Experimental And Numerical Simulation Research On Characteristics Of Underfloor Air Distribution System With Different Point Heat Source

This thesis introduced the status quo, existent problems and tasks which still need to be studied in the domestic and international research on UFAD (underfloor air distribution system), expounded the principle and characteristic of UFAD. Compared with the traditional mixed ventilation,This thesis pointed out UFAD has advantages of specially ventilated air organize, higher ventilation efficiency, flexible collocation, optionally accommodate to realize local environment in control of individual and satisfy personal request for the thermal comfort, and energy saving, and it is a ventilated way of all for human which has broad development foreground. According to this, this thesis adopts three methods which includes experimental tests, numerical simulation and questionnaire inquiry and combines them together to study UFAD.Carried out experimental research on conditions of different point heat source(single, double and many heat sources), and analyzed the influence of such factors as temperature of air-in, amount and distribution of inlets and outlets, heat emission quantity of heat sources and so on, on distribution of indoor air temperature,shape of plume flow,heat lamination height,ventilation efficiency,thermal comfort and so on. Built up numerical simulation model of UFAD system with single heat and pollutant source, adopted FLUENT software to study distribution of temperature,velocity and contamination'concentration, and changes of heat lamination height when temperature and velocity of air-in and surface temperature of heat source were changed and when the leakage of air-in plenum was considered or not. And compared and verified the simulation results with experimental testing data.Adopted the questionnaire form to do subjective estimation for thermal sensation,thermal comfort,effects of ventilation air change and so on in ceiling air conditioning system, parietal air conditioning system and UFAD. And tested air parameters and calculating estimated indexes that are used to reflect thermal environment and thermal comfort. The results suggested the characteristic of saving energy and improving indoor air quality.