液壓滑閥間隙熱形變與污染顆粒分布的仿真研究
發(fā)布時(shí)間：2018-12-12 16:35
【摘要】：液壓閥作為流體動(dòng)力傳動(dòng)與控制的關(guān)鍵元件之一,被廣泛應(yīng)用于液壓系統(tǒng)。然而,隨著液壓技術(shù)的全面發(fā)展,液壓系統(tǒng)出現(xiàn)的故障失效問(wèn)題越來(lái)越多,尤其是黏性耗散導(dǎo)致的滑閥熱卡緊以及顆粒運(yùn)動(dòng)造成的滑閥污染卡緊等影響系統(tǒng)工作穩(wěn)定性的問(wèn)題也越來(lái)越受到重視。在中、高壓系統(tǒng)中,液壓滑閥常常出現(xiàn)的閥芯熱卡緊現(xiàn)象,其主要原因是黏性油液流經(jīng)滑閥閥口時(shí),黏性加熱效應(yīng)使得局部區(qū)域溫度升高、閥芯受熱膨脹、配合間隙減小。與此同時(shí),伴隨著固體顆粒滯留于變形間隙內(nèi),污染卡緊進(jìn)而產(chǎn)生,直接威脅液壓系統(tǒng)的工作平順性和安全性。本論文以典型閥口滑閥為研究對(duì)象,基于流固耦合共軛傳熱方法,運(yùn)用COMSOL軟件內(nèi)置的共軛傳熱、固體力學(xué)、粒子追蹤模塊對(duì)液壓滑閥內(nèi)部的油液黏性加熱、流動(dòng)與傳熱、固體受熱變形、顆粒運(yùn)動(dòng)等多個(gè)物理場(chǎng)之間的耦合過(guò)程進(jìn)行了較為深入的分析。數(shù)值仿真結(jié)果表明:高溫主要集中在速度梯度較大的區(qū)域以及受油液沖擊的節(jié)流槽工作面,滑閥節(jié)流槽區(qū)域產(chǎn)生徑向不均勻環(huán)狀突起變形,閥芯、閥體配合邊形成拋物線狀徑向熱膨脹,固體顆粒在變形后的間隙均壓槽內(nèi)更易高度聚集,這些極有可能導(dǎo)致滑閥卡緊現(xiàn)象。本文的主要內(nèi)容如下:第一章,闡述了本課題研究的背景和意義;介紹了滑閥液壓卡緊與污染卡緊現(xiàn)象,對(duì)熱力耦合形變和顆粒物污染導(dǎo)致滑閥閥芯卡滯故障的國(guó)內(nèi)外相關(guān)研究的進(jìn)展進(jìn)行概述。第二章,簡(jiǎn)述COMSOL軟件功能和應(yīng)用場(chǎng)合,對(duì)所用計(jì)算模塊的內(nèi)置參數(shù)進(jìn)行分析,敘述了滑閥內(nèi)油液黏性溫升的理論依據(jù),根據(jù)閥口結(jié)構(gòu)特點(diǎn),參考等效過(guò)流面積的計(jì)算理論,推導(dǎo)了本文所研究的閥口等效過(guò)流面積計(jì)算公式,并對(duì)不同閥口形式下的閥腔內(nèi)部流動(dòng)與傳熱過(guò)程進(jìn)行了數(shù)值解析。第三章,建立包含流體域和固體域耦合傳熱過(guò)程的單一數(shù)值計(jì)算模型,研究典型工況下滑閥全域的溫度場(chǎng)分布與熱變形規(guī)律,分析黏溫特性、油液含氣泡、熱導(dǎo)率與溫度的線性關(guān)系等現(xiàn)實(shí)因素對(duì)滑閥黏性溫升形變的影響,依據(jù)已有仿真結(jié)果,改進(jìn)閥芯次要結(jié)構(gòu),達(dá)到減小閥芯熱變形量的目的。第四章,建立帶有不同形式均壓槽的二維滑閥全域熱特性模型,探索不同工作壓力、閥口開(kāi)度、間隙大小等因素對(duì)滑閥配合間隙熱特性的影響。第五章,建立帶有不同均壓槽形式的熱變形前后間隙的二維對(duì)稱模型,研究變形以后的滑閥徑向配合間隙對(duì)滑閥內(nèi)的顆粒物分布以及運(yùn)動(dòng)軌跡有何影響,綜合考慮顆粒物滯留間隙與閥芯受熱膨脹之間的聯(lián)系,揭示兩者對(duì)滑閥滯卡的綜合作用機(jī)制。
[Abstract]:As one of the key components of fluid power transmission and control, hydraulic valve is widely used in hydraulic system. However, with the overall development of hydraulic technology, there are more and more failures in hydraulic system. Especially, the problems which affect the stability of the system, such as the thermal clamping caused by viscous dissipation and the slide-valve fouling due to particle movement, have been paid more and more attention. In the medium and high pressure system, the valve core heat clamping phenomenon often appears in the hydraulic slide valve, the main reason is that when the viscous oil flows through the valve mouth, the viscous heating effect causes the local temperature to rise, the valve core is heated to expand, and the matching clearance decreases. At the same time, with the solid particles stuck in the deformation clearance, the pollution jam is produced, which directly threatens the working comfort and safety of the hydraulic system. Based on the fluid-solid coupling conjugate heat transfer method, this paper uses the conjugate heat transfer, solid mechanics, particle tracing module built in COMSOL software to heat, flow and heat transfer the oil viscosity inside the hydraulic slide valve. The coupling processes of several physical fields, such as thermal deformation and particle motion, are analyzed in detail. The numerical simulation results show that the high temperature is mainly concentrated in the area with high velocity gradient and the working face of throttling groove which is impacted by oil, and the radial inhomogeneous annular bulge is produced in the throttle area of slide valve, and the valve core is produced. A parabolic radial thermal expansion is formed on the fitting edge of the valve body, and the solid particles tend to gather more easily in the clearance pressure slot after deformation, which may lead to the slide-valve clamping phenomenon. The main contents of this paper are as follows: the first chapter describes the background and significance of this research; This paper introduces the phenomenon of hydraulic clamping and pollution clamping of slide valve, and summarizes the progress of the research on sliding-valve spool sticking fault caused by thermo-mechanical coupling deformation and particulate contamination at home and abroad. In the second chapter, the function and application of COMSOL software are briefly described, the built-in parameters of the calculation module are analyzed, the theoretical basis of viscous temperature rise of oil in the slide valve is described, and the calculation theory of equivalent overflowing area is referred to according to the structural characteristics of the valve opening. In this paper, the equivalent over-flow area calculation formula of the valve is derived, and the flow and heat transfer process in the valve cavity under different valve orifices are analyzed numerically. In chapter 3, a single numerical calculation model of coupled heat transfer process in fluid domain and solid domain is established. The temperature field distribution and thermal deformation of the whole region of the sliding valve under typical conditions are studied, and the characteristics of viscosity and temperature are analyzed, and the bubbles in oil are analyzed. The effect of the linear relationship between thermal conductivity and temperature on the viscosity temperature rise and deformation of the slide valve is discussed. According to the existing simulation results, the secondary structure of the valve core is improved to reduce the thermal deformation of the valve core. In chapter 4, the global thermal characteristic model of two-dimensional slide valve with different pressure sharing groove is established to explore the influence of different working pressure, valve opening and clearance size on the thermal characteristics of sliding valve fit clearance. In the fifth chapter, a two-dimensional symmetrical model of the gap before and after thermal deformation with different pressure sharing groove is established to study the influence of radial fit clearance on particle distribution and motion trajectory in the sliding valve after deformation. Considering the relationship between the retention clearance of particulate matter and the thermal expansion of the valve core, the mechanism of their comprehensive action on the slide-valve lag card is revealed.
【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TH137.52
[Abstract]:As one of the key components of fluid power transmission and control, hydraulic valve is widely used in hydraulic system. However, with the overall development of hydraulic technology, there are more and more failures in hydraulic system. Especially, the problems which affect the stability of the system, such as the thermal clamping caused by viscous dissipation and the slide-valve fouling due to particle movement, have been paid more and more attention. In the medium and high pressure system, the valve core heat clamping phenomenon often appears in the hydraulic slide valve, the main reason is that when the viscous oil flows through the valve mouth, the viscous heating effect causes the local temperature to rise, the valve core is heated to expand, and the matching clearance decreases. At the same time, with the solid particles stuck in the deformation clearance, the pollution jam is produced, which directly threatens the working comfort and safety of the hydraulic system. Based on the fluid-solid coupling conjugate heat transfer method, this paper uses the conjugate heat transfer, solid mechanics, particle tracing module built in COMSOL software to heat, flow and heat transfer the oil viscosity inside the hydraulic slide valve. The coupling processes of several physical fields, such as thermal deformation and particle motion, are analyzed in detail. The numerical simulation results show that the high temperature is mainly concentrated in the area with high velocity gradient and the working face of throttling groove which is impacted by oil, and the radial inhomogeneous annular bulge is produced in the throttle area of slide valve, and the valve core is produced. A parabolic radial thermal expansion is formed on the fitting edge of the valve body, and the solid particles tend to gather more easily in the clearance pressure slot after deformation, which may lead to the slide-valve clamping phenomenon. The main contents of this paper are as follows: the first chapter describes the background and significance of this research; This paper introduces the phenomenon of hydraulic clamping and pollution clamping of slide valve, and summarizes the progress of the research on sliding-valve spool sticking fault caused by thermo-mechanical coupling deformation and particulate contamination at home and abroad. In the second chapter, the function and application of COMSOL software are briefly described, the built-in parameters of the calculation module are analyzed, the theoretical basis of viscous temperature rise of oil in the slide valve is described, and the calculation theory of equivalent overflowing area is referred to according to the structural characteristics of the valve opening. In this paper, the equivalent over-flow area calculation formula of the valve is derived, and the flow and heat transfer process in the valve cavity under different valve orifices are analyzed numerically. In chapter 3, a single numerical calculation model of coupled heat transfer process in fluid domain and solid domain is established. The temperature field distribution and thermal deformation of the whole region of the sliding valve under typical conditions are studied, and the characteristics of viscosity and temperature are analyzed, and the bubbles in oil are analyzed. The effect of the linear relationship between thermal conductivity and temperature on the viscosity temperature rise and deformation of the slide valve is discussed. According to the existing simulation results, the secondary structure of the valve core is improved to reduce the thermal deformation of the valve core. In chapter 4, the global thermal characteristic model of two-dimensional slide valve with different pressure sharing groove is established to explore the influence of different working pressure, valve opening and clearance size on the thermal characteristics of sliding valve fit clearance. In the fifth chapter, a two-dimensional symmetrical model of the gap before and after thermal deformation with different pressure sharing groove is established to study the influence of radial fit clearance on particle distribution and motion trajectory in the sliding valve after deformation. Considering the relationship between the retention clearance of particulate matter and the thermal expansion of the valve core, the mechanism of their comprehensive action on the slide-valve lag card is revealed.
【學(xué)位授予單位】：蘭州理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TH137.52
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