RESEARCH ON TOTAL SUPPRESSION OF ABNORMAL FLOW PHENOMENAIN TURBOMASCHINERY

叶轮机械在变工况运行时，会出现各种异常流动现象，产生噪声和振动。为了建立一种突出的日本技术特点，在不降低总效率的情况下完全抑制这些异常流动现象，进行了实验研究和数值模拟。在研究的快速步骤中，由于最严重的空化现象经常被观察到，所以对诱导器进行了测试。将J型槽技术应用于几种诱导器，结果表明，在小流量范围内，J型槽的空化得到了显著的抑制，吸气性能提高了一倍；在大流量范围内对J型槽进行了优化，吸气性能也可以提高到常规的15倍。其次，将J型槽技术应用于半开式叶轮的离心泵，在不降低最大效率的情况下，大大改善了泵的吸力性能，但在闭式叶轮的情况下，由于J型槽的形状，应用起来比较困难。提出了一种新型的带J型槽的半封闭式叶轮，在不降低最大效率的情况下，完美地抑制了性能曲线的不稳定性，并改善了大流量范围内的吸气性能。第二步，对通常观察到的最严重喘振的离心式压气机进行了试验。实验表明，J型槽技术在抑制喘振和扩大喘振裕度方面是非常有效的。数值模拟结果表明，扩散器旋转失速的启动是抑制喘振的关键，而J-槽技术在靠近扩散器出口时成功地抑制了旋转失速的启动，并在很大程度上增大了喘振裕度，但在靠近扩散器入口时效果较差。

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.