| Along with the development of economy,more and more new building materials are used for indoor decoration,and at present floor building materials is still one of the indoor building decorating and fitting up materials.However,floor building materials will not only produce a large number of volatile organic compounds(VOCs)in the process of production and construction,but also the floor will continue to release VOCs after the decoration.TVOC is the total amount of volatile organic compounds.This research aims to study the diffusion and distribution of TVOC during floor decoration in an activity center,and study the reduction of indoor TVOC concentration under different ventilation modes by combining with numerical simulation method.These works have certain directive significance for the design of reasonable ventilation methods to improve indoor air quality,and also provide scientific theoretical basis for indoor TVOC pollution control.Research Contents:Firstly,we establish the mathematical model of the TVOC of the floor in the actual environment,and analyze the applicability of the first-order attenuation equation in the model.Then Experiments of contact the concentration of TVOC in an activity center during the decoration.and at the same time,Fitting the curve of emission rate which is in line with the mass transfer model of the floor.Curves are programed to be user-defined function(UDF)and loaded into FLUENT dynamicly.and this provides an initial condition for the numerical simulation of indoor TVOC distribution and exclusion.Lastly,The distribution of TVOC in closed condition and different air distributions and changes in the level of TVOC concentrations under natural ventilation,Airflow pattern and Forced Ventilation were analyzed by numerical simulation method,and the optimal ventilation mode was discussed.Research Methods:In this paper,A method combining the on-site test with numerical simulation.,and the measured data verifie the accuracy of the simulation.The RNG k-emodel is used for the numerical simulation of turbulence model,and it keeps the method of calculation solving the diffusion of TVOC by using the component transport equation.Research Results:(1)We establish the mathematical model of floor emission TVOC and divide it into three layers,from top to bottom respectively:polyvinyl chloride floor layer,adhesive layer and carrier layer.It can be simplified into a dry building materials single emission TVOC model and we also analyze the applicability of the first-order attenuation equation.(2)The measured results show that the activity center was in a serious state of indoor TVOC pollution.The daily average values of TVOC concentration in three stages when the room is stuffy were 0.56mg/m3,0.3mg/m3,and 0.63mg/m3,respectively.Under natural climate,the daily average values of TVOC concentration was 0.52mg/m3,0.26mg/m3 and0.59mg/m3,which were 1.73,0.87 and 1.97 times of the daily average values of TVOC concentration limits of the design standard for indoor air quality control of public buildings.Fitting the daily average values of TVOC concentration over time when the room is stuffy after decoration,and the emission rate equation of indoor TVOC isE(28).0 0015*exp(-t/.488292)(10).00015,and the unit ismg/(m~2×s).(3)Numerical simulation results show that the TVOC accumulations of different source of release is unlike in the closed condition.In natural ventilation,the ventilation efficiency of indoor TVOC first increases and then decreases with the increment of the natural ventilation rates.Ventilation for 15 minutes after the room is closed for 1 hour,the average indoor TVOC concentration was downwards,but there is no quantitative relationship with the increase of the air velocity.The return wind exit is as close together as possible to major sources of pollution under supplying air from the ceiling.The results suggested that slot outlets had the greatest ability to eliminate TVOC under exhaust fan assisting ventitation. |
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