Improvement of planar laser diagnostics by the application of a beam homogenizer

This contribution highlights recent advances in laser diagnostics at high repetition rates. Based on recent improvements in all-solid-state, diode-pumped laser and CMOS camera technology, well known methods such as Mie scattering, particle image velocimetry and planar laser-induced fluorescence are adapted and extended to high repetition rates in the kHz-regime and applied simultaneously to a turbulent opposed jet burner. High temporal resolution enables one to track transient events such as flame extinction and ignition in turbulent combustion. New perspectives into turbulent combustion are thus possible by quasi-4D imaging or multi-dimensional conditioning on transient phenomena.

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Characterization of a Single-Nozzle FLOX® Model Combustor Using kHz Laser Diagnostics

Volume 4B: Combustion, Fuels and Emissions ◽

10.1115/gt2015-43282 ◽

2015 ◽

Cited By ~ 6

Author(s):

Zhiyao Yin ◽

Patrick Nau ◽

Isaac Boxx ◽

Wolfgang Meier

Keyword(s):

Equivalence Ratio ◽

Laser Diagnostics ◽

Interaction Analysis ◽

Combustion Instabilities ◽

Preheat Temperature ◽

Planar Laser ◽

Particle Imaging ◽

Proper Orthogonal ◽

First Time

A single-nozzle FLOX® model combustor was used to produce a confined, premixed CH4-air flame with an equivalence ratio of ϕ = 0.74 and a jet exit velocity of vjet = 150m/s with a preheat temperature of T0=300°C. For the first time for this combustor, surface thermometry was performed on the chamber walls. In addition, particle imaging velocimetry (PIV) and planar laser-induced fluorescence of hydroxyl radical (OH PLIF) were acquired simultaneously in this flame at 5 kHz repetition rate. The interface between burnt and unburnt gas mixture were identified from instantaneous OH PLIF images and were compared with corresponding PIV results for flame-turbulence interaction analysis. Combustion instabilities were analyzed via proper orthogonal decomposition and phase-averaged flow field and OH distribution. A pronounced flapping motion of the jet was identified and its impact on the recirculation of hot burnt gas was characterized.

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THE BRIEF INTRODUCTION OF DIFFERENT LASER DIAGNOSTICS METHODS USED IN AERO-ENGINE COMBUSTION RESEARCH

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194516601848 ◽

2016 ◽

Vol 42 ◽

pp. 1660184

Author(s):

FEI XING ◽

GE SONG ◽

CAN RUAN ◽

JIAN ZHAO ◽

YONGJUN YANG

Keyword(s):

Raman Scattering ◽

Laser Diagnostics ◽

Tunable Diode Laser ◽

Advantages And Disadvantages ◽

Research Activities ◽

Engine Combustion ◽

Aero Engine ◽

Planar Laser ◽

Combustion Flow ◽

High Space

Combustion test diagnose has always been one of the most important technologies for the development of aerospace engineering. Laser diagnostics techniques developed quickly in the past several years. They are used to measure the parameters of the combustion flow field such as velocity, temperature, components concentration with high space and time resolution and brought no disturbance. Planar Laser-Induced Fluorescence, Coherent Anti-Stokes Raman Scattering, Tunable Diode Laser Absorption Spectroscopy and Raman Scattering were introduced systemically in this paper. After analysis their own advantages and disadvantages, it is believed that Raman Scattering system is more suitable for research activities on aero-engine combustion systems.

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Development and Application of Laser Diagnostics for Reacting and Nonreacting Flows at Wright-Patterson AFB

Fluids Engineering ◽

10.1115/imece2002-33156 ◽

2002 ◽

Author(s):

Campbell D. Carter ◽

Jeffrey M. Donbar ◽

Gregory S. Elliott

Keyword(s):

Turbulent Flows ◽

Rayleigh Scattering ◽

Laser Diagnostics ◽

Diagnostic Technique ◽

Diagnostic Techniques ◽

Turbulent Flames ◽

Guiding Principle ◽

Image Velocimetry ◽

Wide Range ◽

Planar Laser

Over the past few years, we have developed and applied a wide range of laser-diagnostic techniques to an equally wide range of complex flowfields at Wright-Patterson AFB. Our guiding principle in these efforts has been to employ laser-based tools to further our understanding of turbulent flames, so that in the end we improve combustor performance (e.g., thrust, emissions, etc.). We have primarily focused on three areas for development (though our areas of application have been much broader): 1) combined planar laser-induced fluorescence and particle-image velocimetry, 2) planar Doppler velocimetry, and 3) filtered Rayleigh scattering. Each of these is a powerful imaging diagnostic technique that allows the study of complex turbulent flowfields. We discuss these tools in the context of their application to turbulent flows as well as future diagnostic development.

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