反转双涡轮机械非定常流动与干涉控制

Unsteady flow and interaction control of counter-rotating double-rotor turbine

为了大幅度提高水力机械的动力性能及运行稳定性,开发研制了反转双涡轮灯泡贯流式水轮机组.水轮机的前后涡轮均采用可动翼型,依新提出的翼型公平负荷设计方法,寻求两涡轮间欧拉能量需求及交换的合理化,在严密取得欧拉能量均衡之下设计两涡轮由轮毂至轮缘的翼型形状;接着通过非定常流动数值解析探讨双涡轮水轮机的欧拉能量平衡程度及干涉控制效果.研究结果表明:流量相等、落差相同、几何尺寸与单涡轮相同时,前后涡轮出力相加动力输出增为2倍.分析了两涡轮间、后涡轮出口与尾水管入口间的非定常流动干涉现象,得到了如下的结论:新开发的双涡轮间流动干涉程度非常小,协联工况时水力脉动只为各落差的2%程度左右,未见压力突变的发生,亦可以说干涉程度得到了成功的控制;反转两涡轮之间的动力矩相平衡,因此稳定性好.

In order to drastically increase the power performance and the operating stability of hydraulic machinery,a new bulb turbine with counter-rotating double-rotor was developed.An adjustable-blade system was applied to both rotors of the turbine.Based on the new concept of fair-blade loading,a logical balance of supply and demand for Euler energies between the two rotors was sought.The blade profiles from hub to tip were designed to keep the equilibrium of Euler energy strictly.By the numerical unsteady flow analysis,the degree of Euler energy balance and the control of their interaction were investigated.The research results show that when the front and rear rotors have the same discharge and head,and is under the same size as that of a single rotor turbine,the sum of output powers from the front and rear rotors was doubled.By analyzing the flow interaction between two rotors and between the outlet of rear rotor and inlet of diffuser,the following conclusions are obtained： the output power is doubled without changing the unit size.The Euler energy interaction between the counter-rotating double-rotor is controlled to be small.The amplitude of hydraulic fluctuations is only about 2% of respective head without pressure surge under the on-cam operation.The rotating torques of the two rotors are compensated with good stability.