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.

为了提高流化床热交换器的性能（尤其是压降），采用了低密度颗粒。通过圆柱管进行测试，通过改变管子的位置，静态床高度，管螺距和空气速度来进行测试。此外，为了使颗粒稳定地围绕管子漂浮，使用了矩形管，因为管子之间的流动区域的变化很小。根据压降评估了平均传热系数。颗粒的影响以及管道直径与粒径与传热的比率的影响。最后，通过使用电容探针在试管表面的颗粒运动的结果讨论了传热机理。结果表明； 1。平均传热系数在后者的情况下与试管的位置和静态床高度无关。 2。平均热传递系数随着管螺距而减小，因为颗粒无法在管子周围稳定漂浮。 3。矩形管的平均传热系数比圆柱管的降低略大。 4。但是，由于矩形管比圆柱管更密集地排列，因此，相等的泵浦功率下的热性能对于圆柱管的泵送功率约为三倍。 5。密集相和瘦小相对于空气流量和粒径变化。 6。局部传热系数通过瘦小酶引起的表面更新的影响增加。