Simulation of overexpanded low-density nozzle plume flow

Chung, Chan-Hong; Witt, Kenneth J. De; Stubbs, Robert M.; Penko, Paul F.

doi:10.2514/3.12812

Cited by 12 publications

(11 citation statements)

References 7 publications

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“…The experimental and numerical investigations of supersonic nozzle and plume flows available in the literature are mainly devoted to the high-vacuum background conditions that are of interest for aerospace applications (Boyd et al 1992;Campbell et al 1994;Rosenhauer et al 1999;George & Boyd 1999). The flow inside a nozzle under conditions close to ours has been studied by Rothe (1971), whose density and rotational temperature measurements of a nitrogen flow, obtained by electronbeam fluorescence diagnostics, are often used for testing the numerical approaches (Kim 1994;Chung et al 1995). Some interesting experimental and numerical results concerning the effect of finite background pressure on the plume flow of hydrogen are reported by Boyd et al (1994).…”

Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of an O $_{2}$ NO supersonic free jet expansion

et al. 2004

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Cold O 2 /NO supersonic expansions through an axisymmetric convergent-divergent nozzle into a low-pressure background gas have been investigated both experimentally and numerically. Temperature and density measurements have been carried out, using tracer NO in an O 2 main flow. NO two-dimensional rotational temperature and density flow field patterns in the jet behind the nozzle have been measured by laser-induced fluorescence (LIF). The spectroscopic investigations are complemented by static and impact pressure measurements along the jet centreline. Two nozzles with the same inner profile but with a short and long divergent section and small and large lip have been examined. Three experiments performed using these nozzles cover a wide range of regimes of underexpanded free jet flow, from highly oscillating multi-cycle structure to the regime with smooth deceleration of the issuing flow by the background gas. The numerical simulation of the whole flow field from the conditions in the stagnation chamber to those in the flooded space is performed in the framework of the full set of Navier-Stokes equations by employing a recently developed algorithm based on a staggered grid. The flow inside a long nozzle is shown to be strongly affected by the boundary layer, which leads to the degeneration of the isentropic core at the nozzle exit and transforms the jet regime from overexpanded for inviscid flow to underexpanded for a real flow. The model reproduces the experimental structures of the low-density free jet flow fairly well.

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Section: Introductionmentioning

confidence: 99%

Experimental and numerical investigation of an O $_{2}$ NO supersonic free jet expansion

et al. 2004

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“…The code has been applied to various low-density flows of gas mixtures in arbitrary shaped flow domains. 22,23 Details of the code may be found in Ref. 22.…”

Section: Dsmc Methodsmentioning

confidence: 99%

Numerical Simulation of Low-Speed Gas Flows in a Microfluidic System

Chung

2005

Journal of Thermophysics and Heat Transfer

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A kinetic theory analysis is made of low-speed gas flows in microfluidic systems consisting of microchannels in series. The Boltzmann equation, simplified by a collision model, is solved by means of a finite difference approximation with the discrete ordinate method. For the evaluation of the present method, the results for simple channels are compared with those from several different methods and available experimental data. Calculations are made for various microfluidic systems such as a sudden expansion, a sudden contraction, and a 90-deg bend. The results compared well with those from the discrete simulation Monte Carlo method. The present method does not suffer from the statistical noise that is common in particle-based methods, and it requires a smaller amount of computational effort. It is also shown that the analytical solution of the Navier-Stokes equations with slip boundary conditions, which is suitable for fully developed flows, can give relatively good results in predicting geometrically complex flows such as a sudden expansion and a sudden contraction. NomenclatureA c = collision frequency d = characteristic length of the flowfield F = Maxwell-Boltzmann distribution f = distribution function g, h = reduced distribution functions K n = Knudsen number λ = mean free path Subscripts d = exit condition 0 = inlet condition

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“…The code has been applied to various low-density flows of gas mixtures in arbitrary shaped flow domains. 29,30 Details of the code may be found in Ref. 29.…”

Section: Flow Around a 5% Flat Platementioning

confidence: 99%

“…29,30 Details of the code may be found in Ref. 29. Calculated pressure contours are compared in Fig.…”

Section: Flow Around a 5% Flat Platementioning

confidence: 99%

Kinetic Model Solution for Microscale Gas Flows

Chung

2005

AIAA Journal

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A kinetic theory analysis is made of low-speed gas flows around microscale flat plates. The Boltzmann equation simplified by a collision model is solved by means of a finite difference approximation together with the discrete ordinate method. The advantage of the present method is that it does not suffer from statistical noise, which is common in particle-based methods. Calculations are made for flows around a flat plate with zero thickness and a 5% flat plate. Results for the 5% flat plate at a freestream Mach number 0.5 showed good agreement with those from the direct simulation Monte Carlo method. It is shown that strong rarefaction effects exist around the leading and trailing edges. Results from the present method at a freestream Mach number 0.087 also showed similar nonequilibrium effects. Comparison of results with those from the information preservation method and numerical solutions of the Navier-Stokes equations showed some differences in details near the leading and trailing edges. NomenclatureA c = collision frequency d = characteristic length of the flowfield F = Maxwell-Boltzmann distribution f = distribution function g, h = reduced distribution functions K n = Knudsen number L = length of flat plate l = normal distance from plate surface R = gas constant t = thickness of flat plate U ∞ = free stream velocity V x = velocity of molecule in the x direction V y = velocity of molecule in the y direction V z = velocity of molecule in the z direction λ = mean free path

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Simulation of overexpanded low-density nozzle plume flow

Cited by 12 publications

References 7 publications

Experimental and numerical investigation of an O $_{2}$ NO supersonic free jet expansion

Experimental and numerical investigation of an O $_{2}$ NO supersonic free jet expansion

Numerical Simulation of Low-Speed Gas Flows in a Microfluidic System

Kinetic Model Solution for Microscale Gas Flows

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