下送风空调系统送风口气流方向对室内气流分布的影响分析

一个设计良好的下送风空调系统具有改善热舒适性、通风效率和室内空气品质，减少能耗、建筑周期花费和层高等优点。本文通过对某一下送风空调系统在送风方向分别与地面之间的夹角（记为a）为0°、45°和90°的条件下，进行了数值模拟计算。分析了不同送风方向时室内气流分布的不同。研究结果表明：a为0°和45°时的室内气流分布类似，室内最大速度都贴近地面。且形成的涡位于室内高度1／2以下，45°时室内产生更多的涡流；a为90°时靠近地面处流速很小，形成的涡位于室内高度1／2以上。对a为0°的情况进行了水模型试验，试验现象表明近地面处速度的分布与模拟计算结果基本吻合。研究结果对预测和控制下送风空调系统的扬尘有理论意义。

Study on the Influence of Different Inlet Wind Directions on Airflow Pattern for Under Floor Air Distribution System

A well-designed under floor air distribution (UFAD) system can provide such benefits as improving thermal comfort, ventilation efficiency and indoor air quality,and meanwhile reduce energy consumption,operation costs and floor-to-floor height in new constructions. This paper fouses on the association betwenn different air supply angles and airflow distribution for UFAD system. The air supply angle ot is the angle between inlet airflow and ground. The airflow distribution of an office with a UFAD system is simulated respectively by CFD when a is 0°45°and 90°Simulation results show that when a is 0°and 45°,the indoor air distributions are similar, the maximal velocity happens close to the floor,vortices are all below half of the storey height,and more vortices are formed when a is 450°when a is 90°the velocities close to the floor are small, and vortices happen above half of the storey height. Similiarity experiment is conducted in water when a is 0°experiment results indicate that velocity distribution agree with simulation results, which serves to predict and control the dust suspension.