Auflistung nach Autor:in "Giebl, Heinrich"

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Properties of jet engine combustion particles during the PartEmis experiment. Hygroscopic growth at supersaturated conditions
(Wiley, 31.07.2003) Hitzenberger, Regina; Giebl, Heinrich; Petzold, Andreas; Gysel, Martin; Nyeki, Stephan; Weingartner, Ernest; Baltensperger, Urs; Wilson, C. W.
During the EU Project PartEmis, the microphysical properties of aircraft combustion aerosol were investigated. This study is focused on the ability of exhaust aerosols to act as cloud condensation nuclei (CCN). The combustor was operated at two different conditions representing old and modern aircraft engine technology. CCN concentrations were measured with the University of Vienna CCN counter [Giebl et al., 2002] at supersaturations around 0.7%. The activation ratio (fraction of CCN in total aerosol) depended on the fuel sulphur content (FSC) and also on the operation conditions. CCN/CN ratios increased from 0.93 through 1.43 to 5.15*10ˉ³ (old cruise conditions) and 0.67 through 3.04 to 7.94*10ˉ³ (modern cruise conditions) when FSC increased from 50 through 410 to1270 μg/g. The activation behaviour was modelled using classical theories and with a semi-empirical model [Gysel et al., 2003] based on measured hygroscopicity of the aerosol under subsaturated conditions, which gave the best agreement.
01A - Beitrag in wissenschaftlicher Zeitschrift
Properties of jet engine combustion particles during the PartEmis experiment. Microphysics and Chemistry
(Wiley, 15.07.2003) Petzold, Andreas; Stein, Claudia; Nyeki, Stephan; Gysel, Martin; Weingartner, Ernest; Baltensperger, Urs; Giebl, Heinrich; Hitzenberger, Regina; Döpelheuer, Andreas; Vrchoticky, Susi; Puxbaum, Hans; Johnson, M.; Hurley, Chris D.; Marsh, Richard; Wilson, Chris W.
The particles emitted from an aircraft engine combustor were investigated in the European project PartEmis. Measured aerosol properties were mass and number concentration, size distribution, mixing state, thermal stability of internally mixed particles, hygroscopicity, and cloud condensation nuclei (CCN) activation potential. The combustor operation conditions corresponded to modern and older engine gas path temperatures at cruise altitude, with fuel sulphur contents (FSC) of 50, 410, and 1270 μg/g. Operation conditions and FSC showed only a weak influence on the microphysical aerosol properties, except for hygroscopic and CCN properties. Particles of size D ≥ 30 nm were almost entirely internally mixed. Particles of sizes D < 20 nm showed a considerable volume fraction of compounds that volatilise at 390 K (10–15%) and 573 K (4–10%), while respective fractions decreased to <5% for particles of size D ≥ 50 nm.
01A - Beitrag in wissenschaftlicher Zeitschrift
Properties of jet engine combustion particles during the PartEmis experiment: Hygroscopicity at subsaturated conditions
(Wiley, 06.06.2003) Gysel, Martin; Nyeki, Stephan; Weingartner, Ernest; Baltensperger, Urs; Giebl, Heinrich; Hitzenberger, Regina; Petzold, Andreas; Wilson, C. W.
Hygroscopic properties of combustion particles were measured online with a Hygroscopicity Tandem Differential Mobility Analyzer (H-TDMA) during PartEmis jet engine combustor experiments. The combustor was operated at old and modern cruise conditions with fuel sulfur contents (FSC) of 50, 410 and 1270 μg/g, and hygroscopic growth factors (HGF) of particles with different dry diameters were investigated at relative humidities RH ≤ 95%. HGFs increased strongly with increasing FSC (HGF[95% RH, 50 nm, modern cruise] = 1.01 and 1.16 for low and high FSC, respectively), and decreased with increasing particle size at fixed FSC, whereas no significant difference was detected between old and modern cruise. HGFs agreed well with a two-parameter theoretical model which provided an estimate of the sulfuric acid content of dry particles, indicating a nearly linear dependence on FSC.
01A - Beitrag in wissenschaftlicher Zeitschrift