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| Numerical simulation of three-dimensional turbulent flow in a transition process of a hydraulic turbine passage with uniform rotation of guide vane |
| WANG Wenquan, LI Weizhong, YAN Yan |
| Department of Engineering Mechanics, Kunming University of Science and Technology, Kunming, Yunnan 650500, China |
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Abstract The three-dimensional transition process in a simplified flow passage of model Francis turbine is researched based on an implicit direct forcing immersed boundary(IB)method combined with the three-step time-splitting method. The coupling mathematical model of the transition process including turbulent flow and rotating rigid guide vanes is established using unsteady Navier-Stokes equation with additional momentum source term. The moment source is not pre-calculated, but determined implicitly in such a way that velocity at the immersed boundary interpolated from the corrected velocity field accurately satisfies the non-slip boundary condition. The temporal distribution of vorticity and turbulent quantity are gained at the whole transient process, also, the drag and lift coefficients as well as other force against attack changing are obtained through the information transferring between the solid grid and fluid background grid. At the same time, the coupling relations among the turbulent flow, the dynamical force response of blade and the rotating of guide vane are achieved, which is helpful to improving the design of hydraulic transition process.
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Received: 16 June 2016
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