Effect of fiber orientation on fiber wetting processes

Mullins, Benjamin J.; Agranovski, Igor E.; Braddock, Roger David; Ho, Chi

doi:10.1016/s0021-9797(03)00729-x

Cited by 67 publications

(60 citation statements)

References 15 publications

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“…However, during filtration of liquid aerosols, both airflow and drag forces must also be considered. A discussion of wet filtration and the filtration of liquid aerosols is given in previous literature [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Observation and modelling of clamshell droplets on vertical fibres subjected to gravitational and drag forces

Mullins¹,

Braddock²,

Agranovski³

et al. 2005

Journal of Colloid and Interface Science

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Extensive experimental investigation of the wetting processes of fibre-liquid systems during air filtration (when drag and gravitational forces are acting) has shown many important features, including droplet extension, oscillatory motion, and detachment of drops from fibres as airflow velocity increases, and also movement or flow of droplets along fibres. A detailed experimental study of the processes was conducted using stainless steel filter fibres and H2O aerosol, which coalesce on the fibre to form clamshell droplets. The droplets were predominantly observed in the Reynolds transition flow region, since this is the region where most of the above features occur. The droplet oscillation is believed to be induced by the onset of the transition from laminar to turbulent flow as the increasing droplet size increases Reynolds number for the flow around the droplet. Two-dimensional flow in this region is usually modelled using the classical Karman vortex street, however there exist no 3D equivalents. Therefore to model such oscillation it was necessary to create a new conceptual model to account for the forces both inducing and preventing such oscillation. The agreement between the model and experimental results is very good for both the radial and transverse oscillations.

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Section: Introductionmentioning

confidence: 99%

Observation and modelling of clamshell droplets on vertical fibres subjected to gravitational and drag forces

Mullins¹,

Braddock²,

Agranovski³

et al. 2005

Journal of Colloid and Interface Science

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“…(4), we can calculate that the maximum possible thickness of a stable film on the fibres used in this experiment is 2.4 lm (as outlined before, the filter was made out of 12 lm diameter polypropylene fibres). Previous work [14] has shown that airflow forces should act to assist Plateau -Rayleigh instability to break up the film into a series of uniformly spaced, barrel-shaped droplets. While this study operated on the boundary of the film/droplet regime of oil coating (a minimal oil-saturation level -equating to only 1 -2% increased packing density), it is not necessarily undesirable to utilize higher filter saturation rates if this will assist in the disinfection of more resilient organisms such as B. subtilis.…”

Section: Discussionmentioning

confidence: 99%

“…In the case of bioaerosol collection, such particles could still be viable and cause corresponding damage to human and animal health. While re-entrainment from an oiled filter may occur, it is most likely that re-entrainment would take the form of large liquid droplets containing particles [14], rather than individual particles themselves. It is likely that this would be a delayed process, and the liquid can cause significant microbial inactivation before reentrainment could occur.…”

Section: Introductionmentioning

confidence: 99%

Removal of Biological Aerosols by Oil Coated Filters

Pyankov¹,

Agranovski²,

Huang³

et al. 2008

CLEAN Soil Air Water

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An elevated risk associated with exposure to bioaerosols calls for the development and implementation of new, efficient and cost effective methods of airborne biological particle control. While filtration remains the most efficient method of removal of airborne particles, some issues related to possible re-entrainment of captured particles from the rear face of the filter back into the air carrier have to be addressed. Obviously, viable biological particles blown off from the filter surface could still cause substantial damage to human and animal health and contaminate the ambient air environment. A new technology utilizing coating of filter fibres by biologically active tea tree oil (TTO) is considered in this paper. It was found that precoating of filter fibres with TTO and following usage of such filters for bioaerosol control could provide significant benefits in terms of rapidly inactivating captured microorganisms and, minimizing the number of live/viable particles possibly blown off from the filter by the air. Three bacterial strains with a range of biological stress sensitivity were used in this research. It was found that 99% of stress sensitive Escherichia coli and Pseudomons fluorescens are inactivated on the surface of the TTO coated filter within 8 and 2 min of exposure, respectively. A robust strain of Bacillus subtilis demonstrated inactivation in the order of one logarithm per 30 min of process operation. These results look very promising for the implementation of this new technology for the control of air quality in domestic and industrial applications.

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“…The New Morris Method has been applied to several models such as the Resource Allocation model (REALM) [4], a droplet flow model [16] and emissions from a fluidizing catalytic cracking unit [20]. For each of these models, the sensitivity analysis gave an important ranking to the input parameters and, in some cases, highlighted problem areas with the proposed model.…”

Section: Introductionmentioning

confidence: 99%

“…Some of the outputs of the REALM model showed significant second-order effects to these numerical convergence factors. For each of the above models [4,16,20], the values for Bruns^and Bresolution^were chosen according to the criteria from Cropp and Braddock [8]. As mentioned above, these sampling criteria were set by an analysis on a well-behaved model (analytical functions), which included, at best, third-order interactions.…”

Section: Introductionmentioning

confidence: 99%

Analysing the sensitivity behaviour of two hydrology models

Matthews

Newton

Braddock

et al. 2006

Environ Model Assess

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Recently, the New Morris Method has been presented as an effective sensitivity analysis tool for mathematical models. The New Morris Method estimates the sensitivity of an output parameter to a given set of input parameters (first-order effects) and the extent these parameters interact with each other (secondorder effects). This method requires the specification of two parameters (runs and resolution) that control the sampling of the output parameter to determine its sensitivity to various inputs. The criteria for these parameters have been set on the analysis of a wellbehaved analytical function (see Cropp and Braddock, Reliab. Eng. Syst. Saf. 78:77-83, 2002), which may not be applicable to other physical models that describe complex processes. This paper will investigate the appropriateness of the criteria from (Cropp and Braddock, 2002) and hence the effectiveness of the New Morris Method to determine the sensitivity behaviour of two hydrologic models: the Soil Erosion and Deposition System and Griffith University Representation of Urban Hydrology. In the first case, this paper will separately analyse the sensitivity of an output parameter on a set of input parameters (first-and second-order effects) for each model and discuss the physical meaning of these sensitivities. This will be followed by an investigation into the sampling criteria by exploring the convergence of the sensitivity behaviour for each model as the sampling of the parameter space is increased. By comparing these trends to the convergence behaviour from Cropp and Braddock (2002), we will determine how well the New Morris Method estimates the sensitivity for each model and whether the sampling criteria are appropriate for these models. It will be shown that the New Morris Method can provide additional insight into the functioning of these models, and that, under a different metric, the sensitivity behaviour of these models does converge confirming the sampling criteria set by Cropp and Braddock.

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Effect of fiber orientation on fiber wetting processes

Cited by 67 publications

References 15 publications

Observation and modelling of clamshell droplets on vertical fibres subjected to gravitational and drag forces

Observation and modelling of clamshell droplets on vertical fibres subjected to gravitational and drag forces

Removal of Biological Aerosols by Oil Coated Filters

Analysing the sensitivity behaviour of two hydrology models

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