Two phase (water/air) suction performance of turbopump inducer

In the present study, the gas-liquid two-phase flow performance of a turbopump with an inducer has been experimentally investigated. In the performance evaluation test, the air bubbles is released from dissolved air at the upstream valve to realize two-phase flow. By this method, a homogeneous bubbly flow is expected just after the valve. The amount of dissolved oxygen (DO) is an important parameter, and the experiment is carried out under the conditions of DO 50%, 100%, 200%, where DO[%] indicates the relative amount of DO against the saturated value at the atmospheric condition. Under each DO condition, the experiment is performed at various water flow rates. As a result, a clear trend that the higher DO is, the worse the performance becomes, is observed. It is found that the mechanism for the head drop of the pump differs between at high and low flow rates. At the high flow rate, the performance does not deteriorate up to relatively high volumetric flow rate ratio of air and water. The cause of performance deterioration seems to be the increased number and/or size of bubbles released at the upstream valve. On the other hand, at the low flow rate, the performance deteriorates at relatively low air-water flow rate ratio. Although the air water volume flow ratio is low, the bubbles can precipitate in inlet flow recirculation and back flow vortices, which seems to cause the performance deterioration.