Numerische Berechnung von Verbrennungslärm

  • Ansprechpartner:

    Dr.-Ing. Feichi Zhang

  • Projektgruppe:

    Prof. Dr.-Ing. D. Trimis

Numerische Berechnung von Verbrennungslärm

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Bisherige Arbeiten zur VOF-Simulation der Primärzerstäubung durch den ehemaligen Kollegen Thomas Müller

Video Gallerie

 

» Large Eddy Simulation (LES) turbulenter Verbrennung

  • Turbulente Strömung und Flammenausbreitung durch 8 rotierende Ventilatoren innerhalb des Explosionsbehälters unter erhöhten Druckbedingungen

 

Geometry and computational mesh with 8 rotating fans and local refinement
 

Grid of the ventilator surface and a slice across the fan

 

LES of turbulent flow generated by rotating ventilators

 

Contours of velocity and vorticity on a slice across the rotating fan.

 

Velocity (top) and vorticity (bottom) fields calculated by LES with moving fans at different pressure conditions: 1 bar (left), 2 bar (middle) and 5 bar (right). Increasing pressure leads to generation of smaller turbulence structures.

 

LES of ignition process of a methane/air mixture at ϕ = 0.9 and T0 = 300 K under turbulent flow conditions generated by rotating fans (5000 rpm) within the bomb vessel at different pressures: 1 bar (left) and 2 bar (right)

 

Time evolution of 3D flame surfaces (top) and 2D contours of temperature (bottom) by LES of ignition of a methane/air mixture at 1 bar (left), 2 bar (middle) and 5 bar (right).

 
  • Lean-premixed, highly turbulent natural gas/air combustion at preheated condition (Matrix Flame)

Overall simulation illustrated by contours of temperature and axial flow velocity : non-reactive flow → ignition → flame propagation → Extinction

 

Contours of axial velocity and vorticity illustrating strong turbulent inflow generated at the inlet boundary and its interaction with the flame front

 

Effect of the inflow turbulence on the flame length: LES without (left) and with (right) prescribed turbulence at inlet

Streamwise velocity used at the inlet boundary
 
  • Partially premixed methane/air combustion in a vitiated coflow (Cabra Flame)

Overall simulation : mixing of cold main jet with hot coflow → ignition → Stabilization at lift-off height. From left to right are contours of streamwise velocity, mixture fraction, temperature, mass fraction of OH and reaction progress variable

 
  • Non-premixed H2/air combustion (Sandia H3 Flame)

Flame surface is illustrated by the iso-contour of stoichiometric mixture fraction; horizontal line indicates measured length of flame

 

  • Magere vorgemischte Erdgas-Luft-Verbrennung, stabilisiert durch einen doppelt konzentrischen Drallbrenner (GCN)

    • Bender, C. and Büchner, H. (2005): Noise emissions from a premixed swirl combustor, Twelfth International Congress on Sound and Vibration, Lisbon.
    • Habisreuther, P., Bender, C., Petsch, O., Büchner, H. and Bockhorn, H. (2006): Prediction of pressure oscillations in a premixed swirl combustor flow and comparison to measurements, Flow Turb. Comb.77, 147-160.

Swirl-stabilized combustion with a recessed pilot lance & without confinement. From left to right and top to bottom are contours of streamwise velocity, vorticity, temperature and progress variable. The inner recirculation zone moves back and forth into the burner

 

Isoterm of T = 1500 K and iso-contour of u = - 1 m/s

 

Swirl-stabilized combustion with a planar pilot lance and a combustion chamber, other boundary conditions are remained the same

 

  • DTBP Auftriebsflamme in Einfach- und Mehrfachanordnung (Poolflamme)

     

Development of a DTBP buoyant flame in single pool arrangement: from left to right are contours of streamwise velocity, mixture fraction, temperature and reaction progress variable

 

Iso-surface of reaction rate and temperature

 

DTBP pool flame in multiple arrangement. Merging of single pool flames to a large fire

 

  • Vorgemischte Erdgas-/Luftstrahlflamme, die mit einem generischen Brenner betrieben wird

     

Moderately turbulent partially-premixed flame with generation of large coherent flow structures which interact with the flame: from left to right are contours of temperature, heat release rate, reaction rate and mass fraction of chemiluminescent OH∗ species

 

Isoterm of T = 500 K: evolution of the flame with the coherent vortices leads to formation of a hazelnut-shaped structure of the flame surface

 

» Direkte numerische Simulation (DNS) der Verbrennung

  • Ungespannte planare vorgemischte Flammen (1D)

Freely propagating methane/air flame: ϕ = 1.0, T0 = 300 K, p0 = 1 atm. The flame is ignited by a heating source within the domain. The result has shown a good agreement with the computational data obtained with the commercial code Chemkin.

  • Instationäre/oszillierende gestreckte Flammen (2D)

 

 
 

Harmonically excited plane-jet hydrogen/air flames with different frequencies and the same amplitude: ϕ = 0.5, unstable region with Le<1, Ma<0. The flame responds faster to the unsteady flow at low frequencies and tends to form instabilities at higher frequencies. At very high frequencies the flame's response is attenuated again.

 

Harmonically excited hydrogen/air flames with different frequencies and the same amplitude: ϕ = 0.8, neutral range with Le ≈ 1, Ma ≈ 0.

 

 

 

Harmonically excited hydrogen/air flames with different frequencies and the same amplitude: ϕ = 6.5, stable range with Le > 1, Ma > 0.

 

  • Sphärische Flammenausbreitung in einem geschlossenen Bombenschiff (3D)

     

DNS of spherically expanding H2/air flame at ϕ = 0.4 fora 3D grid with 144 million grid cells, the flame surface becomes unstable at large flame radii due to thermo-diffusive instability (Le<1). The DNS has been run in parallel with 8192 CPU cores on the Cray-XC40 platform from HLRS.

 

Isoterm of T = 1100 K showing collapse of the spherical flame surface into unstable, cellular structure.

 

Vector-plots of velocity field generated by the spherically expanding flame.

 

Contours of heat release rate: DNS of spherical propagating flame with a dynamically refined mesh.

 

  • Synthetische Methan-/Luftflammen bei unterschiedlichen Turbulenzbedingungen (3D)

     

Synthetical flame front subjected to a turbulent inflow. Case I: the flame is convected by the flow to the outside of the computational domain.

 

Interaction of turbulent flow with flame. The flame front is illustrated with isotherm of T = 1500 K and structures of the vortices are depicted by iso-surfaces of the vorticity.

 

Case II: the inflow conditions are adjusted to let the flame propagate within the computational domain. From left to right are cases with different turbulent Reynolds numbers of Ret = 15, 69 and 123. The cubic domain of 1 cm3 has been discretized equidistantly with 64 million finite volumes. The used reaction mechanism for methane/air combustion contains 19 species and 69 elementary reactions.

 

  • DNS eines generischen Brennersystems (3D)

Contours of resolved temperature and heat release rate (left). Comparison of contours of heat release rate and OH* mass fraction (right).

 
 
 

Zoomed flame tip region showing resolution of the flame front by the DNS
 
 

» Acoustic modeling

  • Komprimierbares DNS des Trompetenflusses

 

 

Temporal evolution of acoustic pressure generated in the trumpet (till 1 m).

 

  • Verbrennungsinstabilitäten durch Wirbelbrenner

     
 

Combustion instabilities caused by Helmholtz resonators, standing waves and vortex shedding.
 
 

Oscillation of temperature and flow fields caused by combustion instability.
 
 

Combustion instability caused by coherent flow structure (left) and helical structures visualized by iso-surface of pressure (right).
 

Aero-acoustic (left) and combustion generated (right) noise sources derived from Lighthill's acoustic analogy.

 

Acoustic sources given by the time derivative of the density.

 

  • Direktes Verbrennungsgeräusch

     
 

Propagation of acoustic waves from a turbulent premixed flame (compressible LES). The wave fronts are indicated by isocontours of the pressure.
 
 
 

Reflection of pressure waves at the opening boundaries in the case of using a small computational domain.
 

Acoustic noise sources derived from compressible LES of turbulent premixed combustion: aero-acoustic (left) and combustion (middle) noise sources obtained from Lighthilll's analogy and acoustic source caused by time fluctuation of heat release (right).

 
 

Publikationen

 
2020

 
2019

 
2018

 
2017

 
2016

  • Feichi Zhang; Thorsten Zirwes; Peter Habisreuther; Henning Bockhorn; Holger Nawroth; Christian Oliver Paschereit; (2016). Vortrag: LES and DNS of Combustion and Combustion Generated Noise. 2nd Colloquium Combustion Dynamics and Noise, Villa Vigoni, Menaggio, Italy, Sept. 19-22,

  • F. Zhang; T. Zirwes; P. Habisreuther; H. Bockhorn; Numerical Simulation of Turbulent Combustion with a Multi-Regional Approach. In High Performance Computing in Science and Engineering ´15, Nagel, Wolfgang E.; Kröner, Dietmar H.; Resch, Michael M. (ed.), Springer International Publishing, Cham, p. 267–280, (doi:10.1007/978-3-319-24633-8_18) 2016.

  • F. Zhang; T. Zirwes; P. Habisreuther; H. Bockhorn; Poster: Identification of Correlation between OH* Chemiluminescence and Heat Release Rate with Direct Numerical Simulation. NIC Symposium 2016, 11-12 February 2016, Forschungszentrum Jülich, 2016.

  • Q. Zhao; F. Zhang; L. Zhang; H. Bockhorn; W. Xu; L. Liu, (2016). Multi-Regional Large Eddy Simulation of Turbulent Combustion. Journal of Propulsion Technology, 37, (2), 324 – 331.(doi:10.13675/j.cnki.tjjs.2016.02.017)

  • Zirwes, T.; Zhang, F.; Habisreuther, P.; Bockhorn, H.; (2016). Vortrag: A DNS Analysis of the Correlation of Heat Release Rate with Chemiluminescence Emissions in Turbulent Combustion. 19th Results and Review Workshop of the HLRS, Stuttgart, Deutschland, 13.–14. Oktober,

  • Zirwes, Thorsten; Zhang, Feichi; Habisreuther, Peter; Bockhorn, Henning; Poster: Flame Response to Unsteady Stretching. 36th International Symposium on Combustion, Seoul, Korea, July 31.-August 5., 36, 2016.

 
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