Basic Studies On A New Fluidized Bed Heat Exchanger

新型流化床换热器的基础研究

基本信息

批准号：
60550150
负责人：
KUMADA Masaya
金额：
$ 1.15万
依托单位：
University of Gifu
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60550150/
关键词：
Heat Exchanger Fluidized Bed Convective Heat Transfer Low Density Particle Single Row Horizontal Rectangular Tubes Rectangular Tubes 静電容量プローブ

项目摘要

In order to improve the performance(especially pressure drop) of a fluidized bed heat exchanger, low density particles were employed. The tests were conducted with cylindrical tubes by varying the location of the tubes, static bed height, tube pitches and air velocities. Furthermore, in order to make particles stably floating around tubes, rectangular tubes were used because the change of the flow area between the tubes is small. Mean heat transfer coefficients were evaluated in relation to pressure drop. And effects of particles and effects of the ratio of tube diameter to particle size to heat transfer were carried out. Finally, mechanism of heat transfer was discussed by the results of the motion of particles at the surface of tubes using a capacitance probe.The results show that; 1. Mean heat transfer coefficients are independent of both the location of the tubes and static bed height in the case of the latter is larger than the former. 2. Mean heat transfer coefficient decreases with the tube pitch decreases, because the particules can not float stably around the tubes. 3. Mean heat transfer coefficients of rectangular tube decrease slightly more than those of cylindrical tubes. 4. But, as rectangular tubes are able to be arranged more densely than cylindrical tubes, the thermal performance under equal pumping power is improved about three times for that of cylindrical tubes. 5. The dense-phase and the lean-phase varied with air flow rate and particle size. 6. Local heat transfer coefficient increased by the effect of surface renewal due to the leanphase.

为了提高流化床换热器的性能（特别是压降），采用低密度颗粒。通过改变管的位置、静态床高度、管间距和空气速度，使用圆柱形管进行测试。此外，为了使颗粒稳定地漂浮在管周围，使用矩形管，因为管之间的流通面积变化较小。平均传热系数是根据压降来评估的。并考察了颗粒和管径与颗粒尺寸之比对传热的影响。最后，利用电容探头对管子表面颗粒运动的结果探讨了传热机理。 1. 在后者大于前者的情况下，平均传热系数与管的位置和静态床高度无关。 2.平均传热系数随管距减小而减小，因为颗粒不能稳定地漂浮在管周围。 3、矩形管的平均传热系数比圆柱管下降幅度稍大。 4、由于矩形管的排列比圆柱管更密集，因此在同等抽气功率下，其热性能比圆柱管提高了三倍左右。 5.密相和贫相随空气流量和颗粒尺寸的变化而变化。 6.由于贫相导致的表面更新效应，局部传热系数增加。