浑水水力分离清水装置内弱旋流动的数值模拟

Numerical simulation of weak swirl turbulent flow in the turbid water hydraulic separation device

本文采用了不同的网格划分方案对装置内的弱旋流场进行计算,将计算结果与实测值对比,选出最优方案。在最优网格数下,分别采用RNGk-ε模型与RSM模型对装置内部流场进行计算,计算结果与实测结果均表明装置内的切向速度场呈现明显的强迫涡特征,有利于装置内的水沙分离;装置内的径向速度随着半径的增加而减小,在中心处取得最大值,并且通过理论分析给出了相同的结论。雷诺应力的初步分析表明装置内的湍流场可以近似为各向同性,因此综合考虑计算精度和计算耗时,RNGk-ε模型就可以较快地计算浑水水力分离清水装置内的湍流场,而不需选择计算时间较长的RSM模型。

The different grid division scheme is adopted to compute the weak swirl flow field in the turbid water hydraulic separation device and then the calculated result is compared with the experiment data, the most superior scheme is selected. The interior flow field is simulated separately with the RNG k -ε model and the RSM model under the selected grid division scheme. Both the simulation and the experiment result indicate that tangential velocity in the device has the characteristics of forced vortex, which is beneficial for the separation of water and sediment. On the other hand, the radial velocity in the device decreases as the radius increases and obtains the maximum value in the c＇enter of the device, which is proved by theoretical analysis. The preliminary analysis of Reynolds stress indicates that the turbulent flow in. the device can approximately be treated as isotropy. Therefore, with considering the calculation precision and time consumption, the RNG k -ε model can calculate the turbulent flow field in the device more quickly than the RSM model, so it is unnecessary to choose the RSM model.