Auflistung nach Autor:in "Hitzenberger, Regina"

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On the effects of organic matter and sulphur-containing compounds on the CCN activation of combustion particles
(Copernicus, 2005) Petzold, Andreas; Gysel, Martin; Vancassel, Xavier; Hitzenberger, Regina; Puxbaum, Hans; Vrochticky, S.; Weingartner, Ernest; Baltensperger, Urs; Mirabel, Philippe
The European PartEmis project (Measurement and prediction of emissions of aerosols and gaseous precursors from gas turbine engines) was focussed on the characterisation and quantification of exhaust emissions from a gas turbine engine. The combustion aerosol characterisation included on-line measurements of mass and number concentration, size distribution, mixing state, thermal stability of internally mixed particles, hygroscopicity, cloud condensation nuclei (CCN) activation potential, and off-line analysis of chemical composition. Based on this extensive data set, the role of sulphuric acid coating and of the organic fraction of the combustion particles for the CCN activation was investigated. Modelling of CCN activation was conducted using microphysical and chemical properties obtained from the measurements as input data. Coating the combustion particles with water-soluble sulphuric acid, increases the potential CCN activation, or lowers the activation diameter, respectively. The adaptation of a Köhler model to the experimental data yielded coatings from 0.1 to 3 vol-% of water-soluble matter, which corresponds to an increase in the fraction of CCN-activated combustion particles from ≤10‾⁴ to ≌10‾² at a water vapour saturation ratio Sw=1.006. Additional particle coating by coagulation of combustion particles and aqueous sulphuric acid particles formed by nucleation further reduces the CCN activation diameter. In contrast, particles containing a large fraction of non-volatile organic compounds grow significantly less at high relative humidity than particles with a lower content of non-volatile OC. The resulting reduction in the potential CCN activation with an increasing fraction of non-volatile OC becomes visible as a trend in the experimental data. While a coating of water-soluble sulphuric acid increases the potential CCN activation, or lowers the activation diameter, respectively, the non-volatile organic compounds, mainly found at lower combustion temperatures, can partially compensate this sulphuric acid-related enhancement of CCN activation of carbonaceous combustion aerosol particles.
01A - Beitrag in wissenschaftlicher Zeitschrift
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. Particle size spectra (d > 15 nm) and volatility
(Wiley, 18.09.2004) Nyeki, Staphan; Gysel, Martin; Weingartner, Ernest; Baltensperger, Urs; Hitzenberger, Regina; Petzold, Andreas; Wilson, Chris W.
Size distributions (d > 15 nm) and volatile properties of combustion particles were measured during test-rig experiments on a jet engine, consisting of a combustor and three simulated turbine stages (HES). The combustor was operated to simulate legacy (inlet temperature 300°C) and contemporary (500°C) cruise conditions, using kerosene with three different fuel sulfur contents (FSC; 50, 400 and 1300 μg gˉ¹). Measurements found that contemporary cruise conditions resulted in lower number emission indices (EI N15) and higher geometric mean particle diameter (dG) than for legacy conditions. Increasing FSC resulted in an overall increase in EIN15 and decrease in dG. The HES stages or fuel additive (APA101) had little influence on EI N15 or dG, however, this is uncertain due to the measurement variability. EI N15 for non-volatile particles was largely independent of all examined conditions.
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