沟槽壁面和温度梯度对环隙内流场稳定性的影响

Experimental Study of Temperature Gradient and Slit Wall Effect on the Flow Stability in the Annular Gap

利用PIV结合折射率匹配法对光壁和沟槽模型内的Taylor-Couette流动进行测量，通过加热内圆柱构建不同的温度梯度工况以及在外圆柱壁面上安装沟槽，研究沟槽和温度梯度对泰勒涡动稳定性的影响规律。试验模型的内外圆柱的半径比为0．825，纵横比为48，雷诺数Re=80～110，研究中考察格拉晓夫数Gr=3600，6700两种不同的温度梯度工况对流场的影响，试验结果表明，温度梯度作用下使得不同模型内的泰勒涡具备了轴向运动的速度，同时泰勒涡的轴向尺寸也发生改变，随着温度梯度增加，环隙内向外圆柱方向的径向速度有所增加；泰勒涡的运动速度随着温度梯度的增加而增加，相同温度梯度下，随着Re的增加，泰勒涡的运动速度也随之增加；沟槽模型的存在增加了环隙内的径向速度，较光壁模型增加了130％，且受到沟槽和温度梯度的共同作用，使得泰勒涡中逆时针旋转的涡胞尺度增加，涡心位置偏离内圆柱。

The Taylor-Couette flow in plain and slit models is studied using PIV measurement. To study the temperature gradient and slit wall effect on the flow instability, different temperature gradient condition is built by heating the inner cylinder, and the slit wall is installed in the inner side of outer cylinder. The radius ratio and aspect ratio are 0.825 and 48, respectively. The temperature gradient considered is 4 ℃and 6 ℃, the Re number is from 80 to 110. The results show that the Taylor vortex has the axial moving velocity because of the temperature gradient effect, and the axial size of the vortex is changed. The moving velocity of Taylor vortex is increased as the temperature gradient increased, at the same temperature condition, as the Reynolds number increased, the Taylor vortex moving velocity also increased. And the existence of slit wall increased the radial velocity, which is 130% larger than plain model. The size of anticlockwise vortex in the vortex pair increased, and the vortex center of this vortex deviation from inner cylinder.