Pressure-Drop Coefficients for Cushioning System of Hydraulic Cylinder With Grooved Piston: A Computational Fluid Dynamic Simulation
Pressure-Drop Coefficients for Cushioning System of Hydraulic Cylinder With Grooved Piston: A Computational Fluid Dynamic Simulation
复制标题
带凹槽活塞液压缸缓冲系统的压降系数：计算流体动力学模拟
作者：
R. Castilla;Ignasi Alemany;A. Algar;P. Gamez;P. Roquet;E. Codina
缓冲是影响液压缸性能的一个重要方面。活塞在撞击端盖之前必须减速，以避免气缸部件中的应力，并减少可能传递给机器的振动。研究最少的方法之一是通过活塞上的凹槽进行内部缓冲。在这种方法中，当活塞到达出口位置时，通过适当设计的沟槽来节流。本文的目的是提出一种估算某型活塞槽的压降系数的方法，以便为建立缓冲系统的动态系统仿真提供一个模型。该方法基于计算流体力学模拟每个活塞的静态位置通过活塞槽到出口的流动。将计算结果与实验测量结果进行了比较，并提出了基于雷诺数的修正方法。对于所有的位置，尤其是最后的沟槽，计算结果与实验测量的偏差小于10%，符合程度均在16%以下。一般来说，数值模拟往往低估了第一道槽的压降，而高估了最后一道槽的计算量。
Cushioning is an important aspect in hydraulic cylinder performance. The piston has to be decelerated before it strikes the end cap in order to avoid stresses in the cylinder components and reduce vibration that can be transmitted to the machine. One of the least-studied methods is internal cushioning by grooves in the piston. In this method, the flow is throttled with adequately designed grooves when the piston reaches the outlet port position. The purpose of the present work is to present a method to estimate the pressure-drop coefficients for a certain design of piston grooves in order to provide a model to develop a dynamic system simulation of the cushion system. The method is based on a computational fluid dynamic simulation of flow through piston grooves to the outlet port for each piston’s static position. The results are compared with experimental measurements, and a correction, based on Reynolds number, is proposed. Good agreement, below 16%, was obtained for all the positions but particularly for the last grooves, for which the numerical result’s deviation to the experimental measurements was less than 10%. In general, the numerical simulation tended to underestimate the pressure drop for the first grooves and overestimate the calculation for the last grooves.