Prediction of Thermophoretic Deposition Efficiency of Particles in a Laminar Gas Flow along a Concentric Annulus： A Comparison of Developing and Fully Developed Flows  

作　　者：Samira Hashemi Ataallah Soltani Goharrizi 

机构地区：[1]Department of Chemical Engineering, Shahid Bahonar University, Kerman, Iran

出　　处：《Chinese Journal of Chemical Engineering》2009年第5期727-733,共7页中国化学工程学报（英文版）

摘　　要：Thermophoresis is an important mechanism of micro-particle transport due to temperature gradients in the surrounding medium.It has numerous applications,especially in the field of aerosol technology.This study has numerically investigated the thermophoretic deposition efficiency of particles in a laminar gas flow in a concentric annulus using the critical trajectory method.The governing equations are the momentum and energy equations for the gas and the particle equations of motion.The effects of the annulus size,particle diameter,the ratio of inner to outer radius of tube and wall temperature on the deposition efficiency were studied for both developing and fully-developed flows.Simulation results suggest that thermophoretic deposition increases by increasing thermal gradient,deposition distance,and the ratio of inner to outer radius,but decreases with increasing particle size.It has been found that by taking into account the effect of developing flow at the entrance region,higher deposition efficiency was obtained,than fully developed flow.Thermophoresis is an important mechanism of micro-particle transport due to temperature gradients in the surrounding medium. It has numerous applications, especially in the field of aerosol technology. This study has numerically investigated the thermophoretic deposition efficiency of particles in a laminar gas flow in a concentric annulus using the critical trajectory method. The governing equations are the momentum and energy equations for the gas and the particle equations of motion. The effects of the annulus size, particle diameter, the ratio of inner to outer radius of tube and wall temperature on the deposition efficiency were studied for both developing and fully-developed flows. Simulation results suggest that thermophoretic deposition increases by increasing thermal gradient, deposition distance, and the ratio of inner to outer radius, but decreases with increasing particle size. It has been found that by taking into account the effect of developing flow at the entrance region, higher deposition efficiency was obtained, than fully developed flow.

关 键 词：THERMOPHORESIS thermophoretic deposition efficiency developing flow ANNULUS 

分 类 号：O413.1[理学—理论物理] TG174.442[理学—物理]