核主泵关键过流部件非定常流动特性分析

为改善核主泵的水力性能,减少核电事故,促进核主泵的国产化,对混流式核主泵的水力单元进行了定常与非定常数值计算,以探究其关键过流部件的流动特性。对流量在0.2~1.0 Q0工况条件下核主泵的外特性进行了分析,重点对其极小流量工况、最优工况以及设计工况下叶轮与压水室的内流特性进行了分析研究。结果表明,叶轮叶片的进口靠近后盖板的位置容易出现涡流,在叶轮的出口部位,压力脉动最为剧烈,而且叶轮的压力波动幅度明显要高于压水室的;压水室类球形蜗壳内的流体流动呈螺旋状,在其近壁面,特别是类隔舌的位置,较易形成不稳定的流动;叶轮与压水室压力脉动的主频与叶频相近,核主泵水力单元的最优工况出现在0.8 Q0,其效率为82.22%;同时研究结果还表明,如果流量过小,则易造成大量的绕流漩涡,而且压力脉动的程度也将随之显著增加。

Unsteady flow characteristics in key flow-passage parts of reactor coolant pump

In order to improve the hydraulic performance , reduce nuclear accidents , and promote the localization of the reactor coolant pump manufacture , we carried out steady and unsteady numerical calculation for the hydraulic unit of mixed -flow reactor coolant pump to study the flow characteristics in the key flow -passage parts .Through the analysis on the external characteristics in the case of 0.2Q0 ~1.0Q0 , the internal flow characteristics of the impeller and pressurized water chamber under the conditions of the minimum flow , optimal condition and design condition were mainly studied .The results show that the vortex takes place easily in blade inlet near the shroud , and the pressure pulsation in impeller outlet is the most intense .The amplitude of pressure pulsation of the impeller is higher than that of the pressurized water chamber .The flow in the spheroid volute case of the pressur-ized water chamber is spiral , which causes the unstable flow near the wall , especially at the volute tongue .The dominant fre-quency of pressure pulsation is close to the blade frequency , and 0.8Q0 is the optimal condition with a high efficiency of 82. 22%.However, a great deal of vortex will be generated around and the pressure fluctuation degree will increase significantly if the flow is too small .