两种截面窄通道内PM_1颗粒沉积数值模拟对比研究  

Contrastive Simulation Research on PM_1 Particles Deposition in Two Narrow Rectangular Channels

作　　者：汝小龙[1] 周涛[1] 林达平[1] 杨旭[1] 

机构地区：[1]华北电力大学核热工安全和标准化研究所,北京102206

出　　处：《核动力工程》2013年第S1期42-46,共5页Nuclear Power Engineering

基　　金：北京市自然基金(No.3092016);教育部博士点基金(No.200800791005)资助项目

摘　　要：基于FLUENT软件,对尺寸为20 mm×20 mm×1000 mm(通道1)和10 mm×30 mm×1000 mm(通道2)的竖直矩形窄通道内,不同温度场中动力学直径小于或等于1μm的颗粒物(PM1)在湍流工况下的沉积规律进行数值模拟研究。气相采用标准k-模型,PM1颗粒采用离散相模型(DPM)。结果表明,矩形通道内湍流扩散、热泳效应和二次流的共同作用使PM1颗粒在近壁面区域富集;湍流扩散使主流区的PM1颗粒在靠近壁面处富集;二次流是PM1在拐角附近产生富集的主要原因;而在温度场内近壁面区域,热泳力是PM1在冷壁上发生沉积的最主要因素;随主流温度的增高,PM1颗粒布朗运动增强,使PM1的无规则运动和扩散加强,不利于PM1形成稳定的富集区,减弱了PM1在冷壁面上的沉积。This paper intends to make numerical simulation to study the regularity of the deposition of PM1 particles under the turbulent condition at different temperatures in two narrow vertical rectangular channels.The channel 1 length is 1000mm,and the sectional dimension is 20 mm × 20mm.Channel 2 sectional dimension is 10 mm × 30 mm,and channel 2 length is as long as channel 1.The gas phase uses the standard k– model and the PM1 particles use DPM(Discrete Phase Model).The study found that,the turbulent diffusion,the thermophoresis and the secondary flow together make the PM1 particles gather in the channel near-wall regions,the turbulent diffusion make PM1 particles concentrate in the channel near-wall regions,and the important reason of PM1 particles concentration is the secondary flow in the corner.In the temperature field in near-wall regions,it can be found that the thermophoretic force is the most important factor for the PM1to deposit on the cold wall.With the rise of the main flow temperature,the random motion and diffusion of the PM1 particles tend to be intensified due to the significant intensification of the PM1 particles Brownian motion,which is not conducive to form the stable gathering areas of PM1 particles in the near-wall regions,and it tends to weaken the deposition of PM1particles on the cold wall.

关 键 词：PM1颗粒 热泳 二次流 

分 类 号：TL33[核科学技术—核技术及应用]