簸箕形进水流道喉部高度对水力性能的影响

The Influence of Height of Throat Section of Dustpan-shaped Inlet Conduit on Hydraulic Performance

为了探究不同喉部高度对簸箕形进水流道水力性能的影响,建立进水前池、进水闸室和簸箕形进水流道的进水结构模型和湍流数学模型,基于雷诺平均N-S方程,选择标准k-ε模型,采用SIMPLE算法,对喉部高度为0.7~0.9倍叶轮直径下的簸箕形进水流道水力性能进行了数值模拟,分析不同喉部高度下,簸箕形进水流道的流速分布、流道水力损失和流道出口流速分布均匀度和速度加权平均角度。研究结果表明:喉部高度过高的流道水流进入簸箕形吸水室后流速较低,分布不均匀,流道出口流速分布均匀度随流量变化较大,流道水力损失较大;喉部高度过低的流道水流进入簸箕形吸水室后流速较高,分布较均匀,流道出口流速分布均匀度与流量大小无关,流道水力损失大;经对不同喉部高度的流道水力性能分析,喉部高度最优方案为0.8倍的叶轮直径,该方案的流道水力损失最小、出口流速分布均匀度和速度加权平均角度分别为96.2%和88°,接近目标函数理想值。

In order to explore the influence of different throat height on the hydraulic performance of winnowing inlet channel,establish inlet pools,inlet chamber and winnowing inlet channel inlet structure physical model and turbulence mathematical model,based on the Reynolds average N-S equation,the standard k-εmodel is selected,SIMPLE algorithm is adopted,numerical simulation is carried out for the hydraulic performance of the dustpan inlet passage with the throat height of 0.7~0.9 times the impeller diameter,and the velocity distribution,hydraulic loss of the inlet passage,velocity distribution uniformity and velocity weighted average angle of the inlet passage with different throat height are analyzed.The results show that the flow velocity in the channel with high throat height is low and uneven after entering the winnowing chamber,the uniformity of flow velocity distribution at the outlet of the channel changes greatly with the flow,and the hydraulic loss of the channel is large.When the throat height is too low,the flow velocity is higher and the distribution is more uniform.The uniformity of flow velocity distribution has nothing to do with the flow size and the hydraulic loss of the flow passage is large.According to the analysis of the hydraulic performance of the channel at different throat heights,the optimal scheme is 0.8 times the impeller diameter.The hydraulic loss of the channel,the distribution uniformity of outlet velocity and the weighted average angle of velocity are 96.2%and 88°respectively,which are close to the ideal value of the objective function.