液压阀的节流温升与热形变的研究

发布时间：2018-05-05 01:15

本文选题：液压阀 + 节流温升　；参考：《兰州理工大学》2011年硕士论文

【摘要】：液压系统中,液压阀控制着系统中液流的压力、流量和方向,因此液压阀的性能对整个系统的性能起着至关重要的作用。液压滑阀和锥阀是常用的两种阀结构,由于滑阀阀芯、阀套(或阀体)间配合间隙较小,其在使用过程中常出现卡滞、卡死、磨损、泄漏等问题。本文采用了理论分析和数值仿真相结合的研究方法,针对液压阀内因节流而产生的油液和阀内温度变化所导致的阀特性的改变进行了深入的研究,计算结果表明:节流作用使得与固体接触的油液和固体部分温度较高,阀口形式对温升影响较大;阀芯、阀体内温度分布不均匀、不对称;阀芯、阀体受节流温升影响局部变形较大。主要内容如下: 第1章,阐述了本课题研究的背景和意义;概述了国内外关于液压阀内温度场、阀结构受热形变的研究现状和存在的问题;概括了本文的主要研究内容。第2章,分析了流体温升理论,对液压系统中温升的主要来源进行了讨论;讨论了材料和零件随温度变化的变化情况。第3章,利用CFD软件FLUENT对滑阀、锥阀、阻尼孔内流场和温度场进行了分析,得到了阀内部压力、速度和温度随阀口形式、开口量和进出口压差变化的分布情况。计算结果表明,阀内液流的温度分布不均匀,阀口流束与固体壁面接近的流体区域温度较高,流束中心部位温度较低,最高温度出现在最靠近流束的壁面区域,节流口后部出现漩涡的流体温度有所升高;这表明流体温度升高主要是由于阀口处的高速流体与壁面及其周边低速流体摩擦产生热量和漩涡的粘性耗散所致。第4章,有限元分析软件ANSYS将第三章分析的温度边界结果加载到对应的阀芯、阀体中,对阀芯和阀体的热变形进行有限元分析。计算结果显示:阀体和阀芯的温度分布不均匀、不对称,阀口区域和流束在阀腔内冲击到的固体壁面有局部高温;节流槽形状和阀口开度对阀内温度分布有较大影响,阀芯和阀体的热变形主要表现为阀芯局部直径变大、阀体孔局部变小,变形量可达数微米,并伴有弯曲变形现象.上述变形可能导致阀芯卡紧。最后,对本论文的研究工作和成果进行了总结,展望了下一步的研究工作。
[Abstract]:In the hydraulic system, the hydraulic valve controls the pressure, flow and direction of the fluid flow in the system, so the performance of the hydraulic valve plays an important role in the performance of the whole system. Hydraulic slide valve and cone valve are two commonly used valve structures. Due to the small gap between the valve core and valve sleeve (or valve body), the hydraulic slide valve and the cone valve often appear some problems in the process of application, such as sticking, wearing, leaking and so on. In this paper, the theoretical analysis and numerical simulation are used to study the change of valve characteristics caused by the change of oil and temperature in hydraulic valve due to throttling. The results show that throttling makes the temperature of oil and solid parts in contact with solids higher, and the form of valve port has a great influence on temperature rise; the valve core, the temperature distribution in the valve body is uneven and asymmetrical, the valve core, the valve core, the valve core, the valve core, the valve core, the valve core, The valve body is affected by throttle temperature rise in local deformation. The main contents are as follows: In chapter 1, the background and significance of the research are described, the research status and existing problems of the temperature field in the hydraulic valve and the thermal deformation of the valve structure at home and abroad are summarized, and the main research contents of this paper are summarized. In chapter 2, the theory of fluid temperature rise is analyzed, the main sources of temperature rise in hydraulic system are discussed, and the variation of materials and parts with temperature is discussed. In chapter 3, the internal flow field and temperature field of slide valve, cone valve and damping hole are analyzed by CFD software FLUENT, and the distribution of internal pressure, velocity and temperature of valve with valve form, opening quantity and inlet and outlet pressure difference is obtained. The results show that the temperature distribution of the liquid flow in the valve is not uniform, the temperature of the flow zone near the solid wall is higher, the temperature of the central part of the flow beam is lower, and the highest temperature appears in the wall region closest to the flow beam. The temperature of the fluid at the back of the throttle is increased, which indicates that the increase of fluid temperature is mainly caused by the friction between the high velocity fluid at the orifice and the low velocity fluid on the wall and the surrounding low speed fluid, which results in the heat and viscous dissipation of the swirl. In chapter 4, the finite element analysis software ANSYS loads the temperature boundary results of the third chapter into the corresponding spool and body. The thermal deformation of the spool and valve body is analyzed by finite element method. The results show that the temperature distribution of the valve body and the valve core is uneven and asymmetrical, and there is local high temperature in the solid wall impacted by the orifice region and the flow beam in the valve chamber, and the shape of throttle and the opening degree of valve opening have great influence on the temperature distribution in the valve. The hot deformation of the spool and the valve body mainly shows that the local diameter of the valve core becomes larger, the hole of the valve body becomes smaller, the deformation amount can reach several microns, and the deformation phenomenon is accompanied by bending. The above deformation may cause the spool to tighten. Finally, the research work and results of this paper are summarized, and the next research work is prospected.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH137.52

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