Numerical simulation and optimization of shaft tubular turbine runner with superlow head
YANG Chun-Xia, ZHENG Yuan, ZHENG Lu, LI Xiao-Xu, ZHOU Da-Qing, LI Ling-Yu
(1. College of Water Conservancy and Hydropower Engineering, Hohai University, Nanjing, Jiangsu 210098, China; 2. College of Energy and Electrical Engineering, Hohai University, Nanjing, Jiangsu 210098, China; 3. College of Business Management, Hohai University, Changzhou, Jiangsu 213022, China)
Abstract:For a hydropower station in North Jiangsu province, a shaft tubular turbine with about 2 m super low head was developed to effectively make use of low head hydro resources. The threedimensional, steady, turbulent flow in the flow passage of the turbine was numerically simulated by using the Navier-Stokes equations and the SIMPLEC algorithm, and the influences of vane section profile, runner diameter and stagger angle on the turbine performance were analyzed. Eventually, an optimal runner was specified by comparing the performance of different design cases. The results showed that after optimization the turbine with 1.75 m diameter and 23° stagger angle not only has met the design requirements by the hydropower station but also exhibits the best efficiency and the highest output power. At the design point (head 2.1 m, flow rate 10 m3/s), the turbine efficiency is 87.6%. Based on the optimized turbine a model turbine GD-WS-35 was made and its performance was measured in laboratory. Under the design condition (flow rate 0.398 m3/s), the best efficiency of the model was 8334%. By applying the scaling law of hydroturbine, the peak efficiency of the prototype of this model will be 8514% at the flow rate of 9.96 m3/s. The CFD predicted peak efficiency is slightly higher than experimental one, suggesting the error is within ±3% range.
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