Effects of Pocket Configuration on the Flow Field in a Rotary Engine Assembly

Laser Doppler anemometry measurements have been made in a motored rotary engine assembly. The purpose of this study was to compare the flow fields of two different rotor pocket geometries experimentally. Two-dimensional measurements were taken over a central plane grid during intake and early compression at a shaft speed of 2000 rpm and wide open throttle. This data is to be used to quantify the central plane flow field and to provide experimental data for comparison with current analytical models. Two rotor pocket geometries were examined. The first rotor pocket geometry was a leading deep recess, and the second was a centrally located symmetric pocket. The same production apex and side seals were used for both rotors. The reduced velocity data was displayed as vector field plots within a computer animation to facilitate observation of the flow field and comparisons to analytical models. A comparison of the flow fields for the two different rotor geometries showed little difference in the regions studied under the stated conditions. The intake flow field for both rotors was dominated by a large scale circulation in the opposite direction of the shaft rotation. The momentum imparted to the intake charge as it was accelerated through the intake port carried the fluid along the rotor face until it reached the leading apex seal. At this point the fluid recirculated along the inner surface of the central rotor housing.