Numerical Study on the Supersonic Mixing Enhancement Using Streamwise Vortices

Experimental and numerical study of transversal microjets injection influence on the supersonic underexpanded jet flow structure has been performed. Data of measurements and calculation have acceptable agreement. Interaction of microjets with main supersonic jet sets to a decrease of an initial gasdynamic region. Microjets lead to a longitudinal streamwise vortices generation and a mushroom-like flow structures create on an external jet mixing layer. Dissipation of longitudinal streamwise vortices was observed at the second jet cell. Complex gasdynamic flow structure of the supersonic underexpanded jet interacting with supersonic microjets has been studied for the first time. This structure contains system of complex chock waves and expansion waves spreading from the position of the impact microjets/main jet localization place. Future of interaction process a chock-wave structure of main jet with additional shock waves has been studied

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Flow structures of a lobed mixer and effects of streamwise vortices on mixing enhancement

Physics of Fluids ◽

10.1063/1.5090425 ◽

2019 ◽

Vol 31 (6) ◽

pp. 066102 ◽

Cited By ~ 4

Author(s):

Xin-xin Fang ◽

Chi-bing Shen ◽

Ming-bo Sun ◽

Richard D. Sandberg ◽

Peng Wang

Keyword(s):

Flow Structures ◽

Mixing Enhancement ◽

Streamwise Vortices

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Influence of Micro-Lobed Burner on the Non-Premixed Combustion of Methane and Oxygen

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4043913 ◽

2019 ◽

Vol 12 (1) ◽

Author(s):

Yi Xie ◽

Chuan-li Yi

Keyword(s):

Mass Fraction ◽

Equivalence Ratio ◽

Premixed Combustion ◽

Maximum Temperature ◽

Mixing Enhancement ◽

Combustion System ◽

Streamwise Vortices ◽

Maximum Temperature Difference ◽

Burner Exit ◽

Combustion Enhancement

Abstract Non-premixed combustion was implemented in a micro-lobed combustion system, and its influence on combustion was studied using both experiments and simulations. The results show that a micro-lobed burner produces streamwise vortices with intensities that increase with the equivalence ratio of methane to oxygen (Φ). Due to the streamwise vortices and the increment of the contact area between methane and oxygen, the gasses mix well in the micro-lobed burner, giving it a larger OH mass fraction and higher temperatures than the micro-splitter burner. Moreover, the equivalence ratio greatly influences the combustion enhancement from the micro-lobed burner, especially near the burner exit. The maximum temperature difference between the two micro-burners at the Z/D = 0.01 cross section is 171 K, when Φ is 0.6. However, when the mixing enhancement caused by the streamwise vortices disappears, Φ has little influence on the combustion temperature of the micro-lobed burner, especially when Φ ≥ 1. In this case, the maximum temperature variation between the micro-lobed burner and micro-splitter burner remains nearly constant.

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