Effects of intake areas and shapes on the flow field of elliptical rotary engines at different speeds

Abstract

Due to the special structure, the flow field of elliptical rotor engines (ERE) shows several flow direction reversals, which is important for ERE working. In this research, a three-dimensional simulation model of ERE was developed using the CONVERGE. The turbulence model was validated through Particle Image Velocimetry (PIV) experiments, allowing for an analysis of the scavenging process. Additionally, the study explored the impact of rotational speed, intake port areas and intake shapes on the flow field within the combustion chamber. The findings reveal that complex flows with multiple directional changes is occurred during the exchange process. With the increase of rotational speed, the volumetric efficiency of ERE increases and then decreases, and the highest point occurs at 4000 rpm. The peak of TKE occurs in the early stage of intake stroke at low rotational speeds, and occurs in the high rotational speed when the port is directly aligned with the recess. Variations in the shape of the intake port change the distribution of gas flowing, with regular trapezoidal and elliptical ports enhancing the swirling intensity in the bottom of the chamber. The elliptical intake port exhibits higher flow intensity at low speeds, while the regular trapezoidal intake port has higher flow strength at high speeds. An increase in the port area intensifies the swirl at the bottom of the chamber while simultaneously reducing the peak TKE. The in-cylinder flow of an elliptical rotor engine can be improved by using an appropriate intake shape and intake area, which improves its working process.