三螺杆泵流场动力学特性数值模拟

Numerical Simulation of Flow Field Dynamics Performance of Three Screw Pump

目前对三螺杆泵的研究目标是实现高速、高压、大流量,其中提高三螺杆泵工作压力的重要途径是提高泵螺杆的型线设计和加工精度,严格控制各传动间隙以减少泵的内部泄漏。利用数值计算方法生成主、从动螺杆型线,并在MATLAB软件进行编程验证。在UG软件中建立了主、从动螺杆的三维模型,导入Fluent软件进行流场仿真分析,获得了主、从动螺杆在不同中心距、不同齿顶间隙条件下流道压力的变化和不同螺杆转角所对应的泵内流场压力和流线的分布规律。仿真结果显示:当齿顶间隙由0.1 mm增大至0.2和0.3 mm时,沿轴向距螺杆端面80~100 mm的三螺杆泵压力分别减小3.85%和8.1%,而不同压力差所对应的压力值依次减少16.9%、16.6%和15.4%,且压力差越大,泄漏越大;三螺杆泵的泵腔压力随中心距的增大而波动,当中心距从45 mm增大到45.3 mm时、输出设定压力差为5 MPa的压力值下降10%,而输出设定压力差为4 MPa和3 MPa压力值则分别下降9.7%和9.6%。

At present,the research goal of triple-screw pump is to achieve high speed,high pressure and large flow.The important way to improve the working pressure of triple-screw pump is to improve the design and processing accuracy of the screw profile,and strictly control the transmission clearance to reduce the internal leakage of the pump.The main and driven screw rotor profiles were generated by numerical calculation method and verified by programming in MATLAB software.The three-dimensional model of the main and driven screw was established in UG software.The simulation analysis was carried out in Fluent software.The flow channel pressure under different center distance and different top clearance of the main screw and the driven screw and the distribution law of the inner flow field pressure and the flow line corresponding to the position of the screw rotation angle were obtained.The simulation results show that when the tip clearance increases from 0.1 mm to 0.2 and 0.3 mm,the pressure decreases by 3.85%and 8.1%respectively along the axial distance from 80 to 100 mm to the screw end face,while the pressure decreases by 16.9%,16.6%and 15.4%respectively under different pressure differences,and the greater the pressure difference,the greater the leakage.The pressure of pump chamber fluctuates with the increase of center distance.When the center distance increases from 45 mm to 45.3 mm,the pressure value decreases by 10%as the output set pressure difference is 5 MPa,while the pressure value decreases by 9.7%and 9.6%respectively as the output set pressure difference is 4 MPa or 3 MPa.