Modeling and experimental evaluation of an aerosol generator for very high number currents based on a free turbulent jet

Koch, Wolfgang; Windt, H.; Karfich, Natascha

doi:10.1016/0021-8502(93)90070-p

Cited by 18 publications

(11 citation statements)

References 7 publications

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“…In such situations a kinetic approach is favored over a classical one, since thermodynamic equilibrium may not be achieved on the timescales of interest. Collision-controlled particle formation and evolution have previously been studied in chemically reacting systems [McMurry and Friedlander, 1979;McMurry, 1983] and turbulent jets [Delattre and Friedlander, 1978;Koch et al, 1993], where theoretical results are found to be consistent with experimental data.…”

Section: Introductionmentioning

confidence: 66%

The formation and evolution of aerosols in stratospheric aircraft plumes: Numerical simulations and comparisons with observations

Yu¹,

Turco²

1998

J. Geophys. Res.

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Abstract. The formation and evolution of aerosols in jet aircraft plumes at high altitude are simulated using a detailed aerosol microphysics model that explicitly resolves particle size and composition. Two approaches are used to simulate the microphysics: a standard, or "classical," approach in which new particle formation initially occurs via homogeneous binary nucleation, followed by condensation and coagulation; and a "kinetic" approach in which the entire course of particle evolution is calculated as a unified collisional mechanism. In the latter approach chemiions generated in the engine combustors can affect molecular cluster growth and ultrafine particle aggregation. Simulations with both approaches reveal that large numbers of volatile ultrafine sulfuric acid particles are generated in the near field behind the engines. The concentrations and subsequent evolution of these "volatile" particles are sensitive to the initial sulfuric acid vapor concentration, the plume dilution rate, and microphysical factors, especially the chemiion abundance, which is brought out through a sensitivity analysis. By contrasting predictions against available field data, it is demonstrated that the kinetic model provides a more realistic representation of particle formation and growth and hence their observable properties than the classical model. Moreover, the effects of chemiions during the early evolution of the plume are found to be crucial to the evolution of the largest volatile aerosols, which may play a role as cloud condensation nuclei. Major sources of uncertainty in the plume aerosol models are noted.

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Section: Introductionmentioning

confidence: 66%

The formation and evolution of aerosols in stratospheric aircraft plumes: Numerical simulations and comparisons with observations

Yu¹,

Turco²

1998

J. Geophys. Res.

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“…Theoretical studies of nucleation in turbulent condensing jets were conducted by Higuchi and O'Konski (1960), Lothe and Pound (1962), and Sutugin and Fuchs (1968). Relevant experimental studies were carried out by Langmuir (1942), Hottel (1942), Levine and Friedlander (1960), Hidy and Friedlander (1964), and Brock et al (1986), and more recently by Strum and Toor (1992), Koch et al (1993), Vatazhin et al (1995), Friedlander (1997, 1998), Lesniewski and Koch (1998), and Barrett (2000). Factors which may have an effect on the particle size distribution of the condensed aerosol are: (1) mass of substance vaporized per second, (2) mass of admixed or entrained air per unit weight of substance, (3) exit velocity of vapor emerging from the nozzle, (4) exit temperature of vapor emerging from the nozzle, (5) "seed" particle size as well as composition and number concentration, and (6) physico-chemical properties of the substance vaporized.…”

Section: Introductionmentioning

confidence: 99%

Investigation of a Novel Condensation Aerosol Generator: Solute and Solvent Effects

Gupta

Hindle

Byron

et al. 2003

Aerosol Science and Technology

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Part I of this article presents results of an experimental study on gas-phase nucleation for three model solutes and their solvent, propylene glycol (PG), with variables being solute concentration and the nature of the solute substance. A single manifestation of an aerosol generator, which forms condensation aerosols by cooling of hot vapor issuing from an electrically heated, pumped capillary, is described and used for all experiments. The effects of solute concentration and solute type were studied for deoxycorticosterone (DOC), benzil (BZ), and phenyl salicylate (PhS). Suppression of homogeneous nucleation and occurrence of heterogeneous condensation of the solvent was observed at different solute concentrations for BZ, PhS, and DOC. The nature and concentration of the solute dissolved in the solvent was shown to determine the final particle size distribution of the condensed aerosol. In the case of the least volatile solute, DOC, solute aerosol and total aerosol size distributions were identical at low solute concentrations. A transitional concentration region then existed in which a bimodal solute aerosol was formed, followed at high concentrations by increasing separation of the solvent-dominated aerosol size distribution and that of the solute.In Part II of this article, the effect of DOC dissolution in different solvents was studied at fixed solute concentration. The effects of six glycol solvents-i.e., PG, ethylene glycol (EG), dipropylene glycol (DPG), diethylene glycol (DEG), triethylene glycol (TEG), and tetraethylene glycol (TetEG)-and three nonglycol solventsi.e., dimethyl sulfoxide (DMSO), formamide (FORM), and oleyl alcohol (OA)-were studied, as these affected the resultant aerosol sizes. Suppression of total aerosol mass median aerodynamic diameter (MMAD) was observed on dissolution of 0.5% w/w DOC in each solvent, although suppression occurred to different extents. It was shown that the boiling point or volatility of the solvent used to dissolve the less volatile DOC had an effect on the final particle We wish to express our appreciation to Chrysalis Technologies Incorporated for providing the equipment and funding for this study.Address correspondence to Michael Hindle, Aerosol Research Group, Department of Pharmaceutics, Box 980533, Virginia Commonwealth University, Richmond, VA 23298-0533. E-mail: mhindle@ hsc.vcu.edu size distribution of the condensed aerosol and whether the aerodynamic size distributions for the solute and the total aerosol were the same or different.

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“…This type of generator uses a two-step process where nuclei of a very high boiling point compound are produced and the lower boiling compound is then condensed on the nuclei. The final particle size distribution depends on the nucleation rate and subsequent particle growth as discussed in texts (Friedlander 2000) and papers (Koch et al 1993;Barrett and Baldwin 2000;Singh et al 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Wood et al (1996) used a condensation generator to produce 0.6-1.4 µm diameter cocaine aerosols for animal studies. An extensive keyword literature search, Science Citation Index search, and review of citations contained in papers on organic particle generation (Koch et al 1993;Dubtsov and Baklanov 1996;Ristovski et al 1998) revealed no prior report of a laboratory condensation particle generator producing hydrocarbon aerosols smaller than 100 nm.…”

Section: Introductionmentioning

confidence: 99%

Vaporization--Condensation Generation of Ultrafine Hydrocarbon Particulate Matter for Inhalation Toxicology Studies

Veranth

Gelein

Oberdörster

2003

Aerosol Science and Technology

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An evaporation/condensation particle generator produced 30-50 nm count median diameter particles from both pure hydrocarbons and from a complex mixture-used motor oil-at a concentration above 1 × 10 6 /cm 3 . The objective was to generate ultrafine aerosols for inhalation toxicology studies using specified organic components as surrogates for the particulate emissions generated by diesel internal combustion engines. This nanoparticle generation system, assembled from commercially available components, produced smaller particle size and higher particle number concentration than has been previously documented using Sinclair-La Mer condensation generator technology. The paper describes both the experiments used to design and characterize the particle generator and the operating conditions used for a specific inhalation experiment as an example of the system capability.

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Modeling and experimental evaluation of an aerosol generator for very high number currents based on a free turbulent jet

Cited by 18 publications

References 7 publications

The formation and evolution of aerosols in stratospheric aircraft plumes: Numerical simulations and comparisons with observations

The formation and evolution of aerosols in stratospheric aircraft plumes: Numerical simulations and comparisons with observations

Investigation of a Novel Condensation Aerosol Generator: Solute and Solvent Effects

Vaporization--Condensation Generation of Ultrafine Hydrocarbon Particulate Matter for Inhalation Toxicology Studies

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