| Aiming at problem of fine particulate matter from outdoor source in the office environment,using computation fluid dynamic method,the filtration effect of an air cleaner and the indoor flow field were simulated.The main contents of this paper are as follows.Aiming at the outdoor source PM2.5 in the office environment,the numerical simulation analysis was carried out on the location of the air cleaner,the air supply angle and the wind velocity on the indoor flow field and PM2.5 purifying effect.The typical office environment and the physical model of the purifier were established by CFD modeling software,and the model was meshed by Gambit software.On the mathematical model,RNG k-ε is chosen as the fluid turbulence flow model.The Euler-Lagrangian method is used to study the motion of particle phase.The particle phase is modeled by discrete term.The CFD software Fluent was used to simulate the indoor flow field and the PM2.5 concentration distribution.Influence of the Position of Purifier on Indoor Air QualityTaking an upward air supply and side air return air cleaner for example,the effect of three kinds of placement on the filtration effect of outdoor source PM2.5 Penetrated into the indoor and the indoor flow field were compared and analyzed.(1)The results show that when the air cleaner is closed to the person,recycled air of the air cleaner plays a major role in the airflow organization around the person,and the thermal buoyancy caused by temperature difference when far away from the person.(2)When the air cleaner is placed in the downwind of penetration air position,the filtration effect is the worst,and the best when placed in the lateral position.Influence of purifier air supply angle on indoor air quality(1)The indoor PM2.5 concentration showed a trend of "S" as the purifier and the horizontal air supply angle increased,reaching a peak at 30 ° and reaching a valley at 75 °.(2)Considering that when the air supply direction of the purifier is at an angle of 75 ° with the horizontal plane,the best purifying effect can be obtained in the personnel sitting breathing zone(1 ~ 1.1m)and the indoor total pollutant concentration.Influence of Purifier Air Supply Velocity on Indoor Air Quality(1)When the purifier to less than 1m / s wind speed,the indoor flow field changes little,the dominant wind direction for the outdoor infiltration of wind.When running at a wind speed greater than 1 m / s,the indoor flow field changes globally and the indoor flow intensifi(2)The variation trend of indoor total concentration decreases with the increase of wind speed.Wind speed at 1m / s,the trend tends to be flat to reduce the consistency of the decline in consistency.When the purifier is located at the upwind B position and the lateral wind direction C position,the concentration is almost the same as the wind velocity trend,which can effectively improve the indoor particulate concentration level.(3)With the exception of the smaller wind speed of 0.1 m / s,the purifier was operated at the remaining wind speed,and the concentration near the ground surface was higher and the concentration decreased with the increase of the height.The deposition effect of PM2.5 particles at high wind speed was obvious. |
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