Aerosol Transport in Sampling Lines and Inlets

Brockmann, J.E.

doi:10.1002/9781118001684.ch6

Cited by 50 publications

(68 citation statements)

References 80 publications

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“…Sometimes the efficiencies are named differently, (e.g. in Brockmann, 2011). Nevertheless, throughout this text we will adhere to terms used by von der Weiden et al (2009):…”

Section: Particle Lossesmentioning

confidence: 99%

“…If the sampling speed is smaller than the ambient wind speed, the term sub-kinetic sampling is used, while for U > U 0 the term super-kinetic sampling is used. It will be used in the following for the turbulent as well as for the laminar regime as it has been done by others before (von der Weiden et al, 2009;Brockmann, 2011). Table 1.…”

Section: Sampling Lossesmentioning

confidence: 99%

“…During ideal sampling conditions, the sampling is isoaxial and isokinetic (Brockmann, 2011). Isoaxial means that the sampling inlet has no inclination with respect to the surrounding wind direction.…”

Section: Sampling Lossesmentioning

confidence: 99%

“…Both regimes need to be taken into account when setting up an inlet system and where and how to position the instrument (Brockmann, 2011). One way of addressing the isoaxial sampling is to put the instrument onto a turntable and letting it continually turn into the main wind direction as done by Vong (1995), Kowalski et al (1997), Kowalski (1999), Wrzesinsky (2000), Burkard et al (2002), Thalmann (2002, Burkard (2003), Eugster et al (2006), andHolwerda et al (2006).…”

Section: Sampling Lossesmentioning

confidence: 99%

“…The aspiration efficiency η asp is the ratio of the number concentration of particles that enter the sampling probe cross section to the number concentration of particles in the ambient air (von der Weiden et al, 2009;Brockmann, 2011). For the FM-100 we calculate the aspiration efficiency for the three different velocity regimes: (1) calm air (surrounding wind velocity U 0 < 0.5 m s −1 ), (2) slow moving air (0.5 m s −1 ≤ U 0 ≤ 2.18 m s −1 , which corresponds to a velocity ratio R v = U 0 /U of up to 0.5; with inlet velocity U ), and (3) moving air (velocity ratio R v = 0.5 to 2) and different angle regimes.…”

Section: Sampling Lossesmentioning

confidence: 99%

See 4 more Smart Citations

Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100)

Spiegel¹,

Zieger²,

Bukowiecki³

et al. 2012

Atmos. Meas. Tech.

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Abstract. Droplet size spectra measurements are crucial to obtain a quantitative microphysical description of clouds and fog. However, cloud droplet size measurements are subject to various uncertainties. This work focuses on the error analysis of two key measurement uncertainties arising during cloud droplet size measurements with a conventional droplet size spectrometer (FM-100): first, we addressed the precision with which droplets can be sized with the FM-100 on the basis of the Mie theory. We deduced error assumptions and proposed a new method on how to correct measured size distributions for these errors by redistributing the measured droplet size distribution using a stochastic approach. Second, based on a literature study, we summarized corrections for particle losses during sampling with the FM-100. We applied both corrections to cloud droplet size spectra measured at the high alpine site Jungfraujoch for a temperature range from 0 • C to 11 • C. We showed that Mie scattering led to spikes in the droplet size distributions using the default sizing procedure, while the new stochastic approach reproduced the ambient size distribution adequately. A detailed analysis of the FM-100 sampling efficiency revealed that particle losses were typically below 10 % for droplet diameters up to 10 µm. For larger droplets, particle losses can increase up to 90 % for the largest droplets of 50 µm at ambient wind speeds below 4.4 m s −1 and even to >90 % for larger angles between the instrument orientation and the wind vector (sampling angle) at higher wind speeds. Comparisons of the FM-100 to other reference instruments revealed that the total liquid water content (LWC) measured by the FM-100 was more sensitive to particle losses than to re-sizing based on Mie scattering, while the total number concentration was only marginally influenced by particle losses. Consequently, for further LWC measurements with the FM-100 we strongly recommend to consider (1) the error arising due to Mie scattering, and (2) the particle losses, especially for larger droplets depending on the set-up and wind conditions.

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“…Sometimes the efficiencies are named differently, (e.g. in Brockmann, 2011). Nevertheless, throughout this text we will adhere to terms used by von der Weiden et al (2009):…”

Section: Particle Lossesmentioning

confidence: 99%

Section: Sampling Lossesmentioning

confidence: 99%

Section: Sampling Lossesmentioning

confidence: 99%

Section: Sampling Lossesmentioning

confidence: 99%

Section: Sampling Lossesmentioning

confidence: 99%

See 3 more Smart Citations

Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100)

Spiegel¹,

Zieger²,

Bukowiecki³

et al. 2012

Atmos. Meas. Tech.

View full text Add to dashboard Cite

show abstract

Impact of co‐flow on the spray flame behaviour applied to nanoparticle synthesis

et al. 2018

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Flame spray pyrolysis (FSP) is an established process to synthesize nanoparticles of various metals and metal oxides. Applying open or enclosed configurations of the FSP reactor is an efficient tool to control the fuel‐oxidizer ratio in the reaction zone and, thus, the temperature distribution and the particle formation and growth process. In the present work, geometrical setups representing an open and an enclosed flame reactor are compared and their influence on the temperature, velocity, and particle characteristics is investigated. In addition, several distinct kinetic mechanisms for the combustion reactions are evaluated and their effects on the local reactor temperature and gas composition distribution are analyzed. An Eulerian‐Lagrangian approach is adopted to describe the multiphase turbulent gas‐droplet flow and a monodisperse approach based on the population balance equation (PBE) model is implemented to predict the particle formation and evolution. From the open reactor results, the air entrainment mass flow rate of gas into the flame is calculated. Several numerical experiments are performed with the enclosed setup. Supplying an appropriate co‐flow rate into the enclosed reactor results in similar flame behaviour as found for the open reactor configuration. By reducing the co‐flow gas, strong recirculation zones and particle deposition on the enclosure walls are observed. In this situation, the local temperature increases considerably, resulting in larger primary nanoparticle diameters.

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Estimation of Sea Spray Aerosol Surface Area over the Southern Ocean Using Scattering Measurements

Moore

Alexander

Humphries

et al. 2022

Preprint

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Aerosol Transport in Sampling Lines and Inlets

Cited by 50 publications

References 80 publications

Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100)

Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100)

Impact of co‐flow on the spray flame behaviour applied to nanoparticle synthesis

Estimation of Sea Spray Aerosol Surface Area over the Southern Ocean Using Scattering Measurements

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