Study of Pump Abnormal Characteristics from Prevention toward Suppression and Control

研究了涡轮泵的各种不稳定特性，提出了稳定泵运行的流量控制方法。通过对涡轮泵中五种不同类型的非定常现象的研究，试图找出各种不稳定现象的公因子。[大阪大学组]：对四个叶片诱导器的进口变形进行了研究，发现叶片上的非定常应力是由进口变形引起的空泡与交替的叶片空化相互作用而产生的。发现三个叶片式诱导轮产生高阶旋转空化。[名古屋大学组]：通过对两种不同比转速的混流泵进行试验，研究在低吸入压力下泵送作用的降低。泵叶轮入口处的流量分布与空化数有关。[九州大学组]：为了抑制和控制高空泡比下的气锁现象，进行了串联式旋转叶栅和大叶片出口角度的试验。并对叶片出口角度控制系统进行了试验，以获得更高的泵效。[九州理工大学组]：对非定常流动结构进行了研究，以获得预失稳信号，以预测扩散泵在低流量时发生不稳定现象。[横滨国立大学组]：对扩散器壁上的狭缝J形槽进行了试验，以抑制锥形扩散器内进口强烈变形时旋转涡核的旋转。J槽被发现对高达46%的强旋转流动引起的压力波动具有有效的抑制作用。

A variety of unstable characteristics of turbopumps were studied to develop the flow control methods for the stable pump operations. Common factor was tried to find for-various unstable phenomena through the study of five different type unsteady phenomena in turbopumps.[Osaka University Group]: Four bladed inducer was studied on inlet distortion, and then unsteady stress on blades was found to be induced by the interaction between cavities induced by inlet distortion and alternative blade cavitations. And three bladed inducer was found to generate the higher order rotating cavitations.[Nagoya University Group]: Two different specific speed mixed flow pumps were tested to study the decrease in pumping action at low suction pressure. Flow distributions at pump impeller inlet are related to cavitations number.[Kyushu University Group] : Tandem type rotating cascade as well as high blade outlet angle was tested to suppress and control the air lock phenomena at high void ratio. And control system for the blade outlet angle was tested to get the higher pump efficiency.[Kyushu Institute of Technology Group]: Unsteady flow structures were studied to get the pre-unstable signals for the prediction of the occurrence of unstable phenomena of diffuser pump at low discharge.[Yokohama National University Group]: Slit on diffuser wail, the J-Groove, was tested to suppress the rotating vortex core at strong inlet distortion in conical diffuser.The J-Groove was found to be effective for the suppression of pressure fluctuations due to strong rotating flow up to 46 percent.