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.