Review of ultra-high repetition rate laser diagnostics for fluid dynamic measurements

Thurow, Brian S.; Jiang, Naibo; Lempert, Walter R.

doi:10.1088/0957-0233/24/1/012002

Cited by 117 publications

(46 citation statements)

References 59 publications

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“…In JHC configurations, only PIV and OH PLIF in combination with flame emission and Schlieren imaging have been employed at kHz rates. With the development and continued improvement of pulse-burst laser systems [48] , methods requiring high laser pulse energies, such as planar Rayleigh scattering for mixture fraction or temperature imaging [49][50][51][52] , or major species concentration via Raman scattering [53] have become possible at multi-kHz acquisition rates.…”

Section: Introductionmentioning

confidence: 99%

The role of temperature, mixture fraction, and scalar dissipation rate on transient methane injection and auto-ignition in a jet in hot coflow burner

Arndt

Papageorge

Fuest

et al. 2016

Combustion and Flame

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a b s t r a c tThe transient injection and subsequent auto-ignition of a methane jet issuing into a laminar coflow of hot exhaust gas from a lean premixed hydrogen air flame was studied using high-speed planar Rayleigh scattering, yielding two-dimensional measurements of mixture fraction, temperature and scalar dissipation rate with high spatio-temporal resolution. The temporal development of the mixing field between the transient fuel jet and the surrounding coflow prior to the occurrence of auto-ignition was examined at a sampling rate of 10 kHz. The impact of the transient jet development on numerical modeling of this test case is discussed. It was found that auto-ignition occurred after the jet transitioned from a transient state into the steady state, thus eliminating the need to model the complete transient fuel injection when the primary focus is on the onset of auto-ignition.Simultaneous high-speed OH * chemiluminescence from two viewing angles was applied to gain 3D-information of the ignition kernel location. This information allowed the selection and analysis of ignition events where the initial kernel formed inside the laser light sheet. Detailed analysis of the dynamics of a single ignition event, as well as statistical analysis of multiple ignition events based on a joint probability density approach, indicated that the ignition kernels occurred at very lean mixture fractions and at locations with low scalar dissipation rates.

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Section: Introductionmentioning

confidence: 99%

The role of temperature, mixture fraction, and scalar dissipation rate on transient methane injection and auto-ignition in a jet in hot coflow burner

Arndt

Papageorge

Fuest

et al. 2016

Combustion and Flame

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“…The advances of optoelectronic components and systems, in particular concerning powerful pulsed lasers (up to 1 J/pulse) with up to megahertz repetition rate and high-speed cameras with megapixel image resolution, allow qualitative flow imaging with ultra-high speed, up to 1 MHz [10]. The combination of powerful lasers and high-speed cameras enables the fast imaging of two or three flow dimensions.…”

Section: Introductionmentioning

confidence: 99%

Imaging Flow Velocimetry with Laser Mie Scattering

Fischer

2017

Applied Sciences

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Abstract:Imaging flow velocity measurements are essential for the investigation of unsteady complex flow phenomena, e.g., in turbomachines, injectors and combustors. The direct optical measurement on fluid molecules is possible with laser Rayleigh scattering and the Doppler effect. However, the small scattering cross-section results in a low signal to noise ratio, which hinders time-resolved measurements of the flow field. For this reason, the signal to noise ratio is increased by using laser Mie scattering on micrometer-sized particles that follow the flow with negligible slip. Finally, the ongoing development of powerful lasers and fast, sensitive cameras has boosted the performance of several imaging methods for flow velocimetry. The article describes the different flow measurement principles, as well as the fundamental physical measurement limits. Furthermore, the evolution to an imaging technique is outlined for each measurement principle by reviewing recent advances and applications. As a result, the progress, the challenges and the perspectives for high-speed imaging flow velocimetry are considered.

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“…As a result, burst-mode laser systems have found significant use for spectroscopic measurements of minor species and flame-front imaging in turbulent flames [38,41,42], scattering for thermography and mixing [43], and tracer-based measurements of mixing [44,45]. With a trade-off in pulse energy, these systems are ultimately scalable to megahertz repetition rates [35,41,46]. The low duty cycle operation of these systems allows high pumping rates, achieving high gain and high perpulse energies ranging from 100's of mJ [36,38,39,41] to >2 J [37,43].…”

Section: Introductionmentioning

confidence: 99%

Effects of repetitive pulsing on multi-kHz planar laser-induced incandescence imaging in laminar and turbulent flames

et al. 2015

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Planar laser-induced incandescence (LII) imaging is reported at repetition rates up to 100 kHz using a burstmode laser system to enable studies of soot formation dynamics in highly turbulent flames. To quantify the accuracy and uncertainty of relative soot volume fraction measurements, the temporal evolution of the LII field in laminar and turbulent flames is examined at various laser operating conditions. Under high-speed repetitive probing, it is found that LII signals are sensitive to changes in soot physical characteristics when operating at high laser fluences within the soot vaporization regime. For these laser conditions, strong planar LII signals are observed at measurement rates up to 100 kHz but are primarily useful for qualitative tracking of soot structure dynamics. However, LII signals collected at lower fluences allow sequential planar measurements of the relative soot volume fraction with a sufficient signal-to-noise ratio at repetition rates of 10-50 kHz. Guidelines for identifying and avoiding the onset of repetitive probe effects in the LII signals are discussed, along with other potential sources of measurement error and uncertainty. RightsThis paper was published in Applied Optics and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: https://www.osapublishing.org/ ol/abstract.cfm?uri=ol-40-9-2029&origin=search. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law. Planar laser-induced incandescence (LII) imaging is reported at repetition rates up to 100 kHz using a burst-mode laser system to enable studies of soot formation dynamics in highly turbulent flames. To quantify the accuracy and uncertainty of relative soot volume fraction measurements, the temporal evolution of the LII field in laminar and turbulent flames is examined at various laser operating conditions. Under high-speed repetitive probing, it is found that LII signals are sensitive to changes in soot physical characteristics when operating at high laser fluences within the soot vaporization regime. For these laser conditions, strong planar LII signals are observed at measurement rates up to 100 kHz but are primarily useful for qualitative tracking of soot structure dynamics. However, LII signals collected at lower fluences allow sequential planar measurements of the relative soot volume fraction with a sufficient signal-to-noise ratio at repetition rates of 10-50 kHz. Guidelines for identifying and avoiding the onset of repetitive probe effects in the LII signals are discussed, along with other potential sources of measurement error and uncertainty.

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Review of ultra-high repetition rate laser diagnostics for fluid dynamic measurements

Cited by 117 publications

References 59 publications

The role of temperature, mixture fraction, and scalar dissipation rate on transient methane injection and auto-ignition in a jet in hot coflow burner

The role of temperature, mixture fraction, and scalar dissipation rate on transient methane injection and auto-ignition in a jet in hot coflow burner

Imaging Flow Velocimetry with Laser Mie Scattering

Effects of repetitive pulsing on multi-kHz planar laser-induced incandescence imaging in laminar and turbulent flames

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