液环泵作真空泵与压缩机工况下的内流场及外特性分析

Analysis of flow field and hydraulic characteristics of liquid-ring pump as vacuum pump and compressor

采用数值模拟和实验相结合的方法,对2BE型液环泵在真空泵与压缩机工况下的内流场及外特性进行对比分析.结果表明:相同的进出口压比时,压缩机体积流量小于真空泵体积流量,体积流量比和效率比均随着压比的增大而逐渐下降;真空泵和压缩机工况下内部的相态场、速度场和压力场分布规律基本一致;压缩机工况下的排气区和过渡区叶轮内旋涡二次流明显要强于真空泵工况下的,相同压比变化时压缩机工况下排气区内壁压力显著增大;液环泵壳体内壁压力的频域特性沿圆周方向存在明显的分区特征;真空泵工况下的各阶主频特性与压缩机工况下的完全一致;在各压比下,压缩机工况的泵壳体内壁压力脉动幅值整体大于真空泵工况的,随着压比的增大,压缩机工况下的排气区和过渡区壳体内壁压力脉动幅值明显增大.

The inner flow and performance of vacuum pump and compressor conditions of 2BE liquid-ring pump were analyzed by using numerical simulation and experimental method.Analysis results show that the volume flow rate of compressor is less than that of the vacuum pump under the same pressure ratio,and the ratio of volume flow rate and efficiency decrease with the increasing of pressure ratio.The distribution of phase,velocity and pressure field are basically the same under the conditions of vacuum pump and compressor.The secondary flow in the exhaust zone and the transition zone of the compressor are obviously stronger than those in the vacuum pump condition.Under the same variation of pressure ratio,the pressure in the exhaust area of the compressor increases significantly.The frequency characteristics of pressure for the pump casing shows obviously partition characteristics along the circumferential direction.The main frequency characteristic of vacuum pump is the same as that of compressor.Under different pressure ratios condition,the pressure fluctuation amplitude of the inner wall of the pump housing in compressor condition is larger than that of the vacuum pump.With the increase of the pressure ratio,the pressure fluctuation amplitude for the compressor exhaust zone and transition zone increases obviously.