The analysis and the computer solution for the flow of a chemically reacting propellant exhaust mixture in a barrier-cooled axisymmetric rocket nozzle are described. The flowfield is represented by two nonmixing gas streams, one for the cool barrier zone near the nozzle wall and the other for the hot core zone. The two streams have the same pressure and flow angle at the streamline dividing the two zones, and each stream is characterized by a given oxidizer/fuel mixture ratio at the combustion chamber. This study allows simultaneous consideration of the nozzle performance losses due to chemical kinetics, nozzle divergence, and barrier cooling. Results of differences in temperature, density, velocity, and chemical composition across the two zones are illustrated, and are compared to the one-dimensional solution having the same over-all mixture ratio. Values of specific impulse are compared to those obtained by simpler and less rigorous methods.
Nomenclature
A, B= see Eqs. (26) and (27), respectively a = nozzle cross-sectional area a kj, bj = reaction-rate parameters C p = specific heat at constant pressure Ci = mass fraction of ith species F, G = see Eqs. (40) and (41), respectively H = see Eq. (42) h = enthalpy /s P = specific impulse KJ = equilibrium constant kRjj kRkj = reaction-rate parameters M = Mach number Mi = third body reaction term Mi = ith species in reaction equation m,ji= reaction-rate ratio mi = molecular weight of ith species HJ = reaction-rate parameter P, Pi = pressure and partial pressure of ith species, respectively R = gas constant r = radial distance perpendicular to nozzle axis; also, r = 0/F = oxidizer/fuel mixture ratio r* = nozzle throat radius T = temperature V = flow velocity Uj v = velocities in x and r directions, respectively X = max flow fraction in outer zone Xj -species production-rate term x = axial distance a = angle between streamline and Mach line . 7 = ratio of specific heats •y = see Eq. (43) e = expansion area ratio 0 = angle between streamline and axis va, v'a = stoichiometric coefficients