Berlin 2005 – wissenschaftliches Programm
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AK: Akustik
AK 5: Thermo- und Strömungsakustik (Sitzungsorganisation: Martin Ochmann und Rafael Piscoya, Berlin)
AK 5.5: Hauptvortrag
Dienstag, 8. März 2005, 14:00–14:30, TU EB222
Determining the sound radiated by combustion by means of the Equivalent Source Method (ESM) and the Boundary Element Method (BEM) — •Rafael Piscoya1, Haike Brick1, Martin Ochmann1, and Peter Költzsch2 — 1TFH-Berlin, University of Applied Sciences — 2Technical University Dresden
Turbulent combustion produces sound that is clearly louder than that of the non reactive flow since the time variations of the heat release are the main sound sources. Those instationary variations can be simulated with the present computational power only near the source, i.e. the acoustic farfield cannot be directly calculated. Hybrid methods, coupling CFD codes and acoustic methods like the acoustic analogy and the linearized Euler equations are used to solve this problem. This research attempts to show that the ESM and the BEM can also be used to determine the sound generated by combustion. These two methods have the advantage that the acoustic quantities must be known only at a surface surrounding the source zone (less data from the CFD simulations is required) and the farfield can be directly computed. The sound power generated from two open diffusion flames have been calculated with both the ESM and the BEM, using the velocity distribution over cylindrical control surfaces computed with a Large Eddy Simulation. Results of the calculations are presented and compared to the measured sound power of the same flames. Good agreement at low frequencies is obtained but the decay of the spectrum at high frequencies has not been reproduced yet. Possibly reasons for the differences and improvements on the calculations will be discussed.