Fluid Dynamical Analysis of Atmospheric Reacting and Isothermal Swirling Flows

A series of unconfined swirling premixed natural gas/air flames was investigated. Reynolds-numbers spanned from 10,000 to 42,300. Respective isothermal flows were studied additionally to gain insight into changes of fluid dynamical features caused by combustion. Statistical moments, Reynolds-stresses, temporal time scales, spatial length scales, and power spectral densities were deduced from one- and two-point laser Doppler velocimetry (LDV) data. Properties of the turbulent flows and dependencies on Reynolds-number, swirl number, and chemical reactions are discussed. Most distinct differences between combusting and isothermal flows were precessing vortex cores (PVC) occurring only for the latter cases. The study is aimed to serve as a database of a generic flame geometry featuring important characteristics of industrial applications for validation of numerical simulations. Therefore, nozzle exit profiles as important inlet conditions to numerical simulations are thoroughly documented.

[1]  David F. Fletcher,et al.  Simulation of Turbulent Swirl Flow in an Axisymmetric Sudden Expansion , 2001 .

[2]  W. Rodi,et al.  New biasing elimination method for laser‐Doppler velocimeter counter processing , 1977 .

[3]  János M. Beér,et al.  Combustion in swirling flows: A review , 1974 .

[4]  Steven Begg,et al.  Book review: Laser and phase doppler measurement techniques. By Albrecht, H.-E., Borys, M., Damaschke, N., and Tropea, C. Springer. In the series: Experimental Fluid Mechanics, 2003 , 2005 .

[5]  A. Melling,et al.  Improved laser Doppler anemometry techniques for two-point turbulent flow correlations , 1995 .

[6]  J. Janicka,et al.  Turbulent length scales in a swirling flame , 1996 .

[7]  Simultaneous velocity and scalar measurements in premixed recirculating flames , 1998 .

[8]  T. O’Doherty,et al.  Vortex breakdown: a review , 2001 .

[9]  Turbulent Mixing and Non-gradient Diffusion in Baffle-stabilized Flames , 1995 .

[10]  S. Pope.  Turbulent Flows: FUNDAMENTALS , 2000 .

[11]  H. Eickhoff,et al.  Experimental and numerical study concerning stabilization of strongly swirling premixed and nonpremixed flames , 1992 .

[12]  Laser-Doppler-Messungen von Teilchenbeschleunigungen und der Dissipationsrate in einem runden Freistrahl , 2002 .

[13]  Johannes Janicka,et al.  MIXING ANALYSIS OF A SWIRLING RECIRCULATING FLOW USING DNS AND EXPERIMENTAL DATA , 2006, Proceeding of Fourth International Symposium on Turbulence and Shear Flow Phenomena.

[14]  Norbert Peters,et al.  The detailed flame structure of highly stretched turbulent premixed methane-air flames , 1996 .

[15]  Israel J Wygnanski,et al.  Some measurements in the self-preserving jet , 1969, Journal of Fluid Mechanics.

[16]  C. Carter,et al.  Strain rates measured along the wrinkled flame contour within turbulent non-premixed jet flames , 2001 .

[17]  Friedrich Dinkelacker,et al.  Structure of locally quenched highly turbulent lean premixed Flames , 1998 .

[18]  M. P. Escudier,et al.  Recirculation in swirling flow - A manifestation of vortex breakdown , 1985 .

[19]  F. Gouldin.  An application of fractals to modeling premixed turbulent flames , 1987 .

[20]  A. Lefebvre.  Gas Turbine Combustion , 1983 .

[21]  R. Chanaud.  Observations of oscillatory motion in certain swirling flows , 1965, Journal of Fluid Mechanics.

[22]  R. Borghi.  On the Structure and Morphology of Turbulent Premixed Flames , 1985 .

[23]  Holger Nobach,et al.  Improved estimator for the slotted autocorrelation function of randomly sampled LDA data , 1999 .

[24]  Robert K. Cheng,et al.  Effects of buoyancy on lean premixed V-flames Part I: laminar and turbulent flame structures , 1999 .

[25]  S. Leibovich.  THE STRUCTURE OF VORTEX BREAKDOWN , 1978 .

[26]  Johannes Janicka,et al.  Diagnostic Challenges for Gas Turbine Combustor Model Validation , 2002 .

[27]  John E. Dec,et al.  Time-Resolved Velocities and Turbulence in the Oscillating Flow of a Pulse Combustor Tail Pipe* , 1991 .

[28]  R. Cheng.  Velocity and scalar characteristics of premixed turbulent flames stabilized by weak swirl , 1995 .

[29]  A. Leipertz,et al.  Lifted reaction zones in premixed turbulent bluff-body stabilized flames , 2002 .

[30]  Clemens F. Kaminski,et al.  SPARK IGNITION OF TURBULENT METHANE/AIR MIXTURES REVEALED BY TIME-RESOLVED PLANAR LASER-INDUCED FLUORESCENCE AND DIRECT NUMERICAL SIMULATIONS , 2000 .