Modeling the heat transfer between fluid-granular medium
Modeling the heat transfer between fluid-granular medium
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DOI：
10.1016/j.applthermaleng.2017.09.064
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发表时间：
2018-01
影响因子：
6.4
通讯作者：
S. Al-Arkawazi
中科院分区：
文献类型：
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作者：
S. Al-Arkawazi
流化床工艺具有各种应用，其中温度场的知识非常重要（燃烧，干燥，冷冻等）。采用离散元法（DEM）与计算流体力学（CFD）耦合的方法，对流化床内固液两相的热行为进行了模拟研究。采用基于有限体积法的热传导-对流方法计算颗粒-流体和颗粒-颗粒之间的传热，并考虑了摩擦耗散和冲击（碰撞）耗散的影响。验证结果表明，热模型已证明其有效性，无论是在固定床或流化床。提出了一种热指示器，它可以知道达到所施加流体温度的颗粒的比例，而这在实践中很难获得。最后，通过流化塔的入口流体速度对流化床中的传热进行了评价。评价揭示了流体速度对流化过程中传热（传导和对流）能量机制的影响。模拟结果与文献中的实验数据一致，这将允许在更长的时间内;在模拟中添加流体和颗粒之间的传热模型和传质模型（例如在干燥过程中）。
Fluidized bed processes to have various applications, where knowledge of temperature fields is very important (combustion, drying, freezing, etc.). Thermal behavior of solid-fluid in fluidized beds has been studied through the simulation by means of coupling Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD). A thermal approach (conduction-convection) based on the finite volume method is proposed to calculate the heat transfer between particle-fluid and particle-particle, the effects of dissipation by friction and impact (collision) were also taken into account. Validation of results depicted that the thermal model has proven its effectiveness whether on a fixed or fluidized bed. A thermal indicator is proposed, which allows knowing the ratio of particles that have reached the temperature of the fluid imposed, which is difficult to access in practice. Finally, an evaluation of heat transfer in fluidized bed has been done, through inlet fluid velocity to the fluidization column. The evaluation revealed the effect of fluid velocity on the mechanisms of heat transfer (conduction and convection) energy in the fluidization processes. The simulations results were agreed and consistency with the experimental data in the literatures, which will allow in the longer term; to add heat transfer models and mass transfer ones between the fluid and particles (for example during a drying process) in simulations.