Particle to Wall Heat Transfer in Circulating Fluidized Beds

由于缺乏对传热基本机理的了解，使用循环流化床(CFB)燃烧的商业规模的工厂的发展一直受到阻碍。这项工作集中于与床壁接触的颗粒的热传递，循环床传热的一个重要组成部分，但了解甚少。控制传热过程的参数是在现有的20厘米循环床试验台上使用颗粒传感器和电容探头对各种不同的颗粒和流态化条件进行测量的，并与床层流体动力学有关。换热系数将被预测，并与实际换热测量结果进行比较。这项工作将加深对循环床内传热和流体力学之间的联系的理解，并有助于循环床燃烧室内换热面的设计。

Development of commercial-scale plants using circulating fluidized bed (CFB) combustion has been hindered by a lack of understanding concerning the basic mechanisms of heat transfer. This work concentrates on the heat transfer from particles in contact with the wall of the bed, an important and poorly understood component of heat transfer in CFB's. The parameters controlling the heat transfer process are being measured in an existing 20 cm CFB test facility using a particle sensor and capacitance probe for various different particles and fluidization conditions and related to the bed hydrodynamics. The heat transfer coefficient will be predicted and compared to actual heat transfer measurements. This work will produce an increased understanding of the link between heat transfer and hydrodynamics in CFB's, and aid the design of heat transfer surfaces in CFB combustors.