Distance effect on the behavior of an impinging swirling jet by PIV and flow visualizations

Impingement pressure characteristics of swirling and non-swirling turbulent jets

“…Apart from experimental investigations into the surface pressure distribution of annular swirling jets [27,28], which impose fundamentally different flow behaviour due to multiple shear layers, there is little data for pressure distributions of turbulent swirling jets. Most swirling impinging jet studies largely deal with the mean and turbulent velocity characteristics upstream of the impingement surface [16,[29][30][31][32][33]. These studies reveal that the formation of flow recirculation between the nozzle exit and the impingement surface depends on the swirl number (0.3 6 S 6 0.5) and the impingement distance (H = 2D-6D).…”

“…The emerging axial flow then enters section T, which introduces the swirling motion via three tangential ports of 12 mm diameter. Aerodynamic swirl generation helps avoid trailing vortices from radial vanes [33] and allow a seamless transition from non-swirling to swirling jet flows. In addition, this technique avoids the complications arising from dead (central) ribs associated with geometrical swirl generation [16,27].…”

Heat Transfer Characteristics of Swirling Impinging Jets

“…In th e case of Felh et al [90], as th e fluid im pinges against a wall th e flow spreads out from th e sta g n a tio n area creatin g an area of near-zero velocity, an exam ple of which is show n in figure 2.47. T his is consistent w ith th e findings of H uang and E l-G enk [73], N ozaki et al [79] and Senda et al [71].…”

“…T h e use of P IV to explore sw irling je ts has been used by Felli et al [90] w ith w ater as th e w orking fluid and B u ra ttin i et al [91] w ith air as th e w orking fluid. B o th studies display a region aro u n d th e cen tral axis of th e sw irling je t w ith near-zero axial velocity, sim ilar to th e results seen by M aciel et al [85] in flgure 2.40.…”

Caractérisation thermique d’un multijet tourbillonnaire en mode confiné avec et sans obstacle

“…La plupart des travaux effectués sur les jets confinés sont orientés vers les chambres de combustion des moteurs, des réacteurs nucléaires et des brûleurs afin d'obtenir un mélange homogène entre carburant et comburant, mais aussi dans les cas d'études des risques inhérents aux incendies en milieu confiné et le contrôle des mouvements de masses gazeuses (contrôle des écoulements de fumées) dans les incendies en espaces semi-confinés [1,2,3], Le soufflage par des buses, a diffusion tourbillonnaire, est l'un des meilleurs moyens passifs de mise en oeuvre pratique du contrôle de l'écoulement d'air. Ces diffuseurs induisent une amélioration du confort thermique, conduisant ainsi à une économie d'énergie [4].…”