- The document discusses numerical simulations of the electrostatic spray painting process using high-speed rotary bell atomizers.
- Experiments were conducted to validate the sensitivity of the simulations to variations in operating conditions like paint flow rate and bell speed, as well as different target geometries.
- The simulations demonstrated good agreement with experimental measurements of film thickness and were able to accurately predict changes based on different operating conditions and target shapes.
Corrosion proceeding review (2016 international congress and exhibition on al...Constellium
Development of an electrochemical depth profiling method to optimize the corrosion protection on aluminium cladded sheets for automotive heat exchangers
Corrosion proceeding review (2016 international congress and exhibition on al...Constellium
Development of an electrochemical depth profiling method to optimize the corrosion protection on aluminium cladded sheets for automotive heat exchangers
The ninth lecture in the module Particle Technology, delivered to second year students who have already studied basic fluid mechanics. The different mechanisms for the removal of dust from gases are covered and the design equations used for control, modelling and understanding of the equipment are presented and derived. Examples of industrial equipment for gas cleaning are included.
Numerical Experiments of Hydrogen-Air Premixed FlamesIJRES Journal
Numerical experiments have been carried out to study turbulent premixed flames of hydrogen-air mixtures in a small scale combustion chamber. Flow is calculated using the Large Eddy Simulation (LES) Technique for turbulent flow. The chemical reaction is modeled using a dynamic procedure for the calculation of the flame/flow interactions. Sensitivity of the results obtained to the computational grid, ignition source and different flow configurations have been carried out. Numerical results are validated against published experimental data. It was found that the grid resolution has very small effect on the results after a certain grid. Also, the ignition source has influenced only the time where the peak overpressure appears. Finally, the different configurations are reported to affect both the peak overpressure and flame position.
Numerical Study Of Flue Gas Flow In A Multi Cyclone SeparatorIJERA Editor
The removal of harmful particulate matter from power plant flue gas is of critical importance to the environment and its inhabitants. The present work illustrates the use of multi-cyclone separators to remove the particulate matter from the bulk of the gas exhausted to the atmosphere. The method has potential to replace conventional systems like electrostatic precipitator due to inherent low power requirement and low maintenance. A parametric model may be employed to design the system based on the requirement of the power station. The present work describes the simulation of flue gas flow through a cyclonic separator. A Finite volume approach has been used and the pressure-velocity coupling is resolved using the SIMPLE algorithm. Discrete phase model is used to inject solid particles from inlet. In this numerical analysis a cluster of four cyclonic separators are considered. Comparisons are made between the available experimental results and the computational work for validation of the numerical models and schemes employed in the work. The separation efficiency and particle trajectories are shown and found comparable to similar cases from literature. The experimental results correlate well for the model under consideration.
Experimental Study of Material Removal Efficiency in EDM Using Various Types ...IJERD Editor
The machining process in electrical discharge machining (EDM) consists of a melting process and a
removal process. A region of the workpiece surface heated by the discharge plasma is melted and a portion of
the melted region is removed from the workpiece body. The rest of the melted region remains on the workpiece
surface and re-solidified as a white layer. In previous research, to evaluate the removal ability, a ratio of the
removal volume to the melted volume is defined as the material removal efficiency.
In this study, the material removal efficiency was investigated to develop an understanding of the
machining mechanism in EDM. As a result of experiments, it is found that the material removal efficiencies
show almost the same value, whereas the removal volume varies with the type of dielectric oil or the discharge
duration. To advance the study about the machining mechanism in EDM, the simulation for the workpiece
temperature distribution, considering the effect of the type of dielectric oil or the discharge duration, should be
conducted further
Analysis for predicting the Input Interactions of HBF Performance at -10 μm P...journal ijrtem
ABSTRACT: Dewatering is an important process in any mineral industry. It is a process which removes the unwanted material from
the liquid solid suspension called slurry by using a filter element which separates the unwanted fluid material from the solids from the
feed. The paper attempts to establish the way towards analysis of Hyper Baric Filter (HBF) performance at -10μm particle size
treating iron ore fines (24% to 29%). Dewatering in HBF, requires reduction in moisture and material throughput rate in terms of per
hour so as to increase the performance of HBF. The present work carried out illustrates a method to predict the influence of process
input parameter such as vessel pressure, snap blow and filter disk rotation for reduction in moisture percentage level and material for
reduction moisture percentage level and material throughput rate for particle size in the range of 24% to 29%. Using Design of
Experiments (DOE) a linear regression model is developed to study the performance of HBF full factorial design method using
ANOVA to analyze the data. Validation of the results is performed by comparing the experimental values and predicted values for
Material through put rate in terms of cycles/hr and reduction in moisture percentage by weight and hot spots.
Keywords: Hyper Baric Filter, dewatering, design of experiments, size of particles, vessel pres
The 10th Annual Utah Health Services Research Conference: Data Collection Through the Eyes of the Newly Arrived - By: Debra Penney, MS, CNM, MPH. March 16, 2015
Patient Centered Research Methods Core, University of Utah, CCTS
A Community Centered Approach to the Development of a Comparative Effectiveness Research Question
Bryan Gibson DPT, PhD
Elisa Amador
Ana Sanchez Birkhead PhD
Nancy Allen APRN, PhD
University of Utah
Presented at the 11th Annual HSR/ PCOR Conference: Partnering for Better Health: Bringing Utah's Patient Voices to Research 2016
The ninth lecture in the module Particle Technology, delivered to second year students who have already studied basic fluid mechanics. The different mechanisms for the removal of dust from gases are covered and the design equations used for control, modelling and understanding of the equipment are presented and derived. Examples of industrial equipment for gas cleaning are included.
Numerical Experiments of Hydrogen-Air Premixed FlamesIJRES Journal
Numerical experiments have been carried out to study turbulent premixed flames of hydrogen-air mixtures in a small scale combustion chamber. Flow is calculated using the Large Eddy Simulation (LES) Technique for turbulent flow. The chemical reaction is modeled using a dynamic procedure for the calculation of the flame/flow interactions. Sensitivity of the results obtained to the computational grid, ignition source and different flow configurations have been carried out. Numerical results are validated against published experimental data. It was found that the grid resolution has very small effect on the results after a certain grid. Also, the ignition source has influenced only the time where the peak overpressure appears. Finally, the different configurations are reported to affect both the peak overpressure and flame position.
Numerical Study Of Flue Gas Flow In A Multi Cyclone SeparatorIJERA Editor
The removal of harmful particulate matter from power plant flue gas is of critical importance to the environment and its inhabitants. The present work illustrates the use of multi-cyclone separators to remove the particulate matter from the bulk of the gas exhausted to the atmosphere. The method has potential to replace conventional systems like electrostatic precipitator due to inherent low power requirement and low maintenance. A parametric model may be employed to design the system based on the requirement of the power station. The present work describes the simulation of flue gas flow through a cyclonic separator. A Finite volume approach has been used and the pressure-velocity coupling is resolved using the SIMPLE algorithm. Discrete phase model is used to inject solid particles from inlet. In this numerical analysis a cluster of four cyclonic separators are considered. Comparisons are made between the available experimental results and the computational work for validation of the numerical models and schemes employed in the work. The separation efficiency and particle trajectories are shown and found comparable to similar cases from literature. The experimental results correlate well for the model under consideration.
Experimental Study of Material Removal Efficiency in EDM Using Various Types ...IJERD Editor
The machining process in electrical discharge machining (EDM) consists of a melting process and a
removal process. A region of the workpiece surface heated by the discharge plasma is melted and a portion of
the melted region is removed from the workpiece body. The rest of the melted region remains on the workpiece
surface and re-solidified as a white layer. In previous research, to evaluate the removal ability, a ratio of the
removal volume to the melted volume is defined as the material removal efficiency.
In this study, the material removal efficiency was investigated to develop an understanding of the
machining mechanism in EDM. As a result of experiments, it is found that the material removal efficiencies
show almost the same value, whereas the removal volume varies with the type of dielectric oil or the discharge
duration. To advance the study about the machining mechanism in EDM, the simulation for the workpiece
temperature distribution, considering the effect of the type of dielectric oil or the discharge duration, should be
conducted further
Analysis for predicting the Input Interactions of HBF Performance at -10 μm P...journal ijrtem
ABSTRACT: Dewatering is an important process in any mineral industry. It is a process which removes the unwanted material from
the liquid solid suspension called slurry by using a filter element which separates the unwanted fluid material from the solids from the
feed. The paper attempts to establish the way towards analysis of Hyper Baric Filter (HBF) performance at -10μm particle size
treating iron ore fines (24% to 29%). Dewatering in HBF, requires reduction in moisture and material throughput rate in terms of per
hour so as to increase the performance of HBF. The present work carried out illustrates a method to predict the influence of process
input parameter such as vessel pressure, snap blow and filter disk rotation for reduction in moisture percentage level and material for
reduction moisture percentage level and material throughput rate for particle size in the range of 24% to 29%. Using Design of
Experiments (DOE) a linear regression model is developed to study the performance of HBF full factorial design method using
ANOVA to analyze the data. Validation of the results is performed by comparing the experimental values and predicted values for
Material through put rate in terms of cycles/hr and reduction in moisture percentage by weight and hot spots.
Keywords: Hyper Baric Filter, dewatering, design of experiments, size of particles, vessel pres
The 10th Annual Utah Health Services Research Conference: Data Collection Through the Eyes of the Newly Arrived - By: Debra Penney, MS, CNM, MPH. March 16, 2015
Patient Centered Research Methods Core, University of Utah, CCTS
A Community Centered Approach to the Development of a Comparative Effectiveness Research Question
Bryan Gibson DPT, PhD
Elisa Amador
Ana Sanchez Birkhead PhD
Nancy Allen APRN, PhD
University of Utah
Presented at the 11th Annual HSR/ PCOR Conference: Partnering for Better Health: Bringing Utah's Patient Voices to Research 2016
11th Annual Health Services Research Conference - Partnering for Better Health: Bringing Utah's Patient Voices to Research
Hosted By: Community Faces of Utah
Description: Interactive panel discussion on what community members want research to focus on and how researchers and communities can successfully work together.
The 10th Annual Utah Health Services Research Conference: Gaps in Insurance Coverage for Pediatric Cancer Patients with Acute Lymphoblastic Leukemia. By: Rochelle Smits-Seemann, Ms; Aimee O. Hersh, MD; Mark N. Fluchel, MS; Kenneth M. Boucher, PhD; Anne C. Krichhoff, MPH, PhD
Patient Centered Research Methods Core, University of Utah, CCTS
The 10th Annual Utah Health Services Research Conference: Data from EHRs in Outpatient Practice Settings: An Emerging but Immature Resource. By: Deepthi Rajeev and Jeff Black - HealthInsight
Health Services Research Conference: March 16, 2015
Patient Centered Research Methods Core, University of Utah, CCTS
Calculation of a Surrogate Measure of Deprivation for use with Patient Centered Care Delivery
Brad Stephenson
Andrew J Knighton PhD, CPA
Lucy Savitz PhD, MBA
Tom Belnap MS
Jim Vanderslice PhD
Presented at the 11th Annual HSR/ PCOR Conference: Partnering for Better Health: Bringing Utah's Patient Voices to Research 2016
The HER Salt Lake Community Engagement Studio Experience. By: HER Salt Lake Contraceptive Initiative; Division of Family Planning, University of Utah; Jessica Sanders (Presenter); David Turok
Collaboration/ Engagement Team: CCTS; Tatiana Allen-Webb, Heather Coulter, and Louisa Stark.
Presented at the 11th Annual HSR Conference: Partnering for Better Health: Bringing Utah's Patient Voices to Research 2016
Bringing Researchers, Families/ Patients, and Providers Together to Improve Asthma Care.
Panelists: Flory Nkoy, MD, MS, MPH (Principal Investigator); Joseph Johnson, MD (PCP Stakeholder); Jordan Gaddis (Parent Stakeholder)
Presented at the 11th Annual HSR/ PCOR Conference: Partnering for Better Health: Bringing Utah's Patient Voices to Research 2016
This presentation explores modern cloning, a brief history of cloning, uses for cloning technology, cloning laws, and connections between current cloning and Cloud Atlas.
The 10th Annual Utah Health Services Research Conference: Recommendations for Transparent Reporting of Data Quality Assessment Results for Observational Healthcare Data By: Lucy A Savitz, Ph.D., MBA
Health Services Research Conference: March 16, 2015
Patient Centered Research Methods Core, University of Utah, CCTS
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
Diffusers are extensively used in centrifugal
compressors, axial flow compressors, ram jets, combustion
chambers, inlet portions of jet engines and etc. A small change in
pressure recovery can increases the efficiency significantly.
Therefore diffusers are absolutely essential for good turbo
machinery performance. The geometric limitations in aircraft
applications where the diffusers need to be specially designed so
as to achieve maximum pressure recovery and avoiding flow
separation.
The study behind the investigation of flow separation in a planar
diffuser by varying the diffuser taper angle for axisymmetric
expansion. Numerical solution of 2D axisymmetric diffuser model
is validated for skin friction coefficient and pressure coefficient
along upper and bottom wall surfaces with the experimental
results of planar diffuser predicted by Vance Dippold and
Nicholas J. Georgiadis in NASA research center [2]
.
Further the diffuser taper angle is varied for other different
angles and results shows the effect of flow separation were it is
reduces i.e., for what angle and at which angle it is just avoided.
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Numerical simulations have been undertaken
for the benchmark problem in a Square cavity by using
computational fluid dynamics software. This work aims at
discussing the fundamental numerical and computational
fluid dynamic aspects which can lead to the definition of
the following meshing methods and turbulence models.
The meshes used for the simulation are hexahedral,
hexahedral cell with near wall refinement, tetrahedral
grid, polyhedral, tetrahedral with near wall refinement
and polyhedral mesh with prism layer cells based the near
wall thickness of Y+ less than one. The turbulence models
used for the simulation work are AKN K-Epsilon Low-Re,
Realizable K-Epsilon, Realizable K-Epsilon Two-Layer,
standard K-Epsilon, standard K-Epsilon Low-Re,
Standard K-Epsilon Two-Layer, V2F K-Epsilon,
SST(Menter) K-Omega, and Standard(Wilcox) K-Omega.
From these meshes and turbulence models, we will
conclude the suitable mesh and turbulence for the
recirculation flow by the grid independent test. These
analytical values of results are compared with reference
data which gives an optimization of experimental work.
Unsteady simulation was ran for all the Grid Independent
mesh with the SST k omega model with the time step of
0.01 sec for 40 seconds. The flow nature is studied with
and without the temperature for Reynolds number, 1000
and 10000.
Investigation on Divergent Exit Curvature Effect on Nozzle Pressure Ratio of ...IJERA Editor
The objective of this project work is to computationally analyze shock waves in the Convergent Divergent (CD) Nozzle. The commercial CFD code Fluent is employed to analyze the compressible flow through the nozzle. The analysis is about NPR (Nozzle Pressure Ratio) i.e., the ratio between exit pressure of the nozzle to ambient pressure. The various models of CD Nozzle are designed and the results are compared. The flow characteristic of shockwave for various design of CD Nozzle is also discussed. The purpose of this project is to investigate supersonic C-D nozzle flow for increasing NPR (Nozzle pressure ratio) through CFD. The imperfect matching between the pressures and ambient pressure and exit pressure leads to the formation of a complicated shock wave structure. Supersonic nozzle flow separation occurs in CD nozzles at NPR values far above their design value that results in shock formation inside the nozzle. The one-dimensional analysis approximations are not accurate, in reality the flow detaches from the wall and forms a separation region, subsequently the flow downstream becomes non-uniform and unstable. Shock wave affects flow performance of nozzle from NPR value 1.63 for existing geometrical conditions of nozzle. Problem of using this nozzle above 1.63NPR is shock wave at downstream of throat. After shock wave, static pressure increases further downstream of flow. It leads to flow separation and back pressure effects. Back pressure makes nozzle chocked. To investigate this problem, geometry of divergent portion is introduced and analysed through CFD. This is expected in resulting of reduction of flow separation and back pressure effect as well as increase in nozzle working NPR.
Investigation on Divergent Exit Curvature Effect on Nozzle Pressure Ratio of ...IJERA Editor
The objective of this project work is to computationally analyze shock waves in the Convergent Divergent (CD) Nozzle. The commercial CFD code Fluent is employed to analyze the compressible flow through the nozzle. The analysis is about NPR (Nozzle Pressure Ratio) i.e., the ratio between exit pressure of the nozzle to ambient pressure. The various models of CD Nozzle are designed and the results are compared. The flow characteristic of shockwave for various design of CD Nozzle is also discussed. The purpose of this project is to investigate supersonic C-D nozzle flow for increasing NPR (Nozzle pressure ratio) through CFD. The imperfect matching between the pressures and ambient pressure and exit pressure leads to the formation of a complicated shock wave structure. Supersonic nozzle flow separation occurs in CD nozzles at NPR values far above their design value that results in shock formation inside the nozzle. The one-dimensional analysis approximations are not accurate, in reality the flow detaches from the wall and forms a separation region, subsequently the flow downstream becomes non-uniform and unstable. Shock wave affects flow performance of nozzle from NPR value 1.63 for existing geometrical conditions of nozzle. Problem of using this nozzle above 1.63NPR is shock wave at downstream of throat. After shock wave, static pressure increases further downstream of flow. It leads to flow separation and back pressure effects. Back pressure makes nozzle chocked. To investigate this problem, geometry of divergent portion is introduced and analysed through CFD. This is expected in resulting of reduction of flow separation and back pressure effect as well as increase in nozzle working NPR.
Design Optimization and Development in Air Pollution Control DeviceIJERA Editor
Electrostatic Precipitators (ESP) is the device used to remove the dust particles from the processed gases coming out of boilers in cement industries, and iron core industries. There are many governing factors that affect the efficiency from that one major reason is to fully filled hopper. When hopper fills 70 % of its full limit the precipitation process stopped of that particular hopper. For remedy dust removal efficiency is increased by hopper vibrator at the time of emptying bagasse ash from the hopper. The maximum displacement is getting by using different hopper wall thicknesses, stiffener spacing as well as different configuration vibrators. Due to minimum time to complete project there are many difficulties to test at every stage to improve the design and this results in increased project cost. For this situation there is one simple way to improve the design of equipment’s through simulation in ANSYS and validation by actual physical measurements. This project presents FEA approach for modeling and analysis the hopper of electrostatic precipitator using Static, Modal and Harmonic analysis. Actual model testing is done for the validation of results. The results coming out from the FEA analysis and testing are discussed.
Asme2009 82287 - Porous Media - Forced Convection FlowHIIO
In this study the flow field and heat transfer properties of a
steady, two-dimensional flow field in a porous domain between
two parallel plates is investigated numerically by using a
discretized numeric code. Analysis has been carried for
Reynolds number based on particle sizes ranging from 60 to
1000. Numerical results are compared with different numerical
methods used for predicting this kind of flow. Results are
obtained for different regime, various p Re numbers and the
effect of Particles size is also investigated. Solutions indicate
that by increasing the
p Re , the flow in the porous media
remains laminar where the flow has turbulence characteristics
for p Re <50. Moreover, by increasing p Re , the value of
average Nusselt number increases. Also, reducing the particle
size affects the Nusselt number and it increases while the
porosity remains the same.
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
The Octavia range embodies the design trend of the Škoda brand: a fusion of
aesthetics, safety and practicality. Whether you see the car as a whole or step
closer and explore its unique features, the Octavia range radiates with the
harmony of functionality and emotion
In this presentation, we have discussed a very important feature of BMW X5 cars… the Comfort Access. Things that can significantly limit its functionality. And things that you can try to restore the functionality of such a convenient feature of your vehicle.
Symptoms like intermittent starting and key recognition errors signal potential problems with your Mercedes’ EIS. Use diagnostic steps like error code checks and spare key tests. Professional diagnosis and solutions like EIS replacement ensure safe driving. Consult a qualified technician for accurate diagnosis and repair.
𝘼𝙣𝙩𝙞𝙦𝙪𝙚 𝙋𝙡𝙖𝙨𝙩𝙞𝙘 𝙏𝙧𝙖𝙙𝙚𝙧𝙨 𝙞𝙨 𝙫𝙚𝙧𝙮 𝙛𝙖𝙢𝙤𝙪𝙨 𝙛𝙤𝙧 𝙢𝙖𝙣𝙪𝙛𝙖𝙘𝙩𝙪𝙧𝙞𝙣𝙜 𝙩𝙝𝙚𝙞𝙧 𝙥𝙧𝙤𝙙𝙪𝙘𝙩𝙨. 𝙒𝙚 𝙝𝙖𝙫𝙚 𝙖𝙡𝙡 𝙩𝙝𝙚 𝙥𝙡𝙖𝙨𝙩𝙞𝙘 𝙜𝙧𝙖𝙣𝙪𝙡𝙚𝙨 𝙪𝙨𝙚𝙙 𝙞𝙣 𝙖𝙪𝙩𝙤𝙢𝙤𝙩𝙞𝙫𝙚 𝙖𝙣𝙙 𝙖𝙪𝙩𝙤 𝙥𝙖𝙧𝙩𝙨 𝙖𝙣𝙙 𝙖𝙡𝙡 𝙩𝙝𝙚 𝙛𝙖𝙢𝙤𝙪𝙨 𝙘𝙤𝙢𝙥𝙖𝙣𝙞𝙚𝙨 𝙗𝙪𝙮 𝙩𝙝𝙚 𝙜𝙧𝙖𝙣𝙪𝙡𝙚𝙨 𝙛𝙧𝙤𝙢 𝙪𝙨.
Over the 10 years, we have gained a strong foothold in the market due to our range's high quality, competitive prices, and time-lined delivery schedules.
Comprehensive program for Agricultural Finance, the Automotive Sector, and Empowerment . We will define the full scope and provide a detailed two-week plan for identifying strategic partners in each area within Limpopo, including target areas.:
1. Agricultural : Supporting Primary and Secondary Agriculture
• Scope: Provide support solutions to enhance agricultural productivity and sustainability.
• Target Areas: Polokwane, Tzaneen, Thohoyandou, Makhado, and Giyani.
2. Automotive Sector: Partnerships with Mechanics and Panel Beater Shops
• Scope: Develop collaborations with automotive service providers to improve service quality and business operations.
• Target Areas: Polokwane, Lephalale, Mokopane, Phalaborwa, and Bela-Bela.
3. Empowerment : Focusing on Women Empowerment
• Scope: Provide business support support and training to women-owned businesses, promoting economic inclusion.
• Target Areas: Polokwane, Thohoyandou, Musina, Burgersfort, and Louis Trichardt.
We will also prioritize Industrial Economic Zone areas and their priorities.
Sign up on https://profilesmes.online/welcome/
To be eligible:
1. You must have a registered business and operate in Limpopo
2. Generate revenue
3. Sectors : Agriculture ( primary and secondary) and Automative
Women and Youth are encouraged to apply even if you don't fall in those sectors.
Why Is Your BMW X3 Hood Not Responding To Release CommandsDart Auto
Experiencing difficulty opening your BMW X3's hood? This guide explores potential issues like mechanical obstruction, hood release mechanism failure, electrical problems, and emergency release malfunctions. Troubleshooting tips include basic checks, clearing obstructions, applying pressure, and using the emergency release.
Ever been troubled by the blinking sign and didn’t know what to do?
Here’s a handy guide to dashboard symbols so that you’ll never be confused again!
Save them for later and save the trouble!
What Are The Immediate Steps To Take When The VW Temperature Light Starts Fla...Import Motorworks
Learn how to respond when the red temperature light flashes in your VW with this presentation. From checking coolant levels to seeking professional help, follow these steps promptly to prevent engine damage and ensure safety on the road.
What Does the PARKTRONIC Inoperative, See Owner's Manual Message Mean for You...Autohaus Service and Sales
Learn what "PARKTRONIC Inoperative, See Owner's Manual" means for your Mercedes-Benz. This message indicates a malfunction in the parking assistance system, potentially due to sensor issues or electrical faults. Prompt attention is crucial to ensure safety and functionality. Follow steps outlined for diagnosis and repair in the owner's manual.
5 Warning Signs Your BMW's Intelligent Battery Sensor Needs AttentionBertini's German Motors
IBS monitors and manages your BMW’s battery performance. If it malfunctions, you will have to deal with an array of electrical issues in your vehicle. Recognize warning signs like dimming headlights, frequent battery replacements, and electrical malfunctions to address potential IBS issues promptly.
Things to remember while upgrading the brakes of your carjennifermiller8137
Upgrading the brakes of your car? Keep these things in mind before doing so. Additionally, start using an OBD 2 GPS tracker so that you never miss a vehicle maintenance appointment. On top of this, a car GPS tracker will also let you master good driving habits that will let you increase the operational life of your car’s brakes.
"Trans Failsafe Prog" on your BMW X5 indicates potential transmission issues requiring immediate action. This safety feature activates in response to abnormalities like low fluid levels, leaks, faulty sensors, electrical or mechanical failures, and overheating.
What Causes 'Trans Failsafe Prog' to Trigger in BMW X5
5460be7c0cf27487b4525bb0
1. The Electrostatic Spray Painting Process with High-Speed
Rotary Bell Atomizers: Influences of operating conditions
and target geometries
J. Domnick, A. Scheibe, Q. Ye
Fraunhofer-Institute for Manufacturing Engineering and Automation
Nobelstr. 12, D-70569 Stuttgart, Germany
Abstract
The present contribution summarises ongoing investigations of the
Fraunhofer-Institute for Manufacturing Engineering and Automation aiming
to extend the range of applicability of numerical simulations applied to the
electrostatically supported painting process with high-speed rotary bells.
Mainly two aspects are considered:
• Sensitivity of the simulations to parameter variations as used in the
practical application
• Interaction of the electrical and the spray flow field with different work
piece geometries
In the first case, a design of experiments (DOE) was performed, including
all relevant operating conditions changing the properties of the spray cone and
thereby the film thickness profile. In total, 32 individual conditions were
experimentally investigated and simulated. Finally, some characteristic
numbers have been compared, e.g. the width of the film profile or the
maximum film thickness. A nice agreement could be achieved, confirming the
applicability and sensitivity of the developed program.
In the second case, a number of different target geometries have been
investigated, including edges, angles and slots. From practice, it is well known
that due to the distortion and concentration of the electrical field lines between
the atomiser and the work piece inhomogeneous film thickness distributions
can be obtained that must be also estimated by the simulation program. Again
a nice agreement between coating experiment and simulation can be found.
These results, obtained with a corona charging atomiser, successfully confirm
the applicability of the chosen models for all electrical effects including space
charge.
1. Introduction
High-speed rotary bell atomizers are widely used in the painting industry for high quality
applications, especially in the automotive industry. They provide a nicely uniform film
thickness with reasonable transfer efficiency due to the additional electrostatic field supporting
the droplet transport towards the target. A basic requirement for this type of paint atomisers is
a fine and reproducible atomisation of a large variety of different paints, ranging from solvent-
2. based material to complex non-Newtonian water-borne systems. Furthermore, a broad range
of paint flow rates must be covered.
In a number of papers [1-3], the authors have successfully demonstrated that by
appropriately extending a commercial CFD code the coating process of electrostatically
supported high-speed rotary bells can be simulated. As a result, film thickness distribution and
transfer efficiency (amount of paint reaching the work piece) can be calculated to a high
degree of accuracy. Apart from the well known operating conditions, e.g. paint flow rate, bell
speed and shaping air flow rate, only a single droplet size measurement is necessary to
complete the set of inlet conditions required. This applies to both the direct charge system,
where up to 80 kV are applied to the bell directly, and the external or corona charge system,
where the charging of the droplets is based on the interaction with free ions created at several
corona needles around the atomizer. In the latter case, an additional conservation equation for
the ion flux and the space charge due to the free ions must be considered.
The present paper basically deals with a sensitivity study, considering different atomizer
operating conditions and work piece geometries. Furthermore, the effect of variations of the
initial droplet size distributions as the only data to be measured is verified. The latter result is
of specific importance, since it determines the experimental efforts that need to be invested in
case of a change in the paint material or the operating conditions. Unfortunately, there is no
applicable correlation available estimating the droplet size distribution as a function of
operating parameters and material properties for the rheologically complex fluids given.
2. Experimental set-up and measuring techniques
The investigations shown here were made with state-of-the-art high-speed rotary bell
atomisers (Dürr Systems GmbH) used in automated paint applications. In general, two
different types of atomizers have to be distinguished: External (or corona) charging atomizers
as shown in Fig. 1 are used together with conducting water based materials. Here charging is
performed through the interaction of free ions emitting from the corona around the needle
electrodes with the paint droplets. Usually, 6 or 8 of these electrodes are arranged
symmetrically around the atomiser body. For non-conducting solvent based paint high voltage
can be applied directly to the bell and droplet charging takes place through direct charge
exchange mainly at the bell edge
In table 1, the major characteristics of the atomiser and the specific operating condition
investigated are summarised. These values correspond to standard applications in the German
automobile industry. At a bell diameter of 55 mm, the bell edge speed varies between 100 m/s
at 35 000 1/min and 130 m/s at 45 000 1/min. Various water based paints have been used with
solid contents between 18 % and 55 %, including also metallic effect paints containing a small
fraction of 5-25 µm aluminium flakes (approximately 1-2 % per mass) that may also influence
the atomisation process.
Both high voltage and shaping air are means to direct the droplets towards the target. As
indicated by Fig. 1, the shaping air is delivered through a ring behind the bell edge at very high
speed and directed along the outer surface of the bell. At the bell edge, its axial velocity has
been measured to be around 35 m/s, accelerating the radially outwards flowing droplets
towards the target. Additional forces are created by the high voltage applied to the electrodes,
charging the droplets mainly in the region close to the electrode tips, directing them towards
the grounded target. In this way the transfer efficiency, i.e. the solid mass fraction of atomised
paint that actually reaches the target, may exceed 90 % when using a large flat plate.
3. As tests were performed with real water-
based paint the experiments had to be
conducted in a closed spray booth equipped
with a full air condition system and constant
downdraft air velocity of approximately 0.3
m/s. To maintain the practical relevance of
results, all tests were performed using a
painting robot and original equipment to
handle and control the atomiser. A typical
result of a so-called static film thickness
distribution (stationary atomizer position with
respect to work piece) is shown in Fig. 2.
Several measuring techniques were used
to investigate the atomisation of the high-
speed rotary bells considered. In former tests
[1] using a Nanolight flash it was found that
the disintegration process is completed within
a few millimetres distance from the bell edge.
Hence, the inlet conditions with respect to the
droplet size distributions could be measured
by positioning the measuring volume of a
Malvern Spraytec Fraunhofer type particle
sizer very close to the bell edge. A similar
Malvern set up has already been used by
Corbeels et al. [4]. Especially while acquiring
appropriate input data for numerical
simulations, it is essential to avoid cross effects with the very complex spray flow altering
measured droplet size distributions in an irreproducible manner. Here, the ability of the
SPRAYTEC system to perform time dependent measurements has been used to verify the
stability of the measurement conditions.
3. Basic principles of the numerical simulations
The full details of the numerical simulations are not be discussed here, as they are based on the
commercial code Fluent in its actual releases and have been discussed before [1], [2]. The
major extensions of the existing numerical code including external charging atomizers are
• Space charge field of free ions (local density of ion current)
Bell diameter 55 mm (no
serrations)
Bell material Stainless steel
Rotary speed 35 000 - 45 000
1/min
Liquid flow rate 80 - 250 ml/min
Voltage 40 - 60 kV
Shaping air flow
rate
100 - 250 l/min
Table 1: Atomiser characteristics considered
1 Bell 3 External Electrodes
2 Shaping air ring (corona charge only)
Fig. 1: External charging high-speed rotary
bell
Fig. 2: Measured static film thickness
distribution
1
2
3
4. • Transient charging of the droplets within the flow domain considered the transient
charging within the flow domain
• Coupling between free ion flow and air flow field (ion wind)
The local density of the ion current and the corresponding space charge field is calculated
by solving a conservation equation for the ion density [5]. The solution of this equation is
integrated completely in the extended Fluent code. The time dependent charging of the
droplets is calculated using a differential form of an equation given by Pauthenier and
Moreau-Hanot [6], which was originally implemented in the Fluent code to simulate powder
paint coating [7]:
t
t
Er
r
r
pq δ
τ
τ
επ
ε
ε
δ
2
)(
0
24
1
1
21
++
−
+=
(1)
In this equation, the charge pq is acquired by a spherical droplet with radius r and relative
permittivity rε ( 80=
r
ε for water based paint) when exposed to an ion flux in a field E. t is the
resident time of the particle and τ is charging time constant that is given by
J
E
0
4ε
τ = (2)
It should be noted, that the current of free ions is approximately a factor of 10 – 15 times
stronger that the current produced by the charged paint droplets. Although several
experimental attempts have been used to determine the charge of the paint droplets accurately,
there is still a significant uncertainty concerning the true charging behaviour of the droplets.
So far, the effect of the ion current on the flow field has not been considered. As the
resulting contribution to the mean air velocity can be assumed to be very small [8], the final
effect of the droplet trajectories and, subsequently, the film thickness distribution on the work
piece can be neglected. Due to the complex flow field in the vicinity of the bell it is essential to
define correct inlet conditions for both, the airflow and the particle phase. Therefore, the
shaping air flow has to be calculated using the exact geometry, i.e. more than 40 individual
nozzles in the shaping air ring behind the bell to obtain a correct velocity profile at the bell
edge and a very fine mesh to be used in this region. As discussed before, the inlet conditions
for the droplets were taken directly at the bell edge. The initial velocity of the droplets was
calculated from the speed of the bell, hence, neglecting velocity or joint size/velocity effects
during the disintegration process. The resulting droplet inlet measurements are between 100
and 130 m/s, depending on the bell speed.
The calculations were performed on a dual-processor PC (Windows2000, 2 Gbyte RAM),
allowing grids with up to 600 000 cells and trajectory calculations of up to 1,2 106
droplets.
This was found to be enough to obtain the necessary statistical reliability of the results,
especially of the film thickness distribution.
4. Some general comments on accuracy
The final aim of the simulations is to predict film thickness distribution and transfer efficiency
applying high-speed rotary bells to arbitrarily shaped work pieces. Hence, the accuracy of the
simulations is always verified through comparisons with corresponding experimental results of
these 2 quantities. A characteristic result for direct charging is shown in Fig. 3. In this case,
cross sections through static film thickness distributions (see also Fig. 2) are compared.
Applying external charging atomizers, the static film thickness exhibits distinct “hot spots”,
being the result of ion charge density in front of the electrodes arranged around the bell, as
indicated by Fig. 4. Here, highly non-symmetric static film thickness distributions prohibit
5. illustrating stable cross sections for comparisons. Consequently, a contour plot of the
calculated static profile is shown in Fig. 4.
Static film thickness distribution
0
5
10
15
20
25
30
35
40
45
50
-500 -300 -100 100 300 500
position (mm)
filmthickness(µm)
measurement
simulation
Fig. 3: Comparison of static film thickness
distribution – direct charging, flat target
Fig. 4: Simulated static film thickness – corona
charging, flat target
In the practical application, the atomizer is moving across the work piece with a certain
travelling speed. Physically, an integration procedure of the static film thickness distribution is
performed, resulting in the so-called dynamic film thickness distribution, which is the major
atomizer characteristic used in the painting industry, as it determines appropriate robot path
lines.
In Fig. 5, the dynamic film
thickness distribution corresponding
to the static result shown in Fig. 4 is
depicted. Clearly, many of the
differences between experiment and
simulation present in the static film
thickness distribution vanish due to
the integration along the path line.
Finally, only some overall parameters,
i.e. the maximum film thickness and
the profile width at half maximum film
thickness Sb50, are left over. Mainly
these parameters are used in the
following discussion.
5. Sensitivity to operating conditions
In the present application, numerical simulations provide a sensible tool only in the case they
are based on known, or, at least, easy to measure inlet and boundary conditions. For a given
atomizer, the most important parameters are the shaping airflow rate, the bell speed, the paint
flow rate and the paint material. In the calculations, paint flow rate and material are primarily
taken into account only indirectly through the paint droplet size distribution. Hence, there are
2 major questions to be discussed:
1. Are the numerical simulations able to deliver the sensitivity that is required in the
practical application?
Fig. 5: Comparison of dynamic film thickness
distribution – corona charging, flat target
Dynamic film thickness distribution
0
2
4
6
8
10
12
14
-0.6 -0.4 -0.2 0.0 0.2 0.4 0.6
position (m)
filmthickness(µm)
measurement
simulation
6. 2. Which variations of the paint flow rate and the paint material can be accepted without
performing additional droplet size measurements?
The latter question is of specific importance since the disintegration process is not
included in the simulations and no appropriate model for the calculation of droplet size
distributions of non-Newtonian fluids present.
Using a direct charging atomizer, a total number of 32 different operating conditions has
been investigated, comparing experimentally and numerically obtained dynamic film thickness
distributions. A DOE scheme was applied varying the most important process parameters, i.e.
paint flow rate, shaping air flow rate, bell speed, voltage and working distance in working
ranges given in tab. 1. The results are expressed in terms of the maximum film thickness and
the profile width Sb50.
Fig. 6: Correlation between experimental and
numerical maximum film thickness
Fig. 7: Correlation between experimental and
numerical profile width Sb50
As indicated by Fig. 6, the agreement between experiment and simulation with respect to
the maximum film thickness is very good. The typical error is around 10 %, which is in the
same range as the experimental reproducibility. A similar quality is obtained with respect to the
correlation between experimental and simulated profile width Sb50, however, covered by an
almost systematic offset between 3 and 5 cm caused by differences in the shape of the profile
edge.
The response of the numerical simulation to variations in the droplet size distribution is
verified through extensive trials with different paint materials and operating conditions. With
respect to the coating performance, however, this can be regarded as an artificial test only,
since by changing the colour not only the atomisation is changed but also additional
parameters, e.g. the material conductivity. On the other hand, modifications of the bell speed
to influence atomisation affect the flow field also.
In the numerical experiment shown below, size distributions being obtained at different bell
speeds has been used to simulate the coating process under constant conditions. As indicated
by Fig. 8, an increase of the bell speed by 20 000 1/min leads to a shift of the measured size
distribution towards smaller droplets. The corresponding Sauter mean diameters D32 are 31,8
µm for 40 000 1/min and 23,4 µm for 60 000 1/min.
As shown in Fig. 9, the change in the droplet size distribution, a smaller droplet size
distribution leads mainly to a reduction of the film thickness around the centre, without
changing the overall shape of the profile significantly. This is nicely corresponding to an
approximately 5 % reduction of the calculated transfer efficiency. Obviously, the size
distribution is not the most dominant parameter affecting the film thickness distribution. From
this result it can be concluded, that smaller changes in the parameters determining the droplet
Correlation of profile width Sb50 (mm)
200
250
300
350
400
450
500
200 250 300 350 400 450 500
Experiment
Simulation
Correlation of maximum film thickness (µm)
0.0
10.0
20.0
30.0
40.0
50.0
60.0
0.0 10.0 20.0 30.0 40.0 50.0 60.0
Experiment
Simulation
7. size distribution, i.e. bell speed and paint flow rate, do not require additional measurements.
This is very important, as the program will be used in the future to simulate complex work
piece coating processes, during which several variations of operating conditions will be
performed. In principle, this argument holds also for different paint materials. In the current
situation, however, verifying droplet size measurements are necessary since the properties
characterizing the rheology of the complex water based paint with respect to atomisation are
not clear.
Droplet size distribution silver metallic
0
0.05
0.1
0.15
0 100 200 300 400 500
droplet diameter (µm)
Vol.-Frac.(-)
FM250;n40000
FM250;n60000
Dynamic film thickness distribution
0
5
10
15
20
25
30
35
40
-500 -400 -300 -200 -100 0 100 200 300 400 500
position (mm)Filmthickness(µm)
Size distribution 2
Size distribution 1
Fig.8: Size distribution measured at different bell
speeds
Fig. 9: Resulting effect of size distribution on
dynamic film thickness distribution
6. Target geometry variations
The results shown above were obtained using a flat plate as target geometry. This geometry
was chosen due to its simplicity. Since the simulations are performed fully 3-dimensional, they
can be extended to more complex work pieces easily. However, additional efforts are
necessary on the experimental side as film thickness and transfer efficiency measurements are
more difficult and require sometimes different procedures.
Various work pieces have already been experimentally and numerically investigated. Their
geometry has been purposely chosen to obtain indications for the accuracy of the different
physical models involved, e.g. turbulence, droplet charging, ion charge density and space
charge effect. In Fig. 10, the simulated static film thickness distribution is shown for the case
of the edge of a flat plate. The corona-charging atomizer is located directly above the edge
with its axis perpendicular to it. Fig. 11 depicts the corresponding measured and simulated
dynamic film thickness distribution for an atomizer moving along the edge. Obviously, there is
a nice agreement between measurement and simulation, except at positions very close to the
edge, where the simulation overestimates the film thickness. The reason for this observation,
which has been made at similar geometries, also is still unclear. One possible explanation might
be flows inside the paint film parallel to the target surface due to the steep thickness gradients
and the air momentum acting on the film surface, equalizing the film thickness.
In a final test, many different simulated static film thickness distributions have been
superimposed to calculate the final film thickness distribution in a more practical case. The
geometry considered herein is shown in Fig. 12. Essentially, it is a stylised rear part of a car
body, i.e. the region around the licence plate. In the experiment, the coating process is
performed traversing the atomizers along the solid line. In total 6 different coating geometries
are simulated representing characteristic local work piece geometries. The geometry of the
8. coating process, i.e. the path line of the atomizer along the work piece surface, corresponds to
the practical application. The result in terms of the comparison between experimental and
simulation film thickness along the line of symmetry of the geometry (dashed line) is shown in
Fig. 13. The notation P1 to P5 given in Fig. 13 corresponds to panel 1 to panel 5 as indicated
in Fig. 12. For clarity, the panels are arranged to lie in one plane.
Dynamic film thickness distribution
0
5
10
15
20
25
0 100 200 300 400 500
position (mm)
filmthickness(µm)
measurement
simulation
panel
edge
Fig. 10: Simulation of the static coating process
of the edge of a flat plate (corona
charging)
Fig. 11: Comparison of measured and simulated
dynamic film thickness distribution
In this test, which clearly demonstrates the usefulness of the developed program for the
practical application, the differences in the
local film thicknesses are usually below 2
µm, which is close to the measurement
accuracy. Although this result is very
encouraging, it should be noted that the
computational efforts are still too high. On
a standard PC, the actual computation time
per static distribution is between 1 and 2
days without the required CAD-work to
prepare the geometry. A future speed up
might be possible by using more powerful
computers and, at the same time, by
implementing faster and simpler models for
the processes involved.
7. Summary and Outlook
The present contribution summarizes the state of the art of the investigations performed at the
IPA to simulate the electrostatically supported spray painting process with high-speed rotary
bell atomizers using both direct charging and corona charging. Measured and simulated static
film thickness distributions are already in good agreement, which applies not only to flat
geometries but also more complex work pieces. Consequently, this result applies also to the
dynamic profiles, which are derived through a relatively simple integration procedure. In
general, arbitrarily shaped work pieces can be coated, if an appropriate number of static cases
are simulated, numerically integrated along the direction of propagation and finally
superimposed. In short term, this might be the solution, but in long term it is necessary to
Fig. 12: Coating process of a stylised car body
rear part
9. perform real unsteady simulations, accounting for the actual robot speeds, accelerations and
path lines. Current state of the art CFD packages deliver already some possibilities, e.g.
adaptive meshing, however, this is still far from handling complex, non-linear movements.
The main objectives of the ongoing investigations, which are mainly supported by the
German automotive industry, are
1. To realize a practical tool for the simulation of the electrostatic painting process. Such
a tool has numerous applications; the most sophisticated one being to incorporate it
into a complete simulation of a painting line. The results presented herein may be taken
as a significant step in this direction.
2. To realise a design program for high-speed rotary bells, e.g. with respect to the outside
geometry of the bell and the shaping air outlet to achieve a maximum sensitivity and
effect of the shaping airflow rate. This is of specific importance, as new requirements
are coming up, e.g. much higher paint flow rates.
The simulations have already been successfully extended to other applicators used the
automotive industry, i.e. powder spray guns and pneumatic atomizers with and without
electrostatic support. Other paint shop related problems to be considered are, e.g., dip coating
or curing and baking.
References
[1] Domnick J., Scheibe A., Steigleder T., Weckerle G., Ye Q.: Simulation of the
Electrostatic Painting Process with High-Speed Rotary Bell Atomizers, 8th
Int. Conference
on Liquid Atomization and Spray Systems, July 16-20, Pasadena, CA, 2000
[2] Domnick J., Scheibe A., Ye Q.: Simulation of the behaviour of sprays from high-speed
rotary bell atomizers with external charging, 17th
Annual Conference of ILASS-Europe on
Liquid Atomization and Spray Systems, September 2-6, 2001, Zürich
[3] Ye Q., Steigleder T., Scheibe A., Domnick J.: Numerical simulation of the electrostatic
powder coating process with a corona spray gun, Journal of Electrostatics, 54 (2002),
189-205
[4] Corbeels P.L., Senser D.W., Lefebvre A.H.: Atomization Characteristics of a high-speed
rotary-bell paint applicator, Atomization and Sprays, Vol. 2, pp. 87-99, 1992
[5] Miller J., Riehle C., Schwab A.J., Löffler F.: Numerische Feldberechnung in Elektrofiltern
im Hinblick auf elektrisch ähnliche Betriebszustände, J. Electrostatics 33 (1994), 213-225
Fig. 13: Comparison of measured and calculated film thickness along the line of symmetry
10. [6] Pauthenier M.M. and Moreau-Hanot, M.: La Charge des particules sphérique dans un
champs ionise, J. d’Physique Radium 7 (1932), 590-613
[7] Domnick J and Ye Q: On the simulation of space charge in electrostatic powder coating
with a corona spray gun, submitted for Powder Technology, 2002
[8] Soldati A.: On the effects of the electrohydrodynamic flows and turbulence on aerosol
transport and collection in wire-plate electrostatic precipitators, J. Aerosol Sci., Vol. 31,
3, pp. 293-305, 2000