Abstract

The treatment of exhaust gas from large diesel engines is an important factor to affect environment. Because of its advantages in reaction efficiency and heat transfer efficiency, circulating fluidized bed (CFB) has shown great potential with regard to save energy and purify emissions from large diesel engines. This paper mainly investigated a three-dimensional modeling of the CFB, and a rolling function is applied to simulate its unsteady working conditions, which is called the rolling circulation fluidized bed (RCFB). Two-fluid model based on Euler-Euler approach is utilized to numerically simulate the gas-solid two phases flow within the RCFB. In order to give the comparable results between the present simulation and the previous experiment, the effect of Stokes number on particle phase distribution behaviors in the RCFB is investigated. By simulating the overall swing condition of the RCFB based on a dynamic grid, the effect of the swing condition on particle radial distribution uniformity in the riser is obtained. The reliability of quantitative modeling is verified based on the experimental results of the extant literature. Based on this simulation, the influence of the Stokes number on the radial distribution of particles as well as the relationship between the uniformity of the distribution and particle size is obtained.

Graphic Abstract

中文翻译：

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斯托克斯数对滚动循环流化床（RCFB）中颗粒相分布行为的影响

摘要

大型柴油机废气的处理是影响环境的重要因素。由于其在反应效率和传热效率方面的优势，循环流化床（CFB）在节省能源和净化大型柴油机的排放方面显示出巨大潜力。本文主要研究了CFB的三维模型，并利用滚动函数模拟了CFB的非稳态工况，称为滚动循环流化床（RCFB）。利用基于Euler-Euler方法的两流体模型对RCFB中的气固两相流动进行了数值模拟。为了在当前模拟和先前实验之间提供可比的结果，研究了斯托克斯数对RCFB中颗粒相分布行为的影响。通过基于动态网格模拟RCFB的总体摆动条件，获得了摆动条件对立管中颗粒径向分布均匀性的影响。根据现有文献的实验结果验证了定量建模的可靠性。基于该模拟，获得了斯托克斯数对颗粒的径向分布的影响以及分布的均匀性和粒径之间的关系。

图形摘要