基于粘度影響的稀薄效應(yīng)下壁面速度滑移的數(shù)學(xué)建模
發(fā)布時(shí)間:2018-11-26 16:05
【摘要】:以氣膜分層理論為基礎(chǔ),根據(jù)近壁層、稀薄層、連續(xù)流層內(nèi)分子運(yùn)動(dòng)形式,結(jié)合層內(nèi)黏度的變化特征,建立壁面滑移模型,并給出相應(yīng)的數(shù)學(xué)表達(dá)式。通過(guò)LAMMPS和2DMD數(shù)值分析的方法,結(jié)合實(shí)驗(yàn)測(cè)試結(jié)果發(fā)現(xiàn):在稀薄層內(nèi),沿豎直方向的速度呈線性變化,越靠近壁面,速度越小;在近壁層內(nèi),由于分子與壁面的摩擦使得近壁層分子速度驟減;在連續(xù)流層內(nèi),氣體分子做全滑移運(yùn)動(dòng);此外,溫度越高,黏度越小,速度滑移越大,近壁層與稀薄層速度差值越大。溫度一定時(shí),無(wú)量綱滑移長(zhǎng)度和Kn數(shù)成線性關(guān)系。
[Abstract]:Based on the theory of gas film stratification, the wall slip model is established according to the molecular motion forms in the near wall layer, the thin layer and the continuous flow layer, and the variation characteristics of the viscosity in the layer, and the corresponding mathematical expressions are given. By means of LAMMPS and 2DMD numerical analysis, combined with the experimental results, it is found that in the thin layer, the velocity along the vertical direction changes linearly, the closer the wall is, the smaller the velocity is. In the near wall layer, the molecular velocity of the near wall layer decreases because of the friction between the molecule and the wall layer, and in the continuous flow layer, the gas molecule makes the whole slip motion. In addition, the higher the temperature, the smaller the viscosity and the greater the velocity slip, the greater the velocity difference between the near wall layer and the thin layer. When the temperature is constant, the dimensionless slip length is linearly related to the Kn number.
【作者單位】: 昆明理工大學(xué)機(jī)電工程學(xué)院;
【基金】:國(guó)家自然科學(xué)基金(51305185)資助
【分類號(hào)】:TH117.2
,
本文編號(hào):2359012
[Abstract]:Based on the theory of gas film stratification, the wall slip model is established according to the molecular motion forms in the near wall layer, the thin layer and the continuous flow layer, and the variation characteristics of the viscosity in the layer, and the corresponding mathematical expressions are given. By means of LAMMPS and 2DMD numerical analysis, combined with the experimental results, it is found that in the thin layer, the velocity along the vertical direction changes linearly, the closer the wall is, the smaller the velocity is. In the near wall layer, the molecular velocity of the near wall layer decreases because of the friction between the molecule and the wall layer, and in the continuous flow layer, the gas molecule makes the whole slip motion. In addition, the higher the temperature, the smaller the viscosity and the greater the velocity slip, the greater the velocity difference between the near wall layer and the thin layer. When the temperature is constant, the dimensionless slip length is linearly related to the Kn number.
【作者單位】: 昆明理工大學(xué)機(jī)電工程學(xué)院;
【基金】:國(guó)家自然科學(xué)基金(51305185)資助
【分類號(hào)】:TH117.2
,
本文編號(hào):2359012
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