Journal: Journal of Engineering for Gas Turbines and Power

Abbreviation

J. Eng. Gas Turbines Power

Publisher

American Society of Mechanical Engineers

Journal Volumes

ISSN

1528-8919
0742-4795
0022-0825

Description

Filters

Reset filters

Search Results

Publications 1 - 10 of 44
  • Solution of Thermoacoustic Eigenvalue Problems With a Noniterative Method
    Item type: Journal Article
    Buschmann, Philip E.; Mensah, Georg A.; Nicoud, Franck; et al. (2020)
    Journal of Engineering for Gas Turbines and Power
    Gas turbine combustors are prone to undesirable combustion dynamics in the form of thermoacoustic oscillations. Analysis of the stability of thermoacoustic systems in the frequency domain leads to nonlinear eigenvalue problems (NLEVP); here, “nonlinear” refers to the fact that the eigenvalue, the complex oscillation frequency, appears in a nonlinear fashion. In this paper, we employ a noniterative strategy based on contour integration in the complex eigenvalue plane, which returns all eigenvalues inside the contour. An introduction to the technique is given, and is complemented with guidelines for the specific application to thermoacoustic problems. Two prototypical nonlinear eigenvalue problems are considered: a network model of the classical Rijke tube with an analytic flame response model and a finite element discretization of an annular model combustor with an experimental flame transfer function (FTF). Computation of all eigenvalues in a domain of interest is vital to assess stability of these systems. We demonstrate that this is generally challenging for iterative strategies. An eigenvalue solver based on contour integration, in contrast, provides a reliable, noniterative method to achieve this goal.
  • Design Considerations of Rotor Cone Angle for Downwind Wind Turbines
    Item type: Journal Article
    Kress, Chistian; Chokani, Ndaona; Abhari, Reza S. (2016)
    Journal of Engineering for Gas Turbines and Power
  • Linear Growth Rate Estimation from Dynamics and Statistics of Acoustic Signal Envelope in Turbulent Combustors
    Item type: Journal Article
    Noiray, Nicolas (2017)
    Journal of Engineering for Gas Turbines and Power
  • Experimental study of aerodynamic and structural damping in a full-scale rotating turbine
    Item type: Other Conference Item
    Kielb, J.J.; Abhari, Reza S. (2003)
    Journal of Engineering for Gas Turbines and Power
  • Effect of Hydrogen Enrichment on Transfer Matrices of Fully and Technically Premixed Swirled Flames
    Item type: Journal Article
    Blondé, Audrey; Schuermans, Bruno; Pandey, Khushboo; et al. (2023)
    Journal of Engineering for Gas Turbines and Power
    Knowledge of flame responses to acoustic perturbations is of utmost importance to predict thermoacoustic instabilities in gas turbine combustors. However, measuring transfer functions linking acoustic quantities upstream and downstream of flames are very challenging in practical systems and these measurements can significantly deviate from state-of-the-art models. Moreover, there is a lack of studies investigating the effect of hydrogen enrichment on the response of natural gas (NG) flames. In this work, measurements of flame transfer matrices (FTMs) of turbulent H2/NG flames in an atmospheric combustor featuring an axial swirler burner have been performed, allowing us to unravel the transition between FTM in fully premixed (FP) and in technically premixed (TP) conditions. Furthermore, imaging of OH* chemiluminescence and OH-planar laser induced fluorescence are obtained for characterizing the topology of the flame for varying H2 fraction and mixing conditions. Transfer matrices are measured using the multimicrophone method for H2 fractions ranging from 12% to 43% in power. Afterward, the flame transfer functions (FTFs), which linearly relate the coherent fluctuations of the heat release rate to the acoustic velocity oscillations, are obtained from the FTM by using the Rankine-Hugoniot jump conditions across the flame. Using the OH* chemiluminescence intensity as a surrogate for the heat release rate, the FTF based on this optical measurement is also extracted and compared to the one exclusively obtained with the multimicrophone method. As expected, the two different methods are in very good agreement for the FP case and significantly differ for the TP case. Indeed, chemiluminescence fluctuations cannot be directly linked to heat release rate fluctuations when the acoustic forcing induces equivalence ratio fluctuations at the flame, making the optical method unusable for TP configurations. We also show that the two methods agree in the high end of the explored excitation frequency range and we provide an explanation to this intriguing finding. Moreover, we investigate the sensitivity of the FTM measurement to the estimate of the speed of sound in the rig in FP conditions. Finally, the measured FTFs are fitted with FTF models based on multiple distributed time delays. This allows us to explain the frequency dependence and the hydrogen fraction dependence of the gain and the phase in FP and TP conditions.
  • Seven-Sensor Fast-Response Probe for Full-Scale Wind Turbine Flowfield Measurements
    Item type: Journal Article
    Mansour, Michel; Kocer, Gulru; Lenherr, Christian; et al. (2011)
    Journal of Engineering for Gas Turbines and Power
  • Experimental Study on Impeller Blade Vibration During Resonance
    Item type: Journal Article
    Kammerer, Albert; Abhari, Reza S. (2009)
    Journal of Engineering for Gas Turbines and Power
  • Using Hydrogen as Gas Turbine Fuel
    Item type: Journal Article
    Gazzani, Matteo; Chiesa, Paolo; Martelli, Emanuele; et al. (2014)
    Journal of Engineering for Gas Turbines and Power
  • Unsteady Flow Field and Coarse Droplet Measurements in the Last Stage of a Low-Pressure Steam Turbine With Supersonic Airfoils Near the Blade Tip
    Item type: Journal Article
    Bosdas, Ilias; Mansour, Michel; Kalfas, Anestis I.; et al. (2017)
    Journal of Engineering for Gas Turbines and Power
  • Flame Dynamics Intermittency in the Bistable Region Near a Subcritical Hopf Bifurcation
    Item type: Journal Article
    Ebi, Dominik; Denisov, Alexey; Bonciolini, Giacomo; et al. (2018)
    Journal of Engineering for Gas Turbines and Power
Publications 1 - 10 of 44