Integration of 3D Combustion Simulations and Conjugate Heat Transfer Analysis to Quantitatively Evaluate Component Temperatures 2003-01-3128

Crucial specifications of an engine are spread widely in various subsystems, such as cooling system, intake and exhaust system, combustion system, etc. Well-informed design decision and optimized design solution cannot be reached without considering interactions among subsystems. Even though significant progresses on CAE technologies have been made to address physical and chemical phenomena in each subsystem, there are few studies in literature to model an engine with a reasonable coverage of subsystems in an integrated fashion. The necessity of such approach is justified from two aspects. Firstly, modifications in one subsystem could result in changes in other subsystems. Secondly, frequently due to experimental constraints or availability of prototypes which is the case for new engine design, boundary conditions for a subsystem of interest can only be obtained from integrated numerical simulations with other subsystems.

In the present work, an integration methodology was developed, intake and exhaust system, combustion system, cooling system, and head/block/gasket component system were coupled. In particular, intake flow, combustion, cooling performance and component temperatures were simulated iteratively for one bank of a V6 gasoline engine. The results show that characteristic time scale combustion model with discrete parcel kernel development model can reproduce combustion rate satisfactorily over a wide range of engine speed. Heat flux and temperature distributions on combustion chamber surfaces are highly non-uniform, uniform temperature assumption results in unacceptable discrepancy in terms of local heat flux and temperature. The integration method is a robust development tool and eliminates some uncertain assumptions in engine simulations.