AN EDDY TRANSFER COEFFICIENT MODEL FOR TURBULENT FREE JETS WITH VARIABLE DENSITY

[摘要] References(22)Cited-By(1)A generalized eddy transfer coefficient model has been experimentally obtained for axisymmetric, nonisothermal variable-density jets, the initial density ratio of which ranges from 0.66 to 5.1. The local variation in the dynamic eddy transfer coefficients for momentum and heat has been measured in the developed region: both transfer coefficients on the jet axis are proportional to the square root of the initial density ratio, but are almost independent of the axial distance from the nozzle exit; the transfer coefficients for momentum and a chemical species remain constant in the inner region whereas the transfer coefficient for heat decreases slightly with increasing radial distance; all the transfer coefficients decrease rapidly in the outer region owing to the intermittent entrainment of the quiescent ambient fluid. The present model can perdict local values of the transfer coefficients over the range of initial density ratio from 0.66 to 5.1 if the initial jet condition alone is specified at a nozzle exit.