AFRPL Graphite Performance Prediction Program. Improved Capability for the Design and Ablation Performance Prediction of Advanced Air Force Propellant Rocket Nozzles.

摘要

A combined experimental and analytic program was conducted to develop improved procedures for predicting the ablation performance of graphite materials in rocket nozzles. Particular emphasis was placed on conditions representative of the throat region of an MX nozle design which would use graphite materials that are representative of the current state of materials development. New kinetic response correlation functions were developed for G-90 and ATJ bulk graphites, 15% silicon carbide modified pyrolytic graphite, c plane pyrolytic graphite, and Pyrocarb 901 carbon-carbon. These functions were included into the Aerotherm GASKET code along with several modifications to improve on thermochemical modeling accuracy. This modified code, GASKET2, includes a number of new chemical species, improved generalized input requirements, and kinetically controlled carbon sublimation models. The GASKET2 code was used in a number of performance studies to predict the performance of a number of rocket nozzles to be tested in other Air Force programs. The rocket nozzle ablation performance prediction procedures for several rocket motor fabricators were mutually compared to determine the probable ranges of predicted variables. These ranges were used in an ablation rate sensitivity study to define the most critical parameters. The mass transfer coefficient and the kinetic rate constants were shown to be the most critical parameters to be accurately known. (Author)