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RISAbsolute/Convective Instability Transition in a Backward Facing Step Combustor: Fundamental Mechanism and Influence of Density Gradient
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: Hydrodynamic instabilities of the flow field in lean premixed gas turbine combustors can generate velocity perturbations that wrinkle and distort the flame sheet over length scales that are smaller than the flame length. ...
Effects of Fuel Staging on the Hydrodynamic Stability of Multinozzle Swirl Flows
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: Hydrodynamic instability in lean premixed gas turbine combustors can cause coherent flow velocity oscillations. These can in turn drive heat release oscillations that when favorably coupled with combustor acoustic modes ...
Nonlinear Phenomena in Thermoacoustic Systems With Premixed Flames
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: Nonlinear analysis of thermoacoustic instability is essential for the prediction of the frequencies, amplitudes, and stability of limit cycles. Limit cycles in thermoacoustic systems are reached when the energy input from ...
Influence of Nonaxisymmetric Confinement on the Hydrodynamic Stability of Multinozzle Swirl Flows
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: Interaction between coherent flow oscillations and the premixed flame sheet in combustors can result in coherent unsteadiness in the global heat release response. These coherent flow oscillations can either be self-excited ...
The Role of the Centerbody Wake on the Precessing Vortex Core Dynamics of a Swirl Nozzle
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: The precessing vortex core (PVC) phenomenon in swirling jets is a helical instability in the flow driven by the coherent precession of the vortex breakdown bubble (VBB) around the flow axis, resulting in the helical rollup ...
Impact of a Centerbody on the Unsteady Flow Dynamics of a Swirl Nozzle: Intermittency of Precessing Vortex Core Oscillations
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: The precessing vortex core (PVC) is a self-excited flow oscillation state occurring in swirl nozzles. This is caused by the presence of a marginally unstable hydrodynamic helical mode that induces precession of the vortex ...
Hysteresis and Bistability in Transversely Excited Swirling Flows
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: We investigate the effect of transverse acoustic excitation on nonreacting swirling jets. The work is motivated by the azimuthal instabilities in annular gas turbine combustor which are one of the major challenges in ...
Impact of Hydrogen Addition on the Thermoacoustic Instability and Precessing Vortex Core Dynamics in a CH4/H2/Air Technically Premixed Combustor
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: We study the impact of H2 enrichment on the unsteady flow dynamics and thermoacoustic instability in the prediction and control of instabilities in industrial turbines (PRECCINSTA) swirl combustor. The experiments were ...
Impact of Precessing Vortex Core Dynamics on Shear Layer Response in a Swirling Jet
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: Combustion instability, the coupling between flame heat release rate oscillations and combustor acoustics, is a significant issue in the operation of gas turbine combustors. This coupling is often driven by oscillations ...