Development of Cold Draft Prevention System Utilizing the Momentum of Airflow along the Window

室内的外围部分容易产生室外的影响，冬季会产生冷风。本课题的研究目的是研制一种能够在靠近窗户的周长处避免通风的设备。这个过程分为三个步骤；1)仿真与实验的比较，2)通过仿真设计设备的尺寸，3)应用于实际房间进行验证。结果表明：(1)二维模拟与全尺寸实验一致，采用线路送风；(2)模拟期望的高性能设备在冬季安装在1F教室和2F角落，测量结果表明该设备防止了通风；(3)三维模拟显示的流态与测量相同，但可能需要更精确的实验。4)产热率对避免气流最有效，其次是设备进出口宽度，其宽度应大于气流形成的边界层厚度。作为总结，设备已建成，性能已确定。即使当发热量率为通过窗户散失热量的70%时，系统也避免了通风。

The part of perimeter in rooms are likely to have the effect of outdoor and the cold draft can occur in winter. This research is aimed to develop the equipment which avoid the draft at the perimeter close to the window.The procedure takes three steps ; 1) the comparison between the simulation and the experiment, 2) the design of the dimension of the equipment by the simulation, and 3) the validation with applying it to actual rooms.The results show ; 1) the 2-dimensional simulation agrees with the full scale experiment that has the line airflow supply, 2) the equipment that is expected high performance by the simulation is installed in a classroom at 1F and a corner at 2F in winter, and the measurement indicates that the equipment prevent the draft, 3) the 3-dimensional simulation shows same flow pattern to the measurement but more precise experiment may be necessary, and 4) the heat generation rate is most effective to avoid the draft and the width of inlet and outlet of the equipment is next, where the width should be more than the thickness of boundary layer developed by the draft.As a summary the equipment is constructed and the performance is confirmed. The system avoid the draft even when the heat generation rate is 70% of the heat loss through the window.