Swirl Flame Response to Simultaneous Axial and Transverse Velocity Fluctuations

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Aditya Saurabh ◽  
Jonas P. Moeck ◽  
Christian Oliver Paschereit
Keyword(s):  
Experimental Study ◽  
Relative Phase ◽  
Transverse Velocity ◽  
Acoustic Velocity ◽  
Velocity Fluctuations ◽  
Thermoacoustic Instability ◽  
Transverse Acoustic ◽  
Flame Response ◽  
Swirl Flame ◽  
The Impact

In this experimental study, we investigate the impact of transverse acoustic velocity fluctuations on flame response to axial velocity fluctuations. Such a scenario where a flame is under the influence of a 2D acoustic field occurs in annular gas turbine combustors during thermoacoustic instability. A generic premixed swirl flame is exposed to simultaneous transverse and axial acoustic forcing. The amplitude of axial forcing was kept constant, while the amplitude and relative phase (with respect to axial forcing) of the transverse forcing was systematically varied. Results obtained indicate that transverse velocity affects flame response, and that both the magnitude of transverse velocity and its phase with respect to axial forcing are important factors.

Swirl Flame Response to Simultaneous Axial and Transverse Velocity Fluctuations

2016 ◽  
Author(s):  
Aditya Saurabh ◽  
Jonas P. Moeck ◽  
Christian Oliver Paschereit
Keyword(s):  
Relative Phase ◽  
Transverse Velocity ◽  
Experimental Investigations ◽  
Velocity Fluctuations ◽  
Transverse Acoustic ◽  
Flame Response ◽  
Acoustic Velocities ◽  
Acoustic Forcing ◽  
Swirl Flame ◽  
The Impact

In this experimental study we investigate the impact of transverse acoustic velocity fluctuations on the flame transfer function in response to axial velocity fluctuations. A generic swirl flame is exposed to transverse acoustic velocities of varying amplitude and relative phase simultaneously with axial acoustic forcing. Results obtained indicate that transverse velocity affects flame response, and both the magnitude of transverse velocity and its phase with respect to axial forcing are important factors. In addition to this key results, considerations for experimental investigations dealing with transverse acoustic forcing have been discussed.

Combustion Instability in a Swirl Flow Combustor With Transverse Extensions

2013 ◽  
Author(s):  
Aditya Saurabh ◽  
C. O. Paschereit
Keyword(s):  
Flow Field ◽  
Combustion Instability ◽  
Swirl Flow ◽  
Reacting Flows ◽  
Acoustic Oscillations ◽  
Test Rig ◽  
Thermoacoustic Instability ◽  
Transverse Acoustic ◽  
Axisymmetric Shear ◽  
Swirl Flame

The present investigation is an analysis of self-excited combustion instability in a swirl flame-based combustor with transverse extensions. Transverse extensions create the possibility of studying flame interaction with transverse acoustic oscillations. Such investigation important for understanding the phenomenon of thermoacoustic instability in annular combustors, where during thermoacoustic instability, azimuthal acoustic modes of the combustor couple with the multiple flames of the combustor. Flame and flow field dynamics during self-excited thermoacoustic instability in the single burner test-rig is presented here. These results are then compared to the dynamics of the isothermal and reacting flows in response to axial and transverse acoustic forcing. Both axial and transverse forcing led to the formation of axisymmetric shear layer vortices. Adding to the insight gained from previous investigations, these results suggest that that swirl flow dynamics in response to transverse acoustics consists of a non-trivial, direct effect of transverse acoustics on the flow field, in addition to its response to longitudinal fluctuations induced by transverse forcing.

Swirl Flame Response to Traveling Acoustic Waves

2014 ◽  
Author(s):  
Aditya Saurabh ◽  
Richard Steinert ◽  
Jonas P. Moeck ◽  
Christian O. Paschereit
Keyword(s):  
Acoustic Wave ◽  
Acoustic Waves ◽  
Test Rig ◽  
Pressure Oscillations ◽  
Acoustic Interaction ◽  
Transverse Pressure ◽  
Transverse Acoustic ◽  
Flame Response ◽  
Swirl Flame ◽  
Insight Into

The advent of annular combustors introduced a new facet of flame-acoustic interaction: flame coupling with standing and spinning azimuthal acoustic waves. Such coupling involves an acoustic field that is essentially transverse to the flame. Recent experiments on single burner test rigs have provided significant insight into flame interaction with transverse standing waves. However, experiments that focus on the spinning/rotating nature of azimuthal instabilities are still lacking. In this report, we demonstrate a methodology for studying spinning azimuthal instabilities on a single burner test rig. This methodology is based on analyzing flame response to a traveling acoustic wave generated in the combustor. We generate traveling acoustic waves in our transverse acoustic forcing test-rig by converting one end of the transverse extensions to a non-reflecting end. This is achieved through the implementation of the technique of impedance tuning. In the paper, we have discussed this implementation, followed by discussions on the effects of a traveling acoustic wave on a swirl-stabilized flame. The discussion is in the form of a comparison of flame oscillations for traveling wave and standing wave transverse forcing cases. Results show that the effect of transverse pressure oscillations dominates the flame response to traveling acoustic waves.

Experimental study of thermohydraulic characteristics and irreversibility analysis of novel axial corrugated tube with spring tape inserts

2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Thermal Performance ◽  
Working Fluid ◽  
The Novel ◽  
Heat Exchanger Tube ◽  
Heat Transfer Augmentation ◽  
Corrugated Tube ◽  
The Impact ◽  
Exchanger Tube

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.

Experimental study of heat transfer in the boundary layer of a flat plate with the impact of weak shock waves on the leading edge

2020 ◽  
Author(s):  
V. L. Kocharin ◽  
A. A. Yatskikh ◽  
D. S. Prishchepova ◽  
A. V. Panina ◽  
Yu. G. Yermolaev ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Experimental Study ◽  
Shock Waves ◽  
Flat Plate ◽  
Leading Edge ◽  
Weak Shock ◽  
The Impact
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