Unsteady combustion modeling of energetic solids

Brewster, M. Q.; Zebrowski, Maria; Schroeder, T. B.; Son, Steven F.

doi:10.2514/6.1995-2859

Cited by 9 publications

(4 citation statements)

References 10 publications

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“…physical factors can affect the pyrolysis law; different physical meaning and values of the parameters appearing in Eqn (57) would then be implied. Similar remarks, but not necessarily the same, were already made by Brewster,[18][19] in the ZN framework; differences are due to the zero-order condensed-. phase decomposition there implemented in lieu of the conventional.…”

Section: Resultsmentioning

confidence: 51%

“…(20) r =~~]F-' whose static limit is where iiis =p crb = iii is the steady surface mass burning rate. A possible correlation among the four sensitivity parameters is revealed by the Jacobian defined as (17) implying (21) is ns=n-nT$ mfs (18) This relationship, inv,?l:ving only surface properties corresponds to the pyrolysis Jacobian recently re-discussedI8,19 in the ZN framework.…”

Section: Linear Frequency Response Functionsmentioning

confidence: 99%

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Surface Pyrolysis of High Energy Materials

DeLuca¹,

Veeri²,

Cozzi³

et al. 1998

DSJ

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The Arrhenius zero-order phenomenological pyrolysis law, commonly used in conjunction with the Vieille ballistic law to study pressure-driven burning of energetic materials, is revisited. Motivated by experimental and theoretical work performed in 1984 in this Laboratory, a relationship among several interplaying parameters is found under steady-state conditions. This relationship corresponds to the Jacobian of the pyrolysis sensitivity parameters used in the Zeldovich-Novozhilov approach. The Arrhenius pyrolysis is still expressed in terms of a global surface activation energy, but consistency with the experimental ballistic law may require an explicit pressure dependence as well. This conclusion is supported by a variety of arguments drawn from different areas. The linear dependence of the pre-exponential factor on surface activation energy (known as kinetic compensation) is proved and extended to the pressure exponent, for any given experimental data set under steady burning. Experimental results are reported for about a dozen solid propellants of different nature. The effects of surface pyrolysis explicit pressure dependence, although modest on steady-state burning, are potentially far -reaching for unsteady regime and/or unstable burning. The paper is mainly focussed on pressure-driven burning and Arrhenius pyrolysis, but the implemented method is believed to apply in general. Thus, enforcing KTSS zero-order, phenomenological pyrolysis with the Vieille ballistic law yields similar results and requires an explicit pressure dependence. In case, the Zeldo\Lich ballistic law is enforced instead of the classical Viei!le law, no explicit pressure dependence is required. The unifying concept for these different trends is the pyrolysis Jacobian as a consistency requirement between the implemented steady pyrolysis and ballistic laws.

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Section: Resultsmentioning

confidence: 51%

Section: Linear Frequency Response Functionsmentioning

confidence: 99%

Surface Pyrolysis of High Energy Materials

DeLuca¹,

Veeri²,

Cozzi³

et al. 1998

DSJ

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“…All the other values were given in conjunction with models without referencing their source. Values ranged from 1.75E-4 18 Parr 22 Beckstead 23 Brewster 24 American Institute of Aeronautics and Astronautics to 7.6E-4 cal/cm-sec-K. Since the thermal conductivity of a liquid is generally higher than that of the solid, we choose a value higher than any of these solid thermal conductivities (1.045e-3 cal/cm-sec-K) which enabled our model to correctly predict the melt layer thickness.…”

Section: Rdx Thermodynamic and Physical Propertiesmentioning

confidence: 98%

Improvements to RDX combustion modeling

Davidson

Beckstead

1996

34th Aerospace Sciences Meeting and Exhibit

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AIAA 34th Aerospace Sciences Meeting and Exhibit, Reno, NV Jan 15-18, 1996Many improvements have been made to models of RDX combustion in the past few years. The one-dimensional model presented in this paper models the solid, two-phase, and gas regions using complex kinetics and concentration and temperature dependent thermophysical properties. Calculated values agree well with experimentally determined burn rate, melt layer thickness, surface temperature, and species concentration profiles. When including laser-assisted burning in the model, a dark zone appeared similar to that seen experimentally. With the laser assisted case, the chemistry controlling the burn rate is significantly different from cases without the laser heat flux. Calculations show that the melt layer thickness is determined primarily by the liquid thermal conductivity, and the surface temperature is controlled by the vapor pressure correlation. All other model predictions are relatively insensitive to these parameters. The weakest areas of the model remain the condensed phase decomposition and evaporation/condensation submodel. AbstractMany improvements have been made to models of RDX combustion in the past few years. The onedimensional model presented in this paper, models the solid, two-phase, and gas regions using complex kinetics and concentration and temperature dependent thermophysical properties. Calculated values agree well with experimentally determined burn rate, a p , melt layer thickness, surface temperature and species concentration profiles. When including laser-assisted burning in the model, a dark zone appeared similar to that seen experimentally. With the laser assisted case, the chemistry controlling the burn rate is significantly different from cases without the laser heat flux. Calculations show that the melt layer thickness is determined primarily by the liquid thermal conductivity and the surface temperature is controlled by the vapor pressure correlation. All other model predictions are relatively insensitive to these parameters. The weakest areas of the model remain the condensed phase decomposition and evaporation/condensation sub-model. Nomenclature A = area (cm 2 ) A = pre-exponential rate constant c = heat capacity (erg/g K) C = molar concentration (moles/cm-*) E a = activation energy (cal/mole) H = molar enthalpy (erg/mole) h = specific enthalpy (erg/g) kk = number of gas phase species rh = mass flow rate (g/s) n = number of bubbles per volume 1 e 13 bubbles/cmp = pressure q = rate of progress variable (moles/cm 3 s) r b = burn rate (cm/s) R = universal gas constant s = sticking factor T = temperature (K) u = gas velocity (cm/sec) V = diffusion velocity (cm/sec) W = average molecular weight (g/mole) W = molecular weight (g/mole) W = molar rate of production (moles/cm 3 s) x = distance from 2-phase-gas interface (cm) X = mole fraction Y = mass fraction P = temperature exponent rate constant (j > = void fraction A.= heat capacity (erg/cm s K) v = stoichiometric coefficient p =density (g/cnH) dp = temperature sensiti...

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“…The heat flux from the gas phase, q^, is then interpolated from the gas phase lookup table based on the parameters at the surface (mass flow rate, temperature, and species mass flux fractions). The mass flow rate (or velocity) is then adjusted and the process repeated until the surface energy balance is satisfied (see equation 14). At this point the steady state solution is complete and the steady state burn rate is known.…”

Section: Steady Condensed Phase Speciesmentioning

confidence: 99%

A numerical model of monopropellant deflagration under unsteady conditions

Erikson

Beckstead

1996

34th Aerospace Sciences Meeting and Exhibit

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A numerical model was developed to calculate the pressure and heat flux responses for burning monopropellants. The QSHOD assumptions were imposed in the model; however, distributed condensed-phase decomposition reactions were allowed. Furthermore, the commonly used gas-phase flame assumptions, such as a flame sheet or simple kinetics, were relaxed in favor of a more rigorous multiple reaction approach. The gas phase utilized the PREMIX code developed by Sandia National Laboratories in connection with a curve-fitting procedure. Results for both Rp and Rq are presented for RDX at 1 atm pressure and compare favorably with experimental laser recoil response data. AbstractA numerical model has been developed to calculate the pressure and heat flux responses for burning monopropellants. The QSHOD assumptions were imposed hi the model, however distributed condensed phase decomposition reactions were allowed. Furthermore, the commonly used gas phase flame assumptions, such as a flame sheet or simple kinetics, were relaxed in favor of a more rigorous multiple reaction approach. The gas phase utilized the PREMK code developed by Sandia National Laboratories in connection with a curve-fitting procedure. Results for both Rp and R, are presented for RDX at 1 atm pressure and compare favorably with experimental laser recoil response data.

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Unsteady combustion modeling of energetic solids

Cited by 9 publications

References 10 publications

Surface Pyrolysis of High Energy Materials

Surface Pyrolysis of High Energy Materials

Improvements to RDX combustion modeling

A numerical model of monopropellant deflagration under unsteady conditions

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