Study On The Flow Characteristics Of Indoor Fine Particles Affected By Air Supply Modes

With the outbreak of large-scale haze weather, the indoor air quality being taken seriously again, so it is an issue of the academic common concern to seek high-quality indoor air quality. This study was based on the research achievements in related fields at home and abroad. The particle concentration of the room included particle source with different air supply modes was studied by adopting numerical simulation and experimental study, to explore the impact of air supply modes on indoor particle concentrations. The designed experimental bench was designed and built to simulate the process of indoor fine particles diffusion effected by the various modes of air supply. The computational fluid software fluent was adopted to simulate the indoor particle concentration differences with different types of particle source experimental model in the various modes of air supply, to explore the change rules of indoor fine particle concentration affected by the air supply modes.The study of experimental data and numerical simulation results were compared and analyzed to improve the conditions of numerical simulation, verify the feasibility of this mathematical model. Though experimental study and numerical simulation of the particle concentration differences in this study, under the working condition set in this paper, it could draw the following conclusions:(1)It could be seen by the simulation results that,under the steady condition, the particle concentration of up-supply up-return and down-supply of the side up-supply was lower and the mode of up-supply of the side was higher with the condition that the dust amount of fine particle by the indoor floor was 0.803μg/s, the particle concentration of down-supply of the side up-supply was lower and the particle concentration of the additional air supply modes was similar with the condition that the dust amount of fine particle by the indoor floor was 1.13μg/s.(2)It could be seen by the simulation results that, under the unsteady condition, the particle concentration of up-supply of the side down-return was highest in the process of releasing particle(between 0 and 300 second) increasing from 0. 175mg/m3 to 0.254 mg/m3, the particle concentration of the additional air supply modes was similar in the process of releasing particle(between 0 and 150 second), the particle concentration of down-supply of the side up-return was lower in the process of releasing particle(between 150 and 300 second).(3)Through the analysis of experimental data, the fine particle concentration in the location of both sides and vertical area of particle point source of up-supply down-return of the side was lowest. The closer the vertical distance to the particle source is, the higher the concentration of fine particle, and the further the horizontal distance to the particle source is, the lower the concentration.(4)The fine particle concentration in the location of vertical area of particle point source of up-supply of the side down-return was lowest. The closer the vertical distance to the air supply inlet is, the lower the concentration of fine particle.(5)The fine particle concentration in the location of vertical area of particle point source of up-supply up-return was highest and the both sides was lowest. The closer the vertical distance to the particle source is, the higher the concentration of fine particle, and the further the horizontal distance to the particle source is, the lower the concentration.(6)The fine particle concentration in the near location of the side of air supply inlet of up-supply of stratum ventilation was lowest. The closer the horizontal distance to the air supply inlet is, the lower the concentration of fine particle, and the further the horizontal distance to the particle source is, the lower the concentration.(7)The fine particle concentration in the location of both sides and vertical area of particle point source of down-supply of the side up-return of the side was lowest. The further the vertical distance to the particle source is, the higher the concentration.(8)Through the analysis of experimental data and the comparison of the five modes of air supply, under the condition of the same time of releasing particle, the fine particle concentration of measuring point a and b was lowest in the mode of down-supply of the side up-return and highest in the mode of up-supply of the side down-return; the fine particle concentration of measuring point c was lowest in the mode of up-supply of the side down-return; the fine particle concentration of measuring point d of up-supply up-return was lowest; the fine particle concentration of measuring point e was lowest in the mode of down-supply of the side up-return and highest in the mode of up-supply down-return of the side.