The Effect of Flow Rate on Characteristics in Centrifugal Impellers.

The characteristics of an unshrouded and a shrouded centrifugal impeller were derived from the impeller passage flow. Effects of flow rates on the characteristics were investigated by comparison of the characteristics for a flow rate corresponding to nearly zero incidence angle and two other flows with reduced and increased flow rates. As the flow rate was reduced, the following results were obtained. The position of the largest blade loading 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, but these increases become smaller in the unshrouded impeller exit. The static pressure increases in the passages of both impellers.