THE 10TH INTERNATIONAL SYMPOSIUM ON FLOW VISUALIZATION
August 26 - 29, 2002, Kyoto, Japan
To present the results obtained from a basic experiment on droplet interaction in a dense linear droplet stream. The interaction of individual droplet with one another and with surrounding influences their transport characteristics.
A vibrating orifice generator produces a stream of monosized droplets. The experiments have been performed by using the electrostatic deviator to obtain the evolution of the main droplet characteristics in a wide range of the spacing parameter value Co (ratio between droplet spacing to droplet diameter). The basic experiment allows quantifying precisely the evolution of the drag coefficient and the droplet evaporation rate for different droplet spacings.
Meridional brightness temperatures were measured on the surface of Titan during the 2004–2014 portion of the
Cassini mission by the Composite Infrared Spectrometer. Temperatures mapped from pole to pole during five twoyear
periods show a marked seasonal dependence. The surface temperature near the south pole over this time
decreased by 2 K from 91.7±0.3 to 89.7±0.5 K while at the north pole the temperature increased by 1 K from
90.7±0.5 to 91.5±0.2 K. The latitude of maximum temperature moved from 19 S to 16 N, tracking the subsolar
latitude. As the latitude changed, the maximum temperature remained constant at 93.65±0.15 K. In 2010
our temperatures repeated the north–south symmetry seen by Voyager one Titan year earlier in 1980. Early in the
mission, temperatures at all latitudes had agreed with GCM predictions, but by 2014 temperatures in the north were
lower than modeled by 1 K. The temperature rise in the north may be delayed by cooling of sea surfaces and moist
ground brought on by seasonal methane precipitation and evaporation.
Heat transfer is the exchange of thermal energy between physical systems. The rate of heat transfer is dependent on the temperatures of the systems and the properties of the intervening medium through which the heat is transferred.
A Possible Relationship between Gravitational Variations and Earthquakes in C...inventionjournals
An earthquake is not simply a sudden movement of the earth's crust, but the final product of a process that may have begun much earlier. In an area subject to tectonic stress, there can be precursory phenomena since this is where crustal deformation accumulates. A variation in gravity, measured instrumentally to the sixth decimal place, is one of the possible candidates to analyse measurable signals that precede, accompany and follow a seismic tremor. To verify the relationship between the number of earthquakes, the energy released, and the variations in gravity, the sequence in Central Italy was examined, above all that of January 2017. Data from a gravimeter located about 270 kilometres from the epicentral areas have been modelled as Standard Deviation, obtained from gravity measurements (400) carried out on the respective days. This indicator, of a statistical and mathematical nature, indicates the degree of dispersion with respect to its mean value, taken as the average value of these gravity measurements, and shows a positive correlation with the number of daily earthquakes and the energy released by the seismic sequence of January 2017.
A REVIEW OF VARIOUS SOIL MOISTUREMEASUREMENT TECHNIQUESBhushan Patil
This paper presents review of the different eight methods for measurement of soil moisture and describes the principle used, methodology, advantages, disadvantages and comparison. Described methods are Gravimetric method, Neutron moderation (NM), Time Domain Reflectometer (TDR), Frequency Domain Reflectometer (FDR), Amplitude Domain Reflectometer (ADR), Phase Transmission (PT), Time Domain Transmission (TDT) and Tensiometer method.
As companies examine their total cost of operations, energy usage and heat recovery deliver cost savings through increased energy utilization and efficiency. Heat exchangers offer companies the opportunity to reuse energy generated for a specific purpose instead of venting that energy to the atmosphere. Shell and tube heat exchangers are in wide use throughout the Food, Dairy, Beverage, Pharmaceutical, Chemicals, Petroleum Refining, and Utility industries. This paper briefly explores three modes of heat transfer and basic designs found in shell and tube heat exchangers. Also included are several case studies from different industries where
Enerquip’s heat exchangers have saved the operators energy and money.
Presentation delivered in the context of the Agricultural Data Interoperability WG meeeting, during the RDA 3rd Plenary Meeting in Dublin, Ireland. 26/3/2014.
The presentation is mostly focused on the work done by the agINFRA project towards proposing a methodology for the definition of Germplasm descriptors as RDF, based on the existing work of experts in the field and making use of the existing effort in this direction.
Meridional brightness temperatures were measured on the surface of Titan during the 2004–2014 portion of the
Cassini mission by the Composite Infrared Spectrometer. Temperatures mapped from pole to pole during five twoyear
periods show a marked seasonal dependence. The surface temperature near the south pole over this time
decreased by 2 K from 91.7±0.3 to 89.7±0.5 K while at the north pole the temperature increased by 1 K from
90.7±0.5 to 91.5±0.2 K. The latitude of maximum temperature moved from 19 S to 16 N, tracking the subsolar
latitude. As the latitude changed, the maximum temperature remained constant at 93.65±0.15 K. In 2010
our temperatures repeated the north–south symmetry seen by Voyager one Titan year earlier in 1980. Early in the
mission, temperatures at all latitudes had agreed with GCM predictions, but by 2014 temperatures in the north were
lower than modeled by 1 K. The temperature rise in the north may be delayed by cooling of sea surfaces and moist
ground brought on by seasonal methane precipitation and evaporation.
Heat transfer is the exchange of thermal energy between physical systems. The rate of heat transfer is dependent on the temperatures of the systems and the properties of the intervening medium through which the heat is transferred.
A Possible Relationship between Gravitational Variations and Earthquakes in C...inventionjournals
An earthquake is not simply a sudden movement of the earth's crust, but the final product of a process that may have begun much earlier. In an area subject to tectonic stress, there can be precursory phenomena since this is where crustal deformation accumulates. A variation in gravity, measured instrumentally to the sixth decimal place, is one of the possible candidates to analyse measurable signals that precede, accompany and follow a seismic tremor. To verify the relationship between the number of earthquakes, the energy released, and the variations in gravity, the sequence in Central Italy was examined, above all that of January 2017. Data from a gravimeter located about 270 kilometres from the epicentral areas have been modelled as Standard Deviation, obtained from gravity measurements (400) carried out on the respective days. This indicator, of a statistical and mathematical nature, indicates the degree of dispersion with respect to its mean value, taken as the average value of these gravity measurements, and shows a positive correlation with the number of daily earthquakes and the energy released by the seismic sequence of January 2017.
A REVIEW OF VARIOUS SOIL MOISTUREMEASUREMENT TECHNIQUESBhushan Patil
This paper presents review of the different eight methods for measurement of soil moisture and describes the principle used, methodology, advantages, disadvantages and comparison. Described methods are Gravimetric method, Neutron moderation (NM), Time Domain Reflectometer (TDR), Frequency Domain Reflectometer (FDR), Amplitude Domain Reflectometer (ADR), Phase Transmission (PT), Time Domain Transmission (TDT) and Tensiometer method.
As companies examine their total cost of operations, energy usage and heat recovery deliver cost savings through increased energy utilization and efficiency. Heat exchangers offer companies the opportunity to reuse energy generated for a specific purpose instead of venting that energy to the atmosphere. Shell and tube heat exchangers are in wide use throughout the Food, Dairy, Beverage, Pharmaceutical, Chemicals, Petroleum Refining, and Utility industries. This paper briefly explores three modes of heat transfer and basic designs found in shell and tube heat exchangers. Also included are several case studies from different industries where
Enerquip’s heat exchangers have saved the operators energy and money.
Presentation delivered in the context of the Agricultural Data Interoperability WG meeeting, during the RDA 3rd Plenary Meeting in Dublin, Ireland. 26/3/2014.
The presentation is mostly focused on the work done by the agINFRA project towards proposing a methodology for the definition of Germplasm descriptors as RDF, based on the existing work of experts in the field and making use of the existing effort in this direction.
This report makes available descriptive material and commentary, including definitions,
statistics, overviews of countries and initiatives and market trends. These are not
comprehensively summarised in this summary except in so far as they are relevant to the key
findings, which are set out below.
EBA supported individuals have actively participated in the recent European Commission Expert
Group on e-Invoicing (The Expert Group), which produced its final report in November 2009.
The executive summary of this report is included as an annex in this document. EBA is very
supportive of the recommendations in the Expert Group report and many of the key findings
below are consistent with the Expert Group report and with the findings developed in the EBAInnopay
‗E-invoicing 2008‘ report.
C5 eCTD Summit: Electronic submissions and the new Variations Regulationseront
Managing and Publishing Electronic Submissions Following the New Variations Regulation (Worksharing and Grouping)
C5 eCTD Summit - September 2010 - Munich, Germany
AWS Enterprise Day | Hybrid IT with AWS: Best of Both WorldsAmazon Web Services
One of the first steps to achieving the benefits of a robust Hybrid IT strategy is the integration of existing on-premise workloads with cloud resources. Learn how to leverage the AWS platform to create your first Hybrid IT solutions based on real-life enterprise customer use cases. Understand how to build your own Virtual Private Cloud, the robust security controls and network connectivity options at your disposal to create fast and reliable connectivity as the foundation of your Hybrid IT vision with AWS.
Effect of Radiation on Mixed Convection Flow of a Non-Newtonian Nan fluid ove...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
Computational Analysis of Natural Convection in Spherical Annulus Using FEVIJMER
HEAT transfer by natural convection from a body to its finite enclosure is of importance
in nuclear reactor technology, electronic instrumentation packaging, aircraft cabin design, the
analysis of fluid suspension gyrocompasses, and numerous other practical situations. The steady
natural convection heat transfer of fluids between two concentric isothermal spheres is investigated
computationally with the help of FEV in ANSYS 14.5. The inner wall is subjected to a higher
temperature and outer is at room temperature. The steady behavior of the flow field and its
subsequent effect on the temperature distribution for different Rayleigh numbers and radius ratios
are analyzed.
Bossious boundary condition is taken for natural convection and which is solved in fluent
module. Steady solutions of the entire flow field is obtained for Rayleigh number (5x101<ra><105),><rr><3). The result shows that the Rayleigh number and
radius ratio have a profound influence on the temperature and flow fields and Prandlt number has
very negligible effect. The results of average Nusselt numbers are also compared with those of
previous numerical investigations. Excellent agreement is obtained.
An Investigation of effect of Temperature Difference and Initial Moisture Con...ijsrd.com
The study of natural convection involves analysis of surface geometry that is having fluid- saturated porous medium. Various temperature differences are considered between the two isolated walls, while the top wall considered being an adiabatic. CFD tool and mathematical analysis was studied and analyzed to carry out the research. By the help of study, it is analyzed that higher intensity rate of natural convection. The simulation of the various temperatures and initial moisture contents were carried out to determine the effect on the performance of the natural convection. It has been noticed that temperature over the porous medium is uniformly distributed due to conduction, which is little higher in the fluid region. It has been recorded that the high moisture contents at the higher temperature side wall than lower one.
technoloTwo dimensional numerical simulation of the combined heat transfer in...ijmech
A numerical investigation was conducted to analyze the flow field and heat transfer characteristics in a vertical channel withradiation and blowing from the wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier–Stokesand energy equations using a control volume finite element method. Turbulent flow with "Low Reynolds Spalart-Allmaras Turbulence Model" and radiation with "Discrete Transfer Radiation Method" had been modeled. In order to have a complete survey, this article has a wide range of study in different domains including velocity profiles at different locations, turbulent viscosity, shear stress, suctioned mass flow rate in different magnitude of the input
Rayleigh number, blowing Reynoldsnumber, radiation parameter, Prandtl number, the ratio of length to width and also ratio of opening thickness to width of the channel. In addition, effects of variation in any of the above non-dimensional numbers on parameters of the flow are clearly illustrated. At the end resultants had been compared with experimental data which demonstrated that in the present study, results have a great accuracy, relative errors are very small and the curve portraits are in a great
agreement with real experiments.
Investigation of the Effect of Nanoparticles Mean Diameter on Turbulent Mixed...A Behzadmehr
Abstract
Turbulent mixed convection of a nanofluid (water/Al2O3, Φ=.02) has been studied numerically. Two-phase
mixture model has been used to investigate the effects of nanoparticles mean diameter on the flow parameters. Nanoparticles distribution at the tube cross section shows that the particles are uniformly dispersed. The non-uniformity of the particles distribution occurs in the case of large nanoparticles and/or high value of the Grashof numbers. The study of particle size effect showed that the effective Nusselt number and turbulent intensity increases with the decreased of particle size.
Early kick detection and nonlinear behavior of drilling mu…Frank-Michael Jäger
The following test measurements serve the quantification of resolution and achievable sensitivity of parameters of sound velocity and sound absorption in wellbore fluids. More precisely, these studies refer to tools and methods to identify the flow of liquids or gases, preferably hydrocarbons in the well bore in real time during the drilling. The aim is a way to show with the highly sensitive and robust tools for use in the deep ocean can be realized.
NUMERICAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFERFROM SQUARE CYLIND...ijmech
The enhancement of natural convection heat transfer using nanofluids from horizontal square cylinder
placed in a square enclosure is investigated numerically. Water-based Cu is used as the working nanofluid.
The investigation covered a range of Rayleigh numbers of 104
- 106
, nanoparticles volume fraction of
(0<ϕ≤0.2), enclosure width to cylinder height ratio, W/H of 2.5. The investigation includes the solution of
the governing equations in the Vorticity-Stream function space with the aid of a body fitted coordinate
system. Algebraic grid generation is used in the initial transformations, followed by an elliptic
transformation to complete the grid generation to computational domain. The resulting discretized system
of equations is solved using an ADI method. The built code is validated and the results showed an increase
in average Nusselt number with increasing the volume fraction of the nanoparticles for the whole range of
Rayleigh number. The isotherms are nearly similar when the volume fraction of nanoparticles is increased
from 0 to 0.2 for each Rayleigh number but a change in the streamlines is observed.
IOSR Journal of Mechanical and Civil Engineering (IOSR-JMCE) is an open access international journal that provides rapid publication (within a month) of articles in all areas of mechanical and civil engineering and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in mechanical and civil engineering. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
EXPERIMENTAL AND NUMERICAL INVESTIGATIONS OF A TURBULENT BOUNDARY LAYER UNDER...Barhm Mohamad
In this article we present an experimental and numerical study of the behavior of the boundary layer type viscous flow in the presence of the thermal effect. The flow was held in a three-dimensional field with a uniform infinite velocity in the case of an adiabatic wall with heat input. The presented experimental work was performed in the Thermal Laboratory (LET) of the Prime Institute of Poitiers (France). It describes the analysis of a turbulent boundary layer created in a wind tunnel on the surface of a flat plate covered with epoxy resin. An HP 6012A power supply system was used to provide circulating heat flux to heat the flat plate to 80°C by the Joule effect. The numerical result shows a clear difference in the evolution of the thermal boundary layer between the three temperatures of the wall.
Technical Support in Thermal Power Generation Sector – Career OpportunitiesAnurak Atthasit
Career opportunities for supporting in thermal power generation business are introduces via this presentation. The presentation had been done for introduction to the undergrad engineering student - Kasetsart University, Thailand.
Combined Cycle Gas Turbine Power Plant Part 1Anurak Atthasit
Introduction to Combined Cycle Gas Turbine Power Plant. Describing the advantage and design limit of the CCGT. Overview of Brayton Cycle and Rankine Cycle - showing some basic thermodynamic to explain some background of CCGT.
High level assessment on Gas Reserves, power demand outlook and the supplies in Thailand and availability shortfall impact with the mitigations foreseen by the government.
A collection came from many sources based on my curiosity - synthesis all of information together with my personal awareness of future crisis. After having heard that China took a major shared of Toulouse Airport - located in the south of France, and many development came across the continents in the same time of economic crisis in Europe and many parts of the world, this is what I curiosly taking my time seeing what was the past performances made by this country. Thanks to many people doing their hard work providing interesting report and articles that I've never forgot to credit to each text and images. Bonne Lecture!
Promenade Culturelle Thailandaise had been carried out in Toulouse in 2003. Ten performers and two painters from Lanna - northern culture of Thailand had performed very special works to french public supported by franco-thai sponsors.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Courier management system project report.pdfKamal Acharya
It is now-a-days very important for the people to send or receive articles like imported furniture, electronic items, gifts, business goods and the like. People depend vastly on different transport systems which mostly use the manual way of receiving and delivering the articles. There is no way to track the articles till they are received and there is no way to let the customer know what happened in transit, once he booked some articles. In such a situation, we need a system which completely computerizes the cargo activities including time to time tracking of the articles sent. This need is fulfilled by Courier Management System software which is online software for the cargo management people that enables them to receive the goods from a source and send them to a required destination and track their status from time to time.
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.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
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.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
Maintaining high-quality standards in the production of TMT bars is crucial for ensuring structural integrity in construction. Addressing common defects through careful monitoring, standardized processes, and advanced technology can significantly improve the quality of TMT bars. Continuous training and adherence to quality control measures will also play a pivotal role in minimizing these defects.
Droplet thermal behavior study with light scattering technique
1. F0210
Droplet thermal behavior study with light scattering
technique
Atthasit, A., Castanet*1
, G., Biscos, Y., Lemoine*1
, F. and Lavergne, G..
ONERA – Centre de Toulouse
BP 4025, 31055 Toulouse Cedex 4, Toulouse, France
Tel:+33-0562252835 / FAX:+33-0562252583
E-mail: lavergne@onecert.fr
*1 LEMTA-UMR 7563, Avenue de la Forêt de Haye
BP 160, F-54504 Vandoeuvre-les-Nancy Cedex France
Keywords: Visualization, Standard Rainbow Thermometry, Droplet interaction, vaporization
The aim of this paper is to present the results obtained from a basic experiment on droplet interaction in a dense linear droplet
stream. The interaction of individual droplet with one another and with surrounding influences their transport characteristics.
A vibrating orifice generator produces a stream of monosized droplets. The experiments have been performed by using the
electrostatic deviator to obtain the evolution of the main droplet characteristics in a wide range of the spacing parameter
value Co (ratio between droplet spacing to droplet diameter). The basic experiment allows quantifying precisely the evolution
of the drag coefficient and the droplet evaporation rate for different droplet spacings.
Measurements of droplet diameter, droplet velocity and droplet temperature are performed using non-intrusive laser
interferometry. Ethanol has been used as simulation fluid for all the experiments. The droplet stream was investigated in
different environment conditions. To study the droplet evaporation with quasi-steady state momentum transport, the high
temperature droplets are injected in the ambient conditions. The stream was also injected in the thermal boundary layer of a
heated plate for studying the dynamical and thermal behaviors due to evaporation processes. For reacting conditions, a heated
coil ignited the droplet and gave a laminar diffusion flame along the stream.
The relative velocity is equal to the droplet velocity Vg because the experiment takes place in a quiscent environment.
The droplets are observed by shadowgraphy to measure their velocity. The measured spacing Sg is used to determine the
velocity, knowing droplet frequency f(Vg=Sg.f).
The Standard Rainbow Thermometry (SRT) has been investigated (e.g., König et al., 1986). This technique is based on
the interactions between a spherical droplet and a light ray which measures the temperature and size of droplets. In our case,
a laser beam is focused along the axis of the droplet stream. The fringe scattering pattern (Fig.1) can be observed in forward
direction. The angular spacing measured between two interference maxima can determine droplet sizing, without knowing
the refractive index accurately, calculated from optical geometry theory.
The first rainbow observed in the backward direction is strong enough to be easily detected. The position of the first
rainbow is recorded by another linear CCD array. The Airy/Walker theory (e.g. Walker J.D., 1976) explains that the position
of the rainbow is also function of the liquid refractive index and size. The refractive index is linked to the droplet temperature
by using a calibration curve obtained from the refractometry
measurements (e.g.,Atthasit et al.,2001).
The experimental results show the problems of the
accuracy of the temperature measuring technique due to the
temperature gradient within the droplet. As main results, this
paper presents the evolution of droplet drag coefficient and
droplet evaporation rate with the droplet spacing.
References
König G., Anders K., Frohn A., 1986, "A new light-scattering
technique to measure the droplet diameter of periodically
generated moving droplets", J. Aerosol Sci., Vol.17,
No.2, 157.
Walker J.D., 1976, "Rainbows from single drops of water and
other liquids", Am.J.Phys., Vol.44, No.5, 421.
Atthasit A., Biscos Y., Giuliani F., Lavergne G., 2001,
"Mesure de la température des gouttes en évaporation et
en combustion par la technique Arc-en-Ciel", Regeuil
des actes 9 FluVisu, Rouen, 79.
Fig. 1 Light Diffusion Phenomena provided by SRT