The Research On The Flow Field And Capture Efficiency Characteristics Of Side Suction Hood Influenced By Muti-heat Source

At present, a large number of dusts, which is diffused disorganized in steel, metallurgy coking and other heavy industries, have caused critical pollution of indoor environment and big hazards of worker’s healthy. Local exhaust ventilation is the most effective way to prevent industrial pollution polluting indoor air. But so far, the local ventilation system under the effect of a single source of pollution, people have a deeper research, and for the local ventilation system under the multi-heat sources, few studies have. The local ventilation system under muti- heat source in industrial production is very common, and the contamination control is very poor, so the study of local exhaust systems under multiple heat sources has great significance.To solve these problems above, on the basis of the research status of the hood and multi-source at home and abroad. experimental and numerical simulation method was used to study the collection efficiency of suction food influenced by double heat source(near and far heat source) and find the effect of naer heat source on the characteristic of flow field and capture efficiency.on this basis,it is studied to the hood influenced by muti-heat source, and finally giving specific optimization methods.Through research, this paper gave the following conclusions:(1). At the basis of complete of the basic experiment set, it is studied that the effect on capture efficiency of the position、the initial velocity and the initial temperature of near heatsource.it is shown that with the increase of the distance between the heat source and the hood, capture efficiency of exhaust hood decrease linearly with the slope of 0.235; with the increase of the the initial velocity, capture efficiency of exhaust hood decrease linearly with the slope of 0.02; with the increase of the the initial temperature, capture efficiency of exhaust hood decrease linearly with the slope of 0.00041; Finally, based on the analysis of experimental data by linear regression analysis, the linear regression model was found when the capture efficiency of side suction hood changes with three factors of the near heat source, obtained the conclusion that the position、the initial velocity and the initial temperature have gradually weakened effect on collection efficiency of exhaust hood.(2).Based on the error analysisi,the capture of exhaust hood was studied when the initial temperature of near heat source was ranged from 450 K-700 K by numerical simulation,and found that with the increase of the the initial temperature, capture efficiency of exhaust hood decrease linearly with the slope of 0.00018.(3). Based on the error analysis, numerical simulation method was used to study the the effect of radius of curvature on capture efficiency of when the two heat source and the hood is on a circle.and then obtained the conclusion that with the increase of the radius of circle,the capture efficiency of exhaust hood increased linearly with the slope of 0.051, and a index was proposed to measure inhomogeneity of the inside and outside of the circle of exhaust hood;(4).Based on the result of flow field and capture efficiency of exhaust hood and conbined with the engineering practice,the exhaust hood influenced by muti-heat source was studied.the study factor includes the exhaust volume of exhaust hood、the size of hood、the angel between hood aperture and vertical direction and height of trilateral baffle of hood.By studying,the following mehhods was proposed: Considering the effect of the pollutants control and fan energy, exhaust volume of hood was recommend 6000 m3/ h; the original exhaust hood in the vertical direction is reduced in size 0.2 m; increasing the angel between hood aperture and vertical direction and the height of trilateral baffle of hood without affecting the technology and human action.