Effect Of The Dynamic Wind On Human Thermal Comfort And Inhalable Particle Distribution

Nowadays, people focus on two major issues about the indoor environment:comfort and air quality. The strategy of fixed wind speed and steady turbulent intensity, which could be easily realized, was basically adopted by the traditional indoor air conditioning. But it can cause the air conditioning syndrome and the problem of energy waste. So the high turbulence and speed time-varying dynamic wind was preferred. At present, most related studies are based on the steady state environment. In this paper, the relationship of different degrees of turbulent intensity and frequencies dynamic wind and human comfort were studied, and the influence of changes in turbulent intensity on the distribution of indoor particle was also analyzed.The dynamic winds were simulated using FLUENT by changing the air flow boundary conditions on two different turbulent intensity and five different frequencies. When air inlet velocity is1.35m/s turbulent intensity is10%, the simulation results Close to reality which appear airflow above the human head due to the body metabolism, the Maximum velocity of heat flow is0.2445m/s. The results showed that the human thermal comfort depended not only on the speed of airflow, but also the turbulent intensity. The most satisfied indoor environment was obtained when the air flow inlet1.35m/s and the turbulent intensity32%. Comparing the simulation results of five different airflow frequency (0.01Hz,0.2Hz,0.3Hz,0.4Hz and1Hz), we found that the body had an unique feeling and selection to the airflow frequency. With the ambient temperature rised, people had a better satisfaction rate for0.4Hz wind frequency.The analysis results of the indoor aerosol particle motion, diffusion and deposition under two turbulent degrees showed that turbulent intensity changed the trajectory of the aerosol particle in supply air, causing the diffusion of the aerosol particle in the axial plane and the concentration of indoor particles (PM20) in the turbulence intensity of32%which is greater than that in the10%turbulence intensity. The deposition amount of inhalable particles (PM10) in32%turbulence intensity was greater than that of10%turbulence intensity. The particle concentration of observation points on the respiratory surface showed that the32%turbulent intensity makes the inhalational probability of aerosol particle (PM5) increased. So the conclusion is that low turbulence intensity could improve a better indoor air quality.The results of the simulation show that the lower average wind speed and higher turbulent intensity and higher frequency of dynamic wind could improve human thermal comfort to the environment. And the lower turbulent intensity of dynamic wind could improve the air quality of indoor environment.