本文選題：真空度特性 + 最大真空度��； 參考：《大連海事大學(xué)》2017年碩士論文

【摘要】：以射流式真空發(fā)生器為真空發(fā)生裝置的真空吸附系統(tǒng)作為一種重要的搬運(yùn)技術(shù),使氣動(dòng)技術(shù)應(yīng)用的領(lǐng)域越來越廣泛。但是射流式真空發(fā)生器存在一個(gè)共同的規(guī)律,真空度在供給壓力0.45 MPa達(dá)到最大,超過0.45 MPa時(shí),真空度會(huì)出現(xiàn)下降;而且在正常工作過程中必須持續(xù)定量供氣,空氣消耗量很大。因此,本文針對此問題分析真空度下降的原因,并通過仿真獲得影響真空度的結(jié)構(gòu)參數(shù),使最大真空度在更低供給壓力下達(dá)到最大值,從而節(jié)省空氣的消耗。由于真空發(fā)生器是根據(jù)拉瓦爾噴管的原理進(jìn)行工作的,首先,本文針對拉瓦爾噴管的工作原理分析其噴管內(nèi)幾種流動(dòng)狀態(tài),研究不同上游與下游壓力比值噴管內(nèi)的流動(dòng)狀態(tài)。利用fluent對其進(jìn)行數(shù)值模擬仿真,仿真結(jié)果表示:改變拉瓦爾噴管的收縮角或擴(kuò)張角,其出口速度基本不變;但改變噴管出口面積與喉部面積比值,噴管出口速度發(fā)生顯著的變化,因此面積比是影響拉瓦爾噴管加速的主要因素,噴管出口速度是由面積比值唯一確定的。由通過拉瓦爾噴管空氣消耗量公式可知,空氣消耗量與供給壓力成正比,因此可通過降低供給壓力的大小來減小空氣的消耗,從而實(shí)現(xiàn)節(jié)能。其次,利用fluent對真空發(fā)生器整個(gè)內(nèi)部流場數(shù)值模擬仿真,分析了真空度下降的原因以及在不同的參數(shù)下真空發(fā)生器真空度曲線的變化,探討了真空發(fā)生器參數(shù)對最大真空度下降點(diǎn)以及峰值的影響。最后,采用3D打印技術(shù)加工設(shè)計(jì)不同結(jié)構(gòu)參數(shù)的真空發(fā)生器,搭建試驗(yàn)臺(tái)并通過試驗(yàn)研究參數(shù)的變化對其性能的影響。試驗(yàn)結(jié)果表明:減小擴(kuò)張管直徑或面積比值的大小,可使真空度在更低壓力達(dá)到最大值。以噴嘴直徑為1mm的為例,在出口直徑為1.8 mm、擴(kuò)張管直徑為2.2 mm,取得最大真空度的供氣壓力為0.3 MPa,最大真空度為86 kPa,降低了取得最大真空度的壓力值,相當(dāng)于減小了空氣消耗量。
[Abstract]:The vacuum adsorption system with a jet vacuum generator as a vacuum generator is an important transportation technology, which makes the application of pneumatic technology more and more widely. But there is a common law in the jet vacuum generator. The vacuum degree will decrease when the supply pressure is 0.45 MPa and the vacuum is over 0.45 MPa. In the normal working process, the quantity of air supply must be sustained and the air consumption is very large. Therefore, this paper analyzes the cause of the decline of the vacuum degree, and obtains the structural parameters affecting the vacuum degree by simulation, so that the maximum vacuum is reached to the maximum under the lower supply pressure, thus saving the air consumption. As the vacuum generator is the root, the vacuum generator is the root. According to the principle of Lawal nozzle, first of all, this paper analyzes several flow states of the nozzle in the nozzle of the Lawal nozzle and studies the flow state within the ratio of the pressure ratio between the upstream and downstream. The numerical simulation of the nozzle is simulated by fluent, and the result is that the contraction angle or expansion of the Lawal nozzle is changed. The outlet speed of the nozzle is basically the same, but the velocity of nozzle exit is greatly changed by changing the ratio of the nozzle area to the throat area, so the area ratio is the main factor affecting the acceleration of the Lawal nozzle. The outlet velocity of the nozzle is determined only by the ratio of the area. It is known that the air consumption through the air consumption formula of the Lawal nozzle can be known. The quantity is proportional to the supply pressure, so the air consumption can be reduced by reducing the size of the supply pressure to achieve energy saving. Secondly, the fluent is used to simulate the whole internal flow field of the vacuum generator, and the reasons for the decrease of the vacuum degree and the change of the vacuum degree curve of the vacuum generator under different parameters are discussed. The effect of the parameters of the vacuum generator on the maximum vacuum drop point and the peak value. Finally, the 3D printing technology is used to process the vacuum generator with different structural parameters. The test bench is built and the influence of the change of the parameters on its performance is studied. The test results show that the size of the diameter or area ratio of the Jian Xiaokuo tube can make the vacuum degree. In the case of the lower pressure, the diameter of the nozzle is 1mm, the diameter of the outlet is 1.8 mm, the diameter of the dilated tube is 2.2 mm, the gas supply pressure of the maximum vacuum is 0.3 MPa and the maximum vacuum is 86 kPa, which reduces the maximum vacuum pressure value, which is equivalent to reducing the air consumption.

【學(xué)位授予單位】：大連海事大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TB75

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