液压锥阀的振动特性研究

发布时间：2018-04-20 19:07

本文选题：液压锥阀 + 振动　；参考：《西南交通大学》2012年硕士论文

【摘要】：作为液压传动与控制中非常重要的基础性元件,液压锥阀具有密封性好,抗污染能力强,构造简单等特点,从而广泛应用于液压系统中。但液压锥阀在使用过程中所产生的振动、空化、噪声等问题严重影响了其应用场合。随着液压技术的发展,对液压元件的性能提出了更高的要求,因此,液压锥阀的振动、静态和空化方面的特性得到了学术界和工业界广泛的关注。论文主要采用CFD软件对液压锥阀的内流场进行建模和仿真,重点研究液压锥阀产生振动的原因以及如何从结构上消振的方法,附带模拟和计算不同结构锥阀的空化特性,从流体可视化的角度,分析不同结构锥阀易于产生空化的位置和强弱。论文主要包括五部分内容：(1)利用STAR-CD对简化的锥阀模型进行参数化六面体网格建模,通过ANSYS CFX的动态和稳态计算,重点分析锥角“A”和阀芯圆周直径“B”的大小对锥阀振动特性和静态特性的影响。并计算和分析阀口倒角对锥阀性能的影响；(2)根据阀芯动力学方程和流量方程,建立锥阀的动态数学模型,并在SIMULINK中搭建系统的数学模型,分析模型得出稳态液动力的大小和方向是对锥阀动态特性有较大影响的参数；(3)对日立建机使用中存在振动问题的锥阀,建立CFD模型并进行不同开度下的稳态计算,综合数学模型和不同开度下的压力分布云图,从结构上指出该锥阀易于产生振动的原因,并对原始结构进行改进,计算改进结构的流场分布并与原始结构比较,最后通过入口阶跃压力作用下的阀芯动态响应计算,验证了关于振动原因理论分析的正确性；(4)对日立建机的原始锥阀结构进行结构优化,研究不同结构参数对锥阀振动特性的影响,得出除了稳态液动力之外,入口的细长环逢节流也易引起锥阀的振动。根据振动的影响因素,提出三种优化结构锥阀,分别对其进行稳态和动态CFD计算,验证了振动因素分析的正确性；(5)对原始结构和改进结构锥阀进行CFD空化模拟,在流场仿真中加入空化模型以研究不同结构锥阀的空化特性,根据计算结果以及阀芯表面的压力分布曲线得出：原始结构锥阀易于振动但不易产生空化,优化和改进结构不易振动但却更易于产生空化,空化现象和振动现象是一对矛盾体存在于锥阀之中。
[Abstract]:As a very important basic component in hydraulic transmission and control, hydraulic cone valve is widely used in hydraulic system because of its good sealing ability, strong anti-pollution ability and simple structure. However, the problems of vibration, cavitation and noise in the process of application of hydraulic cone valve have seriously affected its application. With the development of hydraulic technology, higher requirements for the performance of hydraulic components have been put forward. Therefore, the vibration, static and cavitation characteristics of hydraulic cone valves have been widely concerned by academia and industry. In this paper, the internal flow field of hydraulic cone valve is modeled and simulated by CFD software. The reason of vibration of hydraulic cone valve and the method of how to eliminate vibration from structure are studied, and the cavitation characteristics of different structure cone valve are simulated and calculated. From the point of view of fluid visualization, the position and strength of cavitation of conical valves with different structures are analyzed. The thesis includes five parts: 1) Parametric hexahedron mesh modeling of simplified conical valve model using STAR-CD, and dynamic and steady calculation of ANSYS CFX. The influence of cone angle "A" and valve core circumference diameter "B" on the vibration and static characteristics of cone valve is analyzed. According to the dynamic equation of valve core and flow equation, the dynamic mathematical model of cone valve is established, and the mathematical model of the system is built in SIMULINK. The model shows that the size and direction of steady hydraulic force is a parameter that has great influence on the dynamic characteristics of cone valve. The CFD model is established for the cone valve with vibration problem in the use of Hitachi machine, and the steady-state calculation under different opening degree is carried out. By synthesizing the mathematical model and the pressure distribution cloud diagram under different opening degrees, the paper points out the reason why the cone valve is easy to vibrate from the structure, and improves the original structure, calculates the flow field distribution of the improved structure and compares it with the original structure. Finally, by calculating the dynamic response of valve core under the action of entrance step pressure, the correctness of theoretical analysis of vibration cause is verified. The original conical valve structure of Hitachi machine is optimized. The influence of different structural parameters on the vibration characteristics of conical valve is studied. It is concluded that in addition to the steady hydraulic force, the tapered valve vibration is easily caused by the throttling of the inlet slender ring. According to the influence factors of vibration, three kinds of optimized structural cone valves are put forward, and the steady-state and dynamic CFD calculations are carried out, respectively. The correctness of vibration factor analysis is verified. The CFD cavitation simulation of the original structure and the improved structure cone valve is carried out. Cavitation model is added to the flow field simulation to study the cavitation characteristics of cone valves with different structures. According to the calculation results and the pressure distribution curve of the valve core surface, it is concluded that the original structure cone valve is easy to vibrate but not easy to produce cavitation. The optimization and improvement of the structure are not easy to vibrate but it is easier to produce cavitation. Cavitation and vibration are a pair of contradictory bodies in the cone valve.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH137.52

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