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Three-dimensional transient computations of flow in variable-displacement vane pumps and in gear pumps have been completed. Several innovations were required for this new application of computational fluid dynamics (CFD). New physical insight into the pumping process has been extracted by exercising the model. Likely cavitation sites have been identified, the importance of fluid compressibility has been established, and reductions in flow losses and noise have been realized. Based on these computations, design changes have been proposed and evaluated in hardware for automatic transmission variable- displacement vane pumps. The same methodology is being applied to fixed- displacement gear pumps. These findings have relevance to both the Transmission Designer and the Transmission Analyst.

A comprehensive modeling and visualization study of flow and combustion is reported for a production four-valve-per-cylinder homogeneous-charge four-stroke-cycle spark-ignited engine. Coupled port and in-cylinder computations are presented for five combinations of valve deactivation, valve shrouding, and cam profile. Motored (induction and compression) results are compared with transient-water-analog flow-structure visualizations. A new flamelet model for homogeneous-charge turbulent premixed combustion has been implemented for fired engine simulations. Several issues in the application of CFD to flow and combustion modeling in practical port-and-cylinder systems are addressed. These include numerical inaccuracy, elucidation of the role of induction-generated flow structure and turbulence, and new insights into premixed flame propagation.