Yoon-Jei Hwang

Study on the Performance of a Centrifugal Compressor Using Fluid-Structure Interaction Method

Abstract : In this study, we perform a series of aero-thermo-mechanical analyses to predict the running-tip clearance and the effects of impeller deformation on the performance using a centrifugal compressor. During operation, the impeller deformation due to a combination of the centrifugal force, aerodynamic pressure and the thermal load results in a non-uniform tip clearance profile. For the prediction, we employ the one-way fluid-structure interaction (FSI) method using CFX 14.5 and ANSYS. The predicted running tip clearance shows a non-uniform profile over the entire flow passage. In particular, a significant reduction of the tip clearance height occurred at the leading and trailing edges of the impeller. Because of the reduction of the tip clearance, the tip leakage flow decreased by 19.4％. In addition, the polytrophic efficiency under operating conditions increased by 0.72％. These findings confirm that the prediction of the running tip clearance and its impact on compressor performance is an important area that requires further investigation.

Analytical Study on the Performance of Centrifugal Compressor Considering Running Tip Clearance

In this study, a series of aero-thermo-mechanical analyses were carried out to predict the running tip clearance and the effects of impeller deformation on the performance using two different centrifugal compressors (blade type A and B). In operation, impeller deformation due to the combination of centrifugal force, aerodynamic pressure and thermal load results in non-uniform tip clearance profile. The predicted running tip clearance leads to further findings of its impact on compressor performance. The prediction employs one-way fluid-structure interaction (FSI) method using CFX 14.5 and ANSYS. The results show that the maximum displacement occurs at the leading edge tip of the impeller blade but maximum stress takes place at the blade root of the impeller for these particular designs. The analysis also confirms the centrifugal force has dominant effect on impeller deformation at its operating condition. The predicted running tip clearance shows non-uniform profile over the entire flow passage. In particular, a significant reduction of the tip clearance height has occurred at the leading edge and the trailing edge of the impeller. Due to the reduction of the tip clearance, the tip leakage flow has decreased by 19.4% and 16.2% in the blade type A and B, respectively. Also, the polytropic efficiency of the blade type A and B at operating condition has increased by 0.72% and 1.81%, respectively. These findings confirm that the prediction of running tip clearance and its impact on compressor performance is important area for further investigation.© 2015 ASME