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Highlights CFD/radiative transfer simulations carried out for a Neptune 18 km/s entry or 29 km/s aerocapture. Traces of Methane in Neptune’s atmosphere significantly enhance wall radiative heating. 45° sphere-cone shapes ensure better aerodynamic stability for such flight conditions.
Abstract An aerothermodynamic analysis of representative aerocapture (29 km/s) and entry (18 km/s) flows in Neptune is discussed. Two 60° and 45° sphere-cone shapes are considered, and chemically-reactive, nonequilibrium flowfield solutions are computed for the forebody region, yielding surface heat fluxes from convective heating. A radiative transfer calculation using a line-by-line approach coupled with a ray-tracing routine, yields surface heat fluxes from radiative heating. If the trace amounts of CH4 in Neptune’s atmosphere are accounted for, they dramatically enchance radiative heating, as a result of strong radiative emission from carbonaceous species in the shock layer. For the 18 km/s entry point, radiative heat fluxes accordingly increase by several orders of magnitude, from 0% to about 50% of the total heat fluxes. The post-shock flow features further differ significantly depending on the capsule shape. The sonic line is near the sphere-cone transition zone for the 45° shape and starts detaching from the boundary layer for angles above 55°. The post-shock flow becomes entirely subsonic up to the spacecraft shoulder at 60°. More streamlined shapes will accordingly be more aerodynamically stable.
Aerothermodynamic analysis of Neptune ballistic entry and aerocapture flows
Advances in Space Research ; 71 , 8 ; 3408-3432
2022-12-10
25 pages
Article (Journal)
Electronic Resource
English
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