蜗壳进口截面对液力透平径向力的影响

借助ANSYS-FLUENT软件，通过对一单级液力透平的蜗壳进行再设计，对液力透平在不同蜗壳进口截面情况下的径向力特性进行研究，并分析透平性能的变化情况。结果表明:透平径向力随蜗壳进口截面直径的增大而呈线性增大，当蜗壳进口截面直径大于一临界值时，径向力又缓慢下降；径向力合力的方向与隔舌的相对位置在小流量时为60°~90°，在大流量时为110°~150°；隔舌区域的流动对径向力的分布有较强的影响，经过蜗壳再设计后透平的效率要高于原透平的效率。  

Impact of volute inlet cross-section on the hydraulic turbine radial force

Radial force is one of the important factors affecting the operation stability of the hydraulic turbine. Alternating radial force loading on the hydraulic turbine shaft successively can induce a certain deflection, and other problems like vibration. The volute parameters are closely related to the radial force performance of the hydraulic turbine. In this paper, the volute of a single-stage hydraulic turbine was redesigned, and the ANSYS-FLUENT software was used to study the radial force performance of the hydraulic turbine of different volute inlet cross-sections. And also the changes of the turbine performance were analyzed. The results show that the radial force increases linearly with the increase of the volute inlet cross-section diameter. When the volute inlet cross-section diameter is greater than a critical value, there is a slow decline of the radial force. The relative position between the tongue and the resultant radial force direction is between 60°~90° at a low flow rate, and about 110°~150° at a high flow rate. The flow across the tongue region has a strong influence on the distribution of the radial force. Furthermore, the turbine efficiency with the redesign of the volute is higher than that of the original one.