Broadband Combustion Noise Simulation of the PRECCINSTA Burner Based on Stochastic Sound Sources

Abstract

Combustion noise in the laboratory scale PRECCINSTA (prediction and control of combustion instabilities in industrial gas turbines) burner is simulated with a new, robust, and highly efficient approach for combustion noise prediction. The applied hybrid method FRPM-CN (fast-random particle method for combustion noise prediction) relies on a stochastic, particle-based sound source reconstruction approach. Turbulence statistics from reacting CFD-RANS (computational fluid dynamics–Reynolds-Averaged Navier–Stokes) simulations are used as input for the stochastic method, where turbulence is synthesized based on a first-order Langevin ansatz. Sound propagation is modeled in the time domain with a modified set of linearized Euler equations and monopole sound sources are incorporated as right-hand side forcing of the pressure equation at every timestep of the acoustics simulations. First, the reacting steady-state CFD simulations are compared to experimental data, showing very good agreement. Subsequently, the computational combustion acoustics (CCA) setup is introduced, followed by comparisons of numerical with experimental pressure spectra. It is shown that FRPM-CN accurately captures absolute combustion noise levels without any artificial correction. Benchmark runs show that the computational costs of FRPM-CN are much lower than that of direct simulation approaches. The robustness and reliability of the method is demonstrated with parametric studies regarding source grid refinement, the choice of either RANS or URANS statistics, and the employment of different global reaction mechanisms.

Modelling of combustion acoustics sources and their dynamics in the PRECCINSTA burner test case

“…Consecutively, the PRECCINSTA burner was numerically investigated for a partially premixed operation mode. 50 Good agreement between experiment and CFD simulation was found for flow field and combustion. Experimentally determined sound pressure spectra were well reproduced especially for higher frequencies and the characteristic shape of combustion noise in the encased, swirl stabilized configuration was nicely described.…”

“…The CFD RANS setup was introduced in detail by Grimm et al 50 and will therefore only be sketched here. Different discretisations and reaction mechanisms were tested by Grimm et al 50 and a detailed discussion of results and an opposition with experimental data was provided.…”

“…The CFD RANS setup was introduced in detail by Grimm et al 50 and will therefore only be sketched here. Different discretisations and reaction mechanisms were tested by Grimm et al 50 and a detailed discussion of results and an opposition with experimental data was provided. It was reasoned that the results are in good agreement with experimental data and therefore suitable for the reproduction of sound sources and prediction of measured power spectral densities in the treated model combustor.…”

“…Combustor mid-plane with regions of contribution to the combustion noise source term. Effectively realised target source variance ', evaluated from CFD RANS data and normalised to the maximum value in the inner shear layer ' max 50. CFD: computational fluid dynamics; RANS: Reynolds averaged Navier Stokes.…”

Performance Identification of a Steam Boiler Burner via Acoustic Analysis

“…In this area, the static instability of the plasma arcs [8] and the combustion imbalances in the annulus burners of rotary kiln [9] are studied experimentally for swirl flame. In the case of thermo-acoustic instability [10,11], numerical and experimental methods [12][13][14], experimental flame transfer functions [15,16], large eddy simulations [17,18], fast random particle method [19] and nonlinear network models [20,21] are used. To provide the passive control of thermo-acoustic instability, the slope confinement method is utilized [22].…”