本文選題：分子動力學(xué)　切入點：剪切力學(xué)　出處：《北京理工大學(xué)學(xué)報》2017年09期 　論文類型：期刊論文

【摘要】：考慮固體壁面對流體分子作用力的影響,建立了兩平行壁面-流體系統(tǒng)的分子動力學(xué)模型,模擬了壁面切向運(yùn)動對流體的剪切過程,分析了壁面速度對不同離壁距離流體層微觀剪切力學(xué)特性的影響,研究了剪應(yīng)變率、工作壓力和溫度對流體宏觀剪切力學(xué)特性的作用規(guī)律.研究表明:受到分子無規(guī)則熱運(yùn)動的影響,不同離壁距離流體層的剪切應(yīng)力呈現(xiàn)出波動變化狀態(tài),但隨著流體剪切運(yùn)動的增強(qiáng),剪切應(yīng)力的波動幅值逐漸減小;當(dāng)壁面切向運(yùn)動較大時,近壁層流體在運(yùn)動速度上與壁面之間易出現(xiàn)較大的滑動,壁面-流體出現(xiàn)邊界滑移;工作壓力及溫度影響著分子間距離,壓力升高與溫度降低都將減小分子間的距離,從而引起流體黏度與剪切應(yīng)力的增大.
[Abstract]:Considering the influence of solid wall on the molecular force of fluid, a molecular dynamics model of two parallel wall-fluid systems is established, and the shear process of the wall tangential motion to the fluid is simulated. The influence of wall velocity on the micro shear mechanical properties of fluid layers with different distance from the wall is analyzed, and the shear strain rate is studied. The effect of working pressure and temperature on the macroscopic shear mechanical properties of the fluid. The results show that the shear stress of the fluid layer at different distance from the wall fluctuates under the influence of the irregular thermal movement of the molecule. However, with the increase of shear motion, the fluctuation amplitude of shear stress decreases gradually, and when the wall tangential motion is larger, the near wall layer fluid tends to slip between the wall and the wall at the velocity of movement, and the boundary slip occurs between the wall and the fluid. The pressure and temperature affect the distance between molecules. The increase of pressure and the decrease of temperature will decrease the distance between molecules, which will lead to the increase of fluid viscosity and shear stress.
【作者單位】： 北京理工大學(xué)車輛傳動重點實驗室;
【基金】：國家自然科學(xué)基金資助項目(51305033) 北京理工大學(xué)車輛傳動重點實驗室基金資助項目(9140C340506)
【分類號】：O35
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本文編號：1598091