Numerical investigation of suction performance of inducer with splitter blade

For general-use turbopump inducers, high suction performance is required in a wide operating range including the cut-off point. At the low flow rates, low frequency cavitation surge is known to occur with the strong inlet backflow from the inducer. The reduced inlet blade angle would be favoured for the suppression of this inlet backflow, whereas the reduced inlet blade angle causes the deterioration of suction performance through the reduced inlet throat area. In this study, a splitter blade was adopted for the helical inducer to overcome or relieve these two conflicting problems, and the effectiveness was investigated by CFD considering cavitation. First, the favourable length and the circumferential position of short blade were investigated by 2-D cascade model. Then, the obtained suitable cascade design was applied for the 3-D helical inducer. As a result, the inlet backflow was found to be weakened at the low flow rates as expected, while keeping the good suction performance of inducer in the whole flow rate range.