Towards a general semi-empirical model for the aspiration efficiencies of aerosol samplers in perfectly calm air

Su, Wei‐Chung

doi:10.1016/j.jaerosci.2004.04.003

Cited by 19 publications

(20 citation statements)

References 11 publications

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“…The only possible effects could be the collection of some of the ice crystals on the filters, which sublimated later, leaving the ice nuclei on the filters. However, the chance for this to happen was considered low because of (a) the sampler was facing away from the average wind direction, thus making it difficult for the ice crystals to enter the inlet and (b) the inlet air speed was about 5.6 m s −1 , which implies that we under-sampled the large particles (see Su and Vincent, 2004) and reduced the potential for collecting blowing ice crystals. However, we cannot rule out the possibility that on the balloon ice crystals were collected.…”

Section: Measurements Of Freezing Nuclei From the Balloonmentioning

confidence: 99%

Characteristics of immersion freezing nuclei at the South Pole station in Antarctica

2011

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Abstract. The effectiveness of aerosols as immersion freezing nuclei at the South Pole station was investigated during January and February 2009 using the FRIDGE-TAU. The analysis consisted of testing the freezing temperature of about 100-130 drops per sample containing aerosols collected at ground level and on a balloon lifted to different heights. All the drops froze between −18 • C and −27 • C. The temperature in which 50 % of the drops froze occurred at −24 • C, while nuclei concentration of 1 L −1 at −23 • C was calculated. Meteorological conditions such as wind speed, ice precipitation as well as the trajectories of the air masses affected the ice nuclei concentrations. Higher concentrations were observed on days when the winds were stronger or when the air mass originated from the sea.

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Section: Measurements Of Freezing Nuclei From the Balloonmentioning

confidence: 99%

Characteristics of immersion freezing nuclei at the South Pole station in Antarctica

2011

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“…Constant R Charts to compare to Su (2004) The model was tested for constant R values as defined by Su (2004) where R is the particle settling velocity relative to the air velocity at the sampler inlet.…”

Section: Model Validation Methodsmentioning

confidence: 99%

“…For the purposes of this guide, this open pipe is considered a thinwalled probe. The aspiration efficiency of a thin-walled probe in calm air has been modeled by Su and Vincent (Su 2004). …”

Section: Thin-walled Probe In Calm Airmentioning

confidence: 99%

Guide to Calculating Transport Efficiency of Aerosols in Occupational Air Sampling Systems

Hogue¹,

Hadlock²,

Thompson³

et al. 2013

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“…Hence, in this work, a study is made of the performance of a blunt sampler operating in calm air. Recently experimental studies were undertaken into the sampling performance of thin-walled, and some simple blunt, samplers by Su and Vincent (2002, 2004a, 2004b. Such studies are invaluable in furthering our understanding on this topic as experimental data with which to validate numerical models is lacking due to the difficulties in obtaining it.…”

Section: Introductionmentioning

confidence: 99%

“…In the work of Su and Vincent, the experimental data is displayed in tabular form making it available to compare with numerical models. The experimental data for both the blunt and thin-walled samplers was used by Su and Vincent (2004b), to develop semi-empirical formula to describe the aspiration efficiency of samplers facing upwards, downwards and horizontally.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study of Calm Air Sampling with a Blunt Sampler

Dunnett

Wen

Zaripov

et al. 2006

Aerosol Science and Technology

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It is found that in the case of upwards sampling the bluntness of the sampler only has a significant effect upon aspiration for large sampling velocities, values that would not generally be physically realistic. In the case of downwards sampling an important nondimensional quantity, B 2 R C , is identified, where B represents the sampler bluntness and R C represents the gravitational effects. This quantity determines the physical conditions for which aspiration will not occur and also the limiting values of the aspiration efficiency when aspiration does occur. In the case of low sampling velocities a difference is noted between experimental and numerical results for aspiration efficiency raising the need for more experimental data in this area. For both upwards and downwards sampling the semi-empirical models of Su and Vincent (2004b) have been modified to account for the information gained from the study. This is particularly important in the downwards sampling case where the modified model is found to agree particularly well with the results obtained.

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Towards a general semi-empirical model for the aspiration efficiencies of aerosol samplers in perfectly calm air

Cited by 19 publications

References 11 publications

Characteristics of immersion freezing nuclei at the South Pole station in Antarctica

Characteristics of immersion freezing nuclei at the South Pole station in Antarctica

Guide to Calculating Transport Efficiency of Aerosols in Occupational Air Sampling Systems

A Numerical Study of Calm Air Sampling with a Blunt Sampler

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