通风柜下侧挡板和导流板对流场的影响分析

Analysis of the influence of the underside baffle and deflector of the fume hood on the flow field

针对现有通风柜流场存在涡流以及气体逸出的现象,采用计算流体动力学的方法进行仿真。更改通风柜窗口下侧结构的形状参数,分别使用不同半径的圆弧挡板,不同长度的椭圆弧挡板,以及增设不同半径的导流板。通过分析通风柜内涡流大小以及出现位置来研究结构变化对通风柜内流场的影响,从而得到结构优化的方向。结果表明,下侧挡板高度较低且长度较短时,通风柜的中心位置以及壁面附近存在明显的大涡流;高度大于50 mm,长度大于90 mm的挡板可使通风柜中心处及挡板与侧壁面交界处的涡流明显减小。增设导流板可使中心涡流消失,同时导流板半径不能大于70 mm,否则会在导流板外侧和末端激发明显的涡流,为通风柜的合理化设计提供依据。

For the phenomenon of vortex and gas escape in the flow field of the extant fume hood, the computational fluid dynamics method was used for simulation. This research changed the shape parameters of the underside structure of the fume hood window, used circular arc baffles with different radii, elliptical arc baffles with different lengths, and added deflectors with different radii. Then this research studied the influence of structural changes on the flow field in the fume hood by analyzing the size and location of the vortex to obtain the direction of structural optimization. The results showed that when the height of the underside baffle was low and the length was short, there was obvious large vortex in the center position of the fume hood and near the wall. A baffle with a height greater than 50 mm and a length greater than 90 mm could significantly reduce the vortex at the center of the fume hood and at the junction of the baffle and the side wall. Adding a deflector could optimize the flow field and make the center vortex disappear, and the radius of the deflector should not be greater than 70 mm, otherwise obvious vortices would be excited on the outside and end of the baffle, which provides a basis for the rational design of fume hoods.