本文關(guān)鍵詞： 空化數(shù) 空泡 空蝕 CFD　出處：《西南交通大學(xué)》2011年碩士論文　論文類型：學(xué)位論文

【摘要】：空化和空蝕對(duì)液壓系統(tǒng)中的液壓泵、液壓閥等元件影響嚴(yán)重,是一個(gè)長(zhǎng)期難以解決的問題。當(dāng)系統(tǒng)的壓力低于飽和蒸汽壓時(shí),低壓處會(huì)產(chǎn)生空泡：空泡能改變流動(dòng)系統(tǒng)的流場(chǎng)特性,減小流道有效面積,增加流道阻力。在空泡的初生、發(fā)育、潰滅過程中系統(tǒng)將產(chǎn)生高頻噪聲和壓力脈動(dòng),空泡潰滅產(chǎn)生的微射流沖擊會(huì)造成固體邊壁的剝蝕破壞——空蝕。空蝕的破壞作用巨大,能嚴(yán)重縮短液壓元件的使用壽命。 論文主要利用CFD軟件對(duì)Yamaguchi的空蝕實(shí)驗(yàn)進(jìn)行建模仿真,結(jié)合仿真和實(shí)驗(yàn)結(jié)果,找出參數(shù)評(píng)價(jià)空蝕。論文主要包括四部分內(nèi)容：(1)對(duì)實(shí)驗(yàn)?zāi)Ｐ偷慕Y(jié)構(gòu)尺寸進(jìn)行參數(shù)化,利用STAR-CD的建模命令建立參數(shù)化六面體網(wǎng)格模型。通過網(wǎng)格數(shù)誤差測(cè)試,確定出最適合本文仿真計(jì)算的網(wǎng)格數(shù)及其建模參數(shù)。(2)分析仿真計(jì)算的結(jié)果,提出發(fā)生空蝕的假設(shè)：①速度保護(hù)：試件表面壓力低,流體速度快,氣泡從試件表面快速通過,氣泡在試件表面破裂的數(shù)量少,腐蝕輕。②壓力保護(hù)：試件表面壓力高,流體速度低,大量氣泡在離試件表面較遠(yuǎn)處破裂,氣泡沖不進(jìn)試件表面,氣泡在試件表面破裂數(shù)量少,腐蝕輕。③空蝕破壞：試件表面壓力不夠高,壓力保護(hù)不足,速度不夠快,速度保護(hù)不足；大量氣泡在試件表面破裂,腐蝕嚴(yán)重。(3)根據(jù)假設(shè)找到用空化數(shù)σ評(píng)價(jià)空蝕。對(duì)比σ分布圖和實(shí)驗(yàn)中空蝕量的關(guān)系,得出σ的分布圖能比較準(zhǔn)確的預(yù)測(cè)空蝕的位置和程度。對(duì)比σ分布圖和實(shí)驗(yàn)中試件空蝕圖片的關(guān)系,發(fā)現(xiàn)。分布圖預(yù)測(cè)的試件上空蝕的位置和嚴(yán)重程度與實(shí)驗(yàn)給出的試件空蝕圖片一致。(4)對(duì)Yamaguchi的另一個(gè)空蝕實(shí)驗(yàn)進(jìn)行建模仿真。按同樣的方法得到發(fā)生空蝕時(shí)對(duì)應(yīng)的σ值。作出σ在流場(chǎng)中的分布,對(duì)比實(shí)驗(yàn)發(fā)現(xiàn)σ的分布圖能比較準(zhǔn)確的反映空蝕的位置和嚴(yán)重程度。
[Abstract]:Cavitation and cavitation have a serious effect on hydraulic pump, hydraulic valve and other components in hydraulic system, which is a difficult problem to solve for a long time, when the pressure of the system is lower than the saturated steam pressure. Cavitation will occur at low pressure: cavitation can change the flow field characteristics of the flow system, reduce the effective area of the passage and increase the resistance of the passage. During the process of cavitation initiation, development and collapse, the system will produce high frequency noise and pressure pulsation. The micro-jet impingement caused by cavitation collapse will result in the erosion of solid side wall-cavitation erosion. The cavitation erosion has a huge effect and can shorten the service life of hydraulic components seriously. This paper mainly uses CFD software to model and simulate the cavitation erosion experiment of Yamaguchi, combining the simulation and experimental results. Find out the parameters to evaluate cavitation erosion. The thesis mainly includes four parts: 1) to parameterize the structural size of the experimental model. The parameterized hexahedron mesh model is established by using the modeling command of STAR-CD, and the error of mesh number is tested. The mesh number and its modeling parameter. 2) the results of the simulation calculation are determined. The assumption of cavitation erosion is given: the surface pressure of the specimen is low and the fluid velocity is fast. Bubbles pass quickly from the surface of the specimen, the amount of bubble rupture on the surface of the specimen is less, corrosion protection is light. 2. The surface pressure of the specimen is high, the velocity of fluid is low, and a large number of bubbles rupture in the distance from the surface of the specimen. The bubble can not penetrate the surface of the specimen, the number of bubble rupture on the surface of the specimen is less, and the corrosion is light. 3. The surface pressure of the specimen is not high enough, the pressure protection is not enough, the speed is not fast enough, and the velocity protection is not enough; According to the hypothesis, cavitation number 蟽 is found to evaluate cavitation erosion. The relationship between 蟽 distribution and cavitation erosion in experiment is compared. The distribution map of 蟽 can accurately predict the location and extent of cavitation erosion. It is found that the location and severity of cavitation erosion predicted by the distribution map are consistent with the experimental results. Another cavitation experiment of Yamaguchi is modeled and simulated. The 蟽 value corresponding to cavitation erosion is obtained by the same method, and the distribution of 蟽 in the flow field is obtained. The comparative experiments show that the distribution map of 蟽 can accurately reflect the location and severity of cavitation erosion.
【學(xué)位授予單位】：西南交通大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2011
【分類號(hào)】：TH137.5

【引證文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前2條

1 劉晟昊;水壓密封件的密封性能研究[D];西南交通大學(xué);2012年

2 李惟祥;液壓錐閥的振動(dòng)特性研究[D];西南交通大學(xué);2012年

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本文編號(hào)：1479180