Optimization Design and Performance Analysis of a Pit Turbine with Ultralow Head

摘要

A developed pit turbine with ultralow head was optimization designed under the design head of about 2 meters to achieve the goal of improving the turbine unit's efficiency. At the same time, the turbine's synthetic characteristic curve was drawn to predict the turbine's overall performance. Navier-Stokes equations and SIMPLEC algorithm were used for pit turbine's whole flow passage numerical simulation of the 3D, steady, incompressible, turbulent flow field. Through the CFD numerical simulation, the influence to ultralow head turbine's performance was analyzed by runner blade's different setting angles and guide vane's different axes. Considering the hydraulic performance of various methods, the best blade's setting angle and guide vane's axis were chosen. The results show that, the turbine unit has the best performance on efficiency, hydraulic loss, and so forth, with the blade's setting angle 23° and the angle 72° between the guide vane and the centerline of unit, meeting the power station's design requirements. The development pit turbine with ultralow head shows the highest efficiency of 87.6% under condition of design head of 2.1 meters and design discharge of 10 m~3/s. The energy performance of pit turbine with ultralow head was researched by the model test of GD-WS-35 turbine. The model turbine's characteristic curve was drawn. The model turbine's high efficiency area is wide and the efficiency changes mildly. The numerical simulation results are essentially consistent with the model test results, while the former one is slightly higher than the latter one. The error range is ±3%.