潮流能涡轮机水动力性能与能量损失特性分析

Analysis of hydrodynamic performance and energy loss characteristics on tidal current turbine

为了分析潮流能涡轮机的水动力学性能和评估其能量损失发生的位置与损失机理,以一水平轴涡轮机为研究对象,通过引入熵产理论模型并采用SST k-ω湍流模型对其进行了三维数值模拟研究.研究结果表明:在涡轮机工作范围内,其功率系数C P与推力系数C T值均随尖速比TSR的增大而呈现出先增大而后减小的趋势,涡轮机在高TSR下的瞬时C P与瞬时C T的波动值比低TSR下的大.在相同来流下,涡轮机的黏性耗散熵产值和湍流耗散熵产值均随着TSR的增加而增大,湍流耗散熵产远高于黏性耗散熵产,其在总熵产中的占比达到了99.56%~99.65%.涡轮机在低TSR下的尾流能量损失区域位于叶尖端及轮毂后方,在高TSR下能量损失区域主要位于叶尖端,且高TSR下损失强度要明显大于低TSR下的.此外,涡轮机叶片不同截面处越靠近叶尖,其能量损失也越明显.研究结果揭示了潮流能涡轮机的水力流动特点和能量损失机理,为其优化设计及能量损失识别分析提供了一定的参考依据.

In order to analyze the hydrodynamic performance of tidal turbine,and evaluate the location and mechanism of energy loss.A horizontal axis turbine was taken as the research object,a three-dimensional numerical simulation was carried out by introducing entropy generation theory model and using SST k-ωturbulence model.The results show that the values of power coefficient(C P)and thrust coefficient(C T)of turbine first increase and then decrease with the increase of the tip speed ratio(TSR)under turbine operation conditions.The fluctuating instantaneous values of C P and C T of turbine at high TSR is larger than that at low TSR,and the value of viscous dissipation and turbulent dissipation entropy production increases versus TSR s at same inflow velocity.The turbulent dissipation entropy production is much larger than that of viscous dissipation entropy production,which reaches 99.56%to 99.65%among the total entropy production.Furthermore,the wake energy loss zone is located behind the blade tip and hub at low TSR,while the energy loss zone is mainly located behind the blade tip at high TSR.The energy loss intensity at high TSR is significantly greater than that at low TSR.Besides,the closer the different sections of turbine blades are to the blade tip,the more obvious the energy loss is.The above research results reveal the hydrodynamic flow characteristics and energy loss mechanism of tidal turbine,which offers a reference for the optimal design and energy loss identification.