DOI: 10.1615/TSFP5
JOINT SCALAR VS. JOINT VELOCITY-SCALAR PDF MODELLING OF BLUFF-BODY STABILISED FLAMES WITH REDIM
ABSTRAKT
Two transported PDF strategies (joint velocity-scalar and joint scalar PDF) are investigated for bluff-body stabilised turbulent diffusion flames with variable degree of turbulence - chemistry interaction. Chemistry is modeled by the novel REDIM technique. The (secondmoment closure) turbulence model and the (modified Curl's) micromixing model are not varied. Radiative heat loss effects are ignored. The results for mean velocity and turbulent stresses are very similar for both methods. They agree well with experimental data. Each of the two PDF approaches implies a different closure for the velocity-scalar correlation. This leads to differences in the radial profiles in physical space of mean scalars and mixture fraction variance (due to different scalar flux modelling). Differences are visible in mean mixture fraction and mean temperature, as well as in mixture fraction variance. In general, the joint scalar PDF results are in somewhat better agreement with experimental data. In composition space, where results are reported as scatter plots, differences between the two PDF strategies are small in the calculations at hand, with a little more local extinction in the joint scalar PDF results.