Abstract
The attachment of inducer upstream of main impeller is an effective method to improve the suction performance of turbopump. However, the various types of cavitation instabilities are known to occur even at the designed flow rate as well as in the partial flow rate range. In the present study, we have carried out the flow measurement and CFD analysis to clarify the inlet backflow structure of a 2-bladed flat plate helical inducer at a partial flow rate, where we observe a strong cavitation surge in low suction pressure conditions. It was mainly found that the inlet backflow appearing near the blade tip was associated with the leading edge separation vortex wrapped by the tip leakage flow, and that the flow re-attached immediately forming a separation bubble and the flow just downstream near the blade tip was increased by the radially toward 3-dimensional flow conveying the fluid from the inner region.
