Abstract
A research was conducted on a new mixing device referred as a “vent slot mixer”, using experimental and computational methods. The experiment was conducted in a laboratory-scale supersonic wind-tunnel of Mach number 2. Inflow air was under atmospheric air condition, and hydrogen gas was used as fuel. In addition, the computational simulation approach was performed to support the experimental result. The vent slot mixer can directly entrain the main airflow into the recirculation region, inducing complex flow structures in the recirculation region. This also leads to gradual development of the shear layer to reduce the total pressure loss mainly induced by a recompression shock. Contrary to typical shear layers of step mixer, for the vent slot mixer, two-dimensional large-scale structures and weak shocks were clearly identified around the shear layer through experimental and computational methods. When the fuel was injected from one circular injector in the recirculation region, the high fuel concentration of the vent slot mixer was evenly distributed along the spanwise direction, but with the step mixer the fuel was highly concentrated along the region downstream of the injector. Therefore, the vent slot mixer is effective to uniformly spread the fuel toward the spanwise direction in the recirculation region. As the fuel injection rate increased, the shear layer downstream of the vent slot mixer grew uniformly along the spanwise direction; consequently, shock structures such as a recompression shock and weak shocks on the shear layer were significantly mitigated at J = 3.2.
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Abbreviations
- F1 :
-
Switching function for Menter’s SST model
- J :
-
Momentum flux ratio
- k :
-
Turbulent kinetic energy
- M :
-
Mach number
- P 0 :
-
Total pressure
- P k :
-
Production of turbulent kinetic energy
- p :
-
Static pressure
- u, v:
-
x and y velocity components
- x, y, z:
-
Cartesian coordinates
- α:
-
Shock angle
- β, γ, σ ω 1, σ ω 2 :
-
Closure coefficients in the specific dissipation rate equation
- β*, σk:
-
Closure coefficients in the turbulent kinetic energy equation
- μ, μt :
-
Molecular and turbulent dynamic viscosity
- νt :
-
Kinematic viscosity
- Π:
-
Total pressure loss ratio
- ρ:
-
Density
- ω:
-
Specific dissipation rate
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Communicated by L. Bauwens.
This paper is based on work that was presented at the 22nd International Colloquium on the Dynamics of Explosions and Reactive Systems, Minsk, Belarus, July 27–31, 2009.
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Kim, C., Sung, K., Jeung, IS. et al. Flowfield characteristics on a vent slot mixer in supersonic flow. Shock Waves 20, 559–569 (2010). https://doi.org/10.1007/s00193-010-0280-0
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DOI: https://doi.org/10.1007/s00193-010-0280-0