Limit Cycle Investigations of Pulse Detonation Combustor for Pulse Detonation Turbine Engine

Abstract

A pulse limit-cycle unsteady combustion calculation (PLUCC) model has been established and used for parametric study and optimization of pulse detonation combustor (PDC) for pulse detonation turbine engine (PDTE) applications. This model considers a system consisting of an inlet plenum, an air valve, a main tube with fuel injection, a convergent nozzle, and an exit plenum. A one-step chemical reaction along with variable properties for C2H4/air is implemented in the model. Pressure and heat losses are taken into account using loss coefficients. The effects of key sizing and timing parameters, including PDC length, nozzle area ratio, operation frequency, valve open time ratio, and fuel fill time ratio, were investigated systematically. A hierarchical strategy was implemented to optimize the total pressure ratio across the PDC, while satisfying the given upstream and downstream design constraints. Nomenclature f = operation frequency ff = fill fraction L = PDC length L* = PDC reference length NAR = nozzle area ratio, combustor-to-nozzle-throat area ratio inlet p = inlet pressure (supply pressure to the inlet plenum) r t p 41 = cycle average of total pressures across PDC, inlet t r t p