流化床内单个颗粒传热特性的模拟

单个颗粒的传热过程对于燃煤流化床锅炉中煤的着火和随后的燃烧过程具有重要的影响。本文建立了一个基于Euler-Lagrange方法的数学模型对其进行了数值研究。该模型对流体相的运动和传热规律以Euler。方法描述,对固体颗粒相则以近年来发展起来的离散单元方法(DEM)在颗粒层次上进行描述。研究结果表明颗粒与床层之间有很高的传热系数。另外,对单个颗粒温度变化过程的模拟研究表明,颗粒经过较短的时间便能接近床层的温度,且不同颗粒具有类似的温度变化特性。

SIMULATION OF SINGLE PARTICLE HEAT TRANSFER CHARACTERISTIC IN FLUIDIZED BED

Single particle heat transfer characteristic has a great influence on ignition and combustion of coal particles in FBC boiler. Mathematical model based on Euler-Lagrange approach is established to investigate it, in which, movement and heat transfer of fluid phase is described by Eulerian approach, and movement and heat transfer of solid particle phase is described by Discrete Element Method(DEM) at the level of single particle. Investigation on heat transfer process of virtual tracer particles shows that they have high particle-bed heat transfer coefficients. In addition, temperature of particles inside bed increases rapidly and different particles have nearly same temperature change experience.