Engineering topics
Publications and source records attributed to Howe, J. T..
The application of a 'two-flux' technique is considered for determining the reflective characteristics and approximate temperature distribution in highly backscattering materials characterized by a very small absorption coefficient. With respect to the transmitted internal radiation fields, the internal radiative emission is assumed to be negligible. A comparison of theory and experiment is presented.
Heat shielding for planetary entry probes of future Jovian and Venusian missions will encounter heating levels well beyond those previously experienced. These entries are typically dominated by radiative heating from the shock layer. This paper demonstrates the potential of reflecting this incident radiation diffusely from an ablating material. This technique contrasts with the absorption experienced by char-forming or graphitic ablators. Two dielectric materials, Teflon (polytetra-fluoroethylene) and boron nitride, are examined for their ablative performance, including reflection, in a combined convective- and radiative-heating environment. For Teflon, at the conditions obtained, superimposition of radiative heating upon a convective stream causes no additional increase in surface recession over the convective only results. For boron nitride, an excellent room-temperature reflector in the visible spectrum, a decrease in reflectivity from 90 to 55 percent is experienced when the surface undergoes sublimation at high temperatures. The process of reflection in each of these materials is described in terms of backscattering from crystals. The significance of a sizable reflection as a mode of energy accommodation is demonstrated for Venusian entries as a potential reduction in mass loss due to ablation.
Thermal stress distribution and temperature profiles in nearly opaque spherical shell under radiant and convective heating flux
Reflecting and ablating Teflon heat shields for radiative environment of outer planets atmosphere
Influence of pericapillary plasma on chemical exchange from blood to tissue
Ablation of heat shielding materials subjected to superorbital reentry conditions, noting dependence on heating rate to surface
Diffusive transport term in hydrodynamic equations describing flow over strongly ablating entry objects, discussing charge separation and pressure diffusion
Fluid mechanical problems related with subsonic and supersonic aircraft
Hydrodynamics of plasma flow in pericapillary spaces, postulating fluid annulus outside capillary wall as plasma reservoir responsible for hematocrit ratios
Radiative flux and flux divergence for hot gas, considering spectral frequency, gas volume and spectral variation
Hydrodynamic analysis of dynamic blood plasma flow in capillaries and lymph annulus
Nonequilibrium flow field behind normal shock waves in carbon dioxide
Dissociative reactions of carbon dioxide and their effects on the flow fields behind normal shock during planetary atmospheric entry
Boundary layer equation requirements for compatibility of external vorticity condition
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