Numerical Study of Operability of Combustor With Inflow Oscillations

Numerical study of gas turbine combustion with the inflow oscillation has been conducted using KIVA-3V code. The simulation was based on the solution of Navier-Stokes equations with a time-marching method and models of turbulence and sprays, and a simplified kinetic mechanism of 17-species and 23-step. The transient inflow was assumed by specifying the pressure oscillation in a form of sinusoidal function. Effects of three flow patterns, i.e. quasi-steady, transition and steady patterns corresponding to the oscillation frequency ranges of n ≤ 80, 80 ≤ n ≤ 320 and n ≥ 320 Hz, on combustion performance were investigated. It is found that for the flow in quasi-steady pattern, combustion is in quasi-steady state with flow and combustion properties dependent of time and the analytical approaches for steady combustion can be applied; for the flow in steady pattern, combustion can be treated as if in steady state and the influence of oscillation can be ignored; and in transition pattern, the combustion behaves in-between. Finally, the operability of combustor with inflow oscillation was analyzed, which is useful for the analysis of combustion performance under irregular inflow conditions.Copyright © 2002 by ASME