On the deposition of aerosol particles on cylinders in turbulent cross flow

Douglas, Peter; Ilias, Shamsuddin

doi:10.1016/0021-8502(88)90020-1

Cited by 20 publications

(15 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Alonso et al (2001) investigated an aerosol penetration through a wire screen for nanoparticles and suggested an empirical equation to model particle deposition due to turbulent diffusion based on the Peclet and Reynolds numbers. Douglas and Ilias (1988) investigated that an aerosol deposition on a cylinder in turbulent cross flow can be explained with eddy diffusion as the prime mechanism, and Fu and Tong (2002) showed that the diffusivity around an oscillating cylinder is proportional to the oscillating frequency and amplitude of the cylinder. Lee and Liu (1982) established a filtration model for a fibrous filter and many researchers have modified it for their applications.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Modeling Studies of the Stream-Wise Filter Vibration Effect on the Filtration Efficiency

Kim

Wang

Imagawa

et al. 2006

Aerosol Science and Technology

View full text Add to dashboard Cite

The stream-wise vibration effect of a fibrous filter is studied experimentally and numerically for the purpose of evaluating filtration efficiency. The particle sizes range from 0.02 to 10 µm and the face velocity ranges from 3 to 10 cm/s. The vibrational peak velocity also varied from 0 to 50 cm/s. The filtration efficiency for this wide size range is obtained by combining the individual test results for fine particles (0.02 to 0.5 µm) and large particles (0.5 to 10.0 µm). For the fine particle experiment, Arizona Road Dust (ARD) test particles are generated by an atomizer after an ultrasonic process and measured by a Scanning Mobility Particle Sizer (SMPS). For the large particle experiment, the test particles are generated by a fluidized bed and measured by an Aerodynamic Particle Sizer (APS). When the particles are generated by the atomizer after ultrasonicating, the majority of the particles are in nano scale without the agglomerates on the large particle surface, while particles generated by the fluidized bed are mostly in micro-scale because many nanoparticles are agglomerated on large particle surface. The filtration efficiency increases with the vibrational peak velocity in the impaction-dominant region (D p > 0.1 µm) and diffusion-dominant region (D p < 0.1 µm), due to the increased relative velocity between the particle and the filter fiber and the increased diffusion intensity from turbulence around the fiber, respectively. A model for the filter vibration effect is established with a modified Stokes number for the impaction-dominant region and an empirical analysis for the diffusion-dominant region.

show abstract

Section: Introductionmentioning

confidence: 99%

Experimental and Modeling Studies of the Stream-Wise Filter Vibration Effect on the Filtration Efficiency

Kim

Wang

Imagawa

et al. 2006

Aerosol Science and Technology

View full text Add to dashboard Cite

show abstract

“…There are some experimental studies on particle retention on single tubes surfaces (Douglas and Ilias, 1988;Ranz and Wong, 1952;Wessel and Righi, 1988;Wong and Johnstone, n.d.;Zhu et al, 2000) as well as on adhesion mechanisms of particles impinging on single tubes (Aylor and Ferrandino, 1985;Paw U, 1983;Wang and John, 1988).…”

Section: State Of the Art On Aerosol Retention Across A Tube Bundlementioning

confidence: 99%

“…Their results showed that under the conditions studied, the collection efficiency increases with the Stokes number. Then, Douglas & Ilias, (1988) developed a model to describe deposition of aerosol on an isolated cylindrical tube under turbulent cross flow conditions. The experiments consisted in exposing the tube to an aerosol stream.…”

Section: State Of the Art On Aerosol Retention Across A Tube Bundlementioning

confidence: 99%

“…The parameters are non-dimensional numbers generally defined as the ratio of forces causing particle removal and gas resistance forces opposing to the particle motion (Ranz and Wong, 1952). The product of the turbulent Schmidt number and the square root of the Reynolds number (Sctbt·Re 0.5 ) characterize turbulent deposition mechanism (Douglas and Ilias, 1988). Interception dp/dtube ~10 -4…”

Section: Experimental Matrix 43mentioning

confidence: 99%

See 1 more Smart Citation

Experimental investigations on nuclear aerosols in a severe accident

Tardáguila¹

View full text Add to dashboard Cite

This section is written in my mother tongue since it is the only way that I know to express my gratitude. Please, switch on the radio and play "Things the Grandchildren should know", by Eels. Por favor, encended la radio y que suene "Things the Grandchildren should know", de Eels.Volver a España en plena crisis para dedicarte a la ciencia necesita cierta dosis de pasión y mucha locura. Los que me conocen saben bien que ambas me sobran. Pero ¡qué haríamos sin lo absurdo y lo fugaz de la vida! que decía Frida Kalho.Es por fin el momento de vomitar y sacar de las entrañas la infinidad de emociones e incontables agradecimientos que brotan a raíz de este proyecto. Y es que más allá de lo tangible del manuscrito, la tesis es un conjunto de circunstancias que conduce a un éxtasis de sensaciones. Produce un estado de altibajos encontrados entre exaltante alegría y frustración. Es un sabor de boca agridulce que mientras convives con ella no termina de desaparecer; la melodía con la que te acuestas, sueñas y tienes pesadillas. La tesis es el amigo de infancia que no elegiste y estás obligado instintivamente a querer. Es un estado de ánimo complicado pero a cambio te invita a satisfacer la maravillosa sensación de superación y saciar el instinto más básico con la veracidad del cariño de quienes gratuitamente te acompañan.Mis primeros agradecimientos son a CIEMAT y su séquito de profesionales, particularmente a la Unidad de Seguridad Nuclear y a los que a pie de planta me han ayudado a conseguir todos y cada uno de los ladrillos de este edificio: Pedro, Alfonso y Miguel. Especialmente agradezco a mis directores: Luis Enrique Herranz, mentor de este trabajo, su esfuerzo y a José Luis Muñoz-Cobo, su apoyo. A Marga Vila por su paciencia desde la UPV. To the ARTIST and PASSAM partners, especially to PSI. A CSIC y el magnífico equipo de ultrasonidos: a Manuel, Enrique y Juan, de donde he encontrado sin pedir ni buscar, un apoyo técnico tan profesional y amable que el propio trabajo ha resultado un ejercicio de autoayuda y ánimo en la recta final. Con especial cariño le agradezco el día a día a mi compañero Rafa, que sabe sacar del café la dosis de aroma exacta para hacer la vida más fácil. Y a Patrick Ramboud, "my scientific inventor", who taught me the "well doing mode".En la más profunda amistad biológica le agradezco a mis fresas y particularmente a Ana y Elena el ánimo en los momentos en que los derroteros de la vida nos han hecho crecer juntas en la distancia. También a los que me acogisteis en lugares olvidados que ya nunca olvidaré porque los llevo tatuados: Inma, Isa, Julio, Pablo y a la inconmensurable nobleza de Chuvi. A Elisa, Antonio, Virgi, Rubén, Pedro, Stefan, al picopalismo… gracias! A Noemi, sigues aquí. A Marta porque la precisión de sus palabras son bocanadas de aire y a Ágata, por su tremenda ayuda. A tío Pauli, él lo sabe todo, también por qué. Y a los que también en la distancia su honestidad me ha obligado a creer para crear. To my lovely friend and friendly love Honzi, the purest person I have ever met. M...

show abstract

“…There are some experimental studies on particle retention on single tubes (Douglas & Illias (1988), Wessel et al (1988), Wong et al (1953), Ranz et al (1952), Zhu et al(2000)) as well as on dynamic adhesion of particles impacting on single tubes (Wang & John (1988), Pau (1982), Aylor et al (1985)). Douglas & Ilias (1988) obtained some experimental data for Re D <7200 by exposing a tube inside a wind tunnel to an aerosol stream and collecting the mass retained on it afterwards. Despite scarcity and spreading of data he showed that retention efficiency roughly correlates with Stk number for Stk≤0.1.…”

Section: State Of Art On Aerosol Retention Across a Tube Bundlementioning

confidence: 99%

Experimental characterization of aerosol retention in the break stage of a dry steam generator in SGTR sequences.

Velasco¹,

Javier²

View full text Add to dashboard Cite

Severe accident Steam Generator Tube Rupture (SGTR) sequences are identified as major contributors to risk of Pressurized Water Reactors (PWR). Their relevance lies in the potential radioactive release, in form of aerosol, from reactor coolant system to the environment. However, radioactive particles could be partially retained in the secondary side of the steam generator, even in the absence of water. Lack of knowledge on the source term attenuation capability of the steam generator has avoided its consideration in probabilistic safety studies and severe accident management guidelines. As a consequence, the steam generator filtering capability is not usually taken into account either in the probabilistic risk assessment of nuclear safety or in the severe accident management guidelines.This thesis describes the main activities and results of a bench-scale experimental program focused on getting insights into the aerosol retention in the break stage of the secondary side of a dry steam generator. The thesis is framed in the CIEMAT contribution to the ARTIST project (2003)(2004)(2005)(2006)(2007)(2008) which was supported by te Spanish Nuclear Regulatory Commission (CSN). The general objective of the work was to generate a comprehensive database on fission product retention in the break stage of a dry steam generator during a severe accident SGTR sequence. The specific objectives were to assess the influence of aerodynamic flow field as well as the influence of particle nature on aerosol deposition in the tube bundle. To do so, a scaled-down mock-up with representative dimensions of a real SG was built. The aerodynamic characterization of the flow field within the break stage of the bundle was done via 2D PIV (particle image velocimetry) technique. The particle nature influence on retention was characterized through aerosol retention experiments in the tube bundle mock-up. The major variables investigated were the type of breach (guillotine vs fish-mouth), the inlet gas mass flow rate (75-250 kg/h) and the particle type (polidispersed TiO 2 agglomerates vs. solid, monodisperse SiO 2 spheres).The aerodynamic campaign permitted to characterize the flow field close to the breach for both type of breaches and to asses their similarities. Results showed that the jet flows within the tube bundle following a generic quasi-parabolic trajectory evolving from an oblique cross flow configuration to an axial one. Mean flow field near the breach is substantially affected by the entrainment of initially stagnant gas into the jet. This effect is fostered by the presence of tubes and their tight packing. Jet penetration and turbulence intensity are considerably enhanced when increasing inlet gas mass flow rate.The results of the aerosol campaign showed that particle nature substantially affects retention in the tube bundle: mass retention was low for TiO 2 agglomerates (less than 30%) whereas it was much higher for SiO 2 particles (around 85%). Collection efficiency is also affected by gas mass flow rate: its sensitivity ...

show abstract

On the deposition of aerosol particles on cylinders in turbulent cross flow

Cited by 20 publications

References 4 publications

Experimental and Modeling Studies of the Stream-Wise Filter Vibration Effect on the Filtration Efficiency

Experimental and Modeling Studies of the Stream-Wise Filter Vibration Effect on the Filtration Efficiency

Experimental investigations on nuclear aerosols in a severe accident

Experimental characterization of aerosol retention in the break stage of a dry steam generator in SGTR sequences.

Contact Info

Product

Resources

About