AIAA 2002-0336 Reduced Chemical Kinetic Mechanisms for JP-8 Combustion

Using CARM (Computer Aided Reduction Method), a computer program that automates the mechanism reduction process, six different reduced chemical kinetic mechanisms for JP-8 combustion have been generated. The reduced mechanisms have been compared to detailed chemistry calculations in simple homogeneous reactor calculations. Reduced mechanisms containing 15 and 20 species were found to give good agreement for both temperature and species concentrations (including NO) in adiabatic perfectly stirred reactor calculations for inlet temperatures from 300-1300 K, pressures from 10-40 atm, stoichiometric ratios from 0.5-2.0 and reactor residence times from 0.1 sec. to near blowout. Reduced mechanisms have also been created that compare well to available ignition delay measurements for JP-8. ______________ *Senior Engineer, AIAA Member †Group Leader, AIAA Member ‡Technical Director, AIAA Member §Aerospace Engineer, AIAA Associate Fellow Copyright © 2002 by the authors. Published by the American Institute of Aeronautics and Astronautics, Inc. with permission. INTRODUCTION Detailed chemical kinetic descriptions of aviation fuel combustion require the tracking of hundreds of chemical species and thousands of reaction steps. For the foreseeable future, CPU time and computer memory limitations will prohibit implementation of fully detailed descriptions of combustion chemistry into 3-D CFD simulations of practical devices. Issues such as ignition, flame stabilization, combustion efficiency, and pollutant formation are extremely important in the design of aircraft engines. Accurate simulation of these phenomena requires that significant chemical kinetic detail be retained in computer models. Within CFD simulations, memory usage and CPU time vary linearly with the number of chemical species tracked. Methods that minimize this number while retaining essential features of the detailed chemistry are thus of great importance. The number of species required for simulation of combustion processes depends on the nature of the phenomenon, and the type of information desired from the simulation. The recent development of comprehensive, validated, detailed mechanisms for combustion of kerosene fuels provides a basis for creating reduced chemical kinetic mechanisms containing few enough species to be used in a CFD simulation while accurately simulating the combustion chemistry. Reduced chemical kinetic mechanisms that can represent important aspects of the behavior of these detailed mechanism using few enough scalars that they can be implemented into CFD