基于CFD往复式压缩机气阀的特性分析

发布时间：2019-02-14 12:19

【摘要】：本文对往复式压缩机气阀的动力特性和气体通道形状进行了分析研究。首先采用基础知识分析的方法，计算出了气阀气流通道气速的变化规律和气阀阀片的工作过程曲线，然后运用数学分析的方法，计算出不同形式的气体通道对气阀流速和压力的影响，进而得到最优结构的气阀气流通道。通过对气阀的动力特性分析计算，求得出了阀片的升程曲线、气流速度曲线和阀损曲线，从而得到了气阀通道的气速，并对平均流速和瞬时流速进行了对比；由分析结果可以看出，由于吸气过程初始时，气阀通道开启较小，此时通道里的气速比较大，而且脉动特别明显；当压力足够将进气阀完全打开后，气阀的进气速度近于平稳，波动较小。同样在进气阀关闭的过程中，由于气阀通道的面积变化，气阀通道的气速又出现了明显波动。从分析可知，，气阀的进气速度的最大值要大于气阀的平均气速，所以要更好的反映气流在气阀通道里的流动情况，在计算气速时最好是计算气阀通道的瞬时气速。依据阀片的运动规律，又利用分析软件ANSYS/CFD对两种形式的气体通道进行数值模拟计算，得出了气体流速和压力随气体通道形式的变化，并将计算所得的流速值和压力值进行了比较，结果得出直通式气阀更可靠。模拟结果表明：直通式气阀在气流流通过程中，气阀通流截面没有变化，使气体流通过程稳定顺畅，对阀座的冲击力相对较小；而锥形气流通道的气阀，在气流流通过程中，气阀通流截面由大变小，此时阀隙气速变化比较大，而且波动明显，增加了对阀座的冲击力。所以在进行气阀结构的设计计算时，最好采用直通式气阀，这样可以增加气阀的使用寿命，提高压缩机的稳定性和经济性。
[Abstract]:In this paper, the dynamic characteristics and gas channel shape of reciprocating compressor valve are analyzed and studied. Firstly, by using the method of basic knowledge analysis, the variation law of the gas velocity and the working process curve of the valve plate are calculated, and then the method of mathematical analysis is used to calculate the change law of the gas velocity of the air valve passage and the working process curve of the valve plate. The effects of different gas channels on the flow rate and pressure of the valve are calculated, and the optimal structure of the valve airflow channel is obtained. Through the analysis and calculation of the dynamic characteristics of the valve, the lift curve, the velocity curve and the loss curve of the valve plate are obtained, and the gas velocity of the air valve passage is obtained, and the average velocity and the instantaneous velocity are compared. It can be seen from the analysis results that the opening of the air valve channel is smaller at the beginning of the suction process, and the gas velocity in the passage is larger and the pulsation is especially obvious. When the pressure is enough to completely open the inlet valve, the intake speed of the valve is nearly stable and the fluctuation is small. In the process of valve closing, the gas velocity of the inlet valve also fluctuates obviously because of the change of the air valve channel area. From the analysis, it can be seen that the maximum inlet velocity of the valve is larger than the average gas velocity of the valve, so to better reflect the flow situation of the air flow in the air valve channel, it is better to calculate the instantaneous gas velocity of the air valve channel when calculating the gas velocity. According to the motion law of the valve plate and the numerical simulation of two kinds of gas channels by using the analysis software ANSYS/CFD, the variation of gas velocity and pressure with the gas channel form is obtained. The calculated velocity value and pressure value are compared and the results show that the straight-through valve is more reliable. The simulation results show that the flow section of the straight through valve does not change in the process of air flow, which makes the gas flow process stable and smooth, and the impact force on the valve seat is relatively small. In the conical air flow channel, the flow section of the valve is changed from large to small, and the valve gap gas velocity changes greatly, and the fluctuation is obvious, which increases the impact force on the valve seat. Therefore, in the design and calculation of the valve structure, it is better to adopt the straight-through air valve, which can increase the service life of the valve and improve the stability and economy of the compressor.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH45

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