Effect of back-pressure forcing on shock train structures in rectangular channels

Gnani, Francesca; Zare‐Behtash, Hossein; White, Craig; Kontis, Konstantinos

doi:10.1016/j.actaastro.2018.02.010

Cited by 42 publications

(9 citation statements)

References 39 publications

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“…Here too, their results agree with the experimental results (Sun et al 2003). Gnani et al (Gnani et al 2018b;Gnani et al 2018a) investigated shock train characteristics and their movements under forced back pressure oscillation using 2-dimensional RANS with a k-ω model. Upon using various turbulence models he concluded that the k-ω Wilcox model compares more favorably with the experimental results (Sun et al 2003).…”

Section: Introductionsupporting

confidence: 84%

Numerical Study on Shock Train Characteristics in Divergent Channels

Ram¹,

Kim²,

Kim³

2020

JAFM

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In any supersonic intake, the flow decelerates from supersonic to subsonic speed through a constant or divergent channel "isolator" by a series of bifurcated compression shock waves referred to as a shock train. It is important to understand the characteristics of the shock train which occur inside the isolator to improve the performance of scramjet engines. In the present work, numerical simulations were carried out to investigate the characteristics of the shock train occurring in the divergent channels using coupled implicit Reynolds Averaged Navier-Stokes (RANS) equations along with the two-equation k-w SST turbulence model. Results show that the downstream pressure variation causes the shock train length to decrease and the shock structure phenomenon varies from Mach reflection to Regular reflection. The variation of the inlet Mach number has less influence on the shock train length and the location of the shock train is determined by the area ratio. In comparison with the constant area duct, the shock train structure phenomena varies from Mach reflection to regular reflection in the divergent channel. Also, the increase in divergent angle raises the total pressure loss.

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Section: Introductionsupporting

confidence: 84%

Numerical Study on Shock Train Characteristics in Divergent Channels

Ram¹,

Kim²,

Kim³

2020

JAFM

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“…The combustion process in pulse detonation engine combustor is analyzed by solving three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations, and two realizable k-ɛ turbulence equations with one-step irreversible chemical reaction model (Chapman and Cowling 1970;Smirnov et al, 2017;Gnani et al, 2018;Alam et al, 2018). The computational analysis is considered compressible turbulence model and it is solved by species transport model along with eddy dissipation as well as finite rate chemistry model.…”

Section: Numerical Methodologymentioning

confidence: 99%

Numerical Investigation of Combustion Wave Propagation in Obstructed Channel of Pulse Detonation Engine using Kerosene and Butane Fuels

Alam

Pandey

Sharma

2019

JAFM

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The present computational analysis reports the results of combustion phenomenon in 1200 mm long and 60 mm internal circular diameter (D) of three dimensional obstructed combustion chamber (combustor) of the pulse detonation engine (PDE). The simulation is carried out for stoichiometric mixture of two fuels Kerosene-air and Butane-air mixture at atmospheric pressure and temperature of 1 atm and 300 K respectively along with preheated air. The chemical species of Kerosene and Butane (C12H26 and C4H10) fuel are solved by species transport equation and irreversible one-step chemical kinetics model. The propagation speed of flame, detonation wave pressure and deflagration-to-detonation transition (DDT) run-up length are analyzed by three dimensional reactive Navier-Stokes algorithm along with realizable k-ɛ turbulence equation model. The obstacles are placed inside the combustor tube at spacing (s) of 60 mm (1D) and obstacles having blockage ratio (BR) 0.5 for creating perturbation in propagating combustion flame. This resulted in increase of the surface area of propagating flame and reduces deflagration-to-detonation transition (DDT) run-up length.

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“…The quality and accuracy of simulation results depend on the boundary conditions and the number of elements or cell size of the computational domain [30,31]. The simulation is initiated on unstructured Delaunay mesh with the hexahedral grid for the number of elements 5,48,820, and it gives flame velocity of Mach number 2.013 in the combustor tube.…”

Section: Grid Independence Analysismentioning

confidence: 99%

“…To analyze the reaction rate of a hydrogen-air mixture, the one-step chemical reaction model is used, which follows ideal gas law [17]. The governing equations of continuity, momentum, and energy are solved simultaneously by the finite-volume method through commercial computational fluid dynamics (CFD) software ANSYS FLUENT 14.0 code [27][28][29][30][31][32][33][34]. A modified SIMPLEC scheme (Semi-Implicit Method for Pressure-Linked Equations-Consistent) is used to solve the Navier-Stokes equations.…”

Section: Mathematical and Combustion Modelingmentioning

confidence: 99%

Numerical investigation of flame propagation and performance of obstructed pulse detonation engine with variation of hydrogen and air

Alam

Sharma

Pandey

2019

J Braz. Soc. Mech. Sci. Eng.

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Pulse detonation engine is a new technique of supersonic wave propagation and stands for high impulsive thrust. The objective of the present investigation is to analyze the detonation wave characteristic of a hydrogen-air mixture in the pulse detonation engine (PDE) having obstacles of blockage ratio 0.5. The three-dimensional reactive Navier-Stokes equations with realizable k − ɛ turbulence model are used to simulate the propagation of combustion flame. The reaction rate of excess hydrogen and excess air is modeled by reduced single-step chemical reaction model and simulated using ANSYS software FLUENT 14.0 code. The simulation results of the shock wave overpressure, deflagration-to-detonation transition run-up distance of different flames and flame velocities are reported at initial boundary condition of 0.1 MPa pressure and 293 K temperature. It has been observed that the obstacles create turbulence in the propagating flame and form strong Mach stems of high temperature, resulting in reduction in accelerated flame run-up length. However, the normalized detonation flame run-up distance increases as the mass of fuel increases in the mixture. Thus, the performance of PDE combustor was observed 4.46% at high overpressure generated by excess fuel (ϕ = 1.3).

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Effect of back-pressure forcing on shock train structures in rectangular channels

Cited by 42 publications

References 39 publications

Numerical Study on Shock Train Characteristics in Divergent Channels

Numerical Study on Shock Train Characteristics in Divergent Channels

Numerical Investigation of Combustion Wave Propagation in Obstructed Channel of Pulse Detonation Engine using Kerosene and Butane Fuels

Numerical investigation of flame propagation and performance of obstructed pulse detonation engine with variation of hydrogen and air

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