Efficient Numerical Calculation of Evaporating Sprays in Combustion Chamber Flows

Representing two different conceptual approaches, either Eulerian continuum models or Lagrangian particle models are commonly applied for the numerical description of dispersed two phase flows. Taking advantage of the positive features inherent to each model, a combination approach is presented in this study for the efficient computation of liquid fuel sprays in combustor flows. In the preconditioning stage, Eulerian transport equations for gas phase and droplet phase are solved simultaneously in a block-iterative scheme based on a coarse discretization of spray boundary conditions at the nozzle. Due to the close coupling of both phases, the time expense of this approximate flow field computation is not much higher as for single phase flows. In the refinement stage, Lagrangian droplet tracking is applied with a detailed discretization of initial conditions. To account for complete interaction between gas phase and droplets, gas flow solution and droplet tracking are concatenated by an iterative procedure. In this stage, the numerical description of the spray is enhanced by additional modeling of droplet breakup. Results of numerical simulations are compared with measurements of the two phase flow in a premix duct of a LPP research combustor.

[1]  B. Launder,et al.  The numerical computation of turbulent flows , 1990 .

[2]  Dragoslav Milojevié.  Lagrangian Stochastic‐Deterministic (LSD) Predictions of Particle Dispersion in Turbulence , 1990 .

[3]  Raymond F. Bishop,et al.  Thermo-fluid Dynamic Theory of Two-Phase Flow , 1975 .

[4]  R. Schmehl,et al.  A New Eulerian Model for Turbulent Evaporating Sprays in Recirculating Flows , 1993 .

[5]  Suresh K. Aggarwal,et al.  A Review of Droplet Dynamics and Vaporization Modeling for Engineering Calculations , 1994 .

[6]  A. Lefebvre.  Atomization and Sprays , 1988 .

[7]  Clayton T. Crowe,et al.  Review—Numerical Models for Dilute Gas-Particle Flows , 1982 .

[8]  G. Faeth.  Evaporation and combustion of sprays , 1983 .

[9]  J. Lumley,et al.  Some measurements of particle velocity autocorrelation functions in a turbulent flow , 1971, Journal of Fluid Mechanics.

[10]  A. Gosman,et al.  Aspects of Computer Simulation of Liquid-Fueled Combustors , 1983 .

[11]  S. Wittig,et al.  Computation of turbulent evaporating sprays: Eulerian versus Lagrangian approach , 1993 .

[12]  W. Sirignano.  Fuel droplet vaporization and spray combustion theory , 1983 .

[13]  H. C. Simmons.  The Correlation of Drop-Size Distributions in Fuel Nozzle Sprays—Part I: The Drop-Size/Volume-Fraction Distribution , 1976 .

[14]  R. Schmehl,et al.  CFD Analysis of Spray Propagation and Evaporation Including Wall Film Formation and Spray/Film Interactions , 1999 .

[15]  M. Pilch,et al.  Use of breakup time data and velocity history data to predict the maximum size of stable fragments for acceleration-induced breakup of a liquid drop , 1987 .

[16]  W. K. Melville,et al.  A model of the two-phase turbulent jet , 1979 .

[17]  W. Sirignano,et al.  Droplet vaporization model for spray combustion calculations , 1989 .

[18]  Rolf D. Reitz,et al.  MODELING ATOMIZATION PROCESSES OF PRESSURE-SWIRL HOLLOW-CONE FUEL SPRAYS , 1997 .

[19]  S. Wittig,et al.  Validation and application of a droplet evaporation model for real aviation fuel , 1999 .

[20]  Gerard M. Faeth,et al.  Near-limit drop deformation and secondary breakup , 1992 .

[21]  Stefan A. Krzeczkowski,et al.  MEASUREMENT OF LIQUID DROPLET DISINTEGRATION MECHANISMS , 1980 .