本文選題：微通道 + 凈質(zhì)量流量��； 參考：《真空科學(xué)與技術(shù)學(xué)報(bào)》2017年09期

【摘要】：熱流逸效應(yīng)可輸送氣體并產(chǎn)生壓力差,可利用其抽真空。本文建立了描述熱流逸效應(yīng)及其抽真空泵送特性的數(shù)學(xué)模型,以空氣為例探討了氣體流態(tài)(努森數(shù))、微通道特征尺寸和徑長(zhǎng)比以及溫差等參數(shù)對(duì)壓力比、凈質(zhì)量流量、抽速和無(wú)量綱抽氣時(shí)間的影響。結(jié)果表明,壓力比、凈質(zhì)量流量、抽速和無(wú)量綱抽氣時(shí)間均隨溫差的增大而增大,但過(guò)大的溫差對(duì)提高流量不明顯且使抽真空達(dá)到穩(wěn)態(tài)過(guò)程變得相對(duì)緩慢,應(yīng)根據(jù)實(shí)際條件確定適宜溫差。凈質(zhì)量流量和抽速隨努森數(shù)增大而減小,且在過(guò)渡流區(qū)域還受徑長(zhǎng)比的影響;壓力比和無(wú)量綱抽氣時(shí)間在過(guò)渡流區(qū)域隨努森數(shù)增大而增大,但在自由分子流區(qū)域與努森數(shù)無(wú)關(guān);故應(yīng)根據(jù)實(shí)際需求權(quán)衡凈質(zhì)量流量與壓力比以確定適宜的熱流逸發(fā)生條件、并控制氣體流態(tài)來(lái)調(diào)整抽氣特性。
[Abstract]:Heat flux effect can transport gas and produce pressure difference, which can be used to pump vacuum. In this paper, a mathematical model is established to describe the heat flux effect and the characteristics of vacuum pumping. Taking air as an example, the pressure ratio and net mass flow rate of the gas flow state (Knudsen number, characteristic dimension and diameter ratio of microchannel, temperature difference, etc.) are discussed. Effects of pumping speed and dimensionless pumping time. The results show that the pressure ratio, the net mass flow rate, the pumping speed and the dimensionless pumping time increase with the increase of the temperature difference, but the excessive temperature difference is not obvious to increase the flow rate and make the vacuum to reach the steady state process becomes relatively slow. The appropriate temperature difference should be determined according to the actual conditions. The net mass flow rate and pumping speed decrease with the increase of Knudsen number, and are also affected by the ratio of diameter to length in the transition flow region, and the pressure ratio and dimensionless pumping time increase with the increase of Knudsen number in the transitional flow region, but they are independent of the Knudsen number in the free molecular flow region. Therefore, the ratio of net mass flow to pressure should be weighed according to the actual demand to determine the appropriate conditions for heat flux to occur and to control the gas flow state to adjust the pumping characteristics.
【作者單位】： 廣西大學(xué)化學(xué)化工學(xué)院;
【基金】：廣西自然科學(xué)基金資助項(xiàng)目(2016GXNSFAA380232) 國(guó)家自然科學(xué)基金資助項(xiàng)目(51366001) 廣西研究生教育創(chuàng)新計(jì)劃資助項(xiàng)目(YCSW2017035)
【分類號(hào)】：TB71
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本文編號(hào)：1831891