导向管喷动床床层与埋管表面的换热特性研究

STUDY ON HEAT TRANSFER BETWEEN SPOUTED BED WITH DRAFT TUBE AND IMMERSED VERTICAL TUBE SURFACE

以石英砂作为循环颗粒,研究了颗粒与换热管束壁面的换热特性.在导向管喷动床环隙内,砂子以移动床的形式向下移动.为测定移动床层与埋管表面的换热系数,自制了组合热探头,并用调压器调节组合热探头的功率,使其稳定在不同温度下工作.分别考察了不同电压、不同吹松气量和不同床层轴向位置等对换热系数的影响.通过电压递增与递减的验证性实验,考察了两种方式对实验结果的影响.通过实验可知,换热系数随颗粒循环量的增加而增加.实验在常温常压下进行,喷动床材质为有机玻璃,移动床层与埋管换热壁面的平均换热系数在300 W/（m^2·K^-1）-400W/（m^2·K^-1）之间.

The slica sand in the annulus of spouted bed move downwards in the form of moving bed. The heat coefficient between the draft tube surface and the moving bed were measured by the assembled heat probe. The electric power of the assembled heat probe is regulated by voltage regulation. The paper has mainly studied the effects of voltage, flow rates of loose gas and different axial position of bed on heat coefficient. The experiment was carried out at room temperature and atmosphere pressure. The spouted bed with draft tube was made of organic glass. The average heat transfer coefficient between the moving bed and the buried tube surface is 300 W/（m^2·K^-1）-400W/（m^2·K^-1）.