RESEARCH ON TOTAL SUPPRESSION OF ABNORMAL FLOW PHENOMENAIN TURBOMASCHINERY

汽轮机在非设计工况下运行时，会出现各种异常流动现象，从而产生噪声和振动。为了建立一个突出的日本技术特点，它可以完全抑制这些异常的流动现象，而不降低总效率，实验研究和数值模拟之前，在研究的快速步骤，诱导进行了测试，因为最严重的空化现象通常被观察到。将J型槽技术应用于几种诱导轮上，结果表明，在低流量范围内，J型槽的优化设计可有效抑制诱导轮的汽蚀，使诱导轮的吸气性能提高一倍以上;在高流量范围内，J型槽与止旋器的耦合设计可使诱导轮的吸气性能提高15倍以上。其次，将J型槽技术应用于半开式叶轮离心泵，在不降低最大效率的前提下，显著改善了离心泵的吸入性能，但在闭式叶轮中，由于J型槽的形状，使其难以应用。本文提出了一种新的带J形槽的半封闭式叶轮，在不降低最大效率的情况下，能很好地抑制性能曲线的不稳定性，并能改善大流量范围内的吸气性能。第二步，对离心压气机进行了试验，试验表明，J形槽技术对抑制喘振和扩大喘振裕度是非常有效的。数值模拟结果表明，扩压器旋转失速的发生是抑制喘振的关键，J型槽安装在扩压器出口附近可以有效地抑制旋转失速的发生，扩大喘振裕度，但安装在扩压器进口附近效果不明显。

In operating turbomachinery at off-design conditions, various abnormal flow phenomena occur, resulting in noise and vibration. In order to establish an outstanding technology characteristic of Japan, which can totally suppress these abnormal flow phenomena without dropping total efficiency, the experimental research and the numerical simulations were preceded.In the fast step of research, inducers were tested, as the most severe cavitation phenomena are usually observed. J-Groove technique was applied to several inducers, and the results showed that the cavitation is suppressed drastically in the low flow range and the suction performance is improved to twice the conventional when the groove is optimized In the high flow range the suction performance can also be improved to 15 times the conventional, when J-Groove is coupled with a swirl stop. Next, the J-Groove technique was applied to centrifugal pumps of semi-open impeller, the suction performance is improved considerably without dropping the maximum efficiency, however in the case of closed impeller J-Groove is difficult to apply because of its shape. Here is proposed a new impeller of semi-closed type with J-Groove, resulting in perfect suppression of performance curve instability without dropping the maximum efficiency, and also in improving suction performance in the high flow range.In the second step, centrifugal compressor was tested as the most severe surge is usually observed Experiment revealed that J-Groove technique is very effective in suppressing surge and in enlarging surge-margin. From numerical simulations, it was made clear that the initiation of rotating stall of diffuser is of key importance to suppress surge, and that J-Groove technique is successfully applied to suppress the initiation of rotating stall and to enlarge surge-margin to a large extent when it is mounted near the outlet of diffuser, though its effect becomes less when mounted near the inlet of diffuser.