Study On Influence Factors Of Natural Ventilation In Multi Zone Room

With the development of social economy,the acceleration of Urbanization process,the improvement of people’s living standard.People pay more attention to the building energy efficiency and low energy buildings.Modern building designers pay more attention to building natural ventilation—an ancient but effective measures.The main influencing factors of wind-driven natural ventilation include wind velocities,flow direction,the opening type of windows,the opening areas,the interior of the room is partitioned,air flow around the building,etc.When wind through the building,accompanied by air separation and whirlpool movement,the flow mechanism is very complex.A method which can accurate and fast predict the flow rate in a multi-zone building will promote building energy conservation.The wind tunnel model experiment was carried out to obtain the windward surface,the leeward surface,the static pressure on the inner surface of the room and the corresponding ventilation rate under the natural ventilation condition.Wind tunnel experimental conditions are based on the model with or without partition wall and partition door position is divided into single zone model,the door model and the side door model,as well as the wind window and leeward window size to test.The results of the experiment are analyzed,the main influence of partition wall opening resistance coefficient are opening ratio and the distance of the partition wall from the windward window,then focus on this influence in numerical simulation.For the influence of opening ratio of partition wall on resistance coefficient of partition wall,use LES numerical simulation to calculations resistance coefficient of partition wall with different opening ratio.Then analysis the different result of partition in the middle of the double-zone room and partition in the side of the double-zone room,and get empirical formula of the relationship between the opening ratio ri and the resistance coefficient κi;For the influence of distance of the partition wall on resistance coefficient of partition wall,simulate the distance of the partition wall is 1 to 5 times the diameter of the windward window,and find when the distance from the windward wall is greater than 4 times the diameter of the windward window,the relative error of the flow through partition in the middle of the double-zone room and partition in the side of the double-zone room is less than 5%.The results were obtained for the actual building ventilation calculations,determine the windward and leeward face pressure difference then use multi-zone network model to calculate ventilation rate.Firstly using Phoenics to simulate the transition season ventilation in community,determine the distribution of pressure on each side of the most unfavorable building.Then using CONTAM to calculate ventilation of each room.Compared the result solved by CFD simulation with the result solved by multi-zone network model,found the result solved by multi-zone network model total ventilation less 10% than the result solved by CFD simulation.The reason why different may in multi-zone network model can’t ascertain windows’ position on windward and leeward.But only 10% error meets engineering design requirements.