活塞压缩机管网气流脉动分析

发布时间：2018-10-11 07:14

【摘要】：本文针对往复式压缩机管网系统存在的气流脉动,分别从理论分析、减脉的常用装置、缓冲器模态与流场的分析几个方面做了研究。文章首先介绍了研究往复式压缩机管网系统脉动气流传递的理论方法平面波动理论,并在平面波动理论的基础上由管道系统中的结构单元出发,推导出脉动气流在复杂管道系统中的传递矩阵。对于在平面波动方程基础上得到的传递矩阵,使用有限元分析软件Ansys中的声学模态分析的方法验证了传递矩阵的精确性。其次,对传统的缓冲器进出口接管的方式做了改进,研究切向进口缓冲器及径向进口缓冲器在压缩机不同出口压力条件下对压力波动的减弱效果。分析不同进口缓冲器内部流场,比较各自流场流体迹线规律特点,得出影响减脉性能的流动机理。运用Fluent建立缓冲器及相关接管模型,根据实验所测的缓冲器进出口压力作为边界条件进行数值模拟计算。结果表明在不同压力等级下,缓冲器出口的脉动幅度减小程度基本一致,且切向进口向缓冲器减小压力脉动的效果更优。最后,从不同进口方式缓冲器性能存在差异出发,结合缓冲器内部流场与流体不同的迹线,联系流体流动的纳维斯托克斯方程与推导传递矩阵法的平面波动方程,比较理论计算的传递矩阵法与流体流动方程所忽略的影响因素,即流体介质在实际管网流动过程中由于结构因素所产生的流体在局部的回流、扩散、冲击等造成的能量损失。鉴于此,文章提出计算管网气流脉动的两步法：依照传递矩阵的理论方法得出在管道不同位置的压力脉动值,这个值是在几点假设后由简化的传递模型得到的,第二步即考虑流体流动的动力学性能造成的影响,把过程中存在的能量损失添加到传递矩阵法计算得到的气流的脉动参数值中去,这与工程实际中的值会更加接近。
[Abstract]:In this paper, the flow pulsation of reciprocating compressor pipe network system is studied from several aspects, such as theoretical analysis, common device of reducing pulse, mode of buffer and analysis of flow field. This paper first introduces the theoretical method to study the pulsating air flow transfer of the reciprocating compressor pipe network system, and based on the plane wave theory, it starts from the structural unit in the pipeline system. The transfer matrix of pulsating airflow in complex pipeline system is derived. For the transfer matrix based on the plane wave equation, the accuracy of the transfer matrix is verified by using the acoustic modal analysis method in the finite element analysis software Ansys. Secondly, the traditional way of inlet and outlet nozzle of buffer is improved, and the weakening effect of tangential inlet buffer and radial inlet buffer on pressure fluctuation under different outlet pressure of compressor is studied. The internal flow field of different inlet buffers is analyzed, and the characteristics of the flow trace are compared, and the flow mechanism that affects the performance of pulse reduction is obtained. The model of buffer and related nozzle was established by Fluent, and the inlet and outlet pressure of buffer was numerically simulated according to the boundary condition measured in the experiment. The results show that the amplitude of pulsation at the outlet of the buffer is basically the same at different pressure levels, and the effect of tangential inlet to the buffer is better. Finally, starting from the difference of the performance of different inlet buffers, combining the different traces of flow field and fluid in the buffer, the Navistoks equation of fluid flow and the plane wave equation derived from the transfer matrix method are connected. The transfer matrix method is compared with the influence factors neglected by the fluid flow equation, that is, the energy loss caused by the local flow, diffusion and impact of the fluid produced by the structural factors in the actual pipe network flow process. In view of this, a two-step method for calculating the flow pulsation of pipe network is proposed: according to the theoretical method of transfer matrix, the pressure pulsation value at different locations of the pipeline is obtained by a simplified transfer model after several hypotheses. In the second step, considering the influence of the dynamic performance of the fluid flow, the energy loss in the process is added to the pulsating parameter value of the airflow calculated by the transfer matrix method, which will be closer to the value in the engineering practice.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH45

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