scholarly journals Instantaneous one-dimensional equivalence ratio measurements in methane/air mixtures using femtosecond laser-induced plasma spectroscopy

2019 ◽  
Vol 27 (3) ◽  
pp. 2159 ◽  
Author(s):  
Dayuan Zhang ◽  
Qiang Gao ◽  
Bo Li ◽  
Zhifeng Zhu ◽  
Zhongshan Li
Keyword(s):  
Femtosecond Laser ◽  
Equivalence Ratio ◽  
Plasma Spectroscopy ◽  
One Dimensional ◽  
Laser Induced Plasma

A comparison of nanosecond and femtosecond laser-induced plasma spectroscopy of brass samples

2000 ◽  
Vol 55 (11) ◽  
pp. 1771-1785 ◽  
Author(s):  
V Margetic ◽  
A Pakulev ◽  
A Stockhaus ◽  
M Bolshov ◽  
K Niemax ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Plasma Spectroscopy ◽  
Laser Induced Plasma

Femtosecond-laser-induced plasma spectroscopy for high-pressure gas sensing: Enhanced stability of spectroscopic signal

2018 ◽  
Vol 113 (21) ◽  
pp. 214103 ◽  
Author(s):  
Paul S. Hsu ◽  
Anil K. Patnaik ◽  
Adam J. Stolt ◽  
Jordi Estevadeordal ◽  
Sukesh Roy ◽  
...  
Keyword(s):  
High Pressure ◽  
Femtosecond Laser ◽  
Gas Sensing ◽  
Plasma Spectroscopy ◽  
Laser Induced Plasma ◽  
Enhanced Stability

scholarly journals Machine learning based quantification of fuel-air equivalence ratio and pressure from laser-induced plasma spectroscopy

2021 ◽  
Author(s):  
Jungwun Lee ◽  
brendan mcgann ◽  
Stephen Hammack ◽  
Campbell Carter ◽  
Tonghun Lee ◽  
...  
Keyword(s):  
Machine Learning ◽  
Equivalence Ratio ◽  
Plasma Spectroscopy ◽  
Laser Induced Plasma

High-Pressure Femtosecond Laser Induced Plasma Spectroscopy (FLIPS) for Combustion Diagnostics

2020 ◽  
Author(s):  
Anil K. Patnaik ◽  
Daniel Lauriola ◽  
Eric Braun ◽  
Paul Hsu ◽  
Terrence R. Meyer ◽  
...  
Keyword(s):  
High Pressure ◽  
Femtosecond Laser ◽  
Plasma Spectroscopy ◽  
Laser Induced Plasma ◽  
Combustion Diagnostics

Ammonia measurements with femtosecond laser-induced plasma spectroscopy

2019 ◽  
Vol 58 (5) ◽  
pp. 1210 ◽  
Author(s):  
Dayuan Zhang ◽  
Qiang Gao ◽  
Bo Li ◽  
Jixu Liu ◽  
Zhongshan Li
Keyword(s):  
Femtosecond Laser ◽  
Plasma Spectroscopy ◽  
Laser Induced Plasma

Femtosecond laser-induced plasma spectroscopy for combustion diagnostics in premixed ammonia/air flames

2019 ◽  
Vol 58 (28) ◽  
pp. 7810 ◽  
Author(s):  
Dayuan Zhang ◽  
Qiang Gao ◽  
Bo Li ◽  
Jixu Liu ◽  
Yifu Tian ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Plasma Spectroscopy ◽  
Laser Induced Plasma ◽  
Combustion Diagnostics

scholarly journals Interaction of equivalence ratio fluctuations and flow fluctuations in acoustically forced swirl flames

2021 ◽  
pp. 175682772110155
Author(s):  
Vincent Kather ◽  
Finn Lückoff ◽  
Christian O. Paschereit ◽  
Kilian Oberleithner
Keyword(s):  
Equivalence Ratio ◽  
Transfer Functions ◽  
Transport Model ◽  
Mode Conversion ◽  
Fuel Injector ◽  
One Dimensional ◽  
Flow Fluctuations ◽  
Non Linear ◽  
Non Local ◽  
Acoustic Forcing

The generation and turbulent transport of temporal equivalence ratio fluctuations in a swirl combustor are experimentally investigated and compared to a one-dimensional transport model. These fluctuations are generated by acoustic perturbations at the fuel injector and play a crucial role in the feedback loop leading to thermoacoustic instabilities. The focus of this investigation lies on the interplay between fuel fluctuations and coherent vortical structures that are both affected by the acoustic forcing. To this end, optical diagnostics are applied inside the mixing duct and in the combustion chamber, housing a turbulent swirl flame. The flame was acoustically perturbed to obtain phase-averaged spatially resolved flow and equivalence ratio fluctuations, which allow the determination of flux-based local and global mixing transfer functions. Measurements show that the mode-conversion model that predicts the generation of equivalence ratio fluctuations at the injector holds for linear acoustic forcing amplitudes, but it fails for non-linear amplitudes. The global (radially integrated) transport of fuel fluctuations from the injector to the flame is reasonably well approximated by a one-dimensional transport model with an effective diffusivity that accounts for turbulent diffusion and dispersion. This approach however, fails to recover critical details of the mixing transfer function, which is caused by non-local interaction of flow and fuel fluctuations. This effect becomes even more pronounced for non-linear forcing amplitudes where strong coherent fluctuations induce a non-trivial frequency dependence of the mixing process. The mechanisms resolved in this study suggest that non-local interference of fuel fluctuations and coherent flow fluctuations is significant for the transport of global equivalence ratio fluctuations at linear acoustic amplitudes and crucial for non-linear amplitudes. To improve future predictions and facilitate a satisfactory modelling, a non-local, two-dimensional approach is necessary.

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