Research on Flow Analysis of Dense Gas-Solid Two-Phase Flows with Heat Transfer

本研究的目的是开发分析稠密气固两相流动换热现象的数值格式。用红外热像仪测量了颗粒的温度分布。将实验结果与数值计算结果进行了比较。实验利用红外热像仪测量了二维流态化床层中颗粒的温度分布。前墙中央放置了一扇可以发射红外线的尖晶石窗户。采用两种不同的颗粒材料(玻璃和铝)，通过在床内分别注入50℃和100℃的热风，使颗粒流态化，研究了不同物性对床内传热的影响。结果表明，玻璃颗粒的温度变化比铝颗粒的变化大。与气固两相换热和颗粒对流换热相比，颗粒间换热可以忽略不计。数值分析基于实验结果忽略了颗粒间换热。预测的温度分布与实验结果定性地吻合。我们还建立了具有尺寸分布的系统的阻力模型。在此基础上，提出了一种适用于大规模计算的相似性模型。

The objective of this study is the development of numerical scheme for analyzing the phenomena in dense gas-solid two-phase flows with heat transfer. An infrared thermography was employed to measure the distribution of particle temperature. The experimental results were compared with the numerical results. Our experimental and numerical results are summarized below.ExperimentThe distribution of particle temperature was measured in a 2-D fluidized bed by using an infrared thermography. A spinel window, which can transmit infrared rays, was placed at the center of the front wall. Two different materials (glass and aluminum) of particles were used to study the effect of the physical properties on the heat transfer in the fluidized bed.The hot air (50 and 100 degrees centigrade) was injected in the bed to fluidize the particles. It was found that the temperature of glass particles varied more than that of aluminum particles. It was also found that the inter-particle heat transfer is negligible compared to gas-particle heat exchange and heat transfer by particle convection.Numerical analysisThe inter-particle heat transfer were neglected in our model based on the experimental results. Predicted temperature distribution agreed qualitatively with the experimental results. We also developed a drag force model for the system with size distribution. Further, we proposed a similarity model for large scale computations.