Pseudo mass transfer model of PM2.5 thermophoresis and diffusiophoresis in gas-liquid cross flow array

doi:10.11949/j.issn.0438-1157.20181294

Abstract

Abstract:

Based on the pseudo-fluid characteristics of PM2.5 in aerosol, the pseudo mass transfer mechanism of PM2.5 in gas-liquid heat and mass transfer boundary layer was analyzed, considering the convective mass transfer of PM2.5 caused by thermophoresis, diffusiophoresis and the gas movement, a pseudo mass transfer model of PM2.5 in gas-liquid cross flow array based on thermophoresis and diffusiophoresis is established, and the accuracy of the model is verified through experiments. The influencing of thermophoresis caused by gas-liquid temperature difference, diffusiophoresis caused by gas-liquid humidity difference and particle size on the pseudo mass transfer coefficient of PM2.5 was investigated under fixed convection conditions. The experimental data statistics are consistent with the model expression trend. Under the initial temperature difference of 40℃ and initial humidity of 0.118 kg/kg, the predicted value of the PM2.5 pseudo-mass transfer coefficient model of the exhaust gas cross-flow array is 3.33×10^-3 m/s, experimental value 3.75×10^-3 m/s.

Key words: PM2.5, pseudo mass transfer model, gas-liquid cross flow, thermophoresis, diffusiophoresis

摘要：

基于气溶胶中PM2.5微细颗粒物拟流体特性，对气液交叉流阵列中PM2.5在气溶胶流体传热传质边界层内热泳和扩散泳运动进行拟传质机理分析，与跟随气体的对流传质相叠加，建立了气液交叉流阵列PM2.5热泳和扩散泳拟传质模型，并进行了实验检验。实验在固定对流条件下，考察了不同气液相温度差导致的热泳、不同气相湿度差导致的扩散泳和颗粒粒径等因素对气液交叉流阵列PM2.5拟传质系数的影响。实验数据统计值与模型表达趋势一致，在初始温差40℃、初始湿度0.118 kg/kg条件下，100排气液交叉流阵列PM2.5拟传质系数模型预测值为3.33×10^-3 m/s、实验值为3.75×10^-3 m/s。

关键词: PM2.5, 拟传质模型, 气液交叉流, 热泳, 扩散泳

CLC Number:

TQ 019

Haitao YANG, Zhijian ZHENG, Jiahua ZHU, Zhuo CHEN, Chenpeng YANG, Xun DUAN. Pseudo mass transfer model of PM2.5 thermophoresis and diffusiophoresis in gas-liquid cross flow array[J]. CIESC Journal, 2019, 70(6): 2139-2146.

杨海涛, 郑志坚, 朱家骅, 陈倬, 杨晨鹏, 段旬. 气液交叉流阵列PM2.5热泳和扩散泳拟传质模型[J]. 化工学报, 2019, 70(6): 2139-2146.

Figures/Tables 9

Fig.1 Model mechanism of gas flowing cross gas-liquid cross flow array

Fig.3 Pseudo mass transfer coefficient of PM2.5 caused by gas movement (k TP) with different inlet gas velocity

Fig.4 Pseudo mass transfer coefficient of PM2.5 by a single column of gas-liquid cross flow array

Fig.5 Experimental flow chart of gas-liquid cross flow array to measure pseudo mass transfer coefficient of PM2.5

Fig.6 Al2O3 particles size distribution of inlet

Table 1 Test conditions of gas inlet

工况	气体入口温度T/℃	气体相对湿度φ	液膜温度T _w/℃	温度差/℃	气体初始湿度/(kg/kg)	液膜表面湿度/(kg/kg)	湿度差/(kg/kg)
a	20	1	20	0	0.016	0.016	0
b	60	0.118	20	40	0.016	0.016	0
c	60	0.232	20	40	0.032	0.016	0.016
d	60	0.757	20	40	0.118	0.016	0.102

Fig.7 Pseudo mass transfer coefficient of PM2.5 in 100 columns with different inlet gas operation parameters

Fig.8 Pseudo mass transfer coefficient of PM2.5 in gas-liquid cross flow array (20, 40, 100 columns)

References 30

1	王玮, 汤大钢, 刘红杰, 等 . 中国PM2.5污染状况和污染特征的研究[J]. 环境科学学报, 2000, 13(1): 1-5.
	Wang W , Tang D G , Liu H J , et al . Research on current pollution status and pollution characteristics of PM2.5 in China[J]. Research of Environmental Sciences, 2000, 13(1): 1-5.
2	殷永文, 程金平, 段玉森, 等 . 某市霾污染因子PM2.5引起居民健康危害的经济学评价[J]. 环境与健康杂志, 2011, 28(3): 250-252.
	Yin Y W , Cheng J P , Duan Y S , et al . Economic evaluation of residents health hazard caused by PM2.5 of haze pollution in a city[J]. Journal of Environment & Health, 2011, 28(3): 250-252.
3	杨新兴, 冯丽华, 尉鹏 . 大气颗粒物PM2.5及其危害[J]. 前沿科学, 2012, (1): 22-31.
	Yang X X , Feng L H , Wei P . Air particulate matter PM2.5 in Beijing and its harm [J]. Frontier Science, 2012, (1): 22-31.
4	Davis E J , Schweiger G . The Airborne Microparticle[M]. Berlin : Springer Berlin Heidelberg, 2002.
5	Tucker W G . An overview of PM 2.5 sources and control strategies[J]. Fuel Processing Technology, 2000, 65(1): 379-392.
6	张国权 . 气溶胶力学: 除尘净化理论基础[M]. 北京: 中国环境科学出版社, 1987.
	Zhang G Q . Aerosol Dynamics [M]. Beijing: China Environment Science Press, 1987: 110.
7	王明星, 张仁健 . 大气气溶胶研究的前沿问题[J]. 气候与环境研究, 2001, 6(1): 119-124.
	Wang M X , Zhang R J . Frontier of atmospheric aerosols researches[J]. Climatic and Environmental Research, 2001, 6(1): 119-124.
8	王维, 李佑楚 . 颗粒流体两相流模型研究进展[J]. 化学进展, 2000, 12(2): 208.
	Wang W , Li Y C . Progress of the simulation of particle-fluid two-phase flow[J]. Progress in Chemistry, 2000, 12(2): 208-217.
9	Rudinger G . Fundamentals of Gas Particle Flow[M]. Amsterdam: Elsevier, 2012.
10	Kim J C , Lee K W . Experimental study of particle collection by small cyclones[J]. Aerosol Science & Technology, 1990, 12(4): 1003-1015.
11	周涛, 杨瑞昌, 张记刚, 等 . 矩形管边界层内亚微米颗粒运动热泳规律的实验研究[J]. 中国电机工程学报, 2010, 30(2): 92-97.
	Zhou T , Yang R C , Zhang J G , et al . Experimental study on the thermophoresis movement of submicron particle in the boundary layer of the rectangular pipe[J]. Proceedings of the CSEE, 2010, 30(2): 92-97.
12	刘若雷, 杨瑞昌, 由长福, 等 . 温度梯度场内可吸入颗粒物运动特性及热泳沉积[J]. 化工学报, 2009, 60(7): 1623-1628.
	Liu R L , Yang R C , You C F , et al . Kinematic characteristics and thermophoretic deposition of inhalable particles in temperature gradient field[J]. CIESC Journal, 2009, 60(7): 1623-1628.
13	Prem A , Pilat M J . Calculated particle collection efficiencies by single droplets considering inertial impaction, Brownian diffusion and electrostatics[J]. Atmospheric Environment ( 1967), 1978, 12(10): 1981-1990.
14	王翱, 宋蔷, 姚强 . 脱硫塔内单液滴捕集颗粒物的数值模拟[J]. 工程热物理学报, 2014, 35(9): 1889-1893.
	Wang A , Song Q , Yao Q . Numerical simulation of single droplet capturing particles in the WFGD[J]. Journal of Engineering Thermophysics, 2014, 35(9): 1889-1893.
15	Romay F J , Takagaki S S , Pui D Y H , et al . Thermophoretic deposition of aerosol particles in turbulent pipe flow[J]. Journal of Aerosol Science, 1998, 29(8): 943-959.
16	Walton I C . Eddy diffusivity of solid particles in a turbulent liquid flow in a horizontal pipe[J]. AIChE Journal, 1995, 41(7): 1815-1820.
17	Ayşe A , Kelbaliyev G , Ceylan K . Eddy diffusivity of particles in turbulent flow in rough channels[J]. Journal of Aerosol Science, 2002, 33(7): 1075-1086.
18	Waldmann L , Schmitt K H . Thermophoresis and diffusiophoresis of aerosol[M]//Davies C N. Aerosol Science. New York: Academic Press, 1966: 163-194.
19	Deryagin B V . The theory of the motion of small aerosol particles in a diffusion field[J]. Doklady Akademii Nauk, 1957, 117(6): 959-962.
20	Lehtinen K E J , Hokkinen J , Jokiniemi A A J K , et al . Studies on steam condensation and particle diffusiophoresis in a heat exchanger tube[J]. Nuclear Engineering & Design, 2002, 213(1): 67-77.
21	He C , Ahmadi G . Particle deposition with thermophoresis in laminar and turbulent duct flows[J]. Aerosol Science and Technology, 1998, 29(6): 525-546.
22	Tsai C J , Lin J S , Aggarwal S G , et al . Thermophoretic deposition of particles in laminar and turbulent tube flows[J]. Aerosol Science and Technology, 2004, 38(2): 131-139.
23	陈治良, 魏文韫, 朱家骅, 等 . 横掠液柱流的微粒运动机理及PM2.5捕获(Ⅱ): 重型柴油机尾气PM2.5捕获效率[J]. 化工学报, 2012, 63(7): 2010-2016.
	Chen Z L , Wei W Y , Zhu J H , et al . Mechanism of micro-particle motion across falling liquid cylinder for PM2.5 separation (Ⅱ): Efficiency of PM2.5 separation from heavy-duty diesel exhausts[J].CIESC Journal, 2012, 63(7) : 2010-2016.
24	陈治良, 魏文韫, 朱家骅, 等 . 横掠液柱流的微粒运动机理及PM2.5捕获(Ⅰ): 附面运动轨迹与分离半径[J]. 化工学报, 2012, 63(7): 2001-2009.
	Chen Z L , Wei W Y , Zhu J H , et al . Mechanism of micro-particle motion across falling liquid cylinder for PM2.5 separation (Ⅰ): Trajectory of particle motion towards surface and separation radius[J].CIESC Journal, 2012, 63(7): 2001-2009.
25	Bird R B , Stewart W E , Lightfood E N . Transport Phenomena[M]. New York: John Wiley & Sons Inc., 2002.
26	Brock J R . On the theory of thermal forces acting on aerosol particles[J]. Journal of Colloid Science, 1962, 17(8): 768-780.
27	Khan W A , Culham R J , Yovanovich M M . Analytical model for convection heat transfer from tube banks[J]. Journal of Thermophysics & Heat Transfer, 1971, 20(4): 720-727.
28	Davies C N . Aerosol Science[M]. London and New York: Academic Press, 1966.
29	Huisman I H , Trägårdh C . Particle transport in cross flow microfiltration(Ⅰ): Effects of hydrodynamic and diffusion[J]. Chemical Engineering Science, 1999, 54(2): 271-280.
30	Lee K W , Liu B Y H . Experimental study of aerosol filtration by fibrous filters[J]. Aerosol Science & Technology, 1982, 1(1): 35-46.

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[3]	CHEN Zhiliang1，WEI Wenyun1，ZHU Jiahua1，GUO Shen2，XIA Sulan1,YU Hui1. Mechanism of micro-particle motion across falling liquid cylinder for PM_2.5 separation (Ⅰ)Trajectory of particle motion towards surface and separation radius [J]. CIESC Journal, 2012, 63(7): 2001-2009.
[4]	ZHANG Mingjun，FAN Fengxian. Progress and prospect in numerical simulation on acoustic agglomeration of fine particles [J]. Chemical Industry and Engineering Progree, 2012, 31(08): 1671-1676.
[5]	FAN Fengxian，YANG Linjun, YUAN Zhulin. Progress and prospect in the study of heterogeneous nucleation of vapor on fine particles [J]. , 2009, 28(9): 1496-.
[6]	Samira Hashemi, Ataallah Soltani Goharrizi. Prediction of Thermophoretic Deposition Efficiency of Particles in a Laminar Gas Flow along a Concentric Annulus:A Comparison of Developing and Fully Developed Flows [J]. , 2009, 17(5): 727-733.
[7]	YANG Ruichang, LIU Ruolei, ZHOU Tao, ZHAO Lei. Kinematic Characteristics and Thermophoretic Deposition of Inhalable Particles in Turbulent Duct Flow [J]. , 2008, 16(2): 192-197.