基于全息术的水平偏置椭圆管自然对流换热

Natural convection heat transfer from horizontal offset elliptic tube based on holographic interferometry

采用全息术实验研究水平偏置椭圆管层流自然对流换热,分析了长轴从水平方向到竖直方向不同角度的换热规律,记录了无限大空间水平椭圆管偏置角为0°～90°的干涉图,通过反演椭圆管周围的温度场得到了椭圆管表面的局部和平均Nusselt数。实验结果表明,长轴从水平位置偏置到竖直位置时,换热逐渐增强;长轴位于水平位置和竖直位置时,换热最小值均位于椭圆管上方,最大值则位于椭圆管长轴附近。研究结果与文献中已有的数值和实验结果吻合较好,可为今后热管换热器的设计提供优化方向,也可为工程应用提供检测方法。

Natural convection heat transfer from a horizontal offset elliptic tube is experimentally investigated using holographic interferometry. The effect of the ellipse major axis from horizontal to vertical direction on heat transfer is analyzed. Interferometric fringes of the tube in infinite space at different inclination angles 0°—90° are recorded. The local and average Nusselt numbers are determined according to the reconstruction of the temperature field around the tube. The experimental results indicate that the heat transfer increases with the ellipse major axis inclined from horizontal to vertical direction. The local Nusselt numbers above the tube is the minimum and the maximum is located near the major axis when the direction of the major axis are horizontal and vertical. The results obtained in this investigation show good agreement with the existing experimental and numerical studies, which can contribute to the optimal design of heat exchanger and also provide a test method for engineering applications.