Measurement and numerical simulation of a small centrifugal compressor characteristics at small or negative flow rate

摘要

For centrifugal compressors used in automotive turbochargers, the expansion of the surge margin is demanded because of lower engine speed.In order to estimate the surge line exactly, it is required to grasp the compressor characteristics at small or negative flow rate.In this paper, measurement and numerical simulation of the characteristics at small or negative flow rate are carried out.In the measurement, an experimental facility with a valve immediately downstream the compressor is used to suppress the surge.In the numerical work, a new boundary condition that specifies mass flow rate at the outlet boundary is used to simulate the characteristics around the zero flow rate region.Furthermore, flow field analyses at small or negative flow rate are performed with the numerical results.