2024 Precessing vortex core

Precessing vortex core

Author: loxt

August undefined, 2024

WebJan 13, 2024 · This flow is characterized by phenomena such as vortex transition, precessing vortex core, toroidal recirculation zone, reverse flow core and recirculation zone in the axial… Show more WebOne of these structures is the Precessing Vortex Core (PVC), whose ambiguous characteristics make it an adequate mechanism for chemical mixing whilst being a detrimental component for thermoacoustic stabilisation. The PVC has been extensively characterised in swirling jet flows exhibiting vortex breakdown (in this study named Open …

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WebJan 17, 2024 · Previous work suggested that the existence of a precessing vortex core (PVC) may suppress the receptivity of the shear layer, and the goal of this study is to first, … WebApr 12, 2024 · Figure 3: Precessing ﬂoating drop with attached vortex ﬁla- ments at κ = 1 and ζ = 253: (a) the cross section of the beam by the τ = 0 plane, (b) the cross section of the b eam by the gbig firework finale

Determination of single and double helical structures in a swirling …

WebSep 16, 2024 · Abstract. The precessing vortex core (PVC) is a helically shaped coherent flow structure that occurs in reacting and nonreacting swirling flows undergoing vortex … WebJul 20, 2024 · Case 3 (pilot-only, high AFR) is free from prominent oscillations and exhibits a broadband noise frequency spectrum. Cross-correlations with OH* chemiluminescence support the hypothesis of the precessing vortex core inducing the coherent patterns in the exhaust by linking the temperature profiles to events in the primary zone. WebThis paper will present new information on the occurrence and suppression of the precessing vortex core and its influence on the combustion process and, in particular, the stimulation of acoustic instability in closed systems. A swirl burner which has been extensively characterised over many years is operated in a premixed/partially-premixed … days inn in new braunfels tx

Precessing vortex core in a swirling wake with heat release

The Role of the Centerbody Wake on the Precessing Vortex Core …

WebJun 1, 2016 · Neither the percentage of time spent in the detached state nor the final detachment conditions were predicted by the Damköhler number. The lift-off process involved several coupled phenomena, namely local flame extinction near the flame base, development of a helical precessing vortex core (PVC), and eventual total extinction of … WebJan 12, 2024 · The fast Fourier transform of the sampled velocity and pressure signals indicates a precessing vortex core with a frequency of 22 Hz. This frequency is in line with the one detected by spectral proper orthogonal decomposition, which is utilized to identify the coherent structures in the near-field region of the swirling flow in the present work. days inn in myrtle beach scWebJun 1, 2016 · Precessing vortex core is left-handed co-rotated bending single-vortex structure. •. The precession frequency grows with the heat-source power. •. Growth of the … gbi history

"WebWe report on the experimental study of a precessing vortex core (PVC) in an air model of a Francis turbine. The focus is placed on the modal decomposition of the PVC that occurs in the draft tube of the model turbine for a range of operation conditions. The turbulent flow fluctuations in the draft tube are assessed using stereo particle image velocimetry (PIV) … " - Precessing vortex core

Precessing vortex core

WebJun 8, 2024 · The turbulent flow in the draft tube of a Francis turbine is very complicated while working under off-design conditions. Although the off-design conditions were widely … WebNov 8, 2024 · WPOD results for the 0 % H 2 TPM case reveal intermittent helical precessing vortex core (PVC) oscillations along with axisymmetric hydrodynamic flow oscillations …

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WebSep 1, 2024 · If the swirl is increased to Sw = 0.47, this breakdown bubble is permanently present in the flow field. A large-scale vortical structure, the precessing vortex core, … WebJul 1, 2024 · The simulations successfully capture the quasi-periodic precessing vortex core (PVC) phenomenon. The spectra derived from the temporal signals of different flow …

WebOct 31, 2024 · The precessing vortex core (PVC) represents a helical-shaped coherent flow structure typically occurring in both reacting and nonreacting swirling flows. Until now, the … WebMay 31, 2024 · We report on the experimental study of a precessing vortex core (PVC) in an air model of a Francis turbine. The focus is placed on the modal decomposition of the PVC that occurs in the draft tube of the model turbine for a range of operation conditions.

WebVarious swirl injector configurations and related flow characteristics, including vortex breakdown, precessing vortex core, large-scale coherent structures, and liquid fuel atomization and spray formation, are discussed. Nonlinear behaviors of combustion processes observed in combustors are described. WebFeb 25, 2007 · An experimental analysis of the precessing vortex core (PVC) instability in a free swirling jet of air at ambient pressure and temperature is performed by means of …

WebJan 14, 2024 · The predicted results were compared with the experimental data and good agreements were found between them. In the cold flow field under both conditions, a …

WebNov 30, 2024 · Download PDF Abstract: Global instabilities in swirling flows can significantly alter the flame and flow dynamics of swirl-stabilized flames, such as those in modern power generation gas turbine engines. In this study, we characterize the interaction between the precessing vortex core (PVC), which is the consequence of a global hydrodynamic … days inn in norman okWebThe precessing vortex core (PVC) is a well-known coherent structure whose development, intensity and occurrence has not been well documented. This paper thus adopts an experimental approach to characterize the PVC in a … gbi hobbies havelock ncWebNov 17, 2024 · A precessing vortex core (PVC) is a self-excited helical instability that results from the precession of the vortex core around the flow axis in the upstream region of a vortex breakdown bubble. PVC oscillation in a swirl flow-based combustor aids the thermoacoustic instability that results in hardware damage and poor emission … gbi heat unitWebFeb 5, 2024 · Arndt, M. Stöhr, M. J. Severin, C. Dem, and W. Meier, “ Influence of air staging on the dynamics of a precessing vortex core in a dual swirl gas turbine model combustor,” in 53rd AIAA/SAE/ASEE Joint Propulsion Conference (AIAA, 2024), p. 4683. Google Scholar Crossref; 37. P. S. gbi holdings pty ltdWebApr 1, 2016 · The precessing vortex core (PVC) is a coherent flow structure that is often encountered in swirling flows in gas turbine (GT) combustors. In some swirl combustors, ... gbi house of blessingWebJun 16, 2016 · The influence of combustion effect on unsteady vortex structure in the form of precessing vortex core was studied using the non-intrusive method of laser Doppler anemometry and special procedure of extracting the non-axisymmetric mode of flow fluctuations. The studies show that combustion has a significant effect on the … gbi great bodily injuryWebINIS Repository Search provides online access to one of the world's largest collections on the peaceful uses of nuclear science and technology. The International Nuclear Information System is operated by the IAEA in collaboration with over 150 members. gbi house of shalom