumps, Computation fluid dynamics (CFD) has been used. This work aims to study the performance analysis of a centrifugal mixed flow pump designed to deliver 0.25 m3/s of water with a head of 20 m at a speed of 1450 rpm using ANSYS CFX (ver.14.0). PTC Creo (ver. 2.0) has been used to model the pump unit. The performance of the pump was first determined using the existing vane angles and thickness of the blade then, the inlet vane angle, the outlet vane angle along with the thickness of the blade has been varied to analyze the pump’s performance . The results show that for an initial inlet angle 21.08˚, outlet angle 16.28˚ and blade thickness as 10mm, the efficiency of the pump was 84%. However, the efficiency of pump rises to 89.19% for the optimized angles and blade thickness.
Optimization of design of mixed flow centrifugal pump impeller using cfdeSAT Journals
Abstract
Centrifugal pumps are widely used hydraulic machines, irrespective of the fact that their performance is generally not very good. So, turning them into more efficient machines is quite a challenge. The performance of a centrifugal pump is highly dependent on its geometrical parameters and its vane profile. In order to analyze the flow through complex systems like centrifugal pumps, Computation fluid dynamics (CFD) has been used. This work aims to study the performance analysis of a centrifugal mixed flow pump designed to deliver 0.25 m3/s of water with a head of 20 m at a speed of 1450 rpm using ANSYS CFX (ver.14.0). PTC Creo (ver. 2.0) has been used to model the pump unit. The performance of the pump was first determined using the existing vane angles and thickness of the blade then, the inlet vane angle, the outlet vane angle along with the thickness of the blade has been varied to analyze the pump’s performance . The results show that for an initial inlet angle 21.08˚, outlet angle 16.28˚ and blade thickness as 10mm, the efficiency of the pump was 84%. However, the efficiency of pump rises to 89.19% for the optimized angles and blade thickness.
Keywords: Computational Fluid Dynamics (CFD) Analysis, Mixed Flow Pump, Overall Efficiency.
Numerical Investigation of Single Stage of an Axial Flow Compressor for Effec...IJERA Editor
In present work, a compressor configuration is taken from literature which will be studied for aspect ratio (ratio between length of blade to chord length) influence over performance. Performance in the sense is pressure ratio of compressor. The aspect ratio of the blade is an important parameter and has a strong influence on the performance of axial flow compressor. There are so many literatures available on influence of design parameters of axial flow compressor over its performance. Few literatures only are available for effects of aspect ratio of blade over performance of compressor. A study is proposed to be carried out to verify the effect of aspect ratio on the performance of single stage subsonic compressor through ANSYS-CFX software. The analysis will be carried out for the constant tip diameter of the compressor rotor blade having an aspect ratio 1, 2 and 3 and to obtain the pressure loss and flow parameters of the compressor stage. Further increase in aspect ratio will lead to structural problem of compressor. Therefore, there will be optimum aspect ratio between 2 and 3. Simulation will be conducted to aspect ratios of 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8 and 2.9 to find optimum ratio using ANSYS-CFX commercial CFD software.
Design optimization of an axial flow compressor for industrial gas turbineeSAT Publishing House
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
Mechanical properties of hybrid fiber reinforced concrete for pavementseSAT Journals
Abstract
The effect of addition of mono fibers and hybrid fibers on the mechanical properties of concrete mixture is studied in the present
investigation. Steel fibers of 1% and polypropylene fibers 0.036% were added individually to the concrete mixture as mono fibers and
then they were added together to form a hybrid fiber reinforced concrete. Mechanical properties such as compressive, split tensile and
flexural strength were determined. The results show that hybrid fibers improve the compressive strength marginally as compared to
mono fibers. Whereas, hybridization improves split tensile strength and flexural strength noticeably.
Keywords:-Hybridization, mono fibers, steel fiber, polypropylene fiber, Improvement in mechanical properties.
Material management in construction – a case studyeSAT Journals
Abstract
The objective of the present study is to understand about all the problems occurring in the company because of improper application
of material management. In construction project operation, often there is a project cost variance in terms of the material, equipments,
manpower, subcontractor, overhead cost, and general condition. Material is the main component in construction projects. Therefore,
if the material management is not properly managed it will create a project cost variance. Project cost can be controlled by taking
corrective actions towards the cost variance. Therefore a methodology is used to diagnose and evaluate the procurement process
involved in material management and launch a continuous improvement was developed and applied. A thorough study was carried
out along with study of cases, surveys and interviews to professionals involved in this area. As a result, a methodology for diagnosis
and improvement was proposed and tested in selected projects. The results obtained show that the main problem of procurement is
related to schedule delays and lack of specified quality for the project. To prevent this situation it is often necessary to dedicate
important resources like money, personnel, time, etc. To monitor and control the process. A great potential for improvement was
detected if state of the art technologies such as, electronic mail, electronic data interchange (EDI), and analysis were applied to the
procurement process. These helped to eliminate the root causes for many types of problems that were detected.
Managing drought short term strategies in semi arid regions a case studyeSAT Journals
Abstract
Drought management needs multidisciplinary action. Interdisciplinary efforts among the experts in various fields of the droughts
prone areas are helpful to achieve tangible and permanent solution for this recurring problem. The Gulbarga district having the total
area around 16, 240 sq.km, and accounts 8.45 per cent of the Karnataka state area. The district has been situated with latitude 17º 19'
60" North and longitude of 76 º 49' 60" east. The district is situated entirely on the Deccan plateau positioned at a height of 300 to
750 m above MSL. Sub-tropical, semi-arid type is one among the drought prone districts of Karnataka State. The drought
management is very important for a district like Gulbarga. In this paper various short term strategies are discussed to mitigate the
drought condition in the district.
Keywords: Drought, South-West monsoon, Semi-Arid, Rainfall, Strategies etc.
Life cycle cost analysis of overlay for an urban road in bangaloreeSAT Journals
Abstract
Pavements are subjected to severe condition of stresses and weathering effects from the day they are constructed and opened to traffic
mainly due to its fatigue behavior and environmental effects. Therefore, pavement rehabilitation is one of the most important
components of entire road systems. This paper highlights the design of concrete pavement with added mono fibers like polypropylene,
steel and hybrid fibres for a widened portion of existing concrete pavement and various overlay alternatives for an existing
bituminous pavement in an urban road in Bangalore. Along with this, Life cycle cost analyses at these sections are done by Net
Present Value (NPV) method to identify the most feasible option. The results show that though the initial cost of construction of
concrete overlay is high, over a period of time it prove to be better than the bituminous overlay considering the whole life cycle cost.
The economic analysis also indicates that, out of the three fibre options, hybrid reinforced concrete would be economical without
compromising the performance of the pavement.
Keywords: - Fatigue, Life cycle cost analysis, Net Present Value method, Overlay, Rehabilitation
Laboratory studies of dense bituminous mixes ii with reclaimed asphalt materialseSAT Journals
Abstract
The issue of growing demand on our nation’s roadways over that past couple of decades, decreasing budgetary funds, and the need to
provide a safe, efficient, and cost effective roadway system has led to a dramatic increase in the need to rehabilitate our existing
pavements and the issue of building sustainable road infrastructure in India. With these emergency of the mentioned needs and this
are today’s burning issue and has become the purpose of the study.
In the present study, the samples of existing bituminous layer materials were collected from NH-48(Devahalli to Hassan) site.The
mixtures were designed by Marshall Method as per Asphalt institute (MS-II) at 20% and 30% Reclaimed Asphalt Pavement (RAP).
RAP material was blended with virgin aggregate such that all specimens tested for the, Dense Bituminous Macadam-II (DBM-II)
gradation as per Ministry of Roads, Transport, and Highways (MoRT&H) and cost analysis were carried out to know the economics.
Laboratory results and analysis showed the use of recycled materials showed significant variability in Marshall Stability, and the
variability increased with the increase in RAP content. The saving can be realized from utilization of recycled materials as per the
methodology, the reduction in the total cost is 19%, 30%, comparing with the virgin mixes.
Keywords: Reclaimed Asphalt Pavement, Marshall Stability, MS-II, Dense Bituminous Macadam-II
Laboratory investigation of expansive soil stabilized with natural inorganic ...eSAT Journals
Abstract
Soil stabilization has proven to be one of the oldest techniques to improve the soil properties. Literature review conducted revealed
that uses of natural inorganic stabilizers are found to be one of the best options for soil stabilization. In this regard an attempt has
been made to evaluate the influence of RBI-81 stabilizer on properties of black cotton soil through laboratory investigations. Black
cotton soil with varying percentages of RBI-81 viz., 0, 0.5, 1, 1.5, 2, and 2.5 percent were studied for moisture density relationships
and strength behaviour of soils. Also the effect of curing period was evaluated as literature review clearly emphasized the strength
gain of soils stabilized with RBI-81 over a period of time. The results obtained shows that the unconfined compressive strength of
specimens treated with RBI-81 increased approximately by 250% for a curing period of 28 days as compared to virgin soil. Further
the CBR value improved approximately by 400%. The studies indicated an increasing trend for soil strength behaviour with
increasing percentage of RBI-81 suggesting its potential applications in soil stabilization.
Influence of reinforcement on the behavior of hollow concrete block masonry p...eSAT Journals
Abstract
Reinforced masonry was developed to exploit the strength potential of masonry and to solve its lack of tensile strength. Experimental
and analytical studies have been carried out to investigate the effect of reinforcement on the behavior of hollow concrete block
masonry prisms under compression and to predict ultimate failure compressive strength. In the numerical program, three dimensional
non-linear finite elements (FE) model based on the micro-modeling approach is developed for both unreinforced and reinforced
masonry prisms using ANSYS (14.5). The proposed FE model uses multi-linear stress-strain relationships to model the non-linear
behavior of hollow concrete block, mortar, and grout. Willam-Warnke’s five parameter failure theory has been adopted to model the
failure of masonry materials. The comparison of the numerical and experimental results indicates that the FE models can successfully
capture the highly nonlinear behavior of the physical specimens and accurately predict their strength and failure mechanisms.
Keywords: Structural masonry, Hollow concrete block prism, grout, Compression failure, Finite element method,
Numerical modeling.
Influence of compaction energy on soil stabilized with chemical stabilizereSAT Journals
Abstract
Increase in traffic along with heavier magnitude of wheel loads cause rapid deterioration in pavements. There is a need to improve
density, strength of soil subgrade and other pavement layers. In this study an attempt is made to improve the properties of locally
available loamy soil using twin approaches viz., i) increasing the compaction of soil and ii) treating the soil with chemical stabilizer.
Laboratory studies are carried out on both untreated and treated soil samples compacted by different compaction efforts. Studies
show that increase in compaction effort results in increase in density of soil. However in soil treated with chemical stabilizer, rate of
increase in density is not significant. The soil treated with chemical stabilizer exhibits improvement in both strength and performance
properties.
Keywords: compaction, density, subgradestabilization, resilient modulus
Geographical information system (gis) for water resources managementeSAT Journals
Abstract
Water resources projects are inherited with overlapping and at times conflicting objectives. These projects are often of varied sizes
ranging from major projects with command areas of millions of hectares to very small projects implemented at the local level. Thus,
in all these projects there is seldom proper coordination which is essential for ensuring collective sustainability.
Integrated watershed development and management is the accepted answer but in turn requires a comprehensive framework that can
enable planning process involving all the stakeholders at different levels and scales is compulsory. Such a unified hydrological
framework is essential to evaluate the cause and effect of all the proposed actions within the drainage basins.
The present paper describes a hydrological framework developed in the form of a Hydrologic Information System (HIS) which is
intended to meet the specific information needs of the various line departments of a typical State connected with water related aspects.
The HIS consist of a hydrologic information database coupled with tools for collating primary and secondary data and tools for
analyzing and visualizing the data and information. The HIS also incorporates hydrological model base for indirect assessment of
various entities of water balance in space and time. The framework would be maintained and updated to reflect fully the most
accurate ground truth data and the infrastructure requirements for planning and management.
Keywords: Hydrological Information System (HIS); WebGIS; Data Model; Web Mapping Services
Forest type mapping of bidar forest division, karnataka using geoinformatics ...eSAT Journals
Abstract
The study demonstrate the potentiality of satellite remote sensing technique for the generation of baseline information on forest types
including tree plantation details in Bidar forest division, Karnataka covering an area of 5814.60Sq.Kms. The Total Area of Bidar
forest division is 5814Sq.Kms analysis of the satellite data in the study area reveals that about 84% of the total area is Covered by
crop land, 1.778% of the area is covered by dry deciduous forest, 1.38 % of mixed plantation, which is very threatening to the
environmental stability of the forest, future plantation site has been mapped. With the use of latest Geo-informatics technology proper
and exact condition of the trees can be observed and necessary precautions can be taken for future plantation works in an appropriate
manner
Keywords:-RS, GIS, GPS, Forest Type, Tree Plantation
Factors influencing compressive strength of geopolymer concreteeSAT Journals
Abstract
To study effects of several factors on the properties of fly ash based geopolymer concrete on the compressive strength and also the
cost comparison with the normal concrete. The test variables were molarities of sodium hydroxide(NaOH) 8M,14M and 16M, ratio of
NaOH to sodium silicate (Na2SiO3) 1, 1.5, 2 and 2.5, alkaline liquid to fly ash ratio 0.35 and 0.40 and replacement of water in
Na2SiO3 solution by 10%, 20% and 30% were used in the present study. The test results indicated that the highest compressive
strength 54 MPa was observed for 16M of NaOH, ratio of NaOH to Na2SiO3 2.5 and alkaline liquid to fly ash ratio of 0.35. Lowest
compressive strength of 27 MPa was observed for 8M of NaOH, ratio of NaOH to Na2SiO3 is 1 and alkaline liquid to fly ash ratio of
0.40. Alkaline liquid to fly ash ratio of 0.35, water replacement of 10% and 30% for 8 and 16 molarity of NaOH and has resulted in
compressive strength of 36 MPa and 20 MPa respectively. Superplasticiser dosage of 2 % by weight of fly ash has given higher
strength in all cases.
Keywords: compressive strength, alkaline liquid, fly ash
Experimental investigation on circular hollow steel columns in filled with li...eSAT Journals
Abstract
Composite Circular hollow Steel tubes with and without GFRP infill for three different grades of Light weight concrete are tested for
ultimate load capacity and axial shortening , under Cyclic loading. Steel tubes are compared for different lengths, cross sections and
thickness. Specimens were tested separately after adopting Taguchi’s L9 (Latin Squares) Orthogonal array in order to save the initial
experimental cost on number of specimens and experimental duration. Analysis was carried out using ANN (Artificial Neural
Network) technique with the assistance of Mini Tab- a statistical soft tool. Comparison for predicted, experimental & ANN output is
obtained from linear regression plots. From this research study, it can be concluded that *Cross sectional area of steel tube has most
significant effect on ultimate load carrying capacity, *as length of steel tube increased- load carrying capacity decreased & *ANN
modeling predicted acceptable results. Thus ANN tool can be utilized for predicting ultimate load carrying capacity for composite
columns.
Keywords: Light weight concrete, GFRP, Artificial Neural Network, Linear Regression, Back propagation, orthogonal
Array, Latin Squares
Experimental behavior of circular hsscfrc filled steel tubular columns under ...eSAT Journals
Abstract
This paper presents an outlook on experimental behavior and a comparison with predicted formula on the behaviour of circular
concentrically loaded self-consolidating fibre reinforced concrete filled steel tube columns (HSSCFRC). Forty-five specimens were
tested. The main parameters varied in the tests are: (1) percentage of fiber (2) tube diameter or width to wall thickness ratio (D/t
from 15 to 25) (3) L/d ratio from 2.97 to 7.04 the results from these predictions were compared with the experimental data. The
experimental results) were also validated in this study.
Keywords: Self-compacting concrete; Concrete-filled steel tube; axial load behavior; Ultimate capacity.
Evaluation of punching shear in flat slabseSAT Journals
Abstract
Flat-slab construction has been widely used in construction today because of many advantages that it offers. The basic philosophy in
the design of flat slab is to consider only gravity forces; this method ignores the effect of punching shear due to unbalanced moments
at the slab column junction which is critical. An attempt has been made to generate generalized design sheets which accounts both
punching shear due to gravity loads and unbalanced moments for cases (a) interior column; (b) edge column (bending perpendicular
to shorter edge); (c) edge column (bending parallel to shorter edge); (d) corner column. These design sheets are prepared as per
codal provisions of IS 456-2000. These design sheets will be helpful in calculating the shear reinforcement to be provided at the
critical section which is ignored in many design offices. Apart from its usefulness in evaluating punching shear and the necessary
shear reinforcement, the design sheets developed will enable the designer to fix the depth of flat slab during the initial phase of the
design.
Keywords: Flat slabs, punching shear, unbalanced moment.
Evaluation of performance of intake tower dam for recent earthquake in indiaeSAT Journals
Abstract
Intake towers are typically tall, hollow, reinforced concrete structures and form entrance to reservoir outlet works. A parametric
study on dynamic behavior of circular cylindrical towers can be carried out to study the effect of depth of submergence, wall thickness
and slenderness ratio, and also effect on tower considering dynamic analysis for time history function of different soil condition and
by Goyal and Chopra accounting interaction effects of added hydrodynamic mass of surrounding and inside water in intake tower of
dam
Key words: Hydrodynamic mass, Depth of submergence, Reservoir, Time history analysis,
Evaluation of operational efficiency of urban road network using travel time ...eSAT Journals
Abstract
Efficiency of the road network system is analyzed by travel time reliability measures. The study overlooks on an important measure of
travel time reliability and prioritizing Tiruchirappalli road network. Traffic volume and travel time were collected using license plate
matching method. Travel time measures were estimated from average travel time and 95th travel time. Effect of non-motorized vehicle
on efficiency of road system was evaluated. Relation between buffer time index and traffic volume was created. Travel time model has
been developed and travel time measure was validated. Then service quality of road sections in network were graded based on
travel time reliability measures.
Keywords: Buffer Time Index (BTI); Average Travel Time (ATT); Travel Time Reliability (TTR); Buffer Time (BT).
Estimation of surface runoff in nallur amanikere watershed using scs cn methodeSAT Journals
Abstract
The development of watershed aims at productive utilization of all the available natural resources in the entire area extending from
ridge line to stream outlet. The per capita availability of land for cultivation has been decreasing over the years. Therefore, water and
the related land resources must be developed, utilized and managed in an integrated and comprehensive manner. Remote sensing and
GIS techniques are being increasingly used for planning, management and development of natural resources. The study area, Nallur
Amanikere watershed geographically lies between 110 38’ and 110 52’ N latitude and 760 30’ and 760 50’ E longitude with an area of
415.68 Sq. km. The thematic layers such as land use/land cover and soil maps were derived from remotely sensed data and overlayed
through ArcGIS software to assign the curve number on polygon wise. The daily rainfall data of six rain gauge stations in and around
the watershed (2001-2011) was used to estimate the daily runoff from the watershed using Soil Conservation Service - Curve Number
(SCS-CN) method. The runoff estimated from the SCS-CN model was then used to know the variation of runoff potential with different
land use/land cover and with different soil conditions.
Keywords: Watershed, Nallur watershed, Surface runoff, Rainfall-Runoff, SCS-CN, Remote Sensing, GIS.
Estimation of morphometric parameters and runoff using rs & gis techniqueseSAT Journals
Abstract
Land and water are the two vital natural resources, the optimal management of these resources with minimum adverse environmental
impact are essential not only for sustainable development but also for human survival. Satellite remote sensing with geographic
information system has a pragmatic approach to map and generate spatial input layers of predicting response behavior and yield of
watershed. Hence, in the present study an attempt has been made to understand the hydrological process of the catchment at the
watershed level by drawing the inferences from moprhometric analysis and runoff. The study area chosen for the present study is
Yagachi catchment situated in Chickamaglur and Hassan district lies geographically at a longitude 75⁰52’08.77”E and
13⁰10’50.77”N latitude. It covers an area of 559.493 Sq.km. Morphometric analysis is carried out to estimate morphometric
parameters at Micro-watershed to understand the hydrological response of the catchment at the Micro-watershed level. Daily runoff
is estimated using USDA SCS curve number model for a period of 10 years from 2001 to 2010. The rainfall runoff relationship of the
study shows there is a positive correlation.
Keywords: morphometric analysis, runoff, remote sensing and GIS, SCS - method
-
Effect of variation of plastic hinge length on the results of non linear anal...eSAT Journals
Abstract The nonlinear Static procedure also well known as pushover analysis is method where in monotonically increasing loads are applied to the structure till the structure is unable to resist any further load. It is a popular tool for seismic performance evaluation of existing and new structures. In literature lot of research has been carried out on conventional pushover analysis and after knowing deficiency efforts have been made to improve it. But actual test results to verify the analytically obtained pushover results are rarely available. It has been found that some amount of variation is always expected to exist in seismic demand prediction of pushover analysis. Initial study is carried out by considering user defined hinge properties and default hinge length. Attempt is being made to assess the variation of pushover analysis results by considering user defined hinge properties and various hinge length formulations available in literature and results compared with experimentally obtained results based on test carried out on a G+2 storied RCC framed structure. For the present study two geometric models viz bare frame and rigid frame model is considered and it is found that the results of pushover analysis are very sensitive to geometric model and hinge length adopted. Keywords: Pushover analysis, Base shear, Displacement, hinge length, moment curvature analysis
Effect of use of recycled materials on indirect tensile strength of asphalt c...eSAT Journals
Abstract
Depletion of natural resources and aggregate quarries for the road construction is a serious problem to procure materials. Hence
recycling or reuse of material is beneficial. On emphasizing development in sustainable construction in the present era, recycling of
asphalt pavements is one of the effective and proven rehabilitation processes. For the laboratory investigations reclaimed asphalt
pavement (RAP) from NH-4 and crumb rubber modified binder (CRMB-55) was used. Foundry waste was used as a replacement to
conventional filler. Laboratory tests were conducted on asphalt concrete mixes with 30, 40, 50, and 60 percent replacement with RAP.
These test results were compared with conventional mixes and asphalt concrete mixes with complete binder extracted RAP
aggregates. Mix design was carried out by Marshall Method. The Marshall Tests indicated highest stability values for asphalt
concrete (AC) mixes with 60% RAP. The optimum binder content (OBC) decreased with increased in RAP in AC mixes. The Indirect
Tensile Strength (ITS) for AC mixes with RAP also was found to be higher when compared to conventional AC mixes at 300C.
Keywords: Reclaimed asphalt pavement, Foundry waste, Recycling, Marshall Stability, Indirect tensile strength.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
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
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.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
#vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore#blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #blackmagicforlove #blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #Amilbabainuk #amilbabainspain #amilbabaindubai #Amilbabainnorway #amilbabainkrachi #amilbabainlahore #amilbabaingujranwalan #amilbabainislamabad
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
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.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdf
Numerical assessment of the backward facing steps nozzle
1. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 07 | July-2015, Available @ http://www.ijret.org 1
NUMERICAL ASSESSMENT OF THE BACKWARD FACING STEPS
NOZZLE
Mohamed M. Eldeeb1
, Shaaban Abdallah2
1
Senior Researcher, Technical Research Center, Cairo, Egypt
2
Professor, Department of Aerospace Engineering, University of Cincinnati, Ohio, USA
Abstract
The backward facing steps nozzle (BFSN) is a flow adjustable exit area nozzle for large rocket engines. It consists of two parts,
the first is a base nozzle with small area ratio and the second part is a nozzle extension with surface consists of backward facing
steps. The number of steps and their heights are carefully chosen to produce controlled flow separation at steps edges that adjust
the nozzle exit area at all altitudes (pressure ratios). The BFSN performance parameters are assessed in terms of thrust and side
loads against the dual-bell nozzle (DBN) with the same pressure ratios and cross sectional areas. The DBN is a two-mode flow
adjustable exit area nozzle for low and high altitude. Three-dimensional turbulent flow solutions are obtained for the BFSN
indicating that the flow is axi-symmetric and does not generate significant side loads. Further confirmation of the axi-symmetric
flow is obtained by comparing the three-dimensional flow with the two-dimensional axi-symmetric solutions. The comparison of
the thrust generated over the PR range from 50 to 1500 shows that BFSN generates more uniform and higher thrust than the DBN
in the intermediate pressure ratios. At PR 1500 (high altitude), the BFSN thrust is 0.28% less than the DBN. All numerical
solutions are obtained using the Fluent code.
Keywords: Backward facing steps nozzle, Turbulent flow in supersonic nozzle, Side load in supersonic nozzle.
--------------------------------------------------------------------***----------------------------------------------------------------------
1. INTRODUCTION
In today’s launch vehicles, the main engine usually operates
from takeoff at sea level up to high altitudes with very low
ambient pressures. To get an optimum performance over the
whole trajectory, the nozzle is usually designed for an
intermediate operating PR, at which the exhaust flow is
adapted to the ambient pressure [1]. This leads to flow
separation from the nozzle wall when it operates with over-
expanding conditions (sea-level). The separated flow causes
side loads due to its unsteady nature and its asymmetrical
circumferential distribution [2]. The structural damage
caused by the transient nozzle side loads during testing at
sea level have been found for almost all rocket engines
during their initial development [3]. Many examples for the
nozzle failure caused by side loads are mentioned in
references [4, 5, 6, 7]. As a result, whether during sea-level
testing or in flight, transient nozzle side loads has the
potential of causing real system failure [3].
One possible solution is to adapt the nozzle contour during
flight to changes of ambient pressure mechanically, however
the weight and mechanical complexities of such device is a
big issue [1]. One of the most promising non-mechanical
altitude compensating nozzles is the DBN [8, 9, 10]. It is a
combination of two bell nozzles with different exit area
ratios. Compared to conventional bell nozzle, the DBN has
advantages of providing a stable separated flow at low
altitudes and high specific impulse at high altitudes [11].
The main advantage of the DBN is its simplicity because of
absence of any movable parts and therefore, its high
reliability [12]. However, the DBN suffers from a short time
specific impulse loss and a high side load peak during the
transition from low to high altitude mode [11, 13]. The
specific impulse decrease occurs because the transition from
low to high altitude mode occurs at lower altitude than the
optimum [11]. While the high side load peak occurs during
transition because the flow is potentially separates
asymmetrically within the nozzle extension [13]. Many
studies have been done on the DBN to understand the
transition and side loads generation numerically [14, 15, 16,
17, 18] and experimentally [9, 19, 20, 21]. From the
literature survey about the nozzle flow separation and side
loads, it can be concluded that the key to decrease the side
loads is to control the flow separation at all operating
conditions.
In this study, we developed a new nozzle that provides an
altitude exit area adaptation. The new nozzle consists of two
parts: 1) a conventional bell shape base nozzle with low area
ratio, similar to the base of the dual-bell nozzle, and 2) the
nozzle extension that consists of backward facing steps. The
existence of the backward facing steps guarantees a
controlled symmetrical flow separation at the steps edges for
all operating altitudes (PRs). At sea level, a controlled
symmetrical flow separation occurs at the end of the base
nozzle decreasing the exit area and increasing the specific
impulse. As the nozzle ascends through the atmosphere, the
controlled flow separation moves through the steps edges
providing a symmetrical flow separation at all operating
altitudes which leads to decreasing the occurrence of side
loads. The number of steps and their heights are carefully
chosen to produce an effective exit area (at the step edges)
suitable to the related operating altitudes.
2. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 07 | July-2015, Available @ http://www.ijret.org 2
Three main advantages that can be obtained from the BFSN
compared to the DBN. 1) Perfectly symmetrical controlled
flow separation at the steps edges leads to decrease in the
side loads on the nozzle walls, and 2) the symmetrical
circumferential distribution flow separation makes it
possible to use two-dimensional CFD analysis to study the
BFSN performance and the flow structure at all operating
PRs.
In order to proof these advantages, a complete three-
dimensional numerical study for the BFSN and the DBN;
with same area ratio, throat diameter, and length; are
obtained at several operating PRs. Figure (1) shows the
geometry of the BFSNs and equivalent dual bell nozzle. The
wall pressure distributions over the nozzles walls and the
axial velocity contours at the effective exit area have been
obtained and used to assess the flow symmetrical
distribution for both nozzles at all operating PRs. The flow
parameters at the effective exit area are obtained and the
thrust forces are calculated for all operating PRs. Finally, the
three-dimensional numerical results for the BFSN are
compared to the two-dimensional axi-symmetric numerical
results.
(a) BFSN
(b) DBN
Fig -1: schematic diagrams of the nozzles physical models
2. NUMERICAL METHOD
The commercial CFD software, Ansys Fluent, is used to
simulate the turbulent flow of the sub-scale BFS nozzle and
the DBN shown in Figures (1-a) and (1-b). Both nozzles
have throat diameters of 0.53 inches and area ratios of 89.
The length of both nozzles is 5.6 inches. The SST k-omega
was utilized to predict the turbulence quantities of the flow
field behavior. It was chosen because of its accuracy in
computing the flow separation from smooth surface, and
predicting the details of the wall layer characteristics [22].
Second order accuracy upwind scheme is used which
accurately predicts the interaction between the oblique
shock and the turbulent boundary layer. Ideal air is modeled
as the driving gas at constant inlet pressure and temperature.
Varied ambient pressure is specified at the far downstream
boundary. The computations are done using parallel
processing on eighteen node cluster at OSC (Ohio Super
Computer). Each node is a 2.5 GHz processor.
3. COMPUTATIONAL DOMAIN AND
BOUNDARY CONDITIONS
The grid of the BFSN and the DBN consist of five blocks
for each, two of which located inside the nozzle and the
other three are placed outside as shown in Figure (2). A
preliminary study was done to determine the downstream
distance in the axial and the radial directions for both
nozzles at different PRs. It is concluded from that study that
the computational domain should be extended to 115 D in
the axial direction and 20 D in the radial direction, where D
is diameter of the nozzle throat. Similar computational
domain with similar boundary conditions is used for the
BFSN and the DBN as shown in Figure (2). To model the
flow accurately, the mesh is denser in the turbulent
boundary layer and across the geometrical corners to capture
the flow separation and the concentrated high flow field
gradient. The nozzles walls are assumed to be smooth and
adiabatic during the simulations with no-slip and no-flux
velocity conditions imposed at the walls. A grid dependence
studies are conducted here using the 3-D grids at an
operating PR of 800 for both the BFSN and the DBN
respectively. For the BFSN, the difference in the average
velocity and average static pressure values at the nozzle exit
between the fine grid (4,424,040 grid points) and the coarse
grid (1,532,487 grid points) did not exceed 2 % (in average
flow velocity). A grid size of 2,212,020 grid points is used
in the numerical solution which has an error less than 0.5 %
(in flow velocity) compared to the fine grid. For the DBN,
the maximum difference in the flow parameters (velocity
and pressure) between the fine grid (3,412,547 grid points)
and the coarse grid (1,499,050 grid points) did not exceed
1.8 % (in flow velocity). A grid size of 1,998,478 grid points
is used in the numerical solutions with an error less than
0.7% (in flow velocity) compared to the fine grid. Figures
(3) and (4) show the grid in the mid-plane (x-y plane of
symmetry) inside the BFSN and the DBN respectively.
The quality of the flow solution depends upon the ability to
capture the flow phenomena inside the boundary layers that
are developing along the solid walls. Fluent recommends
locating the nearest grid point along the wall at a distance
that corresponds to parietal coordinate Y+ near one for the
SST k-omega turbulent model [22]. The first cell distance
from the wall is 1.5 micrometer for both the BFSN and the
DBN. From the numerical results, the calculated Y+ average
3. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 07 | July-2015, Available @ http://www.ijret.org 3
is less than 0.8, and 0.75 for the BFSN and the DBN
respectively, that confirm the requirement that Y+ should be
near one.
Fig -2: Cross-section shows the computational domain and
the boundary conditions
Fig -3: Computational grid inside the BFSN at mid-plane
section
Fig -4: Computational grid inside the DBN at mid-plane
section
4. RESULTS AND DISCUSSION
Numerical solutions are obtained for both the BFSN and the
DBN at different operating PRs for assessment of the BFSN
performance against the DBN. Nozzles inlet total pressure
of 15 MPa and total temperature of 2000 K are used with
varied back pressure to simulate the different operating PRs.
The pressure distribution over the nozzles walls are plotted
for each PR at different azimuth angles. Studying the effect
of the 3-D geometry is obtained by detecting the flow
separation location around the nozzles circumferences.
The pressure distributions over the BFSN and the DBN
walls at azimuth angel phi equal 0, 90, 180, and 270 degree
are plotted and compared to each other for PRs of 400 and
600. The results show that the pressure distributions are
identical at all azimuth angels for the BFSN which lead to a
symmetrical flow behavior and flow separation location
over the nozzle circumferential as shown in Figures (5), (6),
(7) and (8). In these Figures, sudden drops in the pressure
occur at the discontinuity points of the nozzle surface which
is caused by expansion of the flow due to sudden change in
the nozzles cross-sectional area. On the other hand, the
pressure distribution over the DBN wall showed an
asymmetrical behavior leads to a difference in the flow
separation locations over the nozzle circumference as shown
in Figures (9), (10), (11), and (12). Similar sudden pressure
drops occurs in the DBN at the wall inflection point. The
maximum difference in the flow separation position is found
to be about 4% and 9% for PR 400 and 600 respectively.
Fig -5: Wall pressure distribution at different azimuth angels
for PR=400
Fig -6: Wall pressure distribution at different azimuth angels
for PR=400 zoomed at 2nd step
4. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 07 | July-2015, Available @ http://www.ijret.org 4
Fig -7: Wall pressure distribution at different azimuth angels
for PR=600
Fig -8: Wall pressure distribution at different azimuth angels
for PR=600 zoomed at 2nd step
Fig -9: Wall pressure distribution at different azimuth angels
for PR=400
Fig -10: Wall pressure distribution at different azimuth
angels for PR=400 zoomed at separation location
Fig -11: Wall pressure distribution at different azimuth
angels for PR=600
Fig -12: Wall pressure distribution at different azimuth
angels for PR=600 zoomed at separation location
Mach contours in the plane of symmetry for PR 400 and 600
are plotted for both the BFSN and the DBN as shown from
Figures (13) to (17). The symmetrical nature of the flow
inside the BFSN can be noticed from the Mach contours for
both PRs of Figures (13) and (14). The BFSN Mach
contours show that the flow separation occurred at the
5. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 07 | July-2015, Available @ http://www.ijret.org 5
second step for PR 400 and 600. Figure (15) shows the
subsonic region in the flow circulation zone near the first
steps corner for PR 600. Similar flow behavior and Mach
contours distribution appears at all closed subsonic
recirculation zones at all operating PRs. The nozzle effective
exit area is the last nozzle cross-sectional area where the
flow is separated for a given PR. The flow parameters at the
effective exit area are used to calculate the nozzle thrust at
different PRs. The asymmetric flow separation inside the
DBN can also be noticed from the Mach contours as shown
in Figures (16) and (17). The Mach contours show an
asymmetric distribution behavior around the nozzle axis of
symmetry which shows that the flow inside the DBN is
asymmetric.
Fig -13: Mach contours at x-y plane of symmetry for
PR=400
Fig -14: Mach contours at x-y plane of symmetry for
PR=600
Fig -15: Mach contours at x-y plane of symmetry for
PR=800 zoomed at 1st step
Fig -16: Mach contours at x-y plane of symmetry for
PR=400
Fig -17: Mach contours at x-y plane of symmetry for
PR=600
Further confirmation of the flow behavior inside the BFSN
and the DBN is obtained by plotting the axial velocity
contours at the nozzle effective exit cross-sectional area
shown in Figures (18), (19), and (20). Figures (18) and (19)
show the cross-sectional axial-velocity contours, for PR 800,
at the third step where the flow is still attached to the nozzle
wall (with minimum positive axial-velocity value near the
wall) and the fourth step where the flow is separated from
the nozzle wall (with minimum negative axial-velocity value
near the wall) respectively . The results show a smooth and
axi-symmetric velocity distribution for both attached and
separated flow cross-sections. The axial velocity contours at
the DBN effective exit cross-sectional area show an
asymmetrical distribution for PR 600 as shown in Figure
(20).
Fig -18: Axial-velocity contours for PR=800 at third steps
exit
6. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 07 | July-2015, Available @ http://www.ijret.org 6
Fig -19: Axial-velocity contours for PR=800 at fourth steps
exit
Fig -20: Axial-velocity contours at effective exit area for
DBN at PR=600
For further confirmation of the axi-symmetric nature of the
flow in the BFSN, two-dimensional axi-symmetric solutions
are obtained computational grid identical to the 3-D grid
plane of symmetry. Comparison between the 3-D and the 2-
D axisymmetric results are shown in table (1). The flow
separation position from the 3-D simulations for each PR
shows a good agreement with its position in the 2-D axi-
symmetric simulation for same PR (at same step edge). The
flow parameters at the flow separation location cross-
sectional area are calculated the 3-D and the 2-D solutions
and compared to each other in table (1). The maximum
difference between the 3-D and the 2-D solutions is less
than 1%.
From these results, we conclude that the flow inside the
BFSN is axi-symmetric. That is a very important finding
which has the following implications: 1) two dimensional
solution can be used to analyze the BFSN, calculate the
nozzle thrust, the flow exit velocity, etc., 2) unsteady flow
solution are now possible because of the major reduction of
the CPU time for 2D solutions compared to 3D solution, and
3) the axisymmetric solution is suitable for design practices
of unsteady flow.
Table -1: Flow parameters comparison between 3-D and 2-
D simulations
PR Parameter 3-D 2-D
difference
%
400
Effective exit
area location
2nd step 2nd step
Pressure [Pa] 2457.65 24803.0 0.84
Velocity
[m/s]
1731.24 1722.33 -0.51
600
Effective exit
area
2nd step 2nd step
Pressure [Pa] 23874.1 24097.4 0.93
Velocity
[m/s]
1748.48 1739.36 -0.52
800
Effective exit
area
3rd step 3rd step
Pressure [Pa] 15942.1 16089.4 0.92
Velocity
[m/s]
1735.14 1723.27 -0.68
1100
Effective exit
area
4th step 4th step
Pressure [Pa] 11247.2 11330.7 0.74
Velocity
[m/s]
1745.48 1733.49 -0.68
4.1 Side Loads Calculation
The side loads are calculated for the BFSN and the DBN at
different PRs from the three-dimensional solutions by
integrating the pressure over the nozzles walls at the
operating PRs 400, 600, and 800. It has been found that the
side loads in the BFSN is 2.3% of the side loads in the DBN
at PR 400, 2.35% at PR 600, and 2.45% at PR 800. Note
that these results are obtained for scaled nozzles. We expect
the values of the side loads in actual nozzles to be much
higher. Table (2) shows the side load values in y- and z-
directions for different PRs for the DBN and the BFSN.
Table -2: Side load values for DBN and BFSN
PR Direction DBN [N] BFSN [N] %
400
y 2.279 0.044
z 1.5366 0.045
total 2.74 0.063 2.31
600
y 2.047 0.038
z 1.57 0.047
total 2.58 0.060 2.35
800
y 1.27 0.03
z 2.36 0.058
total 2.68 0.066 2.45
7. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 07 | July-2015, Available @ http://www.ijret.org 7
4.2 Thrust Calculation and Parametric Study
In order to compare the thrust of the BFSN and the DBN at
PR from 50 to 1500, first the number of the backward facing
steps in the BFSN is varied from two-six. The thrust value is
found to be highest for the BFSN with two backward facing
steps at pressure ratio 1500 as shown in table (3), there for,
the thrust curves for the BFSN with two backward facing
steps and the DBN are shown in Figure (21). It is important
to note here that the thrust curve for the DBN calculated
from the 2-D axi-symmetric solutions following many
studies have been done using the 2-D axi-symmetric
solutions [11], [14], [18], [23], and [24]. The thrust curve is
calculated from the flow parameters (pressure and axial
velocity) based on the base nozzle exit area before the flow
separation point leaves the end of the base nozzle following
Refs [8] and [25]. As the flow separation moves
downstream toward the nozzle exit, the thrust is calculated
based on the nozzle total exit area which takes into account
the effect of the flow in the separation region. The thrust
curve for the DBN shows large drop in the thrust at PR=200
as the flow separation leaves the wall inflection point (base
nozzle exit), while the thrust curve for the BFSN experience
less thrust drop at PR=650 as the flow separation leaves the
base nozzle exit to the first backward facing step edge. As
the PR increases, both thrust curves clime up and at
PR=1500 the BFSN generates thrust 0.28% less that the
DBN.
Table -3: Thrust values for BFSNs and DBN at PR=1500
Nozzle DBN
BFSN-6
steps
BFSN-4
steps
BFSN-2
steps
Thrust [N] 3491.15 3485.93 3483.96 3481.48
Difference
from DBN
%
0 -0.17 -0.23 -0.28
Fig -21: Thrust Curves for the BFSN with two steps and the
DBN with respect to PR
5. CONCLUSION
New flow adaptive area nozzle with backward facing steps
(BFSN) is developed and assessed numerically against to
the well-known DBN using Fluent code. The 3-D numerical
solutions are used to study the flow behavior inside the
BFSN and the DBN at different pressure ratios. The 3-D
solutions show that the flow is 3-dimensional in the DBN,
and axi-symmetric in the BFSN. This is shown in
symmetrical velocity and pressure contours in the cross-
sectional planes in the BFSN and a non-symmetrical
separation in the DBN. Further evidence that confirm the
axi-symmetric flow behavior in the BFSN is shown by
calculating the 2-D solutions and compare it with the 3-D
solutions. Two parameters, the thrust and the side loads
generated in both nozzles are used to assess the BFSN
against the DBN. The thrust curve for the DBN shows large
drop in the thrust at PR=200 as the nozzle mode changes
from mode 1 (small nozzle exit area) to mode 2 (large
nozzle exit area). Similarly, The change in the BFSN exit
area from the base nozzle exit area results in thrust drop that
is less than the DBN. At PR=1500 (high altitude), the BFSN
thrust is 0.28% less than the DBN thrust. The side loads are
calculated in the BFSN and the DBN and the comparison
shows insignificant side loads values generated in the BFSN
because the flow is axi-symmetric. Further studies to
optimize the performance of the DFSN are required by
varying the backward facing steps number, height, and
dynamically eliminating the steps. The axi-symmetric flow
inside the BFSN is a very important finding which has the
following implications: 1) two dimensional solution can be
used to analyze the BFSN, calculate the nozzle thrust, the
flow exit velocity, etc., 2) unsteady flow solution are
possible because of the major reduction of the CPU time for
2D solutions compared to 3D solution, and 3) the axi-
symmetric solution is suitable for design practices of
unsteady flow.
REFERENCES
[1]. S. B. Verma. Study of flow separation in truncated ideal
contour nozzle. Journal of Propulsion and Power,
18(5):1112-1120, September-October 2002.
[2]. Ralf H. Stark and Chloe Genin. Experimental study on
rocket nozzle side load reduction. Journal of Propulsion and
Power, 28(2):307-311, March-April 2012.
[3]. Ten-See Wang and Mike Guidos. Transient three-
dimensional side-load analysis of a film cooled nozzle.
Journal of Propulsion and Power, 25(6):1272-1280,
November December 2009.
[4]. Cikanek H. A. Characteristics of space shuttle main
engine failures. AIAA 87-1939, June 1987.
[5]. Watanabe Y., Sakazume N., and Tsuboi M. Le-7 engine
nozzle problems during the transient operations. AIAA
2002-3841, July 2002.
[6]. Jone J. Shi. Rocket engine nozzle side load transient
analysis methodology - a practical approach. In AIAA 2005-
1860, Austin, Texas, April 2005.
[7]. Winterfeldt L., Laumert B., Tano R., Geneau J. F., Blasi
R., and G. Hagemann. Redesign of the vulcain 2 nozzle
extension. AIAA 2005-4536, Tucson, AZ, 2005.
8. IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308
_______________________________________________________________________________________
Volume: 04 Issue: 07 | July-2015, Available @ http://www.ijret.org 8
[8]. Manuel Frey and Gerald Hagemann. Critical assessment
of dual-bell nozzles. Journal of Propulsion and Power,
15(1):137-143, January - February 1999.
[9]. Gerald Hagemann, Micheal Terhardt, and Dietrich
Haeseler. Experimental and analytical design verification of
the dual-bell concept. Journal of Propulsion and Power,
18(1):116-122, January-February 2002.
[10]. M. Horn and Fisher S. Dual-bell altitude compensating
nozzles. NASA-CR-194719, 1994.
[11]. Dzianis Proshchanka, Koichi Yonezawa, Hidekazu
Koga, and Yoshinobu Tsujimoto. Control of operation mode
transition in dual-bell nozzles with film cooling. Journal of
Propulsion and Power, 28(3):517-529, May-June 2012.
[12]. Gerald Hagemann, Hans Immich, Thong Van Nguyen,
and Gennady E. Dumnov. Advanced rocket nozzles. Journal
of Propulsion and Power, 14(5):620-634, September-
October 1998.
[13]. Chloe Genin and Ralf Stark. Side loads in subscale
dual bell nozzles. Journal of Propulsion and Power,
27(4):828-837, July-August 2011.
[14]. Chloe Genin, Ralf, Sebastian Karl, and Dirk Schneider.
Numerical investigation of dual bell nozzle flow field. 48th
AIAA/ASME/SAE/ASEE Joint Propulsion Conference &
Exhibit, editor, AIAA 2012-4164, Atlanta, Georgia, 30 July
- 01 August 2012.
[15]. Francesco Nasuti, Marcello Onofr, and Emanuele
Martelli. Role of wall shape on the transition in
axisymmetric dual-bell nozzles. Journal of Propulsion and
Power, 21(2), March-April 2005.
[16]. Francesco Nasuti, Marcello Onofr, and Emanuele
Martelli. Numerical study of transition between the two
operating modes of dual-bell nozzles. 38th
AIAA/ASME/SAE/ASEE Joint Propulsion Conference &
Exhibit, editor, AIAA 2002-3989, Indianapolis, Indiana, 7-
10 July 2002.
[17]. Masafumi Miyazawa and Hirotaka Otsu. An analytical
study on design and performance of dual-bell nozzles. 42nd
AIAA Aerospace Sciences Meeting and Exhibit, editors,
AIAA 2004-380, Reno, Nevada, 5-8 January 2004.
[18]. H. Wong and R. Schwane. Numerical investigation of
transition in flow separation in a dual-bell nozzle. 4th Europ
Symp. Aerothermodynamics for Space Applications, editor,
ESA SP-487, Capua, Italy, 15-18 Oct. 2001.
[19]. Chloe Genin, Andreas Gernoth, and Ralf Stark.
Experimental and numerical study of heat flux in dual bell
nozzles. Journal of Propulsion and Power, 29(1), January-
February 2013.
[20]. C. Genin, R. Stark, and O. Haidn. Experimental and
numerical study of dual bell nozzle flow. 4th European
Conference for Aerospace Sciences, 2011.
[21]. G. Hagemann, M. Terhardt, D. Haeseler, and Astrium
Gmbh. Experimental and analytical design verification of
the dual-bell concept. 36th AIAA/ASME/SAE/ASEE Joint
Propulsion Conference & Exhibit, editor, AIAA 2000-3778,
Huntsville, AL, 17-19 July 2000.
[22]. Inc. ANSYS. ANSYS FLUENT User's Guide, 14.5
edition, October 2012.
[23]. Emanuele Martelli, Francesco Nasuti, and Marcello
Onofri. Effect of wall shape and real gas properties on dual
bell nozzle flow field. 41st AIAA/ASME/SAE/ASEE Joint
Propulsion Conference & Exhibit, editor, AIAA 2005-3943,
Tucson, Arizona, 2005.
[24]. Chloe Genin, Ralf Stark, and Dirk Schneider.
Transition behavior of dual bell nozzles: Contour
optimization. In 49th AIAA/ASME/SAE/ASEE Joint
Propulsion Conference, editor, AIAA 2013-3841, San Jose,
CA, July 14-17 2013.
[25]. R. Stark, Ch. Bohm, O. J. Haidn, and H. Zimmermann.
Cold flow testing of dual-bell nozzles in altitude simulation
chamber.