On the calculation of heat, mass and momentum transport in coaxial jets and mixing layers

Abstract

This communication deals with the determination of mass, momentum and heat transport in turbulent mixing layers and with the determination of momentum transport in concentric round jets. Mixing length, k/ϵ and k/ω models are employed in the calculations. The constants appearing in these models are evaluated to yield the correct spreading rate, mean axial velocity, concentration and temperature profiles. A single-point probability density function (pdf) has been employed to calculate heat and mass transport in mixing layers. It is shown that the concentric jet mean velocity profiles are accurately predicted if the constants multiplying the production terms in the ϵ − and ω − equation have values of 1.52 and 1.50. These constants have to be taken equal to 1.44 and 3.80 for mixing layers. The calculated turbulent Schmidt/Prandtl number is 0.70 for mixing layers.