A model for heat transfer in circulating fluidized beds
A model for heat transfer in circulating fluidized beds
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DOI：
10.1016/0009-2509(90)87144-h
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发表时间：
1990
影响因子：
4.7
通讯作者：
R. Wu;J. Grace;C. J. Lim
中科院分区：
文献类型：
--
作者：
R. Wu;J. Grace;C. J. Lim
提出了一种用于预测循环床内换热系数的传热模型。基于对低温和高温提升管中核心-环空流动结构的观测和流体力学测量，该模型假定环空中的颗粒聚集成具有不同空隙率的线束。这些链条被认为经历了一个重复的形成、沿着壁向下移动和解体的过程。热通过具有壁面接触电阻的瞬时热传导在壁面和绞线之间传递。所得到的模型与已公布的光滑表面数据符合得很好。该模型较好地考虑了换热面长度和颗粒尺寸的影响。然而，对于膜或其他非光滑几何形状，在未来的模型中必须考虑换热面几何形状对颗粒流型的影响。
A heat transfer model is proposed for predicting transfer coefficients in circulating fluidizeds beds. Based on observations and on hydrodynamic measurements of the core—annulus flow structure in low- and high-temperature risers, the model assumes that particles in the annulus congregate into strands with different voidages. These strands are assumed to undergo a repeating process of formation, downward movement along the wall, and disintegration. Heat is transferred between the wall and the strands by transient heat conduction with a wall contact resistance. The resulting model gives reasonable agreement with published data for smooth surfaces. It accounts successfully for the effects of heat transfer surface length and particle size. However, it is shown that the effect of the geometry of the heat transfer surface on the flow pattern of particles must be taken into account in future models for membrane or other non-smooth geometrics.