基于CFD的压力交换器压力能转换效率及内部流动特性研究

A study on pressure energy conversion effeciency and internal flow characteristics of pressure exchanger based on CFD

为分析压力交换器的压力能交换效率及内部流动特性,本文采用计算流体动力学(CFD)的方法,对不同进、出流管道半径R和不同转速下压力交换器的流场进行数值模拟计算。通过分析发现:进、出流管道半径越小,压力转换效率越低,高压管路进出口压差越大,高、低浓度盐水的掺混率越高;转速对转换效率的影响并不具有唯一确定性,转速对压力器压力能交换效率的影响程度具有周期性,但是每个周期的幅度不同,其中转速n=1000r/min时压力转换效率最低;转速越小转换效率越高,但是存在转子转速不适应能量转换效率的转速存在,即n=1000 r/min时,不能适合实际应用需求;在给定设计流量和转速情况下,本文设计的压力交换器可以用于压力交换,但效率有待提高,需要进行模型优化。

In order to analyze the pressure energy conversion efficiency and internal flow characteristics of pressure exchanger,this paper performs the calculation of numerical simulation for the radius of inlet/outlet flow pipes and the flow field of pressure exchanger at different rotate speeds by the computational fluid dynamics(CFD).It is found through analysis that the smaller the radius of inlet/outlet flow pipes is,the less the pressure conversion efficiency is,the bigger the differential pressure at the high-pressure pipe inlet/outlet is,and the higher the mixing rate of high-and-low concentration saltwater is.The rotate speed doesn’t exert a unique deterministic impact on the conversion efficiency,and it affects the pressure energy conversion efficiency of pressure exchanger periodically to different degrees.It is the lowest efficiency at a rotate speed(n)of 1000r/min.So the small the rotate speed is,the bigger the conversion efficiency is.However,the rotor speed doesn’t meet the practical requirement when the speed(n=1000 r/min)is not corresponding to the energy conversion efficiency.In the given design flow rate and rotate speed,the pressure exchanger designed in this paper can be used for pressure exchange,but it needs to be optimized by modelling so as for a further improved efficiency.