弥散吊顶通风系统气流相互作用原理分析

Analysis of the Airflow Interaction Principle of Diffuse Ceiling Ventilation System

弥散吊顶通风系统是一种利用多孔吊顶板作为末端向房间送风的新型通风方式,可实现低温送风且室内人员区无冷风感。然而,该通风系统中热源羽流与送风射流的相互作用原理缺乏相关研究。采用理论分析和数值模拟相结合的方法,建立了弥散吊顶通风系统的送风射流与热羽流相互作用模型,分析了热羽流与送风气流的相互作用规律。结果表明:热羽流和送风射流会在某个高度强烈混合,混合区域内热羽流浮力作用与送风射流动量相当;相互作用面高度随热源功率的增加而增加,随送风速度的增加而减小;且当热源大小与送风速度一定时,热羽流所受浮力大小几乎不变,作用面高度与送风温度基本无关。本研究可为弥散吊顶通风系统的设计提供理论基础。

Diffuse ceiling ventilation system is a new type of ventilation method using porous ceiling panels as the terminal device to supply air to the room,which can supply low-temperature air into the room without any cold draught in the occupied zone.However,there is still a lack of relevant research on the interaction principle between the heat source thermal plume and the supply air jet in this ventilation system.In this paper,a combination of theoretical analysis and numerical simulation is used to establish the interaction model of the supply air jet and the thermal plume of the diffuse ceiling ventilation system.The interaction pattern of the thermal plume and the supply air jet is studied.Results show that the thermal plume and the supply air jet strongly mix with each other at a certain height,and the buoyancy effect of the thermal plume in the mixing area is equal to the momentum of the supply air jet.The height of the interaction surface increases with the heat source power but decreases with the supply air speed.When the power of the heat source and the supply air speed are constant,the buoyancy of the thermal plume is almost constant,and the height of the interaction surface is basically independent of the supply air temperature.Research in this paper can provide theory for the design of diffuse ceiling ventilation system.