Spatial distributions of atomic hydrogen and C2 in an oxyacetylene flame in relation to diamond growth

Two-dimensional laser induced fluorescence measurements are applied to the chemical vapour deposition of diamond by an oxyacetylene flame to visualize the distributions of atomic hydrogen and C2 in the gas phase during diamond growth. Experiments are carried out in both laminar and turbulent flames and reveal that atomic hydrogen is ubiquitous at and beyond the flame front. Its presence extends to well outside the diamond deposition region, whereas the C2 distribution is limited to the flame front and the acetylene feather. The diamond layers obtained are characterized by optical as well as scanning electron microscopy and Raman spectroscopy. Clear relations are observed between the local variations in growth rate and quality of the diamond layer and the distribution of H and C2 in the boundary layer just above the substrate. These relations agree with theoretical models describing their importance in (flame) deposition processes of diamond. Three separate regions can be discerned in the flame and the diamond layer, where the gas phase and diamond growth are predominantly governed by the flame source gases, the ambient atmosphere, and the interaction of both, respectively

Spray growth of regular, synthetic, oxygenated and biodiesels in an optical engine

Spray formation has been studied in an optically accessible heavy-duty diesel engine for regular diesel,synthetic, oxygenated and biofuels using a high-speed digital camera. Images are analyzed with custom madealgorithms to obtain spray penetration length and spray cone angle as function of time. Results from 2 out of the 8 nozzle sprays have been used in the data analysis. Variation in spray equilibrium length and angle is observed between the fuels tested. Modelling of the fuel injection, taking great care to account for individual fuel properties, shows good correspondence with experimental results

Laser beam attenuation in LIF measurements on NO in a diesel engine

The effect of laser beam attenuation on nitric oxide measurements in a diesel engine is presented. A number ofexperimental ways to correct for this attenuation are discussed: transmission measurements, bidirectional laserinducedfluorescence, and Raman scattering by N2. Comparison of the results indicates that the attenuation isgenerally not uniform over the cylinder. Instead it seems to be less severe over the field of view (i.e. the upper partof the cylinder)

Laser beam attenuation in LIF measurements on NO in a diesel engine

The effect of laser beam attenuation on nitric oxide measurements in a diesel engine is presented. A number ofexperimental ways to correct for this attenuation are discussed: transmission measurements, bidirectional laserinducedfluorescence, and Raman scattering by N\u3csub\u3e2\u3c/sub\u3e. Comparison of the results indicates that the attenuation isgenerally not uniform over the cylinder. Instead it seems to be less severe over the field of view (i.e. the upper partof the cylinder)

Quantitative nitric oxide measurements by means of laser-induced fluorescence in a heavy-duty Diesel engine

Quantitative in-cylinder laser-induced fluorescence measurements ofnitric oxide in a heavy-duty Diesel engine are presented. Special attention is paid to experimental techniques to assess the attenuation of the laser beam and the fluorescence signal by the cylinder contents.This attenuation can be considerable at certain stages in the combustionstroke. The temperature and pressure dependence of the fluorescence signal is described in various models. In this study, LIFsim was used.Finally, calibration was realized by concentration measurements in the exhaust gas

HIGH-RESOLUTION LAMB DIP SPECTROSCOPY ON OD AND SiCl IN A MOLECULAR BEAM

Contains fulltext : 99073.pdf (publisher's version ) (Open Access

Geen toepassing zonder fundament

Contains fulltext : 83168.pdf (publisher's version ) (Open Access)Afscheidsrede, 29-10-201027 p

State-to-state scattering of oriented OH

Contains fulltext : 28154___.PDF (publisher's version ) (Open Access