Computational Modeling and Experiments of Natural Convection for a Titan Montgolfiere
Computational models are developed to predict the natural convection heat transfer and buoyancy for a Montgolfiere under conditions relevant to the Titan atmosphere. Idealized single- and double-walled balloon geometries are simulated using algorithms suitable for both laminar and (averaged) turbulent convection. Steady-state performance results are compared with existing heat transfer coefficient correlations. The laminar results, in particular, are used to test the validity of the correlations in the absence of uncertainties associated with turbulence modeling. Some discrepancies are observed, which appear to be primarily associated with temperature nonuniformity on the balloon surface. The predicted buoyancy for both the single- and double-walled balloons in the turbulent convection regime, predicted with standard two-equation turbulence models, showed trends similar to those with the empirical correlations. There was also good agreement with recently conducted experiments in a cryogenic facility designed to simulate the Titan atmosphere.
Additional Information© 2010 by Arnab Samanta. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Presented as Paper 2806 at the AIAA Balloon Systems Conference, Seattle, WA, 4–9 May 2009; received 5 June 2009; revision received 29 January 2010; accepted for publication 2 February 2010. This work was supported by NASA Jet Propulsion Laboratory (JPL) under JPL award no. 1294409 and JPL award no. 1363442.
Published - 544925b70cf244fe9ea224d1.pdf