基于核主泵性能预测的数值模拟精度研究

为提高核主泵在全工况点的数值模拟精度，研究了数值模拟过程中近壁面网格尺度、湍流模型、流动状态3种因素对计算精度的影响。结果表明，在定常状态下，重整化群（RNG） k-ε湍流模型和标准壁面函数法在近壁面网格尺度（y+）为50左右时具有较高的计算精度，并且其计算精度高于RNG k-ε增强壁面函数法、低雷诺数k-ε和剪切应力传输（SST）k-ω这3种湍流模型的计算精度，但上述不同网格尺度和湍流模型的计算结果均存在较大的计算误差；采用非定常计算时的计算精度明显高于定常计算，能够反映出扬程曲线在关死点附近的驼峰现象，效率的计算精度也有一定改善，更适合于对核主泵进行性能预测。 

Research of Numerical Simulation Accuracy Based on Performance Prediction of Nuclear Main Pump

In order to improve the numerical simulation accuracy of the nuclear main pump at all the working points, three factors affecting the numerical simulation results, i.e., the near-wall mesh scale, turbulence model and flow state are comprehensively studied. The results show that the RNG k-ε turbulence model and the standard wall function method have higher calculation accuracy when y+=50, and the calculation accuracy is also higher than that of three kinds of turbulence models, i.e., ?the RNG k-ε enhanced wall function method, low Reynolds number k-ε and SST k-ω. However, the calculation results of the above-mentioned different grid scales and turbulence models have large errors. Under the unsteady state calculation, the calculation accuracy of the unsteady state calculation method is significantly improved compared with the steady state calculation method, which can reflect the hump phenomenon of the head curve near the dead point, and the calculation accuracy of efficiency is also improved. The unsteady calculation method is more suitable for performance prediction of nuclear main pump.