The Effect of Flow Rate on Characteristics in Centrifugal Impellers

Abstract

The characteristics of unshrouded and shrouded centrifugal impellers were derived from the impeller passage flow. Effects of flow rate on the characteristics were investigated for a flow rate corresponding to nearly zero incidence angle, and two other flows with reduced and increased flow rates. The following results were obtained as the flow rate decreased. The position of the largest blade load moves upstream in the impeller passage, but this movement in the unshrouded impeller is not as clear as that in the shrouded impeller. The absolute circumferential velocity and the total pressure tend to increase in the inlet-to-outlet passage, but these increases become smaller at the unshrouded impeller exit. Moreover, the static pressure increases in the passages of both impellers.