旋转圆筒表面对流传质特性

Convective Mass Transfer Characteristics of a Rotating Cylinder

为研究水平旋转圆筒多孔介质表面的传质特性,用微型热偶式干湿球温度计测量了圆筒表面边界层温度分布和浓度分布,确定了顺向侧和逆向侧的局部对流传质系数;用硅橡胶板量热计测定了圆筒表面的平均对流传质系数.结果表明,旋转对圆筒表面顺向侧对流传质的强化作用比逆向侧明显;在较低旋转雷诺数下,平均舍伍得数基本保持不变,在较高旋转雷诺数下,平均舍伍得数随旋转雷诺数的增大而增大;旋转圆筒表面的对流传质和传热特性之间具有类比性.在实验数据的基础上,归纳和整理出了反映水平圆筒在静止空气中旋转时表面对流传质特性的准则关联式及临界雷诺数的判别式.

Mass transfer characteristics of a horizontal rotating cylinder was investigated experimentally. The distribution of temperature and concentration on the boundary layer was measured by using a specialized minitype dry and wet bulb thermocouple, and the local mass transfer coefficients of the downstream and upstream regions were determined. The average mass transfer coefficient around the cylinder surface was also measured with a calorimeter. The results indicate that the effect of rotation on the mass transfer of downstream is more obvious than that of the upstream; the average Sherwood number doesn＇t change at low rotational Reynolds, while it increases with rotational Reynolds for larger rotational Reynolds numbers; there is an analogy between the heat and mass transfer characteristics of the rotating cylinder. Based on the experimental data, correlation equations of the average Sherwood number and the critical Reynolds number was obtained.