| With the development of the society,great changes have taken place in people’s work and life.People used to spend most of their activity and work outside,but now they spend most of their time indoors.Therefore,indoor air quality is closely related to the health of modern human beings.Particulate matter is one of the main pollutants in indoor air.It is very important to study the movement distribution of particulate matter in indoor environment to protect human health.On the basis of reading a large number of domestic and foreign literatures,this topic uses the method combining numerical simulation and experiment to study the influence of variable parameters such as indoor heat source location,indoor heat source height,indoor heat source heating intensity,particle size,air supply speed and so on on indoor ultrafine particulate matter motion distribution.In the numerical simulation of this topic,FLUENT computational fluid dynamics software was used to calculate the concentration distribution of indoor particles under various working conditions.The experimental research under various working conditions was carried out by using the comprehensive experimental platform of air particulate control technology,and the experimental data was compared with the numerical simulation data,and the following conclusions were drawn:（1）Only the position of the heat source（X direction）is changed.Through simulation calculation and experiment,it can be obtained that:the attenuation rate of the unit distance of the particle on the intersection line of the plane X=1.44m and the plane Z=0.685m is proportional to the distance of the heat source in the X direction.With the increase of the distance of the heat source in the X direction,the variation trend of the maximum particle concentration in the sitting and standing respiratory zones was firstly increased and then decreased.When X=0.45m,the maximum value was 2.16×10-5kg/m3and 7.31×10-6kg/m3.The maximum concentration of particulate matter increased by 31percent and 75.5 percent,respectively.（2）The wind speed of the supply air remains the same,the intensity of the heat source remains the same,and the particle size remains the same.Only the position of the heat source（Y direction）is changed.Through simulation calculation and experiments,the following results can be obtained:With the increase of the distance of the heat source in the Y direction,the variation trend of the maximum particle concentration value in the sitting and standing respiratory zones was first decreased and then increased.When the temperature was 0.15m and 0.45m,the concentration change was not about 3.4×10-5kg/m3.At the position of Y=0.65m,the maximum concentration was 2.19×10-5kg/m3and 3.26×10-6kg/m3,respectively.When Y=1.15m,the maximum concentration was 2.92×10-5kg/m3and5.03×10-6kg/m3.The maximum particulate concentration increased by 25 percent and 35.2percent,respectively.（3）Only the height of the heat source is changed.Through simulation calculation and experiment,it can be obtained that:with the increase of the height of the heat source,the variation trend of the maximum concentration of the particulate matter in the sitting and standing breathing area is firstly increased and then decreased.When the height is 1.2m,the maximum concentration is 3.4×10-4kg/m3.When Z=0.1m,the maximum concentration is the smallest,which is 1.79×10-5kg/m3.The maximum concentration of particulate matter in the standing respiratory zone first decreased and then increased.When Z=1.2m,the maximum concentration was the smallest,2.24×10-6kg/m3.When Z=1.6m,the maximum value is 1.07×10-4kg/m3.（4）The wind speed of the supply air remains unchanged,the position of the heat source remains unchanged,and the particle size remains unchanged.Only the intensity of the heat source is changed.Through simulation calculation and experiments,the following results can be obtained:With the increase of heat source intensity,the variation trend of the maximum particle concentration in both sitting and standing respiratory zones was continuously increasing,with the minimum values being 1.79×10-5kg/m3and 1.95×10-6kg/m3,and the maximum values being 2.87×10-5kg/m3and 5.62×10-6kg/m3.The maximum concentration of particulate matter increased by 37.6 percent and 65.3 percent.（5）The intensity of the heat source,the position of the heat source and the particle size remain unchanged,and only the air supply speed is changed.Through the simulation calculation,it can be obtained that the attenuation rate of the particle per unit distance on the intersection line of the surface X=1.44m and the surface Z=0.685m increases with the increase of the wind speed.When the wind speed is 1m/s,the maximum value is 1.54,and then remains unchanged.With the increase of air supply velocity,the maximum concentration of particulate matter in both sitting and standing breathing zones decreased,with the minimum values being 2.97×10-6kg/m3and 1.24×10-6kg/m3,respectively,and the maximum values being 2.19×10-5kg/m3and 3.26×10-6kg/m3,respectively.The maximum particulate concentration increased by 86.4 percent and 62 percent,respectively.With the increase of the air supply speed,the aggregation places of particles at Z=1.2m and Z=1.6m are gradually close to the return air outlet.（6）The intensity of the heat source,the location of the heat source and the speed of the air supply remain unchanged.Only the particle size can be obtained through the simulation calculation:with the increase of the particle size,the average particle concentration in the sitting and standing breathing area is basically unchanged,and the average particle concentration in the standing breathing area is also basically unchanged.（7）At the air speed of 0.05m/s,indoor temperature of 25℃,heat source intensity of300W,particle size of 1μm,and heat source location（1.15,1.15,0.8）,the numerical simulation results were compared with the experimental results.There were errors between the numerical simulation results and the experimental results,but the errors were within a reasonable range.And the variation trend of the two results is basically the same.Therefore,the accuracy of the numerical simulation method is verified. |
PDF Full Text Request