Simulating Thermal Balance of Electronics – an AcuSolve approach

1. Knorr-Bremse Group Simulating Thermal Balance of Electronics – an AcuSolve approach June 2014 Stephan Pitzing Knorr-Bremse Systeme für Schienenfahrzeuge GmbH 2. Knorr-Bremse Group  Metros  Streetcars  Multiple units  High-speed trains  Locomotives  Passenger rail cars  Freight cars Knorr-Bremse is the world's leading manufacturer of braking systems for rail and commercial vehicles Answers for a World of Mobility Rail Vehicle Systems  Trucks  Buses  Engines  Special vehicles Commercial Vehicles │2 Technical Analysis Department Munich India 3. Knorr-Bremse Group │3 Technical Challenge 2014 Altair Technology Conference Introduction / Motivation  Brake Control Units (BCU) are safety-critical parts of Trains and are essential to control the braking behavior of the vehicle  They contain standardized electronic device modules in semi-closed 19“ standardized racks and emit thermal power  BCUs are individually tailored depending on the vehicle they are used for Goal / Expectation  Estimate the air temperature inside of BCUs in a project driven environment  Cut down project development time and costs through virtual thermal testing for systems  They need to operate with high environmental temperatures without fan supported cooling 4. Knorr-Bremse Group │4 Solution Strategy Testing the Hardware  Time consuming, High costs due to Test Equipment but: high accuracy  Results may used as a knowledge base  Challenge: Hard- and Software for Brake Control device needs to be present Simulation  Can be done in conception phase  Design versions may be evaluated in short period of time  Simplification of real BCU needed -> accuracy of simulation result reduced  Try with AcuSolve! 2014 Altair Technology Conference 5. Knorr-Bremse Group │5 Using AcuSolve Approach  AcuSolve can be used as Air velocities very low (only free convection) -> incompressible flow  Steady State Simulation  Preprocessing is done using AcuConsole Standard Template.  Effect of Radiation is considered  Ambient air temperature : 50°-70°C  Height from sea level : 1000-4000m  Mesh size : 42 million Model Summary 2014 Altair Technology Conference 6. Knorr-Bremse Group │6 Using AcuSolve Convergence Check  Monitor solution in AcuProbe  Power loss through electronic devices (I/P) = Heat flux over the outer boundary of Air (O/P)  Residual ratio: Temperature, Radiation I/O (Power loss) = 92W O/P (Air heat flux) = 92W Convergence tolerance = 0.01 2014 Altair Technology Conference 7. Knorr-Bremse Group │7 Results How to evaluate the simulated temperature field?  The resulting temperature plots are defined by planes and temperature plot lines  These lines and planes represents the environment temperature for the electronic devices inside the BCU and are a criteria for proper function of the BCU  Acu-Field View is used for Viewing & Plotting the results. 2014 Altair Technology Conference 8. Knorr-Bremse Group │8 Results Examples  The diagram and temperature field plot are used for rate the thermal design of the BCU 2014 Altair Technology Conference 9. Knorr-Bremse Group │9 Results Comparison to test results  BCU with simplified electronic devices (resistors only) has been used for thermal test in climate chamber  Same model has been simulated with CFD software  Matching of both results (with sufficient accuracy) has been detected 2014 Altair Technology Conference 10. Knorr-Bremse Group │10 Using AcuSolve Meshing influence  Mesh size in small holes has to be carefully observed 2014 Altair Technology Conference 11. Knorr-Bremse Group │11 Using AcuSolve Advantages  Licensing system is based on HyperWorks Units (HWU), doesn’t require separate license  Model Setup is very easy.  Simulation is very fast and result accuracy is comparable with other CFD software  Live Monitoring of results Why using AcuConsole and not HyperMesh for PreProcessing?  Automatically separates internal faces  No geometry cleanup required  Mesh generation process is comparatively easier and faster Drawbacks  AcuSolve can be used only when Air velocity is low (only free convection)  Geometry Modifications is not allowed 2014 Altair Technology Conference 12. Knorr-Bremse Group │12 Summary / Outlook AcuSolve for Thermal Simulation  Automation of simulation process using database template file  Python Scripting  Template Driven Analysis 2014 Altair Technology Conference 13. Knorr-Bremse Group Thank you! Questions? Knorr-Bremse Systeme für Schienenfahrzeuge GmbH Moosacher Strasse 80 80809 München Tel: +49 89 3547 1320 E-Mail: [email protected] Website: www.knorr-bremse.com Mr. Sauraba Gupta Ms. Neha Sharma E-Mail: [email protected] [email protected] Acknowledgement/Credits Slide 4; Picture Climate Chamber: Weiss Group www.weiss.info