ANALYSIS OF STEADY, TWO-DIMENSIONAL, CHEMICALLY REACTING NONEQUILIBRIUM FLOW BY AN UNSTEADY, ASYMPTOTICALLY CONSISTENT TECHNIQUE
Abstract
A method has been developed for solving the equations governing two-dimensional, unsteady, chemically reacting nonequilibrium flow. Subsonic, transonic, and supersonic flow fields can be analyzed using this technique. The steady state solution is obtained as the asymptotic solution to the unsteady equations, with steady flow boundary conditions applied, for large time. Interior mesh points are computed using MacCormack's method while all boundary points are calculated by a reference-plane characteristic scheme. The overall algorithm is inconsistent in time in the treatment of the species continuity equations but it becomes consistent at the steady state limit. The species continuity equations are integrated by a second-order accurate implicit method along streamlines within the flow field. The technique allows the specification of nonuniform, nonequilibrium conditions at the nozzle inlet. A production-type computer program was developed and was used to analyze several different problems including the effects of finite-rate chemical kinetics. The chemical kinetics model considers 19 species formed from the elements carbon, hydrogen, oxygen, nitrogen, flourine, and chlorine and 48 chemical reactions. Unburned hydrocarbons and a sub-global oxidation reaction for these species may also be included in the model. In addition to nonequilibrium flows, the program can also be used to analyze frozen and equilibrium flows and flows with constant specific heat ratios. Verification of the results is difficult because, at present, there are no other methods available for the solution of the subject problem. However, for the cases studied, the solutions are quite reasonable and agree well in a mass-averaged sense with accepted one-dimensional finite-rate chemical kinetics solutions. Computational time appears to be highly problem dependent. For the cases studied to date, converged solutions have been obtained in times ranging from five minutes to one hour using a CDC 6500 computer.
Degree
Ph.D.
Subject Area
Aerospace materials
Off-Campus Purdue Users:
To access this dissertation, please log in to our
proxy server.