Computing combustion noise by combining large eddy simulations with analytical models for the propagation of waves through turbine blades

Abstract

Two mechanisms control combustion noise generation as shown by Marble and Candel [1]: direct noise, in which acoustic waves propagate through the turbine stages and indirect noise, in which vorticity and/or entropy waves generate noise as they are convected through turbine stages. A method to calculate combustion-generated noise has been implemented in a tool called CHORUS. The method uses the Large eddy simulations of the combustion chamber obtained with the unstructured solver AVBP developed at CERFACS [2] and analytical models for the propagation through turbine stages. The propagation models [3] use the compact row hypothesis to write matching conditions between the inlet and the outlet of a turbine stage. Using numerical simulations, the validity of the analytical methods is studied and the errors made quantified. Résumé Méthode de calcul du bruit de combustion combinant des simulations aux grandeséchelles avec des méthodes analytiques pour la propagation des ondesà travers lesétages de turbine. Deux mécanismes sont responsables de la génération de bruit de combustion : le bruit direct, dans lequel les ondes acoustiques se propagentà travers lesétages de la turbine et le bruit indirect, dans lequel les ondes de vorticité ou entropiques génèrent du bruit quand elles sont convectées. Une méthode pour calculer le bruit de combustion aété mise en place dans l'outil CHORUS. La méthode utilise des simulations aux grandeséchelles (LES) pour la chambre de combustion, avec le code AVBP developpé au CERFACS [2], et des méthodes analytiques pour la propagation des ondesà travers lesétages de la turbine. Le modèle est validé avec des simulations numériques.

Numerical investigation of combustion noise generation in a full annular combustion chamber

“…23,7,8,24,25 In a blade-to-blade plane, the flow is considered two-dimensional, inviscid and isentropic. Using this compact assumption, conservation equations through the rows are linearised and expressed in terms of the fluctuations.…”

A nonlinear model for indirect combustion noise through a compact nozzle

“…The subsonic configuration has been reproduced numerically by Mühlbauer et al (2009), Giauque et al (2012) and Durán, Moreau & Poinsot (2013b) and has also been investigated analytically by Howe (2010). Dealing with the turbine configuration, Leyko et al (2010), Durán et al (2013a) and Mishra & Bodony (2013) numerically investigated the actuator disk theory by comparing two-dimensional simulations with the analytical model of Cumpsty & Marble (1977) in the presence of small amplitude entropy perturbations. Leyko et al and Durán et al conducted LES of an isolated blade row and separate stator vane and rotor blade, respectively, while Mishra and Bodony performed Euler simulations of a flow past a realistic stator stage.…”

Numerical Prediction of Far-Field Combustion Noise from Aeronautical Engines

“…Future aeroengines must be designed to limit cruising speed consumption, pollutant emissions and noise at landing and takeoff phases. With the development of new low NOx-emission combustion chambers, such as lean premixed, rich-quench-lean or staged-injection combustion chambers, combustion noise is becoming a significant contributor to the overall aircraft noise and, therefore, the focus of many recent studies [1][2][3][4][5][6]. The latter show that two mechanisms creating combustion noise must be distinguished: direct and indirect noise.…”

“…Although stators and rotors are assumed compact, these travel times between rotors and stators make the formulation frequency dependent. The limits of validations of this model have been assessed for a stator and a stator-rotor (stage) case [1,22,25,41,42]. Using fully unsteady simulations with AVBP, Leyko et al, Duran et al and Bauerheim et al showed that the planar entropy wave is not conserved through a row [22,25,41]: turbulent mixing, combined with the acceleration and deviation induced by the turbine blades, leads to a scattering of planar entropy waves through each passage so that energy is redistributed into other azimuthal modes [20,22].…”