矩形管边界层内亚微米颗粒运动热泳规律的实验研究  

Experimental Study on the Thermophoresis Movement of Submicron Particle in the Boundary Layer of the Rectangular Pipe

作　　者：周涛[1] 杨瑞昌[2] 张记刚[1] 赵磊[2] 王世超[1] 刘若雷[2] 

机构地区：[1]华北电力大学能源与动力工程学院,北京市昌平区102206 [2]清华大学热能工程系,北京市海淀区100084

出　　处：《中国电机工程学报》2010年第2期92-97,共6页Proceedings of the CSEE

基　　金：教育部博士点基金项目(200800791005);北京市自然科学基金项目(309201)

摘　　要：建立带有玻璃窗的由"煮黑"工艺完成的矩形通道实验装置,对已有的颗粒动态分析(particle dynamicsanalyzer,PDA)测量技术进行了改进,并以此方法对矩形通道内的不均匀温度场中近壁区的亚微米颗粒的运动情况进行了测量。改进的PDA测量方式可更有效地了解近壁面颗粒运动状况。利用实验数据对在温度场中亚微米颗粒的受力情况和运动情况进行了分析。研究表明:亚微米颗粒在湍流温度场中运动,既有湍流和热泳的沉积效应,也存在较小颗粒的团聚效应。热泳力对较小粒子的作用强于较大粒子,但如果粒径太小,粒子在主流中的跟随性变强。热泳力对亚微米颗粒作用较强,湍流对较大颗粒作用较强。由于亚微米颗粒能够跟随气流运动,对沉积也带来不利的影响。当温度较高时,在边界层内,热泳力超过由于速度梯度造成的横向沙夫曼力,是使细颗粒发生热泳沉积的重要原因。布朗扩散可能对亚微米颗粒运动起到主导作用。The ＇cooking black＇ technology for the channel wall surface and the use of three quartz glasses as the windows of the channel were adapted. A general particle dynamics analyzer （PDA） measure technology was improved. The change of sub-micron particle motion regulation near wall was measured under the temperature field in the rectangular channel through using the improved measure method of PDA. The sub-micron particle motion near wall may be expressly observed and studied by the new measure method. The stress and motion property of the sub-micron particle in the temperature field was analyzed by using the experiment dates. The research shows that thermophoretic force on smaller particle is stronger than it on bigger particle and The following of the smallest particle in the mainstream become stronger. There are some adverse influences for the particle deposition due to the sub-micron particle moving with gas flow. The sub-micron particle deposition is due to the thermophoretic force in boundary layer under high gas flow temperature. Brown diffuse may be dominant operation for the sub-micron particle motion.

关 键 词：亚微米颗粒 热泳 近壁面 沉积 湍流 

分 类 号：X513[环境科学与工程—环境工程]