水平旋转圆筒表面温度和浓度边界层的测量

Measurement of Temperature and Concentration Boundary Layers on a Horizontal Rotating Cylinder

用自制的微热偶式测温和测湿装置分别对大直径水平旋转圆筒表面温度边界层和浓度边界层进行了测量．实验表明，旋转对顺向侧和逆向侧的影响情况有所不同顺向侧边界层的温度梯度和浓度梯度随旋转雷诺数的增加一直增大，而逆向侧的温度梯度和浓度梯度随旋转雷诺数的增加先减小后增加用微热偶式测温装置测量边界层温度分布时，由辐射引起的温度测量误差不超过3%,用微热偶式测湿装置测量边界层浓度分布时，由辐射引起的湿球温度测量误差在3％～8％，且离圆筒越近测量误差越大。

Temperature and concentration boundary layers on a large diameter horizontal rotating cylinder were measured by using a specialized minitype thermocouple and dry-wet bulb thermocouple. Experimental results showed that the influence of rotation on the downstream side is different from that on the upstream side. With the increase of rotational Reynolds number, the temperature and concentration gradients increase consistently in the downstream side, while decrease initially and then increase in the upstream side. The temperature error caused by the radiation is less than 3% when measuring the temperature distribution of the heat transfer boundary layer. The wet bulb temperature error caused by the radiation is from 3% to 8% when measuring the concentration distribution of the mass transfer boundary layer, and the smaller the distance between the thermocouple and the cylinder is, the larger the measurement error becomes.