双流道泵内非定常流动数值模拟及粒子图像测速测量

为探讨双流道泵内部的非定常流动机理，采用Fluent软件，基于滑移网格技术、 湍流模型计算了一双流道泵在不同工况下的内部流动，并将计算结果与粒子图像测速仪(Particle image velocimeter, PIV)实测结果进行比较。结果表明：计算所得双流道泵内部流场符合叶轮机械内部流动的一般规律，且与PIV实测结果总体变化趋势一致；由于双流道泵结构特殊，其进口处的流动状态与普通叶轮相差较大，出口处的流动状态与普通叶轮类似；叶轮进口处，流体基本沿流道吸力面流动，流道工作面上的相对速度很小，存在严重的脱流和旋涡；叶轮出口处，压力面和吸力面的速度趋于相等，射流—尾迹现象并不明显；由于叶轮—蜗壳动静干涉，两个叶轮流道内的静压分布有所不同；同一流道内，静压随着半径的增加而逐步增大，压力面侧静压大于吸力面侧；蜗壳流道内静压随半径增大，最大静压值在隔舌处。此项研究不仅加深了人们对双流道泵内非定常流动图画的理解，从而进一步完善双流道泵设计方法，同时也可为其他类型泵的内流研究提供借鉴。

Numerical Simulation and Particle Image Velocimeter Measurement for Unsteady Turbulent Flow in Double-channel Pump

To further study the unsteady flow mechanism in double-channel pump, simulations of turbulent flow in its whole flow channel are performed by using the flow computational software Fluent under different operating conditions, based on the sliding mesh technology and two-equation turbulence model. The calculation results are compared with the experimental data by particle image velocimeter (PIV). From the numerical and experimental research, it is found that, the calculated flow field conforms to the general flow rule in turbine machines, and its overall change tendency agrees well with PIV results; compared with the ordinary centrifugal-type impeller, its inlet flow status is quite different and outlet flow status changes little because of its special structure; in the impeller inlet, the fluid basically flows along the suction side, and the relative velocity is very small along the pressure side accompanied by serious separate flow and vortex; in the impeller outlet, the velocity on the pressure and suction side tends to be uniform, and jet flow phenomenon is not observed; as a result of interaction between the impeller and volute, static pressure distribution in one passage is different from another; in one flow channel, static pressure gradually increases with the radius increase, static pressure on pressure side is larger than that on suction side, and the biggest static pressure is near the tongue. This research will strengthen people’s understanding of the unsteady turbulent flow pattern in double-channel pump, thus further improve the design method of double-channel pump, simultaneously might provide reference for internal flow research of other types of pumps.