Numerical investigation of turbulent coaxial jets through gradual enlargements and contractions

Abstract

Turbulent flow field calculations for confined coaxial streams are presented. The cases of gradual duct enlargement and contraction are analyzed. Turbulence is handled with the standard k-ε model. A marching-forward numerical integration technique is used to sweep the computational domain. Within contractions, turbulence is damped, whereas in expansions the valued of k is increased. Also, general turbulence kinetic energy levels are greater when the internal jet is faster than the annular stream.