Heat Transfer From Radiatively Heated Material in a Low Reynolds Number Microgravity Environment.
Heat Transfer From Radiatively Heated Material in a Low
Reynolds Number Microgravity Environment.
(851 K)
Yamashita, H.; Baum, H. R.; Kushida, G.; Nakabe, K.;
Kashiwagi, T.
Journal of Heat Transfer, Vol. 115, 418-425, May 1993.
Sponsor:
National Aeronautics and Space Administration,
Washington, DC
Keywords:
heat transfer; reynolds number; microgravity;
mathematical models; vapor phases; equations; fluid flow
Abstract:
A mathematical model of the transient three-dimensional
heat transfer between a slowly moving ambient gas stream
and a thermally thick or thin flat surface heated by
external radiation in a microgravity environment is
presented. The problem is motivated in part by fire
safety issues in spacecraft. The gas phase is
represented by variable property convection-diffusion
energy and mass conservation equations valid at low
Reynolds numbers. The absence of gravity and low
Reynolds number together permit the flow to be
represented by a self-consistent velocity potential
determined by the ambient velocity and the thermal
expansion in the gas. The solid exchanges energy with
the gas by conduction/convection and with the
surroundings by surface absorption and re-emission of
radiation. Heat conduction in the solid is assumed to
be one dimensional at each point on the surface as a
consequence of the limited times (of order of 10
seconds) of interest in these simulations. Despite the
apparent simplicity of the model, the results show a
complex thermally induced flow near the heated surface.
The thermal exchange between the gas and solid produces
an outward sourcelike flow upstream of the center of the
irradiated area and a sinklike flow downstream. The
responses of the temperature fields and the associated
flows to changes in the intensity of the external
radiation and the ambient velocity are discussed.
