Abstract In this paper, the hydrodynamics and gas-solid heat transfer characteristics during bed material heating process are investigated using the CFD-DEM approach, and the heating rate and bed temperature uniformity are quantitatively analysed. After model validation, gas-solid heat transfer characteristics in a typical case is analysed. On this basis, the effects of operating conditions is further discussed. The results show that overheating phenomenon at bed bottom is weakened obviously by solid internal circulation behavior in fluidized bed. As time marches, bed temperature uniformity is effectively improved with increasing mean bed temperature. Specially, a temperature drop at particle scale is captured by tracer particle method. A simplified energy balance model is developed to explain the relationship between bulk heating rate and operating conditions, and qualitatively consistent between simulation results and model analytical solutions is captured. Furthermore, the temperature uniformity under different operating conditions is qualitatively discussed by standard deviation of particle temperature.

中文翻译：

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流化床升温速率及温度均匀性模拟研究

摘要 本文采用CFD-DEM方法研究了床层物料加热过程中的流体力学和气固传热特性，定量分析了床层材料的加热速率和温度均匀性。模型验证后，对典型案例中的气固传热特性进行分析。在此基础上，进一步讨论了运行条件的影响。结果表明，流化床固体内循环行为明显减弱了床底过热现象。随着时间的推移，床温均匀性随着平均床温的升高而得到有效改善。特别地，粒子尺度的温降是通过示踪粒子方法捕获的。开发了一个简化的能量平衡模型来解释整体加热速率和操作条件之间的关系，并捕获模拟结果和模型解析解之间的定性一致性。此外，通过颗粒温度的标准偏差定性讨论了不同操作条件下的温度均匀性。