Numerical Flow Simulation in a Centrifugal Pump atDesign and Off-Design Conditions

[摘要] The current investigation is aimed to simulate the complex internal flow in a centrifugal pump impeller with six twisted blades by using a three-dimensional Navier-Stokes code with a standardk-εtwo-equation turbulence model. Different flow rates were specifiedat inlet boundary to predict the characteristics of the pump. A detailed analysis ofthe results at design load,Qdesign, and off-design conditions, Q = 0.43Qdesignand Q = 1.45Qdesign, is presented. From the numerical simulation, it shows thatthe impeller passage flow at design point is quite smooth and follows the curvatureof the blade. However, flow separation is observed at the leading edge due to nontangentialinflow condition. The flow pattern changed significantly inside the volute as well, with doublevortical flow structures formed at cutwater and slowly evolved into a single vortical structure at the volute diffuser. For the pressure distribution, the pressureincreases gradually along streamwise direction in the impeller passages. Whenthe centrifugal pump is operating under off-design flow rate condition, unsteady flowdeveloped in the impeller passage and the volute casing.

[学科分类] 力学，机械学