COMPUTATION OF ISOTHERMAL AND REACTING FLOWS IN TURBOJET AFTERBURNERS

Computations have been made of the three-dimensional flow field develo pment, chemical reaction and combustion processes in a typical turboje t afterburner system under both isothermal and reacting flow condition s, The calculations are based upon a numerical solution of the time-av eraged transport equations for mass, momentum, turbulence kinetic ener gy, dissipation rate, enthalpy and species concentrations using a fini te-volume formulation. The physical models include the k-epsilon turbu lence model, the eddy break-up model, a two-step reaction model, a dro plet vaporization and combustion model and a six-flux radiation model. The mean flow structures are presented in important longitudinal and cross-sectional planes which show certain striking similarities and co ntrasting differences for isothermal and reacting flows. The flame sta bilizer flow is shown to be dominanted by a complex combination of rec irculation and vortex patterns. Combustion alters convergence and mixi ng flow patterns downstream of the flame stabilizer, thus influencing the selection of the fuel injection system. The predicted reacting flo w parameters identify a number of design parameters such as fuel injec tor location, high degree reaction zone, nozzle opening area and the c orresponding fuel flow rate.