Research Triangle Park, NC--Not long ago, the way to improve a system such as an automotive defroster was to build a prototype, test it, build another prototype, test it.
Chrysler engineers now use computational fluid dynamics (CFD) software to speed up the design process. In one minivan project, they sought to improve flow distribution, reduce pressure drop, and quiet a defroster duct.
To generate the defroster duct geometry and finite element mesh, the engineering team used PATRAN from PDA Engineering. FIDAP code from Fluid Dynamics International provided the analysis. With 31,000 elements in the model, the solution ran on a single CPU of Chrysler's CRAY Y-MP 8I system.
To display and animate the data set from the 3-D analysis, the engineers selected EnSight from Computational Engineering International (CEI). EnSight is a post-processing system that displays and animates the results of sophisticated finite element modeling techniques. EnSight ran in a distributed mode with the graphics on a Silicon Graphics Personal IRIS and the compute-intensive portion running on the CRAY.
In a related project, Chrysler engineers studied the de-icing action of the defroster in the LH series sedans. Realistic simulation required a model of the passenger compartment.
Engine flow patterns
Starting with CAD surface data generated by CATIA, the geometry was imported to ICEM-CFD to generate the multi-domain mesh. The model contained 110,000 cells and 50 domains. Then, CFD-ACE code from CFD Research Corp. solved the steady-state flow field and the transient ice-clearing process.
Post-processing the CFD-ACE code results with EnSight produced the animation of ice-melting patterns. "The wealth of flow field information enables us to make better design decisions earlier in the design cycle," says John Tripp, Chrysler fluid dynamics engineer.
Additional details, program...Contact Tom Palmer, Computational Engineering International, Box 14306, Research Triangle Park, NC 27709, (919) 481-4301.
Additional details, application...Contact John Tripp, Chrysler Corp., 800 Chrysler Drive East, Auburn Hills, MI 48326.