Methods for the analysis of high-pressure, high-enthalpy constrictedarc heaters

Nicolet, W. E.; Shepard, C. E.; Clark, K. J.; Balakrishnan, A.; Kesselring, J.; Suchsland, K. E.; Reese, J. J.

doi:10.2514/6.1975-704

Cited by 17 publications

(21 citation statements)

References 18 publications

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“…(1)(2)(3). Even though nonequilibrium effect cannot be neglected at the core of arc, it may be restricted within the core in the type of segmented constrictor, because pressure is high in constrictor and the fluctuation of arc is much smaller in space and time than other types of arc heater.…”

Section: A Governing Equationsmentioning

confidence: 95%

“…Even though nonequilibrium effect cannot be neglected at the core of arc, it may be restricted within the core in the type of segmented constrictor, because pressure is high in constrictor and the fluctuation of arc is much smaller in space and time than other types of arc heater. Thus, the working gas in a constrictor was assumed to be in a chemical equilibrium state [1][2][3][4][5][6]. In addition, to reflect the separated injection of air and argon, it was treated as a mixture of air and argon in the present paper, and the continuity equation of argon gas with a diffusion term was added to the governing equations.…”

Section: A Governing Equationsmentioning

confidence: 99%

“…In all previous computations [1][2][3][4][5][6][7][8][9][10], the working gas was treated as a pure-air or a mixture-with-fixed-argon-ratio case, although an argon gas was injected separately in the case of a real segmented arc heater. In this study, to increase the reality of gas injection, air was supplied from the wall of the constrictor, and argon was injected from the upstream surface of the anode chamber and the wall of the cathode chamber.…”

Section: B Boundary Conditionsmentioning

confidence: 99%

“…Historically, many numerical investigations have been carried out with this purpose. In the 1970s, Nicolet et al [1] developed the ARCFLO code based on the work of Watson and Pegot [2]. However, the applicability of the ARCFLO code was quite restrictive in the actual design or development of arc heaters because it employed the space marching technique, which requires knowledge of upstream conditions in advance.…”

Section: Introductionmentioning

confidence: 99%

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Computation of Segmented Arc-Heater Flows Considering Injection of Electrode Shield Gas

Lee

Jeong

Kim

2011

Journal of Thermophysics and Heat Transfer

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The computer code ARCFLO4, used to solve segmented arc-heater flows, is improved to consider argon gas injected into the electrode chambers and air injected from the constrictor wall. The additional species continuity equation for argon gas including the diffusion term is solved with the original governing equations for total working gas. Also, a numerical wall boundary condition, wherein air is injected from small gaps between constrictor disks, is applied to predict heat flux more realistically. This code is used to simulate flows at the Panel Test Facility, the Aerodynamic Heating Facility, and the Interaction Heating Facility of the NASA Ames Research Center. The computations show that the argon ratio changes dramatically in the arc heater, and it strongly influences the distribution of the thermodynamic and transport properties of the flow. At the upstream region of the constrictor, the arc column is broad and the radiation increases. In addition, a periodic distribution of conductive heat flux on the constrictor wall occurs along the axial direction due to gas injected from gaps between the constrictor disks. The average heat flux on the disk is higher than the previous result that considered working gas with a fixed argon ratio. Finally, through comparison between computation and experiment, it is confirmed that the proposed computation effectively predicts the total heat flux on the arc heater. Nomenclature c Ar = mass fraction of argon gas c i = mass fraction of species c p;i = specific heat of species at constant pressure, J=kg K D Ar = effective diffusion coefficient of argon gas, m 2 =s D ij = multicomponent diffusion coefficient, m 2 =s D im = effective binary diffusion coefficient, m 2 =s E = voltage gradient, V=m e t = total internal enthalpy, J=kg H = total enthalpy, J=kg H a = mass-averaged enthalpy, J=kg H c = centerline enthalpy, J=kg I = current, A j = current density, A=m 2 k = Boltzmann constant, 1:380622 10 23 J=K L = length of constrictor, m M i = molecular weight of species i, kg=kg mole N s = total number of species n i = number density of species i, m 3 p = pressure, Pa q C = conductive heat flux, W=m 2 q R = radiative heat flux, W=m 2 R = universal gas constant, 8314:3 J=kg mole K T = temperature, K u = axial velocity, m=s V = voltage, V v = radial velocity, m=s x = axial coordinate, m y = radial coordinate, m = arc-heater efficiency = density, kg=m 3 ij = stress tensor, N=m 2

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Section: A Governing Equationsmentioning

confidence: 95%

Section: A Governing Equationsmentioning

confidence: 99%

Section: B Boundary Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Computation of Segmented Arc-Heater Flows Considering Injection of Electrode Shield Gas

Lee

Jeong

Kim

2011

Journal of Thermophysics and Heat Transfer

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“…The swirl coefficient S,~ [Eq. (22)], which takes this effect into account, is one of the parameters of the model. After about 10 cm in the constricted part of the arc, the swirl coefficient has decreased by a factor of 2.…”

Section: Swirl Coe~cientmentioning

confidence: 99%

Modeling of the cathode jet of a high-power transferred arc

Gonzalez

Gleizes

Vacquié

et al. 1993

Plasma Chem Plasma Process

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A physical model of two zones (constricted arc' and cathode jet) of a I-MW transferred arc in air is presented. It is based on the solution of consert,ation equations by a.finite-difference method. Turbulence is treated with Prandtl's approximation, whereas radiatit,e tran.sJ-er is solved considering a nonhomogeneous nlediunl, with the hypothesis of gray spectral bands. The inlluence of radiatit, e transler on the temperatare field is illustrated using two-band and lbur-band radiation models.We also show the ir~[luence t~f set,eral parameters on plasma .jet properties: current intensity between 500 and 1500 A: gas rnass flow rate between l O and 90 g/s; vortex injection. The arc characteristics are analyzed in accordance with physical mechanisms such as heat conduction, radiation, turbulence, confection, and mixing qf cold gas.

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