旋幕式排风罩收集电焊烟尘的数值模拟
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摘要
为解决电焊烟尘气流无组织排放对焊工健康和环境造成的严重影响,得出旋幕式排风罩的最佳设计参数及气流组织形式,选择GAMBIT软件建立排风罩的物理模型并进行网格划分,选用雷诺平均N-S方程(RANS)、Realizableκ-ε湍流模型及DPM离散相模型,利用Fluent计算流体力学软件对旋幕式排风罩捕集效率的相关参数进行模拟计算。结果表明:旋幕式排风罩能有效控制电焊烟尘气流的扩散;喷口角度对涡流产生的大小、位置和强度影响最大;最佳设计参数为有效吸程1. 5 m,喷口角度80°,喷口宽度14 mm;在该设计参数条件下,当罩面吸口风速为0. 3 m/s、喷口风速为1. 1m/s时,捕集效率达到最高,为98. 28%。
The purpose of the paper is to reveal the vortex effect and gas-solid coupling in treating the welding fumes by cyclone air curtain exhaust hood,so as to obtain the optimum design size parameters and reasonable air flow organization in the welding zone. To achieve the purpose, the paper has chosen the GAMBIT software to create a physical model of the exhaust hood and mesh it,then introducing them into the Fluent Computational Fluid Dynamics( CFD) software. Of course,such tests have also been done by using the Reynolds average numerical simulation,the realizable κ-ε turbulence model and the DPM discrete phase model. What is more,we have also managed to combine all the factors that can have more or less effects on the trapping efficiency,such as the spout angle and width,the effective suction stroke,the suction hole speed in the hood and the wind speed of the spout,whereas the other influential factors can also be classified into 45 groups of different conditions for the numerical simulation and calculation in accordance with the actual conditions to set related assumptions and boundary situations. The research results we have gained in this paper show that the cyclone air curtain exhausting hood can perform marvelously in controlling the diffusion of the welding fumes,whereas the vortex can be fixed on the lower edge of the hood,with the angle of the spout affecting the size,position and the strength of the said vortex. Therefore,the optimized design factor parameters should be illustrated as follows: The effective suction stroke: 1. 5 m; the angle of the spout: 80°; and,the width of spout: 14 mm. When all the above mentioned design parameters can be made satisfied enough,it would be possible for the trapping efficiency to reach the maximum efficiency of 98. 28% whereas the suction hole speed of the hood can reach 0. 3 m/s with the wind speed of spout being 1. 1 m/s. Thus,the paper can be said successful in proposing a novel idea of collecting welding fumes by using a cyclone air curtain exhaust hood and providing a support for the future practical applications.
The purpose of the paper is to reveal the vortex effect and gas-solid coupling in treating the welding fumes by cyclone air curtain exhaust hood,so as to obtain the optimum design size parameters and reasonable air flow organization in the welding zone. To achieve the purpose, the paper has chosen the GAMBIT software to create a physical model of the exhaust hood and mesh it,then introducing them into the Fluent Computational Fluid Dynamics( CFD) software. Of course,such tests have also been done by using the Reynolds average numerical simulation,the realizable κ-ε turbulence model and the DPM discrete phase model. What is more,we have also managed to combine all the factors that can have more or less effects on the trapping efficiency,such as the spout angle and width,the effective suction stroke,the suction hole speed in the hood and the wind speed of the spout,whereas the other influential factors can also be classified into 45 groups of different conditions for the numerical simulation and calculation in accordance with the actual conditions to set related assumptions and boundary situations. The research results we have gained in this paper show that the cyclone air curtain exhausting hood can perform marvelously in controlling the diffusion of the welding fumes,whereas the vortex can be fixed on the lower edge of the hood,with the angle of the spout affecting the size,position and the strength of the said vortex. Therefore,the optimized design factor parameters should be illustrated as follows: The effective suction stroke: 1. 5 m; the angle of the spout: 80°; and,the width of spout: 14 mm. When all the above mentioned design parameters can be made satisfied enough,it would be possible for the trapping efficiency to reach the maximum efficiency of 98. 28% whereas the suction hole speed of the hood can reach 0. 3 m/s with the wind speed of spout being 1. 1 m/s. Thus,the paper can be said successful in proposing a novel idea of collecting welding fumes by using a cyclone air curtain exhaust hood and providing a support for the future practical applications.
引文
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[3] FANG Disheng(方迪生). Study on indirect arc charac-teristics of three-wire gas protection and welding process ofthick-walled narrow gap(气体保护三丝间接电弧特性及其厚壁窄间隙焊接工艺研究)[D]. Dalian:DalianUniversity of Technology,2017.
[4] STERJOVSKI Z,NORRISH J,MONAGHAN B J. Theeffect of voltage and metal transfer mode on particulatefume size during the GMAW of plain carbon steel[J].Welding in the World,2010,54(9/10):249-256.
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[6] LIU Ronghua(刘荣华),LI Xibing(李夕兵),SHI Shil-iang(施式亮),et al. Numerical simulation of a new cy-clone air curtain exhaust hood[J]. Environmental Engi-neering(环境工程),2009,27(4):68-72.
[7] NG C S. A study of the effectiveness of local exhaust venti-lation(LEV)in training facilities building using computa-tional fluid dynamics(CFD)approach[D]. Tun HusseinOnn:University Tun Hussein Onn Malaysia,2013.
[8] ZHANG Daming(张大明),MA Yundong(马云东),LUO Genhua(罗根华). On a new control and removaldust system with a perfect wind curtain and duster by wayof numerical simulation[J]. Journal of Safety and Envi-ronment(安全与环境学报),2015,15(6):82-86.
[9] HE Suyan,LI Yunfei. Numerical simulation and experi-mental study of a kind of local exhaust ventilation hood[J]. Chinese Journal of Mechanical Engineering,2003,16(4):433-436.
[10] YANG Yang(杨洋),WANG Yi(王怡),LI Yanbin(李艳斌). The characteristics of the flow field under jetflow[J]. Journal of Southwest Jiaotong University(西南交通大学学报),2015,50(2):347-353.
[2] YE Jun(叶军). Overview of the US welding market andwelding industry[J]. Welding Machine(电焊机),2014,44(3):8-12.
[3] FANG Disheng(方迪生). Study on indirect arc charac-teristics of three-wire gas protection and welding process ofthick-walled narrow gap(气体保护三丝间接电弧特性及其厚壁窄间隙焊接工艺研究)[D]. Dalian:DalianUniversity of Technology,2017.
[4] STERJOVSKI Z,NORRISH J,MONAGHAN B J. Theeffect of voltage and metal transfer mode on particulatefume size during the GMAW of plain carbon steel[J].Welding in the World,2010,54(9/10):249-256.
[5] MEREDITH P,LIVCHAK A. Exhaust hood with air cur-tain:US,2933601[P/OL]. 2001-01-10[2018-04-18].https://worldwide. espacenet. com/publication Details/original Document? CC=AU&NR=2933601&KC=&FT=E.
[6] LIU Ronghua(刘荣华),LI Xibing(李夕兵),SHI Shil-iang(施式亮),et al. Numerical simulation of a new cy-clone air curtain exhaust hood[J]. Environmental Engi-neering(环境工程),2009,27(4):68-72.
[7] NG C S. A study of the effectiveness of local exhaust venti-lation(LEV)in training facilities building using computa-tional fluid dynamics(CFD)approach[D]. Tun HusseinOnn:University Tun Hussein Onn Malaysia,2013.
[8] ZHANG Daming(张大明),MA Yundong(马云东),LUO Genhua(罗根华). On a new control and removaldust system with a perfect wind curtain and duster by wayof numerical simulation[J]. Journal of Safety and Envi-ronment(安全与环境学报),2015,15(6):82-86.
[9] HE Suyan,LI Yunfei. Numerical simulation and experi-mental study of a kind of local exhaust ventilation hood[J]. Chinese Journal of Mechanical Engineering,2003,16(4):433-436.
[10] YANG Yang(杨洋),WANG Yi(王怡),LI Yanbin(李艳斌). The characteristics of the flow field under jetflow[J]. Journal of Southwest Jiaotong University(西南交通大学学报),2015,50(2):347-353.