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RISAdjoint Methods as Design Tools in Thermoacoustics
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: In a thermoacoustic system, such as a flame in a combustor, heat release oscillations couple with acoustic pressure oscillations. If the heat release is sufficiently in phase with the pressure, these oscillations can grow, ...
Adjoint Methods as Design Tools in Thermoacoustics
Publisher: American Society of Mechanical Engineers (ASME)
Abstract: In a thermoacoustic system, such as a flame in a combustor, heat release oscillations couple with acoustic pressure oscillations. If the heat release is sufficiently in phase with the pressure, these oscillations can grow, ...
A Hybrid Adjoint Network Model for Thermoacoustic Optimization
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: A method is proposed that allows the computation of the continuous adjoint of a thermoacoustic network model based on the discretized direct equations. This hybrid approach exploits the self-adjoint character of the duct ...
A Theoretical Approach for Passive Control of Thermoacoustic Oscillations: Application to Ducted Flames
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: In this paper, we develop a linear technique that predicts how the stability of a thermoacoustic system changes due to the action of a generic passive feedback device or a generic change in the base state. From this, one ...
Effects of Nozzle Helmholtz Number on Indirect Combustion Noise by Compositional Perturbations
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: By modeling a multicomponent gas, a new source of indirect combustion noise is identified, which is named compositional indirect noise. The advection of mixture inhomogeneities exiting the gas-turbine combustion chamber ...
Flow Inhomogeneities in a Realistic Aeronautical Gas-Turbine Combustor: Formation, Evolution, and Indirect Noise
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: Indirect noise generated by the acceleration of combustion inhomogeneities is an important aspect in the design of aero-engines because of its impact on the overall noise emitted by an aircraft and the possible contribution ...
Uncertainty Quantification of Growth Rates of Thermoacoustic Instability by an Adjoint Helmholtz Solver
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: Thermoacoustic instabilities are often calculated with Helmholtz solvers combined with a low-order model for the flame dynamics. Typically, such a formulation leads to an eigenvalue problem in which the eigenvalue appears ...
Methods for the Calculation of Thermoacoustic Stability Boundaries and Monte Carlo-Free Uncertainty Quantification
Publisher: The American Society of Mechanical Engineers (ASME)
Effects of Asymmetry on Thermoacoustic Modes in Annular Combustors: A Higher-Order Perturbation Study
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: Gas-turbine combustion chambers typically consist of nominally identical sectors arranged in a rotationally symmetric pattern. However, in practice, the geometry is not perfectly symmetric. This may be due to design ...
Thermoacoustic Modes of Quasi-One-Dimensional Combustors in the Region of Marginal Stability
Publisher: The American Society of Mechanical Engineers (ASME)
Abstract: It may be generally believed that the thermoacoustic eigenfrequencies of a combustor with fully acoustically reflecting boundary conditions depend on both flame dynamics and geometry of the system. In this work, we show ...