Study On Indoor Flow Field Under The Crowding Conditions By Experiments And Numerical Simulations

Nowadays, the human body usually has been ignored in the building air distribution design. In the mechanical ventilation room,human body will block the air flows and change the original airflow organization. Especially in the crowd places, the influence of the crowd may greatly change the indoor air movement and even worsen the environment. So it is necessary to study the influence of the human body to the indoor flow field. The paper studied the subject systematically. The major research content contains the follow four parts:(1) Design and construct the indoor air flow distribution experimental platform under crowding condition.(2) PIV measurement and analysis of the flow field in the model of small chamber under the typical operating conditions.(3) Comparison and verification of CFD simulation for indoor flow field under crowding condition.(4) Simulating the change of the indoor air flow field and age of air distribution under crowding condition. Simulating the change of the age of air distribution under different personnel densityThe paper applied the method of Particle Image Velocimetry(PIV) and numerical simulation(CFD). The conclusions are as follows:To the empty room, the accuracy is almost uniform between the Standard k-ε model, the RNG k-ε model and the Realizable k-ε model. And the accuracy of the RNG k-ε model is the highest. To the crowding room, the accuracy of the three models is different. The Standard k-ε model is the best, the Realizable k-ε model is worse and the RNG k-ε model is worst.The crowding could change the magnitude and distribution of the age of air. Under the conditions of the upside in same underside out 、the top in double underside out and the top in top out, the mean age of air of the whole room and the plane of respiratory decrease obviously. But under the conditions of the top in double underside out and the top in top out, the maximum value of age of air of the plane of respiratory increase apparently.Under the conditions of the upside in same underside out、the top in double underside out and the top in top out, the mean age of air of the whole room and the plane of respiratory decrease with the increase of personnel density. Under the conditions of the upside in contrary underside out, the mean age of air increase first and then decrease with the increase of personnel density. When the personnel density is larger than 0.6 person/m2, the influence of the crowding on the air distribution is large, cannot be ignored. When the personnel density is less than 0.6 person/m2, the influence of the crowding on the air distribution is small, can be ignored.