偏心距对核主泵径向力影响的数值分析

为了研究核主泵所受径向力,基于RNG k-ε模型分别对原型核主泵和重心偏移后的核主泵进行数值模拟.通过模拟分别获得了原型泵和不同偏心距下核主泵外特性、中心截面的静压分布及作用在蜗壳和叶轮上的径向力特性,并将其与理论值进行对比分析.研究结果表明:对比试验与数值计算外特性曲线趋势一致,说明所建立的核主泵径向力计算模型具有一定的准确性;4种方案下叶轮与导叶内部的静压区别不大,而蜗壳内部的静压变化较明显,各偏心距下的静压呈非对称分布,偏心距的变化对核主泵的内外特性具有一定的影响;核主泵在设计点运行时径向力最小但不为零,偏心10 mm左右时所受径向力最小;通过对比不同偏心距下径向力数值预测值和Stepanoff理论公式计算值可知,不同偏心距所受径向力与理论公式值变化趋势一致,说明数值模拟的方法验证了用经验公式计算径向力的准确性.

Numerical analysis on effects of nuclear main pump radial force under different eccentricities

In order to study the radial force of nuclear main pump, the prototype pump and the offset of the center of gravity of the nuclear main pumps had been investigated numerically by CFD calculation based on the RNG k-ε model. Results of performance of the nuclear main pumps, distribution of static pressure at the center section and the radial force features acting in the volute and impeller features had been obtained from the simulation, and were compared with the theoretical analysis. The results showed that the test results and numerical calculation were in good agreement in this paper thus the results of numerical calculation of radial force calculation model for nuclear main pump has certain accuracy. There is no great difference in distribution of static pressure within four schemes in the impeller and guide vane, but in the volute varies obviously, the static pressure distribution of different eccentricity were asymmetric, and the change of eccentricity had a certain influence on the internal and external performances of nuclear main pump. The radial force of nuclear main pump was minimum when it operated at the design point, but not equal to zero,the radial force was optimum when the eccentricity were 10 millimeter. By comparing the predicted radial force and the Stepanoff theoretical ones under different eccentricities it could be known that, the curves trend of the radial force under different eccentricities were consistent with the theoretical ones and the method of the numerical simulation verified the accuracy of the radial force calculated by the empirical formula.