水平90°弯管内冰浆流体流动特性的数值模拟

Numerical Simulation of Ice Slurry Flow in a Horizontal 90° Elbow Pipe

以水平面上90°弯管内冰浆流体等温流动为研究对象,采用双流体混合模型,借助于计算流体力学(CFD)模拟方法,研究了90°弯管内冰浆流体三维流动特性。结果表明,冰浆流体在弯管内湍流流动过程中,会呈现出类似于单相流体流经弯管时的二次流现象。弯管内的二次流动加剧了冰粒子与液体相间的混合,使得冰粒子在弯管出口截面处趋于均布。通过比较不同湍流模型计算获得的冰浆流体管道压降,发现模拟值与实验值间的相对误差均可控制在±20%内,但模型精度不尽相同;当浆体处于低速高浓度区域时,k-ε湍流模型预测效果较为理想。随着冰粒子浓度降低,由k-ω和SA(Spalart-Allmaras)湍流模型得到的管道压降模拟结果与实验测试值更为接近。

The two fluids mixture models were applied to simulate the ice slurry flow in a horizontal 90° elbow pipe without considering ice melting process. The results reveal that the secondary flow appears in the elbow pipe, which is similar to the single-phase fluid flow. The mixing process between ice particles and the carrier fluid is enhanced because of the secondary flow, and thus leading to the uniform concentration distribution of ice particles at the elbow outlet. By comparing different turbulence models for predicting pressure drop, all the models are found being able to provide results in good agreement with the experimental data. The relative errors are limited to 4-20%, though there are slightly different accuracies among different models. The k-ω turbulence model is suitable for large ice particle concentration when flowing velocity is low. With reduced ice particle concentration, the k-ω and SA models both have good accuracy.