-
Article
Improved measurement precision in decay time-based phosphor thermometry
This study comprises a continuation of the previous efforts of the authors to characterize different sources of errors in phosphor thermometry based on the determination of luminescence decays from thermograp...
-
Article
Effect of Partial Premixing on Stabilization and Local Extinction of Turbulent Methane/Air Flames
The stabilization characteristics and local extinction structures of partially premixed methane/air flames were studied using simultaneous OH-PLIF/PIV techniques, and large eddy simulations employing a two-sca...
-
Article
Quantitative imaging of a non-combusting diesel spray using structured laser illumination planar imaging
Due to its transient nature, high atomization process, and rapid generation of fine evaporating droplets, diesel sprays have been, and still remain, one of the most challenging sprays to be fully analyzed and ...
-
Article
Laser-induced plasma in methane and dimethyl ether for flame ignition and combustion diagnostics
In this paper we report the investigation of the laser-induced breakdown and ignition behaviour of methane/air and dimethyl ether (DME)/air mixtures. Moreover, the optical emission from the induced plasma is u...
-
Article
Quantitative C2H2 measurements in sooty flames using mid-infrared polarization spectroscopy
Quantitative measurements of acetylene (C2H2) molecules as a combustion intermediate species in a series of rich premixed C2H4/air flames were non-intrusively performed, spatially resolved, using mid-infrared pol...
-
Article
Detection of C2H2 and HCl using mid-infrared degenerate four-wave mixing with stable beam alignment: towards practical in situ sensing of trace molecular species
A stable and convenient optical system to realize the forward phase-matching geometry for degenerate four-wave mixing (DFWM) is demonstrated in the mid-infrared spectral region by measuring DFWM signals genera...
-
Article
Hydroxyl radical consumption following photolysis of vapor-phase hydrogen peroxide at 266 nm: Implications for photofragmentation laser-induced fluorescence measurements of hydrogen peroxide
The decay of OH concentration following photolysis of room-temperature vapor-phase hydrogen peroxide is studied as a function of photolysis fluence at 266 nm in an open air environment. The rate of decay is fo...
-
Article
Investigation of potential laser-induced heating effects when using thermographic phosphors for gas-phase thermometry
The spectral emission from thermographic phosphors in free flow and its dependence of laser energy per cross section area (laser fluence [J/cm2]) has been investigated. Temperature measurements in gaseous flows u...
-
Article
Four-wave mixing with non-resonant pump and resonant probe for OH detection in flames
A new type of two-color four-wave mixing spectroscopy is theoretically and experimentally demonstrated. By employing a non-resonant pum** and resonant probing scheme, OH radicals are detected in a laminar, a...
-
Article
Simultaneous 2D flow velocity and gas temperature measurements using thermographic phosphors
In this paper a new approach for simultaneous 2D velocity and temperature measurements using phosphoric particles is presented. The phosphoric particles respond to the temperature changes in the flow while act...
-
Article
Two-dimensional gas-phase temperature measurements using phosphor thermometry
A new technique based on phosphor thermometry for measurements of two-dimensional gas-phase temperature, was examined as a new laser diagnostic. Calibration of Dy:YAG phosphor was carried out on the surface of...
-
Article
High resolution polarization spectroscopy and laser induced fluorescence of CO2 around 2μm
High resolution Infrared Polarisation Spectroscopy (IRPS) and Infrared Laser Induced Fluorescence (IRLIF) techniques were used to probe CO2/N2 binary gas mixture at atmospheric pressure and ambient temperature....
-
Article
Determination of surface normal temperature gradients using thermographic phosphors and filtered Rayleigh scattering
Wall temperature as well as the temperature distribution within or close-by the boundary layer of an electrically heated axisymmetric jet im**ing on a flat plate were monitored to deduce wall-normal temperat...
-
Article
Application of advanced laser diagnostics for the investigation of the ionization sensor signal in a combustion bomb
The ionization sensor is an electrical probe for diagnostics in internal combustion engines. Laser-induced fluorescence (LIF) imaging of fuel, hydroxyl (OH), and nitric oxide (NO) distributions has been employ...
-
Article
2D-temperature imaging of single droplets and sprays using thermographic phosphors
A novel 2D-technique for temperature visualization of single droplets and sprays is presented. Laser induced emission from thermographic phosphor seeded to the investigated liquid was detected by a fast framin...
-
Article
Detection of methane with mid-infrared polarization spectroscopy
We report on the application of polarization spectroscopy in the mid-infrared spectral region for the detection of methane by probing its asymmetric ro-vibrational transitions. Tunable infrared laser radiation...
-
Article
Soot visualisation by use of laser-induced soot vapourisation in combination with polarisation spectroscopy
A novel approach to the visualisation of soot is presented. It relies on a combination of laser-induced soot vapourisation and consecutive polarisation spectroscopy. Upon soot vapourisation, molecular fragment...
-
Article
Quantitative three-dimensional imaging of soot volume fraction in turbulent non-premixed flames
A three-dimensional (3-D) imaging system for studies of reactive and non-reactive flows is described. It can be used to reveal the topology of turbulent structures and to extract 3-D quantities, such as conce...
-
Article
Picosecond laser-induced fluorescence from gas-phase polycyclic aromatic hydrocarbons at elevated temperatures. II. Flame-seeding measurements
Picosecond laser-induced radiative emission from flames injected with aromatic substances has been measured spectrally and temporally resolved. The measurements were performed in various seeded regions and for...
-
Article
Picosecond laser-induced fluorescence from gas-phase polycyclic aromatic hydrocarbons at elevated temperatures. I. Cell measurements
The aim of the work was a first step to investigate the possibility to use temporal selection as a complement to spectrally resolved measurements in combustion diagnostics to discriminate between different aro...
