基于CFD的液压冲击器流场的仿真与研究

发布时间：2018-05-27 14:14

本文选题：液压冲击器 + 计算流体动力学　；参考：《上海工程技术大学》2011年硕士论文

【摘要】：本文阐述了液压冲击器国内外发展趋势和最新研究现状，以某一型号气液联合式液压冲击器为研究对象，建立了液压冲击器的二维和三维模型，分析了它的工作原理，介绍了它的主要参数。通过建立冲击器系统的数学模型，研究了冲击器系统各参数对冲击器工作性能的影响。运用MATLAB的Simulink仿真软件包分别对液压冲击器的回程加速过程和冲程过程进行仿真研究，并对氮气室预充压力对冲击器冲击性能的影响程度进行了深入分析。结果表明：氮气室预充压力过大，则会导致液压油推不动活塞进行回程，液压冲击器起动不了；压力过小则很容易造成冲击压力升不上去，冲击能小。在参阅大量国内外有关计算流体动力学、流场的数值模拟方法、流场可视化技术等相关资料的基础上，利用AutoCAD和CATIA软件分别建立了冲击器管道和换向阀的几何模型；然后利用前处理软件GAMBIT进行网格的划分。应用CFD分析软件FLUENT，用有限元方法对各种复杂流道和换向阀节流口处的流场进行数值模拟。并将计算结果以图像的形式给出，在此基础上定性分析了流体速度、流线、漩涡与能量损失的关系。本文通过对直角弯管、偏心相交管道流场进行的数值模拟，分别得出了直角弯管、偏心相交管道的压力、速度、流线可视化图象，指出了流体流动时涡旋产生的位置和强弱情况。通过对流场数值模拟，得出了直角弯管进油流量与压力损失差之间的关系。阐述滑阀式换向阀的工作特点及工作过程，结合其工作特点选择了流体控制体积，确定了研究区域的边界条件。模拟了换向阀工作过程中的流场结构的变化情况，，定性的分析换向阀产生能量损失的原因。本文进行的研究工作为液压冲击器系统的结构设计和性能优化提供一定的参考依据，将为液压冲击器的设计与开发提供指导。
[Abstract]:In this paper, the development trend and the latest research status of hydraulic impactor at home and abroad are described. Taking a certain type of gas-liquid combined hydraulic impactor as the research object, the two-dimensional and three-dimensional models of hydraulic impactor are established, and its working principle is analyzed. Its main parameters are introduced. By establishing the mathematical model of the impactor system, the influence of the parameters of the impactor system on the working performance of the impactor is studied. The acceleration process and stroke process of hydraulic impactor are simulated by Simulink software package of MATLAB, and the influence of nitrogen chamber precharge pressure on impact performance of hydraulic impactor is deeply analyzed. The results show that if the pressure of nitrogen chamber is too large, it will lead to the return of the hydraulic oil impinging piston, the hydraulic impactor can not start, and the pressure too small can easily cause the impact pressure to rise and the impact energy to be small. On the basis of referring to a lot of relevant data about computational fluid dynamics, numerical simulation method of flow field, visualization technology of flow field and so on, the geometric models of impactor pipeline and directional valve are established by using AutoCAD and CATIA software respectively. Then we use the pre-processing software GAMBIT to divide the grid. The flow field at the throttle of various complex flow channels and directional valves is numerically simulated by using CFD analysis software fluent and finite element method. The results are given in the form of images. On this basis, the relationship between fluid velocity, streamline, vortex and energy loss is analyzed qualitatively. Based on the numerical simulation of the flow field of right angle curved pipe and eccentric intersection pipe, the visualization images of pressure, velocity and streamline line of right angle bend pipe and eccentric intersection pipe are obtained in this paper. The position and strength of vortex in fluid flow are pointed out. Through the numerical simulation of the flow field, the relationship between the inlet flow rate and the pressure loss difference is obtained. This paper describes the working characteristics and working process of the slide valve type directional valve, selects the control volume of the fluid and determines the boundary conditions of the study area according to its working characteristics. The change of flow field structure during the operation of reversing valve is simulated and the reason of energy loss is analyzed qualitatively. The research work in this paper provides a certain reference for the structure design and performance optimization of the hydraulic impactor system, and will provide guidance for the design and development of the hydraulic impactor.
【学位授予单位】：上海工程技术大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH137

【参考文献】