Accession Number:

ADA010930

Title:

Monopropellant Droplet Decomposition for Large Activation Energies.

Descriptive Note:

Interim rept.,

Corporate Author:

INSTITUTO NACIONAL DE TECNICA AEROESPACIAL MADRID (SPAIN)

Personal Author(s):

Report Date:

1974-12-01

Pagination or Media Count:

46.0

Abstract:

The quasi-steady decomposition of a monopropellant droplet in a quiescent atmosphere is analyzed for an Arrhenius reaction. An analytical relation is obtained for the pre-exponential rate constant, or the Damkohler number, as a function of the droplet vaporization rate. For low values of the ambient temperature, the curve giving the vaporization rate in terms of the Damkohler number is S shaped and, thus, exhibits ignition-extinction characteristics. The lower bend of the S curve correspond to a nearly frozen regime, under which ignition conditions occur due to the large temperature sensitivity of the reaction rate. The upper bend of the S Curve corresponds to a regime, where nearly complete decomposition of the reactant occurs when it reaches a thin reactive-diffusive zone, after crossing a transport zone. This zone becomes thin, and thus planar, for large Damkohler numbers, resulting in a droplet decomposition rate proportional its radius. For low ambient temperatures a segment of the curve between the two bends of the S curve corresponds to a regime of partial decomposition in a thin reaction zone.

Subject Categories:

  • Combustion and Ignition

Distribution Statement:

APPROVED FOR PUBLIC RELEASE