Timeaveraged and timedependent computations of isothermal flowfields in a centerbody combustor
Abstract
A numerical investigation of the nearwake region in a ducted bluffbody combustor by finitedifference computations is reported. The numerical predictions are based upon: (1) the Reynoldsaveraged Navier Stokes equations and the kepsilon turbulence model; and (2) the timedependent, compressible NavierStokes equations, The standard Kepsilon turbulence model was modified to account for the effect of streamline curvature and for the preferential influence of normal stresses. The timeaveraged calculations addressed the turbulent mixing under isothermal conditions in: (1) the large and smallscale centerbody combustor configurations, due to annular air flow and central CO2 flow; and (2) the twodimensional mixinglayer configuration, due to two streams of nitrogen at different velocities. The timedependent calculations addressed the nearwake flowfield of the largescale centerbody combustor configuration with only the annular air stream present. The Reynoldsaveraged predictions examined the influence of the turbulence model corrections and geometric scale under varying annular and central flows on: (1) the axial and radial distributions of the mean and fluctuating components of the axial and radial velocities and of the mean CO2 concentrations; and (2) the axial and the radial locations of the vortex center, as well as the magnitude and location of the minimum centerline mean axial velocity. Comparison of the predicted results with experimental data emphasizes and clarifies the complex flowfield interactions of the recirculating nearwake region.
 Publication:

Final Report
 Pub Date:
 December 1984
 Bibcode:
 1984dayu.reptR....K
 Keywords:

 Combustion Chambers;
 Ducted Bodies;
 Mathematical Models;
 Numerical Analysis;
 Prediction Analysis Techniques;
 Two Dimensional Flow;
 Annular Flow;
 Carbon Dioxide;
 Centerbodies;
 Compressible Flow;
 Finite Difference Theory;
 Flow Distribution;
 Isotherms;
 KEpsilon Turbulence Model;
 Mixing Layers (Fluids);
 NavierStokes Equation;
 Nitrogen;
 Stress Analysis;
 Time Dependence;
 Turbulent Flow;
 Wakes;
 Fluid Mechanics and Heat Transfer