Entrainment, momentum flux and temperature in vertical free turbulent diffusion flames

Abstract A systematic study has been made of jet spread rate, mass entrainment rate, and momentum growth rate in vertical free turbulent diffusion flames, and general correlations have been developed for predicting these quantities. The principal dimensionless parameter geverning the system behavior is the Richardson ratio which determines the transition between forced and natural convection. There is evidence for a marked change in large eddy structure in this transition; the trend is towards increased large-eddy size and accentuated meandering and break-up of flames in the natural convection limit. The result is a dramatic drop in maximum temperature levels and a large increase in entrainment rate.