Numerical investigation of effect of aspect ratio of rectangular nozzles

Abstract

In this research the fluid and thermal characteristics of a rectangular turbulent jet flow is studied numerically. The results of three dimensional jet issued from a rectangular nozzle are presented. A numerical method employing control volume approach with collocated grid arrangement was employed. Velocity and pressure fields are coupled with SIMPLEC algorithm. The turbulent stresses are approximated using k-epsiv model with two different inlet conditions. The velocity and temperature fields are presented and the rates of their decay at jet centerline are noted. The velocity vectors of a main flow and secondary flow are illustrated. Also effect of aspect ratio (AR) on mixing in rectangular cross section jets is considered. Investigated AR was among 1:1 to 1:4. The results showed that the jet entrains more with smaller AR. Special attention has been drawn on the influence of the Reynolds number (based on hydraulic diameter) as well as the inflow conditions on the evolution of the rectangular jet. An influence on the jet evolution is found for smaller Re, but the jet is close to a converged state for higher Reynolds numbers. The influence of the inflow conditions on the jet characteristics is so strong.