Доступ предоставлен для: Guest
Портал Begell Электронная Бибилиотека e-Книги Журналы Справочники и Сборники статей Коллекции
Journal of Flow Visualization and Image Processing
SJR: 0.11 SNIP: 0.312 CiteScore™: 0.1

ISSN Печать: 1065-3090
ISSN Онлайн: 1940-4336

Выпуски:
Том 26, 2019 Том 25, 2018 Том 24, 2017 Том 23, 2016 Том 22, 2015 Том 21, 2014 Том 20, 2013 Том 19, 2012 Том 18, 2011 Том 17, 2010 Том 16, 2009 Том 15, 2008 Том 14, 2007 Том 13, 2006 Том 12, 2005 Том 11, 2004 Том 10, 2003 Том 9, 2002 Том 8, 2001 Том 7, 2000 Том 6, 1999 Том 5, 1998 Том 4, 1997 Том 3, 1996 Том 2, 1995 Том 1, 1993

Journal of Flow Visualization and Image Processing

DOI: 10.1615/JFlowVisImageProc.2018025857
pages 79-97

INVESTIGATION OF ROTATIONAL SYMMETRY IN VORTEX-DRIVEN ACOUSTIC OSCILLATIONS IN A LABORATORY-SCALE SWIRL COMBUSTOR

Vikram Ramanan
Department of Aerospace Engineering, National Center for Combustion Research and Development, Indian Institute of Technology, Madras, Chennai-600036, India
Satyanarayanan R. Chakravarthy
Department of Aerospace Engineering, National Centre for Combustion Research and Development, Indian Institute of Technology Madras, Chennai 600036, India

Краткое описание

Combustors in gas turbines exhibit thermoacoustic instability marked by high-amplitude pressure oscillations, during which the characteristics of the flame undergo significant changes. In the present work, a laboratory-scale swirl combustor is characterized by its stable and unstable flame behavior. The chemiluminescence of the CH* radicals in the flame is recorded at high framing rates simultaneously with the measurement of the acoustic pressure excited in the combustor. The combustor is unstable at low fue-air equivalence ratio and high air flow rate (represented in terms of Reynolds number, Re). Under unstable conditions, the high-speed CH chemiluminescence images reveal the evolution of a mushroom-shaped flame structure at the pressure maximum in every acoustic cycle, which eventually flares into an axisymmetric flame convecting downstream. The flame curling associated with the mushroom-shaped pattern is investigated for the signature of vortex-driven combustion instability by means of rotational symmetry in the flame images. A scale-invariant feature tranform algorithm is employed to detect rotational symmetry for this purpose. The results reveal the appearance of rotational symmetry at the zero pressure crossings and pressure maxima. The number of frames bearing the rotational symmetry is correlated with the duration over which peak pressure prevails across several acoustic cycles, to reinforce the role of vortex combustion in exciting pressure oscillations in the combustor.


Articles with similar content:

Flow structure of swirling turbulent propane flames
ICHMT DIGITAL LIBRARY ONLINE, Vol.0, 2009, issue
Sergey Alekseenko, Dmitriy M. Markovich, Yuriy S. Kozorezov, Sergei I. Shtork, Vladimir M. Dulin
DIAGNOSTICS AND CONTROL OF LARGE-SCALE STRUCTURES IN SWIRLING PREMIXED FLAMES
TSFP DIGITAL LIBRARY ONLINE, Vol.6, 2009, issue
Sergey Alekseenko, Dmitriy M. Markovich, Yuriy S. Kozorezov, Sergei I. Shtork, Vladimir M. Dulin
FLOW AROUND A CORRUGATED AIRFOIL
Journal of Flow Visualization and Image Processing, Vol.25, 2018, issue 3-4
Amit Agrawal, P. Sooraj
IDENTIFICATION OF LOCAL AND GLOBAL OSCILLATIONS IN A PLAS~A JET
Progress in Plasma Processing of Materials, 1999, Vol.1, 1999, issue
V. Nenicka, J. Hlina
Investigation of unsteady reacting flow in a swirl burner by planar optical techniques and POD
ICHMT DIGITAL LIBRARY ONLINE, Vol.0, 2015, issue
I. M. Vereshchagin, Shota Alexsandrovich Piralishvili, Dmitriy M. Markovich, D. K. Sharaborin, Vladimir M. Dulin, A. S. Lobasov