Numerical Simulation And Experimental Research On The Rotated Air Curtain Exhaust Hood

How to efficiently control and drain breathing dust and harmful gas which may float and diffuse in the air is a very important problem in the field of dust removal by ventilation ,but still can not be solved. Domestic and foreign experts have recognized that problem can not be thoroughly solved unless traditional way of suction be given up, that is, substituting soft brattice or blast suction air for rigid apron, and extending suction entrance near harmful substance or surrounding it. However, the suction efficiency may obviously decrease due to the deformation of brattice or the destroy of blast air resulting from disturbance outside.In order to solve this problem, some people proposed we can make the use of the strong anti-interference characteristic property of the rotated air curtain, enhance the control of harmful thing source diffusing, raise catch and collection effect of curtain type exhaust hood. Because of the lack of the system theory research, the use are still at attempt stage. In order to disseminate and apply the new technology much better, In this paper, the rotated air curtain exhaust hood is object of study. Aiming at the mechanism of action, drawing support from hydromechanics, aerodynamics, turbulent jet theory and other relevance theory; adopting analogue experiment means and the computer simulation technology, from structure of rotated air curtain, controlling mechanism and drift law of blow and exhaust flow etc., many aspects have been carried out system and synthetical study on the rotated air curtain exhaust hood:(1) Theoretical analysis the formation process of rotated air curtain, define the shield and control mechanism of rotated air curtain.(2) Analysing structure characteristic property of rotated air curtain, according to hydromechanics, aerodynamics, heat transfer and other relevance theory, structure mathematic model of flow field of rotated air curtain exhaust hood is established, Selecting and using CFD commercial software FLUENT , the gas flow field of rotated air curtain exhaust hood is simulated, reflecting out the impact of angle and velocity of air supply, width of supply air outlet and exhaust air capacity on stability of rotated air curtain and the best supply air parameter and the best ratio of blow and exhaust are obtained; using CO gas as representative of noxious substance,number simulation of concentration and temperature distribution is done under the control of rotated air curtain of heat source. The results show: the rotated air curtain can control noxious substance and heat source diffusion effectively and raise arresting efficiency of exhaust hood.(3) By simulation test, study impact further of relevance factors over exhaust hood function, verify and theoretical analysis structure mathematic model of flow field of rotated air curtain exhaust hood.