【作者】 林爱晖；

【导师】 刘荣华；

【作者基本信息】 湖南科技大学 ， 供热、供燃气、通风及空调工程， 2007， 硕士

【摘要】 如何对那些已经产生并有可能在空气中漂浮和扩散的呼吸性粉尘或有害气体进行有效控制处理或排放是通风领域中一个非常重要但尚未得到很好解决的问题。国内外有关专家已意识到,要切底解决这个问题,必须放弃传统的抽吸方式,利用柔性的风幕或吹吸气流代替刚性的挡板。将吸口放到有害物附近或干脆将其“罩住”。但当外部干扰较大时,因风幕变形或吹气流破坏,效果明显降低。为了解决这一问题,有人提出了利用旋转风幕抗干扰能力强的特性,加强对有害物源扩散的控制,提高气幕式排风罩的捕集效果。由于对这种排风罩缺乏系统理论研究,至今处于尝试阶段。为了更好地推广应用这一新技术,本论文以旋转风幕排风罩为研究对象,针对其作用机理,借助流体力学、空气动力学,紊动射流理论及其它相关理论,采用模拟试验手段和计算机仿真技术,从旋转风幕的结构、控制机理及吹吸气流流动规律等多个方面对旋转风幕排风罩气流流场进行了系统综合的研究:(1)理论分析旋转风幕的形成过程,阐述旋转风幕的屏蔽控制作用机理。(2)分析旋转风幕气流流场结构特性,根据流体力学、空气动力学、传热学等相关基础理论,建立旋转风幕排风罩气流流场结构数学模型。选用CFD商用软件FLUENT对旋转风幕排风罩气流流场进行数值模拟,反映出风幕的送风角度、送风量、送风口宽度及排风量对旋转风幕稳定性的影响,得出了最佳送风参数及吹吸流量比;并分别以CO气体和余热作为有害物的代表,在旋转风幕的控制作用下,对流场内CO浓度分布和温度分布进行了数值模拟。模拟结果表明:旋转风幕能有效地控制有害物及热源扩散,提高排风罩的捕集效率。(3)通过模拟试验,进一步研究相关因素对排风罩性能的影响,验证理论分析。更多还原

【Abstract】 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.更多还原