双吸式液环泵内流场及壳体压力脉动分析

Analysis of Internal Flow Field and Shell Pressure Pulse of Double Suction Liquid Ring Pump

为分析大流量液环泵内流场与外特性,文章对双吸式液环泵内部流动进行数值模拟,对轴向不同位置的内流场和壳体压力脉动特性进行研究。结果表明:轮毂直径的变化主要影响气相的分布,过渡区气相面积随着轮毂直径的减小逐渐增加。叶轮流道内速度流线曲率变化剧烈,吸排气口附近流速较高,二次流旋涡主要集中在压缩区和过渡区,在轴向上中间截面过渡区内旋涡更加明显。壳体内壁压力脉动幅值在圆周角50°和300°附近出现极大值,压力脉动幅值极差随着轮毂直径的减小而降低,各特征截面压力脉动幅值极差分别为4.9 kPa、4.8 kPa、4.7 kPa。轴向不同位置相同角度处压力系数的主频特征基本相同,压缩区壳体内壁压力脉动一阶主频为轴频,其他区域的主频为叶频。从吸气区至排气区,叶频对应的压力脉动幅值逐渐减小,在压缩区达到最小值后呈增加趋势。

In order to analyze the flow field and external characteristics,a double-suction large-flow liquid ring pump was simulated to analyze the internal flow field and pulsation characteristics of shell pressure in different axial positions.The results show that the change in the hub diameter mainly affects the distribution of the gas phase,and the gas phase area gradually increases with the decrease of the hub diameter.The curvature of the velocity streamline in the blade passage changes sharply,and the flow velocity near the suction port and exhaust port is high.The secondary flow vortices mainly gather in the compression region and the transition region,and the vortices are more obvious in the transition region of the middle section.The maximum amplitude of pressure pulsation on the inner wall of the shell appears around the circumference angles of 50°and 300°,and the range of pressure pulsation amplitude declines with the decrease of the hub diameter,which is 4.9 kPa,4.8 kPa,and 4.7 kPa on the three characteristic sections in sequence.The frequency characteristics of different axial locations at the same angle are basically the same.The first-order frequency of the shell pressure pulsation in the compression region is the axial frequency,while that in the other regions is the blade frequency.From the suction region to the exhaust region,the pressure pulsation amplitude corresponding to blade frequency gradually decreases,and increases after reaching the minimum in the compression zone.