Research On The Dispersion Regularity Of Electric Welding Workshop Air Pollutant Under The Condition Of Ventilation Control

Welding process plays more and more important role in modern industrialtechnology,it has broad market demand. However welding process is also a smallmetallurgical process, producing a lot of smoke,which can causeserious occupational diseases,when the staff inhale it.Welding smoke has becomeone of the most hazards of environmental pollution.Therefore, it is a very significativething for reducing the risk of occupational diseases by studying the law of diffusingabout welding smoke in deep,which find out the way to control smoke and otherhazardous,to reduce harm on the human body.Based on CFD simulation technology, this paper select a big electric weldingworkshop in Xi’an as the model.It mainly studies on the releasing mechanism,diffusion,the regularity of sedimentation and the control method of welding soot t in the big space,the main content is as follows:(1)It analyses the producing and movement mechanism of welding smoke from thetheoretical.The formation process of welding smoke are two ways, coagulation andaggregation, the diffusion process is turbulent motion. Through the process of diffusionwelding smoke stress analysis, it can be seen that the movement of welding smoke donot rely on the initial velocity of motion, although the particles are ejected out at a speedof1000cm/s, the speed decay quickly, so its horizontal movement distance is very short,A particle which the diameter is1μm, the horizontal movement distance is only0.006cm.(2)One hand, we choose several worke sites inside the workshop to measure the concentration of each measuring point at a speed of1m/s of natural ventilation. Theother hand, We establish the physical model of airpak to calculate the concentration ofmeasuring point in this condition.By the comparision of experimental data and thesimulation data,it can be seen that the average of experimental data is6.7%more thanthe simulation data,indicating that the numerical simulation of airpak is effective andfeasible.(3)By the comparision of the organizational form and the smoke concentrationindoor in five different work conditions,it can be seen that the wind which blown fromfront has more influence in organizational form than side face.From the smokeconcentration of each measuring point,it can be seen that,when the wind blown from thefront,the concentration of smoke reduce to half the original value with the wind speeddoubling.The position which close to the vent (Z=70m section),the concentration ofsmoke decreas faster, reduceing to one-third of the original. When the speed of windwhich blown from the front is higher than the speed of1m/s, it can purify the smokeonly rely on natural ventilation.the concentration of smoke can achieve the standard.It isnot necessary to open the mechanical ventilation.