Gaseous oxygen cooling of the Space Transportation System launch padenvironment

The microexplosion of a slurry droplet is experimentally and theoretically investigated. The microexplosion was considered to be caused by the shell formation and the following pressure build-up in the shell which would be promoted by the suppression of evaporation, subsequent superheating and heterogeneous nucleation of a liquid carrier. Experimentally, the microexplosion phenomena was examined for various surfactant concentrations and particle loading under dierent ambient temperature ranges (500±900 K). To closely investigate the pressure buildup and the heterogeneous nucleation, a numerical model was introduced by considering the three stages such as the shell formation, suppression of evaporation and pressure build-up inside. The microexplosion time was estimated by postulating the limit of superheat for heterogeneous nucleation. The simulation yielded a reasonably good agreement with experimental results for Al/n-heptane slurry droplets under various solid loadings (10±40 wt.%). #

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“…In this zone, the following mass, energy, and species equations are considered for both the porous region (e=e sh ) and the gas ®eld (e=1) [11]:…”

Section: Assumptions and Governing Equationsmentioning

confidence: 99%

Microexplosion of aluminum slurry droplets

Byun

Baek

Cho

1999

International Journal of Heat and Mass Transfer

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Negatively Buoyant Flow Along Vertical Cylinders at High Rayleigh Numbers

Ahmad¹,

Mathias²,

Boraas³

1992

Heat Transfer Engineering

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Space transportation system launch pad summer environmental effects

Ahmad¹

1994

Journal of Thermophysics and Heat Transfer

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The external tank (ET) of the space transportation system (STS) contains liquid oxygen and liquid hydrogen as oxidizer and fuel for the Space Shuttle main engines. This article describes a two-dimensional flow and thermal forced convection analysis to determine solar heat effects on the Space Shuttle launch components subsequent to the ET loading operation in extremely hot conditions. An existing computational fluid dynamics (CFD) code, parabolic hyperbolic or elliptical numerical integration code series (PHOENICS '81) was used in the study. The analysis was done for a two-dimensional slice between planes perpendicular to the longitudinal axis of the STS and passing through the lower portions of the redesigned solid rocket motors (RSRMs), the ET, and the or biter wing. The results are presented as local and average values of surface temperatures and Nusselt numbers around the RSRMs and the ET. Solar heating effects increased surface temperatures of the RSRMs by 5-6.1°C. Comparisons were based on the local Nusselt number at the forward stagnation point and on the average Nusselt number around the West RSRM. Nomenclature D = diameter of RSRM, 12.2 ft (3.72 m) or ET, 28 ft (8.54 m) Gr D = Grashof number of free convection based on outer diameter of RSRM or ET, gf3(T s -r.)D 3 /^2 g = acceleration due to gravity, ft/s 2 (m/s 2 ) h = convective heat transfer coefficient, Btu/h-ft 2 -°F (W/m 2 -°C) /y, IZ -cell numbers in domain, Fig. 2 k = thermal conductivity of air, Btu/h-ft-°F (W/m-°C) Nu D = local Nusselt number based on outer diameter, hDlk Pr = Prandtl number, 0.7 q'^ = solar heat flux, Btu/h-ft 2 (W/m 2 ), Fig. 3 Re D = Reynolds number of forced convection, U x Dlv T = temperature, °F (°C) t = half the thickness of adjacent air cell to a surface, in. (mm) U x = freestream wind velocity, ft/s (m/s) Y, Z = Cartesian coordinates, Figs. 2 and 4 /3 = coefficient of volumetric expansion of air, I/TV, OR-1 (K" 1 ) g = dissipation rate of turbulence kinetic energy per unit mass, (ft 2 /s 2 )/s (m 2 /s 2 )/s 6 = angular direction, deg (Figs. 2 and 3) K = turbulence kinetic energy per unit mass, ft 2 /s 2 (m 2 /s 2 ) fji = dynamic viscosity, Ibm/ft-s (kg/m-s) v = kinematic viscosity of air, ja/p, 0.6482 ft 2 /h (6.0221 x 10-2 m 2 /h) p = air density, lbm/ft 3 (kg/m 3 ) Subscripts c = cell adjacent to a surface D = based on diameter fsp = forward stagnation point on the west RSRM, 6 -150 deg / -inside RSRM cavity or ET fuel tank / = laminar m = arithmetic mean, measured s = surface sol = solar t = turbulent o° = freestream conditions Superscript

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Gaseous oxygen cooling of the Space Transportation System launch padenvironment

Cited by 4 publications

References 4 publications

Microexplosion of aluminum slurry droplets

Microexplosion of aluminum slurry droplets

Negatively Buoyant Flow Along Vertical Cylinders at High Rayleigh Numbers

Space transportation system launch pad summer environmental effects

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