【作者】 刘艳鹏；

【导师】 李安桂；

【作者基本信息】 西安建筑科技大学 ， 供热、供燃气、通风及空调工程， 2007， 硕士

【摘要】 空调设计的首要目的是为空调房间的工作或生活人员提供一个适宜的热舒适环境和可接受的空气质量。随着人们对舒适性尤其是室内空气品质要求的提高，置换通风作为一种较好的气流组织方式，在许多场合得到应用。根据置换通风的原理，采用底部侧送风的形式无疑是最佳的气流组织方案；但在某些场合，下送风是难以实现的。赵鸿佐、李安桂教授建议，可否根据送风射流对侧墙的贴附效应，产生空气池现象(Air Pool)，从而形成和置换通风类似的气流组织?本文在此思路的指导下，通过数值模拟的方法对每一种影响竖壁贴附送风气流组织效果的因素做进一步探讨，与可视化的实验对照，验证了这一设想的可行性。竖壁贴附送风效果的影响因素很多，本文建立竖壁贴附送风计算模型，研究当工况中各参数变化时对于竖壁贴附射流空气池的影响。本文研究表明：对于冷射流，当顶棚送风口距侧墙的垂直距离比较小时，竖壁贴附送风可以依靠侧墙的贴附效应在房间下部产生空气池现象，距离大时，贴附消失；在小风速时，贴附效果显著，随着送风风速增大时贴附的程度减弱，但是射流卷吸能力增强，射流区域扩大；送风温度增大时，贴附作用程度增强；条缝风口尺寸小，贴附效果好；同样当房间尺寸或者粗糙度变化时，对于冷射流来说，都影响贴附效果，但影响幅度较小，仍能形成贴附效应。更多还原

【Abstract】 The primary objectives in HVAC design are to provide thermal comfort and acceptable indoor air quality for building occupants. With more demands on comfort and better interior air quality, displacement ventilation has come into use in many occasions as one better air-flow organization form. According to principle of displacement ventilation, supplying air from air diffuser at bottom of room is the best strategy. However, it is impossible to arrange air diffuser at bottom of room in some occasion. There is Professor Zhao Hongzuo and Li Angui’ s suggestion: based on Coanda effect of air jet to side vertical wall and the air pool phenomenon , can supplying fresh air from ceiling to floor achieve similar indoor environment of displacement ventilation?Based on the idea above, CFD method was used to discuss the performances of factors to downward directed vertical wall jets (DDVWJ) further. To ensure the feasibility of the final conclusions, flow visualizing experiment is contrasted with the numerical prediction.There are many factors that influence the effect of downward directed vertical wall jets. The paper established the computational model of DDVWJ .Study was performed to achieve the performance of DDVWJ when only one parameter varied. The conclusion of this paper show that, when the vertical distance between ceiling air diffuser and side wall is small enough, DDVWJ can supply fresh air from ceiling to floor and induce "air lake" phenomena above floor. When the distance becomes larger, such similarity will decrease dramatically. As to the small velocity, coanda effect can generate as the air outlet velocity varies. When the velocity becomes larger, the degree of coanda effect reduces. But the entrainment capability of the jet increases, the domain of the jet becomes larger. When the air outlet temperature rises, the degree of the coanda effect increases too. The smaller tuyere, the better coanda effect. For the cool jet, as the room size or roughness becomes, the coanda effect becomes too. But the argument is small, coanda effect can generate too.更多还原