48 巻 (2011) 12 号 p. 847-858
The behavior of flows in engineering applications such as a fluidized bed and a pneumatic conveyer is highly complex and a reliable numerical model has been desired. The flows are usually with solid walls that give considerable effects on flow field. To enhance the prediction capability of a model, it is important to include its effect properly. Observation of microscopic flow near walls shall enhance our understandings on flow behavior and model improvements. In the present study, direct simulations were performed to investigate the effect of walls on a flow field in the microscopic level. The effects of void fraction, particle Reynolds number and particle diameter were discussed. A prediction performance of existing correlation equations usually used in model calculations was also investigated. It is found that, by using Ergun and Beetstra equations, there is a large discrepancy in the region within 1 particle diameter from a wall.