Overall Approach to the Validation of Charge Air Coolers 2005-01-2064
This paper gives a brief overview of the Behr reliability management system, including, as an integral element, the validation process. It describes the application of test methods as well as simulation tools and associated coupling strategies which are used to validate charge air coolers.
Simulation of the main validation tests for charge air coolers are performed. For this study a CFD simulation is carried out to predict surface temperature distribution. The results are evaluated and compared with temperature measurements from an infrared camera. By mapping these temperature distributions, obtained either from computations or measurements, onto an FE model as boundary conditions, structural analyses are performed for the thermal cycle test. The stresses computed are compared with strain gage measurements from the test rig.
Due to the very high temperature values and varying boost pressures involved, pressure cycle fatigue tests, in which the component is pressurized with hot air, have to be performed. The stress results from the simulation can be compared with cycles-to-failure from the test rig. In a double logarithmic scale this leads to an s-n-curve with constant slope valid for a specific failure mode.
With the aid of a global FEA modeling standard the results of different simulations and tests can be compared. With this s-n-curve new design variants can be evaluated and necessary improvements can be implemented without prior testing.