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The reactants are generally injected into the industrial furnaces by jets. An effective method to act on combustion in such systems is to control the way injection jets. The present study concerns the control of an air-flow generated through a coaxial burner. The effects of passive control on a turbulent flow were investigated experimentally. The principal idea consists in adding small obstacles on the outlet side of the burner’s annular jet with an aim of increasing the turbulence intensity in the vicinity close to the edge of injection and of having an act on the central flow. The objective of this study consists to study of a swirling flow in a circular pipe and conceiving of a control system significantly improving the mixture on a non-reactive flow in order to apply it to a reactive situation. The various profiles speed for various values of the air-flow injected into the annular tube will be presented in order to propose the effectiveness of our inspecting device in terms of improvement of the mixture between the two jets as well as the mixture with the ambient air. The particle image velocimetry technique has been used to characterize the dynamic field. Results show that the control by adding small obstacles has a considerable effect on the dynamic behavior. [ABSTRACT FROM AUTHOR]

A Lagrangian-Eulerian model for the dispersion of solid particles in sudden-expansion flows is reported and validated. The fluid was calculated based on the Eulerian approach by solving the Navier-Stokes equations. A Lagrangian model is also applied, using a Runge-Kutta method to obtain the particle trajectories. The effect of fluid turbulence upon particle dispersion is taken into consideration through a statistical model. The predicted axial mean velocity and turbulent kinetic energy of both phases agree well with experimental data reported by Sommerfield. [ABSTRACT FROM AUTHOR]

This paper deals with a numerical analysis of the evaporation of a thin binary liquid film by forced convection inside a channel constituted by two parallel plates. The first plate is externally insulated and wetted by a thin water ethylene glycol film while the second is dry and isothermal. The liquid mixture consists of water (the more volatile component) and ethylene glycol while the gas mixture has three components: dry air, water vapour and ethyleneglycol vapour. The set of non linear and coupled equations expressing the conservation of mass, momentum, energy, and species in the liquid and gas mixtures is solved numerically using a finite difference method. Results concerns with the effects of inlet ambience conditions and the inlet liquid concentration of ethylene glycol on the distribution of the temperature, concentrations profiles, and the axial variation of the evaporation rate of species i. [ABSTRACT FROM AUTHOR]