旋转圆筒表面对流质交换边界层实验研究

用微热偶式干湿球温度计．在稳定对流质交换状态下，对水平旋转圆筒多孔介质表面边界层的温度场和浓度场进行了测量。实验表明：对流质交换边界层的厚度随船，的增大而减小；浓度边界层的厚度大于温度边界层的厚度；热质交换边界层的温度梯度小于纯对流热交换边界层的温度梯度；旋转对于顺向侧和逆向侧对流质交换的影响结果不同．在顺向侧．由于旋转受迫对流和自然对流的作用方向一致，二者相互叠加的结果，使得边界层浓度梯度加大，厚度减小，而在逆向侧，情况则正好相反。

Experimental Study of the Convective Mass-exchange Boundary Layer of a Rotating Cylindrical Surface

Under the status of a stable convective mass-exchange the temperature field and concentration field of the porous-medium surface boundary layer of a horizontal rotating cylinder were measured by using a dry-wet bulb thermometer of micro thermocouple type.The results of the measurements indicate that the thickness of the boundary layer of the convective mass exchange will decrease with an increase in Re_r and the thickness of the concentration boundary layer is greater than that of the temperature boundary layer.The temperature gradient of the heating mass-exchange boundary layer is smaller than that of the pure convective heat-exchange boundary layer.Rotation can produce a different impact on the convective mass-exchange at the consequent side and the inverse side.At the consequent side,due to the coincidence of the action direction of both the rotation-enforced convection and the natural convection,the result of this overlap has led to an increase in the boundary layer concentration gradient and a decrease in boundary layer thickness.However,at the inverse side,an exactly opposite situation will prevail.