In this study, the high-resolution numerical simulations of the two-dimensional (2D) multi-component inert and reactive highly underexpanded jets are conducted to quantify the influences of the injected gas mixture properties on the flow structure. First, the gas mixture with the specified species mass fractions is imposed to exhaust into the quiescent air with a Mach number of 1.0, of which the specific heat ratios (γe) range from 1.3 to 1.6. Our results indicate that the larger γe yields a relatively shorter and thinner jet core under the same inlet pressure ratio due to the sound speed increasing. Next, we focus on the chemical reaction effects on the jets with a premixed hydrogen–air mixture injection. The results reveal that the shock-induced combustion develops into a detonation, inducing numerous vortices behind the combustion wave, while the combustion in the mixing layer cannot be preserved due to the instability of the supersonic shearing. During the detonation process, the increasing pressure accompanied by the heat release forces the Riemann wave to move upstream compared with the inert one. The violent detonation periodically propagates between the two jet triple points. The detonation collision leads to the intersection of their slip lines, which causes distinct vortex formation. In addition, the main frequencies, corresponding to the Riemann wave movement, the oscillation of the shock-induced ignition positions, the periodical propagation of the detonation, and the collision of the detonation triple points, are explored to explain the unsteady process of the reactive highly underexpanded jet.
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Numerical simulations of inert and reactive highly underexpanded jets
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March 2020
Research Article|
March 18 2020
Numerical simulations of inert and reactive highly underexpanded jets
Hongmin Su (粟虹敏);
Hongmin Su (粟虹敏)
Department of Fluid Mechanics, School of Aeronautics, Northwestern Polytechnical University
, Xi’an 710072, China
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Jinsheng Cai (蔡晋生);
Jinsheng Cai (蔡晋生)
Department of Fluid Mechanics, School of Aeronautics, Northwestern Polytechnical University
, Xi’an 710072, China
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Kun Qu (屈崑);
Kun Qu (屈崑)
Department of Fluid Mechanics, School of Aeronautics, Northwestern Polytechnical University
, Xi’an 710072, China
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Shucheng Pan (潘书诚)
Shucheng Pan (潘书诚)
a)
Department of Fluid Mechanics, School of Aeronautics, Northwestern Polytechnical University
, Xi’an 710072, China
a)Author to whom correspondence should be addressed: shucheng.pan@nwpu.edu.cn
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a)Author to whom correspondence should be addressed: shucheng.pan@nwpu.edu.cn
Note: This paper is part of the Special Topic, Papers Selected from the 8th International Symposium on Physics of Fluids.
Physics of Fluids 32, 036104 (2020)
Article history
Received:
January 08 2020
Accepted:
March 03 2020
Citation
Hongmin Su, Jinsheng Cai, Kun Qu, Shucheng Pan; Numerical simulations of inert and reactive highly underexpanded jets. Physics of Fluids 1 March 2020; 32 (3): 036104. https://doi.org/10.1063/1.5144558
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