스캘럽형상이 구심터빈 효율에 미치는 영향

Abstract

In this study, efficiency improvement according to the scallop shape of the radial-type turbine was investigated. Four different rotors with a scallop ratio of 0.71 were used. The angle of the scallop was increased from 0 degree to 15, 30 and 40 degrees so that the shape of the scallop was designed to follow the flow path within the rotor. To apply the turbine to the organic Rankine cycle, R245fa was used as the working fluid, and the operating conditions were applied on the basis of the working conditions obtained from the cycle analysis. The results of the efficiency improvement were studied numerically, and the numerical algorithm was validated based on the experimental results of the radial-type turbine. As a conclusion, the proper angle for the scallop was required to improve the efficiency of the turbine. The greatest efficiency improvement was obtained when the scallop angle was 30 degree. In addition, the effects of the scallop geometry on the efficiency were analyzed from the results of the flow field within the rotor.