高温高压磁力泵流场模拟及轴向力分析

Flow field simulation and axial thrust analysis of high temperature and pressure magnetic drive pump

为满足炼油装置能够连续性生产的要求,对泵轴的密封性提出很高的要求,研究出用于输送高温热油的磁力泵技术.运用CFX软件对高温高压磁力泵进行全流场数值模拟,分析磁力泵流场的压力、速度、流线分布,比较磁力泵在高温热油介质和常温常压水2种介质下的外特性曲线,同时分析模型泵的轴向受力情况,验证设计的合理性.结果表明:设计的高温高压磁力泵适合在1.0Qd～1.6Qd的流量区间内工作,此时内部流线较为顺畅,叶片压力分布均匀,叶轮叶片未出现脱流现象,运行状况良好;介质的物理特性对磁力泵外特性性能曲线影响不大,磁力泵在高温热油和常温水2种介质下均可适用;内磁转子产生的轴向力相对于其他因素产生的轴向力较小,高温高压磁力泵产生的轴向力随流量的增大而减小,叶轮流道受到的合力随流量的增大而增大,叶轮各部分的静压力减小,总的轴向力减小;对磁力泵的水力结构及轴向力进行了校核,可为高温高压磁力泵设计提供参考.

To meet the requirement of continuous production of refinery units,quit high requirements are imposed on the shaft-sealing of pump,eventually,magnetic drive pump technique is developed for transporting hot oils. Flow filed in a high temperature and pressure magnetic drive pump was simulated numerically by using software ICEM and CFX. Pressure,velocity and streamline distributions were analysed,and the pump characteristic curves of high temperature oil and 20 ℃ water were compared,further axial thrust acting on the pump rotor was estimated to examine the rationality of pump design.The magnetic drive pump can work properly when flow rate is in a range of 1.0 Qd-1.6 Qd,specially,internal flow lines are smooth,and the pressure distributions on blade suction and pressure sides are even,and no flow separation phenomenon emerges as well. Physical property of the media shows littleeffect on magnetic pump performance curves so that the pump is applicable for two kinds of media. The axial thrust generated in inner magnetic rotor can be ignored compared with the axial thrust by the other factors. The total axial thrust is decreased with increasing flow rate. The resultant force in the impeller flow passages increases with increasing flow rate,and the static pressure around the impeller is reduced; hence the total axial thrust is lowered. Hydraulic structure and axial thrust of the magnetic drive pump have been verified,the paper provides a reference to design of high temperature and pressure magnetic drive pump.