Response of a Swirled Non-Premixed Burner to Fuel Flow Rate Modulation

Abstract

Combustion instability studies require the identification of the combustion chamber response. In non-premixed devices, the combustion processes are influenced by oscillations of the air flow rate but may also be sensitive to fluctuations of the fuel flow rate entering the chamber. This paper describes a numerical study of the mechanisms controlling the response of a swirled non-premixed combustor burning natural gas and air. The flow is first characterized without combustion and LDV results are compared to Large Eddy Simulation (LES) data. The non-pulsated reacting regime is then studied and characterized in terms of fields of heat release and equivalence ratio. Finally the combustor fuel flow rate is pulsated at several amplitudes and the response of the chamber is analyzed using phase-locked averaging and first order acoustic analysis.

Numerical study of coupled fluid–structure interaction for combustion system

“…The walls are handled using a dynamic logarithmic law-of-the-wall formulation for velocity and temperature: the thermal treatment mimics the convective losses due to the cooling channel with a conjugate approach, imposing a heat resistance and prescribing the cooling air temperature. A full description can be found in [1,8]. Runs are performed on very fine grids of the order of 2.7 millions tetrahedra (element sizes of the order of 1 mm), with time steps in the order of 1.5×10 −7 s and a maximum Courant-Friedrichs-Lewy (CFL) number equal to 0.7.…”

“…The numerical simulation of fluid-structure interaction (FSI) problems occurs in many engineering and scientific applications, ranging from airfoil oscillations or aero-hydrodynamics, blade flutter analysis in turbomachinery, to power generation in the design of gas turbine combustors [1,2].…”

Evaluation of numerical strategies for large eddy simulation of particulate two-phase recirculating flows

“…The choice of the numerical scheme (low or high-order), the grid resolution and type (hexahedra or tetrahedra) and the solver type (implicit or explicit) is not straightforward. Whether results are more accurate with a low-order scheme used on a refined grid or with a high-order scheme coupled with a coarser grid is still an open question, for instance [75]. While Colin and…”

Mode-selective terahertz emission from rippled air irradiated by femtosecond laser pulses

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