本文選題：錐閥　切入點(diǎn)：穩(wěn)定性　出處：《浙江大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：液壓傳動(dòng)具有功率密度高、傳輸功率大等優(yōu)點(diǎn),被廣泛應(yīng)用于工業(yè)領(lǐng)域,對(duì)科技發(fā)展產(chǎn)生重要推動(dòng)作用。隨著現(xiàn)代電力技術(shù)迅猛發(fā)展以及人們對(duì)設(shè)備操作舒適性、環(huán)保性要求日益提高,給液壓傳動(dòng)帶來(lái)嚴(yán)峻挑戰(zhàn),液壓技術(shù)要取得生存與發(fā)展必須朝高能量利用效率、高壓力、大流量、低噪聲等方向發(fā)展。為提高能量利用效率,閉式系統(tǒng)是液壓技術(shù)發(fā)展的方向。錐閥具有響應(yīng)快、成本低、抗污染能力強(qiáng)等特點(diǎn),被大規(guī)模應(yīng)用于閉式系統(tǒng)中,但錐閥液動(dòng)力大,液動(dòng)力突變易引起錐閥失穩(wěn),產(chǎn)生嚴(yán)重的振動(dòng)與噪聲問題。此前關(guān)于錐閥的研究主要基于開式系統(tǒng),錐閥應(yīng)用于閉式系統(tǒng)時(shí)先前被忽略的問題可能變得非常突出。因此,為更好地設(shè)計(jì)閉式系統(tǒng),需對(duì)錐閥固有問題重新進(jìn)行仔細(xì)研究。本課題主要針對(duì)錐閥振蕩流場(chǎng)流動(dòng)噪聲展開研究,希望通過本課題研究,深化人們對(duì)液壓閥噪聲的認(rèn)識(shí),為低噪聲液壓系統(tǒng)設(shè)計(jì)提供理論依據(jù)。本課題結(jié)合實(shí)驗(yàn)測(cè)量、理論分析以及數(shù)值仿真等手段,對(duì)錐閥振蕩流場(chǎng)流動(dòng)噪聲增強(qiáng)機(jī)制展開了系統(tǒng)而深入地研究,得到了有、無(wú)空化下錐閥振動(dòng)特性隨無(wú)量綱參數(shù)閥座比變化的規(guī)律,分析了空化噪聲增強(qiáng)的機(jī)制,提出空泡潰滅事件增加是錐閥振動(dòng)后空化噪聲加劇的主要原因。針對(duì)錐閥嘯叫噪聲,提出了錐閥嘯叫噪聲是射流激勵(lì)閥腔產(chǎn)生流體共振的假設(shè),并對(duì)假設(shè)進(jìn)行了論證,結(jié)果表明錐閥中流體與聲學(xué)耦合產(chǎn)生亥姆霍茲共振是導(dǎo)致錐閥只對(duì)特定頻率噪聲信號(hào)進(jìn)行選擇性放大的原因。論文的主要研究工作如下：1.驗(yàn)證了錐閥振動(dòng)的機(jī)理,利用實(shí)驗(yàn)研究和理論分析相結(jié)合的方法分析了錐閥空化對(duì)振動(dòng)特性的影響,觀測(cè)到有、無(wú)空化兩種工況下錐閥振動(dòng)特性差異隨閥座比R*的變化規(guī)律,結(jié)合錐閥中空化流流態(tài)闡述了導(dǎo)致有、無(wú)空化兩種工況下的錐閥振動(dòng)特性差異的原因。2.觀測(cè)到錐閥振動(dòng)后空化噪聲增強(qiáng)的現(xiàn)象,提出錐閥振動(dòng)后空化噪聲急劇增強(qiáng)主要由空泡潰滅事件增加所導(dǎo)致的觀點(diǎn),利用實(shí)驗(yàn)與仿真等手段揭示了振蕩流場(chǎng)中空泡潰滅事件增加的機(jī)制,指出錐閥振動(dòng)破壞了回流低壓區(qū)中固定型空化結(jié)構(gòu),使氣核通過回流低壓區(qū)時(shí)發(fā)展成空泡的事件增加,加劇了空化程度,基于錐閥中空化現(xiàn)象產(chǎn)生機(jī)理給出了低空化噪聲錐閥的優(yōu)化方案。3.采用頻譜分析的方法研究了錐閥嘯叫噪聲頻譜特征,利用實(shí)驗(yàn)與仿真相結(jié)合的方法分析了嘯叫噪聲的噪聲源,通過大量的實(shí)驗(yàn),觀測(cè)到多相流、變開度及變閥腔體積下嘯叫噪聲基頻漂移規(guī)律,提出錐閥嘯叫噪聲是由流-聲耦合作用引起流體共振產(chǎn)生的假設(shè),利用閥腔聲學(xué)共振頻率公式對(duì)假設(shè)進(jìn)行了驗(yàn)證,揭示了高頻嘯叫噪聲對(duì)特定噪聲信號(hào)的選擇性放大機(jī)理,為錐閥嘯叫噪聲的抑制提供了理論依據(jù)。
[Abstract]:Hydraulic transmission has the advantages of high power density and high transmission power. It is widely used in industrial fields and plays an important role in the development of science and technology. With the rapid development of modern power technology and the comfort of equipment operation, The requirement of environmental protection is increasing day by day, which brings severe challenge to hydraulic transmission. In order to survive and develop hydraulic technology, it is necessary to develop in the direction of high energy utilization efficiency, high pressure, large flow rate, low noise and so on. Closed system is the development direction of hydraulic technology. Conical valve has the characteristics of fast response, low cost and strong anti-pollution ability. It is widely used in closed system, but the fluid power of conical valve is large, and the sudden change of hydraulic force can easily lead to the instability of cone valve. Causing serious vibration and noise problems. Previous studies on conical valves were mainly based on open systems, and previously neglected problems with conical valves when applied to closed systems may become very prominent. Therefore, for better design of closed systems, It is necessary to re-study the inherent problems of conical valve. This subject mainly focuses on the flow noise of conical valve oscillating flow field, hoping to deepen people's understanding of hydraulic valve noise through this research. This paper provides a theoretical basis for the design of low noise hydraulic system. By means of experimental measurement, theoretical analysis and numerical simulation, the mechanism of flow noise enhancement in conical valve oscillating flow field is studied systematically and deeply. In this paper, the mechanism of cavitation noise enhancement is analyzed and the mechanism of cavitation noise enhancement is analyzed. It is pointed out that the increase of cavitation collapse event is the main reason for the increase of cavitation noise after cone valve vibration. The hypothesis that the screeching noise of the cone valve is the fluid resonance of the jet excited valve cavity is proposed, and the hypothesis is proved. The results show that the Helmholtz resonance caused by the fluid and acoustic coupling in the cone valve is the cause of selective amplification of the noise signal of the cone valve only at certain frequencies. The main research work in this paper is as follows: 1. The mechanism of the vibration of the cone valve is verified. The effect of cone valve cavitation on vibration characteristics is analyzed by means of experimental study and theoretical analysis. The variation of vibration characteristics of cone valve with seat ratio R * is observed under two conditions without cavitation. Combined with the hollow flow pattern of cone valve, the causes of the difference in vibration characteristics of cone valve under two conditions, I. e., cavitation and non-cavitation, are expounded. 2. The phenomenon of cavitation noise enhancement after cone valve vibration is observed. It is pointed out that the sharp increase of cavitation noise after conical valve vibration is mainly caused by the increase of cavitation collapse events. The mechanism of cavitation collapse events in oscillating flow field is revealed by means of experiment and simulation. It is pointed out that the vibration of conical valve destroys the fixed cavitation structure in the reflux low pressure region, increases the number of cavitation events when the gas core passes through the reflux low pressure region, and intensifies the cavitation degree. Based on the hollowing mechanism of cone valve, the optimization scheme of low altitude noise cone valve is given. The spectrum characteristics of cone valve howling noise are studied by spectrum analysis method, and the noise source of screech noise is analyzed by combining experiment and simulation. Through a large number of experiments, we observed the fundamental frequency drift law of roar noise in multiphase flow, variable opening and variable valve cavity volume, and proposed the hypothesis that cone valve roar noise is caused by fluid-acoustic coupling. The hypothesis is verified by the acoustic resonance frequency formula of the valve cavity, and the selective amplification mechanism of the high frequency whistling noise to the specific noise signal is revealed, which provides a theoretical basis for the suppression of the cone valve howling noise.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TH137

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本文編號(hào)：1632814