Numerical calculation of particle collection by a row of cylinders in a viscous fluid

Mclaughlin, Carroll; McComber, Pierre; Gakwaya, A.

doi:10.1002/cjce.5450640206

Cited by 14 publications

(10 citation statements)

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“…In this case, the presence of neighbor tubes, modifies the flow field in the tube analyzed resulting in a different aerosol retention efficiency and thus in a non-uniform deposition across the tubes of the bundle. Tsiang et al (1982), McLaughlin et al (1986), andIngham et al (1989) dealt with arrays of fibers in cross-flow for low Re numbers (which is out of the range of interest of the present research).…”

Section: Introductionmentioning

confidence: 99%

Aerosol Retention in the Vicinity of a Breach in a Tube Bundle: An Experimental Investigation

Sánchez-Velasco

Prá

Herranz

2010

Aerosol Science and Technology

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This article summarizes the main results of a bench-scale program focused on experimentally assessing the aerosol retention near the tube breach in a tube bundle. The major variables investigated were particle nature (polydispersed TiO 2 agglomerates vs. solid, monodisperse SiO 2 spheres) and Re D (0.8−2.7·10 5 ). In addition, comparisons to other data sets provided insights into the particle aerodynamic size effect on retention efficiency. Results showed that particle nature substantially affects aerosol retention in the tube bundle: mass retention efficiency was low for TiO 2 agglomerates (less than 30%) whereas it was much higher for SiO 2 particles (around 85%). Retention efficiency is also affected by Re D : its sensitivity was found to follow a log-normal behavior with a maximum retention attained at Re D near 1·105 . This evolution with Re D was similar for both types of compounds. Particle size also influences retention efficiency: the bigger the TiO 2 agglomerates the lower retention efficiency (no data were available for SiO 2 ). Among all these variables, particle nature was noted to have a prime importance for in-bundle retention, whereas Re D and particle aerodynamic size, although also affect retention efficiency, did not play such a key role. In light of the results, the presence of retention-inhibiting mechanisms such as fragmentation, resuspension or bouncing has been discussed. The data recorded will enhance the overall understanding of the governing mechanisms involved and will serve as a database against which compare model predictions. Nevertheless, further experimental data would be desirable to set up a sound database.

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Section: Introductionmentioning

confidence: 99%

Aerosol Retention in the Vicinity of a Breach in a Tube Bundle: An Experimental Investigation

Sánchez-Velasco

Prá

Herranz

2010

Aerosol Science and Technology

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“…None of the techniques described so far have accounted for the entrance effects of the flow into afibrous filter. An attempt to do this was made by McLaughlin et al (1986) who examined the small Reynolds number flow through an infinitely long single row of equally spaced cylindrical fibres, arranged so that their axes lie in a plane normal to the bulk flow of fluid. Invoking a symmetry argument, the solution domain was reduced to a semi-infinite strip, and McLaughlin et al (1986) used finite element methods to solve the governing two dimensional equations for the fluid flow.…”

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confidence: 99%

“…An attempt to do this was made by McLaughlin et al (1986) who examined the small Reynolds number flow through an infinitely long single row of equally spaced cylindrical fibres, arranged so that their axes lie in a plane normal to the bulk flow of fluid. Invoking a symmetry argument, the solution domain was reduced to a semi-infinite strip, and McLaughlin et al (1986) used finite element methods to solve the governing two dimensional equations for the fluid flow. The solid particle paths were than found by solving the governing Stokes equation for the particles, again using finite element methods coupled with an approximate Newton-Raphson technique, with initial conditions applied a few radii upstream of the single row or cascade of fibres.…”

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The particle collection efficiency of a cascade of cylinders

1989

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The entry flow and the trajectories of small solid particles into a fibrous filter, which is modelled as a single row or cascade of cylinders, is examined. Both large (potential) and small (creeping) Reynolds number flows through the cascade of cylinders are treated using the Boundary Element Method (BEM). Results for the collection efficiency are presented as functions of the Stokes number for both types of flow and are shown to be in excellent agreement with existing published results. An asymptotic expansion of the flow is developed both upstream and downstream of the cascade and it is shown to significantly affect the collection efficiency.

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“…85 aerosol retention efficiency and thus in a non-uniform deposition across the tubes of the bundle. Tsiang et al (1982), McLaughlin et al (1986) and Ingham et al (1989) dealt with arrays of fibers in cross-flow for low Re numbers (which is out of the range of interest of the present research).…”

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

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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 ...

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Numerical calculation of particle collection by a row of cylinders in a viscous fluid

Cited by 14 publications

References 8 publications

Aerosol Retention in the Vicinity of a Breach in a Tube Bundle: An Experimental Investigation

Aerosol Retention in the Vicinity of a Breach in a Tube Bundle: An Experimental Investigation

The particle collection efficiency of a cascade of cylinders

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

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