Accession Number : ADA325435

Title :   Launch Abort Chemistry Model.

Descriptive Note : Technical rept.,

Corporate Author : AEROSPACE CORP EL SEGUNDO CA TECHNOLOGY OPERATIONS

Personal Author(s) : Brady, B. B. ; McIlroy, A. ; Martin, L. R.

PDF Url : ADA325435

Report Date : 08 FEB 1997

Pagination or Media Count : 50

Abstract : Computer models provide a framework for better understanding of complex phenomena. Events such as launch aborts are rare, and detailed field information about the chemical load they introduce into the atmosphere is rare. A good model will make predictions about the time dependence of the chemical concentrations and temperatures in such an event and, therefore, makes it possible to correlate and evaluate incomplete data on chemical observations. A model should make it possible to scale field experiments. For the actual event, a good model should predict the statistical likelihood for certain chemical loads to occur, and it should be able to forecast the effect of meteorological conditions (e.g., relative humidity, dispersion rate) on the severity of the event. The launch abort problem is especially difficult because there are separate initial clouds of fuel and oxidizer, with regions of mixing between them. In this report, we deal with this problem with a 'multi-bin' approach, which treats the fuel and oxidizer and an interface as separate bins, but keeps the computation tractable. The computer program we use is based on SURFACE CHEMKIN, a standard chemical kinetic subroutine package. The model results show, thus far, that the outcome is highly dependent on initial conditions. However, we feel that a likely scenario for Titan IV will result in 24% of the initial oxidizer remaining, of which at least half is transformed into nitric acid, and 2% of the initial fuel remaining. These source strength numbers are roughly half those given by Lockheed-Martin for hydrazine and oxidizer, and about one-third those presently used for the oxidizer in REEDM.

Descriptors :   *CHEMISTRY, *LAUNCHING, *ABORT, COMPUTER PROGRAMS, COMPUTERIZED SIMULATION, SOURCES, CLOUDS, DISPERSING, TIME DEPENDENCE, HYDRAZINES, MODELS, FIELD TESTS, NITROGEN, SURFACES, FUELS, SCALE, METEOROLOGY, OXIDIZERS, MIXING, NITRIC ACID, ATMOSPHERES, HUMIDITY, TETROXIDES.

Subject Categories : Inorganic Chemistry
      Computer Programming and Software
      Guided Missiles

Distribution Statement : APPROVED FOR PUBLIC RELEASE