旋流流化床密相区埋管传热的冷态试验研究

在自建的旋流流化床冷态实验台上，采用基于微型热流密度感应薄膜制成的传热探针，测量了旋流流化床中埋管与床料的传热系数，研究流化风速、颗粒粒径、探针位置和密相区二次风射流等因素对埋管传热系数的影响。结果表明：当流化风速超过最小流化风速，传热系数随流化风速的提高迅速增加，并且会达到最大值，然后会稍有下降；传热系数沿探针的周向是变化的，背风面的传热系数总体上比迎风面的大；垂直于旋流方向布置探针的纵向传热系数高于平行旋流方向布置的横向传热系数，合理的颗粒级配和二次风射流有利于旋流的形成和传热效果的增强。

Study on Heat Transfer of Immersed Tube in a Horizontal Swirling Fluidized Bed

A novel horizontal swirling fluidized bed(HSFB) was designed through a specially designed distributor and secondary air injection to make bed material horizontal swirl in a dense zone.Heat transfer coefficients between immersed tube and bed materials in HSFB were measured with help of a fast response heat transfer probes.The influences of fluidization velocity,bed material particle size,bed height,probe orientation and secondary air injection,etc.on heat transfer coefficient were investigated.Results show that the heat transfer coefficients increase with fluidization velocity,and reach their maximum value at the certain fluidized velocity.The heat transfer coefficient in the backward orientation is higher than that in the upward orientation.It decrease with increasing of bed height.The bed material size is inversely proportional to heat transfer.The secondary air injection generates preferred hydrodynamics in the dense zone and enhanced heat transfer.