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Thermal Protection Systems
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Thermal
Protection Systems (TPS) are commonly used as
protection from intense heat in combustion chambers
and during re-entry of a space vehicle or sample
return canister. TPS methods typically use an
ablative material as an expendable surface coating.
Such systems have been used in early manned space
missions (Mercury, Gemini, and Apollo), and continue
to be used in many planetary exploration missions
such as the Athena Rovers on Mars, Stardust and
Genesis. |
When exposed
to extreme heat fluxes, the ablative material absorbs
large amounts of heat, changing its physical state
ablation (shedding mass). Some materials will also
undergo a chemical change ("charring") prior
to ablating.
Recent
enhancements to SINDA/FLUINT provide a new approach
to model noncharring ablation. (Note: Charring simulation
is in progress for future releases.) The user can
model 1-D ablation using the new subroutine ABLATE.
The ablative material properties, total thickness,
and the number of layers to break the ablative material
into must be specified. In Thermal Desktop this is
done by providing ablative material properties and
then defining insulation on a surface.
Major
advantages of this new method for modeling ablation
directly within SINDA is the ability to exploit thermal
modeling options such as optimization, sizing, temperature
mapping to NASTRAN and ANSYS, and postprocessing techniques.
Below
is an example of a simple return capsule modeled in
Thermal Desktop. Geometric postprocessing can be performed
for temperatures, fluxes, or ablative material thickness.
Additionally XY plotting of various parameters can
be performed. In the sample the heat shield has been
postprocessed for thickness. The EZ-XY plot shows
the various layers of material increasing to the ablation
temperature. As layer ablates, the next layer increases
in temperature reaching the ablation temperature as
the previous layer finishes ablating.
Customization
and Consulting
C&R
also provides consulting and
custom software solutions to specifically meet
your needs. |
