【摘要】：為了探討槽道中纖維懸浮湍流場特性,本文對修正的雷諾平均納維-斯托克斯方程、含纖維項(xiàng)的湍動能和耗散率方程、纖維動力學(xué)方程以及纖維取向概率密度函數(shù)方程進(jìn)行了數(shù)值研究,同時(shí)進(jìn)行了相關(guān)實(shí)驗(yàn)以驗(yàn)證計(jì)算結(jié)果.研究結(jié)果表明,流場中尤其是近壁區(qū)域,纖維取向趨向于與流動方向一致,且該現(xiàn)象隨著雷諾數(shù)和纖維濃度的減小以及纖維長徑比的增大而更為明顯.纖維在槽道中分布不均勻,但隨著雷諾數(shù)的增大和纖維長徑比的減小趨于均勻.相對于單相流,纖維懸浮流的流向平均速度剖面更陡峭,且剖面斜率隨著纖維濃度、長徑比的增大以及雷諾數(shù)的減小而變大,纖維的存在使湍流場的湍動能和雷諾應(yīng)力減小,且減小程度隨著纖維濃度和長徑比的增大以及雷諾數(shù)的減小而增加.流場中的第一法向應(yīng)力差小于0.05且遠(yuǎn)小于剪切應(yīng)力.從壁面到中心,剪切應(yīng)力增加而第一法向應(yīng)力差減小.剪切應(yīng)力和第一法向應(yīng)力差都隨著纖維濃度和長徑比的增大而增大.隨著雷諾數(shù)的增大,剪切應(yīng)力增大而第一法向應(yīng)力差減小.纖維濃度對于剪切應(yīng)力和第一法向應(yīng)力差的影響比纖維長徑比更顯著.
[Abstract]:In order to investigate the characteristics of fiber suspension turbulent field in the channel, the modified Reynolds average Neville-Stokes equation, the turbulent kinetic energy and dissipation rate equation with fiber term, the fiber dynamics equation and the fiber orientation probability density function equation are studied numerical. At the same time, the related experiments are carried out to verify the calculated results. The results show that the fiber orientation tends to be consistent with the flow direction in the flow field, especially in the near-wall region, and the phenomenon is more obvious with the decrease of Reynolds number and fiber concentration and the increase of fiber aspect ratio. The fiber distribution in the channel is not uniform, but with the increase of Reynolds number and the decrease of fiber aspect ratio, it tends to be uniform. Compared with single-phase flow, the average velocity profile of fiber suspension flow is steeper, and the slope of the section increases with the increase of fiber concentration, aspect ratio and Reynolds number. The turbulent kinetic energy and Reynolds stress of turbulent flow field decrease with the presence of fiber, and the degree of decrease increases with the increase of fiber concentration and aspect ratio and the decrease of Reynolds number. The first normal stress difference in the flow field is less than 0.05 and much smaller than the shear stress. From the wall to the center, the shear stress increases and the first normal stress difference decreases. The shear stress and the first normal stress difference increase with the increase of fiber concentration and aspect ratio. With the increase of Reynolds number, the shear stress increases and the first normal stress difference decreases. The effect of fiber concentration on shear stress and first normal stress difference is more significant than that of fiber aspect ratio.
【作者單位】： 浙江大學(xué)航空航天學(xué)院力學(xué)系;
【基金】：國家自然科學(xué)基金重大項(xiàng)目(批準(zhǔn)號:11132008)資助的課題~~
【分類號】：O357.5

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