权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

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.

为了改善沸腾换热器的性能(特别是压降)，采用了低密度颗粒。通过改变管子的位置、静态床层高度、管子间距和空气速度来进行圆柱管试验。此外，为了使颗粒稳定地漂浮在管子周围，由于管子之间的流动面积变化很小，所以采用了矩形管子。计算了平均换热系数与压降的关系。研究了颗粒的影响以及管径与颗粒尺寸比对换热的影响。结果表明：1.当静态床层高度大于静态床层高度时，平均换热系数与管子位置无关。2.平均换热系数随着管距的减小而减小，这是因为颗粒不能稳定地漂浮在管子周围。3.矩形管的平均换热系数下降幅度略大于圆柱管。4.由于矩形管可以比圆柱管布置得更密集，在相同泵浦功率下的热工性能比圆柱管提高了近3倍。5.浓相和贫相随空气流量和颗粒大小的不同而不同。6.贫化相引起的表面更新效应增加了局部换热系数。