Heat transfer and crevice flow in a hydrogen-fueled spark-ignition engine: Effect on the engine performance and NO exhaust emissions

The present work investigates the effect of heat and mass transfer on the combustion process of a hydrogen-fueled spark-ignition engine, using an in-house CFD code. The main scope is to compare the calculated local heat fluxes with the available measured ones, using three heat transfer models of increasing complexity (two existing and one developed by the authors). Moreover, the effect of mass transfer through the crevice regions is also investigated using a phenomenological crevice model. The calculated results (cylinder pressure traces, local heat fluxes and NO exhaust emissions) are compared with the corresponding measured data, at various operating conditions, maintaining constant engine speed and altering the compression ratio and the equivalence ratio. It is revealed, that the proposed heat transfer model is more accurate than the standard wall-function formulation, while with the use of the crevice model a more reliable prediction of engine performance is achieved.