Mechanisms of lobed jet mixing: About circularly alternating-lobe mixers
Mechanisms of lobed jet mixing: About circularly alternating-lobe mixers
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波瓣喷射混合机制：关于圆形交替波瓣混合器
DOI：
10.1016/j.ast.2019.105660
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发表时间：
2020-03
期刊：
影响因子：
--
通讯作者：
徐义华
中科院分区：
文献类型：
--
作者：
盛志强;刘景源;姚玉;徐义华
采用了两种环形布置的交替波瓣喷嘴结构，形成了有/无混合管的波瓣混合器。在一次流和二次流初始条件不变的情况下，对每个混合器的射流混合进行了数值模拟，但改变了二次流的初始速度。结合流场结构的演变和混合场内的传热传质过程，综合分析了圆形交替波瓣混合器的射流混合机理。研究发现，横向流动通常是由波瓣几何形状引起的，在某些情况下，主流的卷吸也起到一定作用。波瓣波峰和波谷的横向流动偏转有两种机制。其中一种机制是被抑制以使流动偏转，另一种机制是通过反作用力和诱导效应来偏转。一次流和二次流的偏转使它们之间产生横向间隔，随后在横向间隔出现流向涡核。在径向和周向辐射中，偏转流动不断地“挖”，增加了流向涡的尺寸。横向流速降低，流向变得不稳定，导致流向涡破裂。横向流动带来了传热传质。在这两种机制下，一次流和二次流的边界发生偏转。最初，一次流和二次流绕着流向涡核流动。随后，混合流绕涡核流动，混合流区逐渐向外扩展。当流向涡破裂时，换热和传质的尺度减小。由于界面处的速度梯度，产生剪切不稳定，从而产生正常的涡环。热质传递推动界面，导致法向涡环的拉伸。混合速度因传热传质的不同而不同。速度梯度在快速混合段衰减较快，法向涡环最先破裂。
Two configurations of circularly arranged alternating-lobe nozzles were adopted to form lobed mixers with/without a mixing duct. The jet mixing of each mixer was numerically simulated with the unchanged initial conditions of the primary and secondary streams, except the altered initial velocity of the secondary stream. The jet-mixing mechanisms of the circularly alternating-lobe mixers were synthetically analysed by combining the evolution of the flow field structures and the process of heat and mass transfer in the mixing field. It is found that the transverse flow is usually caused by the lobed geometry, and the entrainment of the primary stream also plays a role in certain circumstances. There are two mechanisms for the deflection of the transverse flow at the lobe peaks and troughs. One of these mechanisms is to be suppressed to deflect the flow while the other is deflected by the reaction force and induction effect. The primary and secondary streams deflect to bring the transverse interval between them, and subsequently, the streamwise vortex core appears at the transverse interval. The deflected flow consistently “digging” in the radial and circumferential radiation increases the dimension of the streamwise vortices. The transverse flow velocity decreases and the direction becomes unstable leading to the breakdown of the streamwise vortices. The transverse flow brings the heat and mass transfer. Under the two mechanisms, the frontiers of the primary and secondary streams deflect. Initially, the primary and secondary streams flow around the streamwise vortex core. Subsequently, the mixed stream flows around the vortex core, and the mixing stream area gradually expands outward. The heat and mass transfer decrease in scale when the streamwise vortices break down. Because of the velocity gradient at the interface, shear instability occurs to generate the normal vortex ring. The heat and mass transfer pushes the interface, which leads to the stretch of the normal vortex ring. The mixing speed varies due to the heat and mass transfer. The velocity gradient decreases fast in the rapid mixing segment, where the normal vortex ring breaks first.
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影响因子：
4
作者：
Jun-hong Feng;Chi-bing Shen;Qian-cheng Wang
通讯作者：
Jun-hong Feng;Chi-bing Shen;Qian-cheng Wang
影响因子：
5.7
作者：
Jing-zhou Zhang;Cheng-xiong Pan;Yong Shan
通讯作者：
Jing-zhou Zhang;Cheng-xiong Pan;Yong Shan
影响因子：
6.4
作者：
Pan Cheng-xiong;Zhang Jing-zhou;Shan Yong
通讯作者：
Pan Cheng-xiong;Zhang Jing-zhou;Shan Yong
DOI：
10.1115/1.4024043
发表时间：
2012-06
影响因子：
1.5
作者：
A. Wright;Zhijun Lei;A. Mahallati;Mark Cunningham;J. Militzer
通讯作者：
A. Wright;Zhijun Lei;A. Mahallati;Mark Cunningham;J. Militzer
入口涡流呈线性径向分布的波瓣混合器混合机理数值研究
DOI：
10.1177/0957650915571954
发表时间：
2015-02
期刊：
Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy
影响因子：
--
作者：
Zhijun Lei;Yanfeng Zhang;Zihao Zhu;Junqiang Zhu
通讯作者：
Junqiang Zhu