Detached eddy simulation of non-reacting swirling flow in a vortex burner

Abstract

An unconfined high turbulent swirling flow is investigated using Detached Eddy Simulation (DES) in a premixed vortex burner. The burner operates with propane-air mixture at high swirl number Sn = 1.05 under atmospheric pressure. In this analysis, the focus of the investigation is the isothermal flow and its expansion at the burner exit. Comparisons of experimental data show that the DES results are capable of predicting the unsteady flow structure and mean velocity profiles. DES results show that the swirling flow is responsible of the formation of a recirculation zone (CRZ) in the center of the burner exit. A helical precessing vortex core (PVC) is detected in the inner shear layer (ISL). Phase-angle analysis of the instantaneous flow field shows the presence of unsteady stagnation points strongly associated with PVC. In addition, phase-angle analysis of the radial profiles of the instantaneous velocities (u, w) is employed to clarify better the instantaneous flow field. The vortex core inside the PVC is analyzed using two slices perpendicular to its axis. It is found that the vortex core is characterized by the limits of its circumferential velocity u(R) and its radius R.

Heat transfer characteristics of a high-pressure turbine under combined distorted hot-streak and residual swirl: an unsteady computational study

“…It is aligned with the vane leading edge and rotates in the clockwise direction. The swirl intensity used is S i = 0.4 and its defined based on the swirl injector geometry in the combustion chamber and flow velocity [ 42,43 ].…”

Numerical prediction of heat transfer characteristics on a turbine nozzle guide vane under various combustor exit hot‐streaks

“…Moreover, the swirl intensity formula could be reduced to include only U and W velocities, such as S = W/U. 2,4 To highlight the influence of the swirling flow on the inlet temperature transport, three cases of axial DHS (with no-swirl, S = 0) are considered (D1A, D2A, and D3A). Then, a high swirl (S = 0.5) is introduced with each DHS to form the cases D1S, D2S, and D3A.…”

“…The LBC is equipped with swirled fuel injectors that generate high swirling flows to stabilize the flame. [1][2][3][4] They contain also several film cooling slots to dilute the hot burned gases. 5,6 The combined effect of both swirling flames and dilution films generate high levels of turbulence and nonuniform temperature contours (known as hot-streak 7 ) at the LBC exit and the high-pressure turbine (HPT) inlet.…”