Research On Regularity Of Ventilation Efficiency On Displacement Ventilation

Compared with the traditional mixing ventilation, displacement ventilation, a new concept in air-conditioning system, has showed several remarkable advantages on many occasions. However, in China, the research of displacement ventilation has just been carried out. There are a lot of problems being solved before its extensive application.The ventilation efficiency of displacement ventilation room mainly reflects the characters of the vertical distribution of indoor temperature, and is one of the important indicators to evaluate ventilation system performance, which regulation research is a significant engineering foundation work.A typical classroom with displacement ventilation and hot source was used as research object. The technique of computational fluid dynamics (CFD) was adopted to simulate the character of the displacement ventilation. The indoor zero-equation model and steady model were used in this simulation. According to the definition of ventilation efficiency, the physical factors of the three temperature varieties were found, and then the possible influencing factors of ventilation efficiency were obtained. For these factors, a typical model room was chose, and correspondingly the mathematic model which was comprised these influencing factors was established. The relation of the ventilation efficiency and these factors was computed, and then ventilation efficiency variety regulation of these factors was analyzed. The calculation database based on the simulated 82 typical models were researched, and combined with the experimental and numerical simulation data in literature, the factors influencing ventilation efficiency in the thermally controlled ventilation rooms were analyzed, a concrete form of the criterion equation that can be expanded to the same buildings was gained.For the sake of lacking experimental research of the displacement ventilation, toverify the reasonable of these assumptions, a experiment about displacement ventilation was performed in meeting room of Xi'an SiLian Corporation. Compared the simulation data with the experimental data, the conclusion was gained that these models of the displacement ventilation were suitable.