基于CFD的混砂罐出口排液问题分析

CFD-based Analysis of the Outlet Drainage of Mixing Sand Tank

混砂罐试验时若以清水为介质作业,一切正常,而以滑溜水为介质作业,则会出现混砂罐出口离心泵排量提不上去且出口压力波动很大的问题。鉴于此,先建立存在排液问题的混砂罐原始模型,再对原始模型的搅拌区液面形状进行较精确的分析,即基于计算流体力学软件Flu-ent对该混合过程进行两相流非定常数值模拟;最后运用理论公式再次设计混砂罐模型,并对修正后的混砂罐液面变化进行仿真分析。仿真分析结果表明,修正后的混砂罐避免了上搅拌桨的顶端露出液面而导致上搅拌桨同时搅拌液体和空气而引起压力波动。该设计可为混砂罐结构的优化设计和流场的预测提供参考和依据。

The mixing sand tank is normal when the test takes clear water as the medium. But if slickwater is used as the operating medium, the centrifugal pump displacement at tank outlet cannot increase and the outlet pressure fluctuation is remarkable. Therefore, the height from tank bottom to upper stirring paddle of the tank was first calculated according to the theoretical formula. Then, the computational fluid dynamics （CFD） software Fluent was applied to simulate the variation of the tank liquid level in order to prove the correctness of height. As a result the pressure fluctuation is avoided which is caused by the fact that the upper mixing paddle may mix liquid and air simultaneously owing to its top arising above the liquid level. The design method is of great importance to the optimal design of mixing sand tank.