simulating thermal balance of electronics an acusolve...

Knorr-Bremse Group

Simulating Thermal Balance of Electronics – an AcuSolve approach

June 2014

Saurav Gupta

Neha Sharma

Knorr-Bremse India Private Limited

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

Knorr-Bremse Group │3

Technical Challenge

2014 Altair Technology Conference - India

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


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


Using AcuSolve


Approach

AcuSolve can be used as Air velocities very low

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


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


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.


Results


Examples

The diagram and temperature field plot are used for rate the thermal design of the BCU


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


Using AcuSolve


Meshing influence

Mesh size in small holes has to be carefully observed


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

Relatively insensitive to element topology and mesh quality

Can be customized according to your need

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.

Geometry Modifications is not allowed


Outlook


Automation for Acusolve

Automation of simulation process using database template file

Python Scripting

Template Driven Analysis



Questions or Suggestions!

Knorr-Bremse Group

Thank you!

Knorr-Bremse India Pvt. Ltd.

Neha Sharma

51/4, Delhi-Mathura Road, Village & P.O.–

Baghola, Palwal, 121102-Haryana

Tel: +91 1275 22 2672

E-Mail: [email protected]

Website: www.knorr-bremse.com

Sauraba Gupta

Stephan Pitzing

E-Mail: [email protected]

[email protected]

Acknowledgement/Credits

Slide 4; Picture Climate Chamber: Weiss Group

www.weiss.info

mailto:[email protected]



http://www.knorr-bremse.com/









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