The formation mechanisms of flow field in a compound intake ported rotary engine considering apex seal leakage

The development of rotary engines is severely restricted by its low combustion efficiency and high emission. In‐cylinder flow field is known to play a major role in combustion process for rotary engines. Therefore, in the present article, a three‐dimensional dynamic simulation model considering leakage through apex seals was developed and verified by the two‐dimensional particle image velocimetry experiment results on the rotor housing central plane. Based on the three‐dimensional dynamic simulation model, the formation mechanisms of flow field in a compound intake ported rotary engine under different apex seal leakage gap sizes (0.02, 0.04, 0.06, and 0.08 mms) and engine speeds (2,000, 3,500, and 5,000 rpms) were numerically studied. The simulation results showed that there exist two formation mechanisms of the flow field in the intake stroke, that is, “side intake port dominance” and “peripheral intake port dominance.” For the three engine speeds (2,000, 3,500, and 5,000 rpms), with the increase of apex seal leakage gap size, the formation mechanism of the flow field gradually changed from “side intake port dominance” to “peripheral intake port dominance.” In addition, the influences of apex seal leakage on the volume coefficient and the turbulence kinetic energy in the combustion chamber were also investigated in detail.