引射/强迫式波瓣混合器开设通气狭缝的流动分离控制

为了抑制大扩张角波瓣混合器主流侧瓣顶内存在的流动分离现象,在基准波瓣混合器上开设了通气狭缝,通过数值模拟的方法研究了上述处理对次流分别为受迫流动和引射流动两种情况下的波瓣混合器抑制主流流动分离的效果.研究结果表明:①波瓣扩张角小于35°时,波瓣混合器内没有任何的流动分离的现象发生,当波瓣扩张角增大到35°时,波瓣内开始出现流动分离,继续增大波瓣扩张角,则波瓣混合器内流动分离加大；②对于次流为受迫流动的大波瓣扩张角波瓣混合器而言,开设了通气狭缝后,流动分离得到了有效的抑制；③对于次流为引射流动的波瓣混合器而言,对存在流动分离的大波瓣扩张角波瓣混合器开设了通气狭缝后,流动分离并未得到了有效的抑制,通气狭缝的存在提前诱发主流侧流体的分离.

Flow separation control of lobed ejector/forced mixer by ventilation

To control flow separation inside the lobed mixer with a big lobed angle, ventilating treatment was performed on a baseline lobed mixer to reveal the effectiveness of ventilation on eliminating separation bubble inside the lobed mixer when secondary flow is forced or ejected by numerical simulation. Results show that:(1)When the lobed angle is below 35 degrees, no separation is observed; when the lobed angle is at 35 degrees, separation bubble begin to appear inside the lobed nozzle, when the lobed angle is above 35 degrees, separation bubble augments.(2)Ventilating treatment on lobed forced mixer with a big lobed angle is able to eliminate the separation bubble inside the nozzle.(3)The same treatment on the other hand does not banish the separation bubble inside the lobed ejector mixer with a big lobed angle. In fact,the ventilating gap brings forward the separation phenomena rather than avoiding it.