- Author
-
Yamashita, H.
|
Baum, H. R.
|
Kushida, G.
|
Nakabe, K.
|
Kashiwagi, T.
- Title
- Heat Transfer From Radiatively Heated Material in a Low Reynolds Number Microgravity Environment.
- Coporate
- Nagoya Univ., Japan
National Institute of Standards and Technology, Gaithersburg, MD
Osaka Univ., Japan
- Journal
-
Journal of Heat Transfer,
Vol. 115,
418-425,
May 1993
- Sponsor
- National Aeronautics and Space Administration, Washington, DC
- Contract
- NASA-C-32000-R
- Keywords
-
heat transfer
|
reynolds number
|
microgravity
|
mathematical models
|
vapor phases
|
equations
|
fluid flow
- Identifiers
- condensed phase model; numerical methods; linear analytical solution
- 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.