喷管加装小突片强化射流混合的PIV测量

PIV measurements of the jet flows enhanced by tabs fixed on convergent-divergent (C-D) nozzles

在常温、超声速流动状态下,采用PIV技术定量测量了收敛喷管和收扩喷管加装小突片时射流纵截面的速度场和涡量场,并对其速度场和涡量场进行了比较。结果表明,对于收扩喷管,虽然其速度边界层厚度明显大于收敛喷管,但加装小突片结构也能够明显的强化射流的混合。并且发现,小突片结构不仅能产生流向涡,而且对周向涡有明显的强化作用。

To study the jet mixing enhancement by small tabs, a PIV system was used to conduct two-dimensional measurements of supersonic air jet flows exhausted from a convergent nozzle and two convergent-divergent (C-D) nozzles. The instantaneous quantitative velocity and vorticity fields were obtained to analyze the characteristics of the mixing process in the jet flow. It is found that the tabs fixed on C-D nozzles also enhances the jet mixing distinctly, although the boundary layers of the jets from C-D nozzles are greater than that from the convergent nozzle. And the tabs intensify the circumferential vortices greatly in addition to the generation of streamwise vortices.