A semi-analytical model for the prediction of the behavior of turbulent coaxial gaseous jets

Abstract

In diffusion combustion systems, fuel and oxidizer (usually air) are admitted into the combustion chamber separately in the form of turbulent jets. Most often, fuel enters the furnace from a round nozzle and air is admitted through an annulus surrounding the central fuel nozzle. Momentum of the fuel and air jets is utilized for directing the flame and controlling the mixture formation which is typically the rate-limiting step of the combustion process. Hence the behavior of turbulent coaxial jets must be well understood prior to any detailed analysis of these systems. In this study, a set of relations is proposed to predict the behavior of turbulent coaxial gaseous jets using curve-fits to the computational fluid dynamics solutions and the fluid flow governing equations as well as the ideal gas equation of state. A computer program is developed to implement the presented model. Results are compared with existing data and reasonable agreement is observed. According to the results, the presented model makes sufficiently accurate estimates of the flow and concentration fields in a very short time.