The Flow Field Characteristics Of One-side Constrained Buoyant Jet And Optimization Research Of Exhaust Hood

In industrial buildings, buoyant jet with pollutants is generated and then emits into theenvironment with continuously entrainment of ambient air, in many productive processes. Forexample, air with pollutants is heated and keeps rising in the productive process ofiron and steel enterprise. In this process the harmful pollutants and heat emit into thesurrounding environment. It is harm to the surrounding environment and workers’health.To improve the industrial productive environment and the capture efficiency, this papersummarizes the research of buoyant jet and exhaust hood firstly. Then the physicalmodel and boundary conditions were determined based on experiment data andnumerical error analysis.And linear difference method is used to set the related physicalproperties such as density, specific heat and temperature in numerical simulation, toensure the numerical simulation results with greater precision.This paper studies the effect of the wall restricted conditions on the flow fieldcharacteristics of buoyant jet. At the same time, flow field characteristics andcoanda effect of one-side constrained buoyant jet were researched, under the conditionsof different initial velocity, different initial temperature, different outlet size anddifferent distances between outlet and wall.In practice, due to building structure or process conditions, the size of hood is lessthan that of pollution source, this causes the control effect of exhaust hood on buoyantjet with pollutants reduced. Therefore, this paper studies the capture efficiency when thesize of exhaust hood above buoyant jet is less than that of pollution source. And effectlaw between baffle and capture efficiency of buoyant jet is analyzed under the conditionof limited space. Meanwhile the effect rule of adding tilted baffle and vertical baffle on capture efficiency is researched on the basis of exhaust hood with a baffle on one side.The research results provide guidance for improving capture efficiency in engineeringpractice when the exhaust hood size is limited.