کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
158308 | 457003 | 2008 | 13 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: A multiscale mass transfer model for gas–solid riser flows: Part 1 — Sub-grid model and simple tests A multiscale mass transfer model for gas–solid riser flows: Part 1 — Sub-grid model and simple tests](/preview/png/158308.png)
The gas–solid mass transfer in circulating fluidized bed (CFB) riser flow is both structure-dependent and dynamic in nature. Recent progress in multiscale computational fluid dynamics (CFD) allows fresh insight into the dynamic flow structure, yet its influence on the mass transfer remains to be settled. To this end, a multiscale mass transfer model is established in this paper based on the extended framework of the energy-minimization multiscale (EMMS) model. The relevant algorithm named EMMS/mass is proposed for CFD-coupled mass transfer computation. Two testing cases accounting for sublimation of naphthalene and decomposition of ozone, respectively, are presented to demonstrate the characters of the model. It is shown that structural consideration can have significant effects on the model prediction. The normally used Reynolds number is not adequate to characterize these effects, while the combination of gas velocity and solids flux seems to capture the structural effects and allows to explain the variation of Sherwood number reported for CFB risers in the literature. Sub-grid coupling of this multiscale mass transfer model and CFD approach can be expected to provide a promising tool to probe the dynamic and structure-dependent nature of mass transfer in CFB risers.
Journal: Chemical Engineering Science - Volume 63, Issue 10, May 2008, Pages 2798–2810