Experimental and numerical investigation of the thermal and dynamic behavior of a heated vortex multijet system impacting a flat plate

Abstract

This study concerns the experimental and numerical study of the thermal and dynamic behavior of a configuration of a system of vortex jets impacting a flat plate, The objective of this study is to study the behavior of the thermal and dynamic field of vortex blowing of hot air from a multi-jet system impacting a flat plate. The experimental test bench comprising a support of three diffusers of diameter D, impacting the perpendicular plate. A uniform inlet temperature (T, T, T) is imposed such that the impact height H = 4D. The vortex is obtained by a vortex generator made up of 12 fins arranged at 60° from the vertical, placed just at the outlet of the diffuser. A thermo-anemometer device, to measure the blowing temperature at the point in question. The system was numerically simulated by the fluent code using a k-ε RNG turbulence model. It should be noted that the multi-jet system first appears as a free jet: going from the injection orifice to the impact zone, the axial velocity weakens, the jet undergoes considerable deflection, this is the deflection zone the velocities become mainly radial and the thickness of the boundary layer increases radially: this is the parietal flow zone, the structure of the velocity field has two zones of intense deflection with a wall jet on both sides other, favoring a good development of the resulting jet. The results show that this configuration (T, T, T) gave a better optimized distribution of temperature and velocity on the surface of the plate. This homogenization of the temperatures results from a better thermal transfer of the plate.The k-ε RNG model gave acceptable results, which coincide with those of the experimental results.