Numerical investigation of combustion noise from aeronautical combustor to far-field

Author(s):  
Mélissa Férand ◽  
Thomas Livebardon ◽  
Stephane Moreau ◽  
Thierry Poinsot ◽  
Claude Sensiau
Acoustics ◽  
2019 ◽  
Vol 1 (1) ◽  
pp. 174-198 ◽  
Author(s):  
Mélissa Férand ◽  
Thomas Livebardon ◽  
Stéphane Moreau ◽  
Marlène Sanjosé

A hybrid methodology combining a detailed Large Eddy Simulation of a combustion chamber sector, an analytical propagation model of the extracted acoustic and entropy waves at the combustor exit through the turbine stages, and a far-field acoustic propagation through a variable exhaust temperature field was shown to predict far-field combustion noise from helicopter and aircraft propulsion systems accurately for the first time. For the single-stream turboshaft engine, the validation was achieved from engine core to the turbine exit. Propagation to the far field was then performed through a modeled axisymmetric jet. Its temperature modified the acoustic propagation of combustion noise significantly and a simple analytical model based on the Snell–Descarte law was shown to predict the directivity for axisymmetric single jet exhaust accurately. Good agreement with measured far-field spectra for all turboshaft-engine regimes below 2 kHz stresses that combustion noise is most likely the dominant noise source at low frequencies in such engines. For the more complex dual-stream turbofan engine, two regime computations showed that direct noise is mostly generated by the unsteady flame dynamics and the indirect combustion noise by the temperature stratification induced by the dilution holes in the combustion chamber, as found previously in the turboshaft case. However, in the turboengine, direct noise was found dominant at the combustor exit for the low power case and equivalent contributions of both combustion noise sources for the high power case. The propagation to the far-field was achieved through the temperature field provided by a Reynolds-Averaged Navier–Stokes simulation. Good agreement with measured spectra was also found at low frequencies for the low power turboengine case. At high power, however, turboengine jet noise overcomes combustion noise at low frequencies.


2012 ◽  
Vol 472-475 ◽  
pp. 1528-1531
Author(s):  
Tie Min Xuan ◽  
Zhi Xia He ◽  
Zhao Chen Jiang ◽  
Yi Yan

Numerical Investigation of Effect Pilot Injection on Combustion Noise and Exhaust Emission of Diesel Engine The traditional mechanical fuel supply system has already been no way to satisfy the requirement of more stringent fuel consumption and emission legislation. For the past few years, it has been a hot topic to improve performance of diesel engine combustion and emission through optimizing the fuel injection strategy. All kinds of spray, combustion and emission models were studied and then the numerical models for the single-injection combustion of 1015 diesel engine were setup and validated through comparing with results from experimental data. With the above verified models, different injection strategies were further investigated to get the effect mechanism of pilot injection (PI) timing and quantity on combustion noise and exhaust emission.


Author(s):  
César Becerril ◽  
Stéphane Moreau ◽  
Michael Bauerheim ◽  
Laurent Gicquel ◽  
Thierry Poinsot

Author(s):  
Anton Rossikhin ◽  
Sergey Pankov ◽  
Victor Mileshin

The results of the first booster stage tone noise numerical investigation for a model of low pressure compressor are presented. The investigation was performed using the frequency domain numerical method of multistage turbomachines tone noise simulation, developed in CIAM (Central Institute of Aviation Motors) and implemented in the 3DAS (3 Dimensional Acoustics Solver) in-house solver. The model under consideration included high bypass ratio fan, stator, booster and bypass duct. Calculation was performed at the approach operating conditions. Far field directivities for two tones in the forward hemisphere were obtained. One tone corresponded to the blade passing frequency of the first stage rotor, the other - to the sum of this frequency with the blade passing frequency of the fan. The results of the computation were compared with the experimental data obtained in the CIAM C-3A acoustic test facility. In general satisfactory correspondence between calculation and experiment was obtained.


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