Effects of Nonlinear Modal Interactions on the Thermoacoustic Stability of Annular Combustors

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Alessandro Orchini ◽  
Georg A. Mensah ◽  
Jonas P. Moeck
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Network Model ◽  
Rotational Symmetry ◽  
Stability Criteria ◽  
Describing Function ◽  
Modal Interactions ◽  
Dynamical Features ◽  
Theoretical And Numerical Analysis ◽  
Flame Describing Function

In this theoretical and numerical analysis, a low-order network model is used to investigate a thermoacoustic system with discrete rotational symmetry. Its geometry resembles that of the MICCA combustor (Laboratoire EM2C, CentraleSupelec); the flame describing function (FDF) employed in the analysis is that of a single-burner configuration and is taken from experimental data reported in the literature. We show how most of the dynamical features observed in the MICCA experiment, including the so-called slanted mode, can be predicted within this framework, when the interaction between a longitudinal and an azimuthal thermoacoustic mode is considered. We show how these solutions relate to the symmetries contained in the equations that model the system. We also discuss how considering situations in which two modes are linearly unstable compromises the applicability of stability criteria available in the literature.

Effects of Nonlinear Modal Interactions on the Thermoacoustic Stability of Annular Combustors

2018 ◽  
Author(s):  
Alessandro Orchini ◽  
Georg A. Mensah ◽  
Jonas P. Moeck
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Network Model ◽  
Rotational Symmetry ◽  
Stability Criteria ◽  
Modal Interactions ◽  
Dynamical Features ◽  
Theoretical And Numerical Analysis ◽  
Low Order

In this theoretical and numerical analysis, a low-order network model is used to investigate a thermoacoustic system with discrete rotational symmetry. Its geometry resembles that of the MICCA combustor; the FDF employed in the analysis is that of a single-burner configuration, and is taken from experimental data reported in the literature. We show how most of the dynamical features observed in the MICCA experiment, including the so-called slanted mode, can be predicted within this framework, when the interaction between a longitudinal and an azimuthal thermoacoustic mode is considered. We show how these solutions relate to the symmetries contained in the equations that model the system. We also discuss how considering situations in which two modes are linearly unstable compromises the applicability of stability criteria available in the literature.

scholarly journals Theoretical and numerical analysis of the evaporation of mono- and multicomponent single fuel droplets

2021 ◽  
Vol 910 ◽  
Author(s):  
Alejandro Millán-Merino ◽  
Eduardo Fernández-Tarrazo ◽  
Mario Sánchez-Sanz
Keyword(s):  
Numerical Analysis ◽  
Fuel Droplets ◽  
Theoretical And Numerical Analysis

Abstract

scholarly journals Theoretical and numerical analysis of novel COVID-19 via fractional order mathematical model

2021 ◽  
Vol 20 ◽  
pp. 103676
Author(s):  
Amjad Ali ◽  
Muhammad Yasin Khan ◽  
Muhammad Sinan ◽  
F.M. Allehiany ◽  
Emad E. Mahmoud ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Numerical Analysis ◽  
Fractional Order ◽  
Theoretical And Numerical Analysis

Dose-window dependence on Si crystal orientation in separation by implanted oxygen substrate formation

2004 ◽  
Vol 19 (12) ◽  
pp. 3607-3613 ◽  
Author(s):  
H. Iikawa ◽  
M. Nakao ◽  
K. Izumi
Keyword(s):  
Experimental Data ◽  
Numerical Analysis ◽  
Crystal Orientation ◽  
Oxygen Ion ◽  
The Difference ◽  
First Time ◽  
Good Agreement

Separation by implemented oxygen (SIMOX)(111) substrates have been formed by oxygen-ion (16O+) implantation into Si(111), showing that a so-called “dose-window” at 16O+-implantation into Si differs from Si(100) to Si(111). In SIMOX(100), an oxygen dose of 4 × 1017/cm2 into Si(100) is widely recognized as the dose-window when the acceleration energy is 180 keV. For the first time, our work shows that an oxygen dose of 5 × 1017/cm2 into Si(111) is the dose-window for the formation of SIMOX(111) substrates when the acceleration energy is 180 keV. The difference between dose-windows is caused by anisotropy of the crystal orientation during growth of the faceted buried SiO2. We also numerically analyzed the data at different oxidation velocities for each facet of the polyhedral SiO2 islands. Numerical analysis results show good agreement with the experimental data.

Identification of the Flame Describing Function of a Premixed Swirl Flame from LES

2012 ◽  
Vol 184 (7-8) ◽  
pp. 888-900 ◽  
Author(s):  
H. J. Krediet ◽  
C. H. Beck ◽  
W. Krebs ◽  
S. Schimek ◽  
C. O. Paschereit ◽  
...  
Keyword(s):  
Describing Function ◽  
Flame Describing Function ◽  
Swirl Flame
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