Wang Leqin

Three dimensional flow simulation of load rejection of a prototype pump-turbine

Three dimensional (3D) unsteady, incompressible flows in a pump-turbine during a transient process of load rejection were studied using the computational fluid dynamics method. The dynamic mesh (DM) method and remeshing method combined with non-conformal grid boundaries were applied to simulate the rotation of guide vanes. The fluid coupling and DM method were used to calculate the rotational speed for each time-step. Calculations were performed based on the

Dynamic balancing of dual-rotor system with very little rotating speed difference

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Novel boundary element method for resolving plate bending problems

turbulence model to incorporate the near-wall turbulence anisotropy as well as non-local pressure–strain effects. Results show that

Numerical simulation of transient flow past impulsively started circular cylinder based on dynamic mesh method

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Sealing device for pump shaft

model is thought to be suitable to predict characteristics of the transient process during load rejection in a pump-turbine. The transient explicit characteristics, such as the flow-rate, head, torque of the runner, etc., during the process of load rejection are analyzed. Pressure fluctuation was larger in the region close to the runner during the load rejection. Stalls and reverse flow in the runner resulted in the decrease of the torque of runner at turbine mode and turbine-braking mode. Simulation results were also compared and verified by experimental results. 3D simulations can be used instead of experiments to study the influence of inner flow to the external characteristics during transient processes. This calculation was based on a prototype of a pumped storage power station, and the computational method could be used in the fault diagnosis of transient operation.

Cam rotor pump for conveying high-viscosity medium

With regard to the reactor coolant pump and high flow-rate circulating pump, the requirements on the compactness of the structure, safety, and hydraulic performance are particularly important. Thus, the mixed-flow pump with cylindrical casing is adopted in some occasions. Due to the different characteristics between the special cylindrical casing and the common pump casing, the influence of the special casing on a mixed-flow pump characteristics was numerically investigated to obtain better performance and flow structure in the casing. The results show that the models with cylindrical casing have much worse head and efficiency characteristics than the experimental model, and this is caused by the flow in the pump casing. By moving the guide vanes half inside the pump casing, the efficiency gets improved while the low pressure zone at the corner of outlet pipe and pump casing disappeared. When the length of pump casing increases from the size equal to the diameter of outlet pipe to that larger than it, the efficiency drops obviously and the flow field in the outlet pipe improved without curved flow. In addition, the length of the pump casing has greater impacts on the pump performance than the radius of it.