振动流化床与浸没水平管平均传热特性理论分析与实验研究

在二维流化床(240mm×80mm)中,以平均粒径dp为1.83mm的玻璃珠为物料,研究了振动流化床与浸没水平管间传热规律;考察了流化数、振动频率、床高、水平管管径等因素对平均传热系数的影响。采用自制探头对浸没加热管束和振动流化床层间平均传热系数进行实验测定,利用颗粒团模型,建立了振动流化床层与浸没水平管间平均传热模型,并对平均传热系数的理论预测值与实验测定值进行了比较。结果表明:计算值与实验值吻合较好,误差在±15%范围内。在较高流化数、低振动频率时,实验值处于理论值上方;随着振动频率、管径增大,平均传热系数实验值逐渐趋于理论预测值甚至低于理论预测值。结果可为带浸没水平管的振动流化床设计和研究提供参考。

Theoretical prediction and experimental investigation on the average heat transfer characteristic between vibrated fluidized beds and horizontal tubes

Experiments using the glass beads with the average diameter dp of 1.83mm was conducted in atwo-dimensional vibrated fluidized bed. The average heat transfer laws have been investigated. The effect of the fluidization numbers, vibration frequency, static bed height, and the tube diameter on the average heat transfer coefficient have been analyzed. The average heat transfer coefficients was experimentally investigated with self-made probe. A mathematical model is proposed to predict the average heat transfer coefficients between vibrated fluidized bed and immersed horizontal tubes based on the particle packets renewal theory. The results show that the values of theoretical prediction are in good agreement with experimental data, and the error is inrange of ±15%. The values of experimental above the theoretical prediction at the higher fluidization numbers and lower vibration frequency. They are consistent with each other and even lower than theoretical prediction with increasing vibration frequency and tube diamete. The results can provide references for future designing and researching on the vibrated fluidized beds with immersed horizontal tubes.