Vortex Breakdown Types and Global Modes in Swirling Combustor Flows with Axial Injection

Formation and flame-induced suppression of the precessing vortex core in a swirl combustor: Experiments and linear stability analysis

“…This is consistent with previously conducted stability analysis of similar configurations (with simplified or no turbulence models), where the predicted growth rates were wrong, but the frequencies were predicted correctly [23,[40][41][42]59]. The good estimation of the limit-cycle gives credibility to the present turbulence model.…”

“…In other combustors, the PVC forms for non-reacting cases, while it is suppressed for certain, but not necessarily all reacting cases [14][15][16][17][18]. It was further observed that the suppression of the PVC in a swirl flame can be triggered by changes of steam content and preheat temperature [19], swirl number [20], thermal power [21], pilot flow rate [22], or axial air injection [23]. The suppression of a PVC in a flame is usually accompanied by a major change of the flame shape [20], which in turn affects the combustor performance in terms of thermoacoustics, NO x emissions, flashback or blowout.…”

Experimental study and RANS calculation on velocity and temperature of a kerosene-fueled swirl laboratory combustor with and without centerbody air injection

“…The liquid kerosene stored in a fuel tank is driven by a nitrogen gas (1) of 2.0 MPa to flow through the fuel-feed pipe (5) and then is injected into the combustion chamber (16) in the form of fuel droplets with a 60°h ollow-cone. A combined Pitot tube and inclined-tube manometer (Product Model Number: YYT-200B) (19) were used to measure the velocity. Temperature was measured by calibrated thermocouples (Platinum/rhodium alloy thermocouple, Type B).…”

“…However, an excessive swirl may cause the central recirculation flow to move into the inlet annulus and lead to the occurrence of flame flashback in premixed combustion [16][17][18]. To solve the flashback problem in premixed combustors, Terhaar et al [19] introduced an axial air injection through the centerbody and found that the axial air injection provided a suitable flow field for flame stabilization and flashback-proof. For non-premixed combustors, which although are completely free from flashback, the overheating problem of the fuel nozzle and combustion chamber wall is arisen [20,21].…”

Helical modes in low- and high-swirl jets measured by tomographic PIV

“…[16] Intensive velocity oscillations have long been detected in high-swirl turbulent flows with bubble-type VB and are usually caused by a coherent mode, associated with a distinct peak CONTACT Vladimir M. Dulin vmd@itp.nsc.ru in the velocity fluctuation spectrum. These strong oscillations at a certain frequency are detected for different geometries of swirl burners [17,18], inducing aero-engine combustors [19][20][21], and are often attributed to the effect of PVC (see review by [7]). A better understanding of unsteady dynamics of swirling flows is important for the development of more efficient combustion devices.…”