Studying the Hydrodynamics of Air Flow in the Fuel Combustion System of a Jet-Recess Type

Abstract

The purpose of this scientific paper is to improve the startup characteristics of jet-recess system (JRS) by changing its configuration after the analysis of the hydrodynamic structure of flow. A change in the configuration of recess cavity covers a change of its rectangular shape for the trapezoidal shape with further establishment of the so-called ²flow structurator² represented by the flat apron above the recess in the front wall. The flow structure, in particular velocity profiles averaged in time and their pulsations were measured experimentally using the heat loss anemometer-based technology in isothermal conditions in the air channel provided that the recess is available. The experimental data are given for the distributions of average velocities and their pulsations in the central part of recess cavity. The experiment was carried out in the range of Reynolds numbers of 23∙10 3 to 84∙10 3 . An equivalent channel diameter of the burner was used as a defining dimension in the Reynolds number and the flow velocity in the central part of burner channel was used as a defining velocity. The JRS startup analysis during the combustion showed a certain decrease in startup and stalling fuel consumptions in conditions of a changed geometry of recess cavity. Thus, we can state that the use of ²flow structurator² allows us on the whole to improve JRS startup properties due to the flow structure transformation and somewhat decrease the turbulence intensity in the recess. Such a transformation allows us to shift the fuel combustion mechanism towards a higher diffusibility of process.