Accession Number : AD0679148

Title :   RAYLEIGH PROBLEM WITH SURFACE REACTION AND THE ONSET OF SURFACE COMBUSTION IN STILL ATMOSPHERE.

Descriptive Note : Technical rept. Jul 67-Jun 68,

Corporate Author : AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS

Personal Author(s) : Liu,S. W.

Report Date : SEP 1968

Pagination or Media Count : 33

Abstract : The onset of surface combustion in still atmosphere is studied by the use of a Rayleigh-type fluid model, in which the surface temperature experiences a sudden increase. The only fluid motion is provided by the emergence of the surface mass flux as a result of a simple one-step irreversible reaction. The result provides some insight into the interaction of the surface energy and mass balance and the roles they play in a surface combustion process. From a stability consideration, a criterion of flammability is established for the nonconvective and low-g environment prevalent in the interior of a space capsule. On the basis of this criterion, pertinent parameters for both the combustible material and the oxidizing atmosphere are examined in detail, and the choices of the surface material and the atmosphere in terms of these parameters in order to minimize the fire hazard are discussed. The general result for Lewis number of unity are presented with sufficient coverage of the pertinent parameters that they are expected to be useful for a broad variety of surface material and atmosphere combinations anticipated in most practical applications. An illustrative example using a graphite surface is presented. (Author)

Descriptors :   (*SPACECRAFT CABINS, *COMBUSTION), (*FIRE SAFETY, CONTROLLED ATMOSPHERES), SURFACE TEMPERATURE, MATHEMATICAL ANALYSIS, GAS FLOW, FLAMMABILITY, FIRE RESISTANT MATERIALS, OXIDIZERS

Subject Categories : Safety Engineering
      Unmanned Spacecraft

Distribution Statement : APPROVED FOR PUBLIC RELEASE