Study on the effect of cell size on the cluster identification in CFB risers
The gas-solid flow in a CFB riser is modeled by means of LES-DSMC method.The effect of cell size on the identification of clusters in the core and near wall regions is studied respectively based on a cluster identification criterion.The results show that the independent cluster identification cell can be used to eliminate the dimensional restriction of gas computational cell effectively,and decreasing cell size is an effective way to increase the precision of cluster identification and obtain the distributions of cluster characteristics in detail.In the core region,the bed-averaged cluster characteristics almost vary linearly with the cell size.In the near wall region,the obtainable data points decrease and the number-averaged cluster characteristics deviate increasingly from the actual values with the increase of cell size.The approach for predicting the mean solid concentration and descending velocity of cluster in the wall film is proposed and the calculation results have a good agreement with the experimental data.
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维普
