小径吸込み管と旋回止めの併用によるインデューサの入口逆流抑制

抄録

For long-time operation of general-use turbopump with inducer, instability-free operation is required as well as high suction performance in a wide operating range from shut-off to over flow rates. However, low frequency cavitation surge is known to often occur in low flow rate range, and it is hardly avoided because it is associated with the inlet backflow. In our previous study, we have tried to suppress the cavitation surge in a turbopump by installing an obstruction plate or a reduced-diameter suction conduit just upstream of the inducer. It has been found that the suppression of inlet backflow is effective in weakening/suppressing cavitation surge. However, in the both method, the effect is imperfect in the extremely low flow rate region. In the present study, to further suppress the inlet backflow, swirl breakers were combined with reduced-diameter suction pipe and its effectiveness was investigated by CFD. As a result, it was found that the inlet backflow is suppressed more remarkably by the smaller-diameter suction pipe equipped with swirl breakers.