Simulation of liquid fuel combustion start-up dynamical behavior

Abstract

A successful ignition is the consequence of corresponding conditions of fuel mass flow rates, mixture ratio, as well as initiation energy in time and space. If ignition does not take place accurately, serious damages can take place within or outside the engine. The dynamical behavior of the combustion chamber was investigated during ignition. Single shear coaxial injector combustion chamber test case is used in the present study. At the time of propellant injection, mostly the pressure and temperature remain subcritical. When injected these increases promptly and convert into supercritical conditions. The thermodynamic state usually changes from subcritical to supercritical during ignition. Navier Stokes equations along with Soave Redlich Kwong equation model has been applied during steady-state, while transient simulations with ideal gas assumptions are performed to analyze the dynamical behavior of the combustor. All the simulations were performed in the present study using the ANSYS Fluent 16.2 code. The computational findings have strong analytical consistency with the experimental data. Due to inappropriate modeling of the equation of state and limited information about initial and boundary conditions for ignition transient results have some differences with experimental data. The difference between the observed chamber pressure during the experiment and numerical computation using 0.4 RFL value is only 2 bar (approximately 7% difference).

Keywords

• CFD
• Supercritical combustion
• Ignition transients
• Real gas
• Kerosene/oxygen combustion