On the sensitivity of a helicopter combustor wall temperature to convective and radiative thermal loads

Berger, Sandrine; Richard, Stéphane; Duchaine, Florent; Staffelbach, Gabriel; Gicquel, Laurent

doi:10.1016/j.applthermaleng.2016.04.054

Cited by 30 publications

(45 citation statements)

References 24 publications

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“…Radiation from the gas (H 2 O, CO 2 ) and from the hot walls downstream of the combustion zone is neglected. Furthermore, walls at the same height of the flame holder are assumed to have a temperature close to the fresh gas and to behave as black bodies: T ext = T u = 300 K. This simple coupling strategy has been already used in several studies with good results [12,30] .…”

Section: Coupling Strategymentioning

confidence: 99%

Influence of flame-holder temperature on the acoustic flame transfer functions of a laminar flame

Mejía

Miguel-Brebion

Ghani

et al. 2018

Combustion and Flame

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. a b s t r a c tThe occurrence of combustion instabilities in high-performance engines such as gas turbines is often affected by the thermal state of the engine. For example, strong bursts of pressure fluctuations may occur at cold start for operating conditions that are stable once the engine reaches thermal equilibrium. This observation raises the question of the influence of material temperature on the response of flames to acoustic perturbations. In this study, we assess the influence of the temperature of the flame holder for a laminar flame. Both experiments and numerical simulations show that the Flame Transfer Function (FTF) is strongly affected by the flame-holder temperature. The key factors driving the evolution of the FTF are the flame-root location as well as the modification of the flow, which affects its stability. In the case of the cooled flame-holder, the formation of a recirculation zone is identified as the main impact on the FTF.

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Section: Coupling Strategymentioning

confidence: 99%

Influence of flame-holder temperature on the acoustic flame transfer functions of a laminar flame

Mejía

Miguel-Brebion

Ghani

et al. 2018

Combustion and Flame

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“…• Type 4: Fully coupled LES/heat conduction solver in the combustor walls: the whole combustor solid structure is also meshed and the temperature within the solid structure is computed by a solver coupled with the LES flow solver [17,[33][34][35] .…”

Section: Introductionmentioning

confidence: 99%

“…However, the benefits of going to a type 4 simulation are obvious as shown by Berger et al [35] : the LES becomes fully predictive and does not rely on any ad hoc evaluation of wall temperatures in the solid. For a cooled chamber, the only input data is the cooling water temperature and the convection coefficient in the cooling passages between water and combustor walls.…”

Section: Introductionmentioning

confidence: 99%

Coupling heat transfer and large eddy simulation for combustion instability prediction in a swirl burner

Kraus

Selle

Poinsot

2018

Combustion and Flame

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao. Large eddy simulations (LES) of combustion instabilities are often performed with simplified thermal wall boundary conditions, typically adiabatic walls. However, wall temperatures directly affect the gas temperatures and therefore the sound speed field. They also control the flame itself, its stabilization characteristics and its response to acoustic waves, changing the flame transfer functions (FTFs) of many combustion chambers. This paper presents an example of LES of turbulent flames fully coupled to a heat conduction solver providing the temperature in the combustor walls. LES results obtained with the fully coupled approach are compared to experimental data and to LES performed with adiabatic walls for a swirled turbulent methane/air burner installed at Engler-Bunte-Institute, Karlsruhe Institute of Technology and German Aerospace Center (DLR) in Stuttgart. Results show that the fully coupled approach provides reasonable wall temperature estimations and that heat conduction in the combustor walls strongly affects both the mean state and the unstable modes of the combustor. The unstable thermoacoustic mode observed experimentally at 750 Hz is captured accurately by the coupled simulation but not by the adiabatic one, suggesting that coupling LES with heat conduction solvers within combustor walls may be necessary in other configurations in order to capture flame dynamics.

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“…Thermal efficiency improvement is crucial but limited by the thermal resilience of nozzle guide vanes used in gas turbines (Lefebvre 1999;Facchini et al 2004;Duchaine et al 2009;Berger et al 2016). Moreover, the compactness of future systems is likely to enhance material stresses (Dreizler and Bohm 2015).…”

Section: Introductionmentioning

confidence: 99%

“…The development of new materials that can withstand higher temperatures, raises the need to better understand their behavior in a combustion environment (Padture et al 2002;Hooker and Doorbar 2000). Among others, flame-wall interactions and subsequent heat transfer in a combustor need to be carefully addressed as they can influence pollutant formation (Popp and Baum 1997;Mann et al 2014;Jainski et al 2017), flammability limits (Lakshmisha et al 1991;Lamouroux et al 2014;Xavier et al 2017), flame stability (Guiberti et al 2015;Mercier et al 2016;Berger et al 2016) or combustion instabilities (Tay-Wo-Chong 2013; Mejia et al 2015;Kraus et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Phosphor thermometry on a rotating flame holder for combustion applications

et al. 2018

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao. AbstractThis study presents a method to measure wall temperatures of a rotating flame holder, which could be used as a combustion control device. Laser-induced phosphorescence is found to be a reliable technique to gather such experimental data. The paper first investigates how the coating (thickness, emissivity and lifetime) influence the flame stabilization. While the low thermal conductivity of the coating is estimated to induce a temperature difference of only 0.08-0.4 K, the emissivity increases by 40% . Nevertheless, the transient and steady-state flame locations are not affected. Second, because temperature measurements on the rotating cylinder are likely to fail due the long phosphor lifetimes, we modify the classical point-wise arrangement. We propose to illuminate a larger area, and to correct the signal with a distortion function that accounts for the displacement of the target. An analytical distortion function is derived and compared to measured ones. It shows that the range of measurements is limited by the signal extinction and the rapid distortion function decay. A diagram summarizes the range of operating conditions where measurements are valid. Finally, these experimental data are used to validate direct numerical simulations. Cylinder temperature variations within the precision of these measurements are shown not to influence the flame location, but larger deviations highlight different trends for the two asymmetric flame branches.

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On the sensitivity of a helicopter combustor wall temperature to convective and radiative thermal loads

Cited by 30 publications

References 24 publications

Influence of flame-holder temperature on the acoustic flame transfer functions of a laminar flame

Influence of flame-holder temperature on the acoustic flame transfer functions of a laminar flame

Coupling heat transfer and large eddy simulation for combustion instability prediction in a swirl burner

Phosphor thermometry on a rotating flame holder for combustion applications

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