RESEARCH ON TOTAL SUPPRESSION OF ABNORMAL FLOW PHENOMENAIN TURBOMASCHINERY

涡轮机械在非设计工况下运行时，会出现各种异常流动现象，产生噪声和振动。为了在不降低总效率的情况下完全抑制这些异常流动现象，建立日本突出的技术特点，进行了实验研究和数值模拟。在研究的快速阶段，由于通常会观察到最严重的空化现象，因此对诱导剂进行了测试。将j型槽技术应用于多个诱导器，结果表明：在低流量范围内，j型槽能明显抑制诱导器的空化现象，使诱导器的吸力性能提高到常规诱导器的2倍；在大流量范围内，j型槽加旋流止动器，诱导器的吸力性能提高到常规诱导器的15倍。然后，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情况下，显著提高了泵的吸力性能，但在闭式叶轮情况下，j型槽由于其形状难以应用。本文提出了一种带有j型槽的新型半封闭式叶轮，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，并提高了大流量范围内的吸力性能。实验结果表明，j型槽技术在抑制喘振和增大喘振裕度方面是非常有效的。数值模拟结果表明，扩压器旋转失速的起爆对抑制喘振至关重要，j型槽安装在扩压器出口附近时，成功地抑制了旋转失速的起爆，并在很大程度上扩大了喘振余量，而安装在扩压器进口附近时，j型槽的效果较差。

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.