【摘要】 为研究转动部件对受限空间内对流换热的影响,数值分析了二维封闭方腔内转动圆柱引起的混合对流换热,对比了圆柱转动方向对流场、温度场和换热的影响.结果表明,随着理查森数Ri的增大,方腔内的流动逐渐由强制对流占主导地位向混合对流以及自然对流占主导地位过渡.Re=150,圆柱逆时针转动时平均Nu随Ri增大而增大,而圆柱顺时针转动时平均Nu随Ri增大先减小后增加;Ri=0.1及Ri=1时,圆柱逆时针转动时的局部Nu峰值高于顺时针转动,且最大相差分别为1.89%和19.33%.Gr=5×10~4,圆柱逆时针转动时的平均Nu随Ri增大而减小,而顺时针转动时的平均Nu随Ri增大也呈现先减小后增加的趋势;Ri=0.1及Ri=1时,圆柱逆时针转动与顺时针转动时的局部Nu峰值间最大相差分别为3.96%和26.17%.在Ri=2时,Nu具有最小值且圆柱转动方向对方腔内Nu的影响最大,对于固定Re和Gr两种情况下,圆柱逆时针转动时平均Nu比顺时针转动时分别提高约91.9%和93.6%.更多还原

【Abstract】 In order to study the effect of rotating parts on the convective heat transfer in a confined space, the mixed convection in a two-dimensional square cavity with a rotating cylinder is analyzed by numerical simulation.The influences of the rotation direction of the cylinder on the temperature field, flow field and Nu number of the cavity are compared between cases with different Ri number.The results show that the flow in the square cavity gradually changes from forced convection to mixed convection and then to natural convection as the Ri number increases.For the fixed Re=150,the average Nu number increases as the Ri number increases when the cylinder rotates counter-clockwise, while the average Nu number decreases first and then increases as the Ri number increases when the cylinder rotates clockwise.The peak value of the local Nu number when the cylinder rotates counterclockwise is higher than that when it rotates clockwise, and the maximum differences are separately 1.89% and 19.33% for Ri=0.1 and Ri=1.For the fixed Gr=5×10~4,the average Nu number decreases as the Ri number increases when the cylinder rotates counter-clockwise, while the average Nu number decreases first and then increases as the Ri number increases when the cylinder rotates clockwise.The maximum difference in the local Nu number between the cases with the cylinder rotating counter-clockwise and clockwise is 3.96% and 26.17% for Ri=0.1 and Ri=1,respectively.Nu is the minimum and the difference in Nu between different rotating directions is the largest when Ri equals to 2.The average Nu of the cylinder rotating counter-clockwise increases by 91.9% and 93.6% compared with that when the cylinder rotates clockwise for the cases with fixed Re and Gr,respectively.更多还原