对撞射流下通风空间的流场结构实验研究
Experimental study on flow field structure of ventilation space under colliding jets
摘要：
为了研究送风口和回风口位置对室内流场结构的影响,本文搭建了采用多条缝对置撞击送风的通风缩比模型实验平台,利用激光粒子测速技术研究了等温和非等温工况下多条缝通风空间中不稳定气流场的速度和湍流信息。结果表明:等温和非等温工况下,送风口截面的流场速度、湍动能和涡量的空间分布类似,最大值分别可以达到1.3 m/s、0.1 m2/s2和60 s-1,射流碰撞形成2个大尺度涡旋,造成流场结构不稳定;CS4.5截面,流场速度、湍动能和涡量最大值分别可以达到0.9 m/s、0.04 m2/s2和30 s-1;CS3.5截面,速度与涡量最大值均出现在近壁面附近,分别为0.42 m/s、8 s-1,湍动能最大值出现在截面中间位置,为0.13 m2/s2,且流场中形成了大规模的涡旋;非等温工况下,送风口截面和CS3.5截面中小尺度涡旋增加,大尺度涡旋减少,热羽流抑制了大尺度流场结构,增加了小尺度流场结构。
Abstract：
In order to study the influence of the positions of the air supply outlet and return outlet on the indoor flow field structure, this paper builds a ventilation scale model experiment platform using multiple slots to impinge air supply, and uses the particle image velocimetry technique to study the velocity and turbulence information of the unstable airflow field in the multiple slot ventilation space under isothermal and non-isothermal conditions.The results show that under isothermal and non-isothermal conditions, the spatial distributions of flow field velocity, turbulent kinetic energy and vorticity in the air supply outlet section are similar, and the maximum values can reach 1.3 m/s, 0.1 m2/s2and 60 s-1, respectively. Two large-scale vortices are formed due to jet impingement, resulting in unstable flow field structure. In the CS4.5 section, the maximum flow field velocity, turbulent kinetic energy and vorticity can reach 0.9 m/s, 0.04 m2/s2and 30 s-1, respectively. In the CS3.5 section, the maximum velocity and vorticity appear near the wall, which are 0.42 m/s and 8 s-1, respectively, the maximum turbulent kinetic energy appears in the middle of the section, it is 0.13 m2/s2, and the large scale vortices are formed in the flow field.Under the non-isothermal condition, the medium and small scale vortices of the air supply outlet section and the CS3.5 section increase, while the large scale vortice decreases. Therefore, the thermal plume inhibits the large scale flow field structure and increases the small scale flow field structure.
Keywords:colliding jet; ventilation space; flow field structure; isothermal condition; non-isothermal condition; velocity; turbulent kinetic energy; vorticity