Knowledge Base

Found 22 Results

« Previous 1 2

Article

Convective mass transport from rectangular cavities in viscous flow

Occhialini, J.M., Higdon, J.J.L.

1992J. Electrochem. Soc.139(10)2845-2855

Keywordscavity flow, cleaning, decontamination, mass transfer, shear flow

DisciplinesChemical Engineering, Fluid Mechanics

CategoryNumerical simulations

Non-expert summaryThe authors conduct a comprehensive numerical study of convective mass transport from 2-D rectangular cavities in low‐Reynolds‐number flows, i.e. the flow set up in a long rectangular trench by the motion of a steady shear flow across the top. They calculate the velocity field in the trench and the associated mass transport (enhancement of diffusion). The flow field is calculated by a high‐order implementation of the boundary‐integral method, while the convective diffusion equation is solved using the spectral‐element method. Results are presented in the form of concentraton contours and local mass fluxes, for cavity aspect ratios from 1:1 to 4:1 and for Péclet numbers from 0 to 100,000. They investigate the effects of inlet flow profile and system boundaries on the system.

[... Show more]

Review article

The fluid mechanics of cleaning and decontamination of surfaces

Landel, J. R., Wilson, D.I.

2021Annual Review of Fluid Mechanics53147-171

Keywordscleaning, decontamination

DisciplinesChemical Engineering, Fluid Mechanics

CategoryReview

Scale1e-9 to 1e-6 m, 1e-6 m, 1e-6 to 1e-3 m, 1e-3 m, 1e-3 to 1 m, 1 to 10 m, 10 to 1000 m, greater than 1 km / less than 1e-3 s, 1e-3 to 1 s, 1 to 60 s, 1 to 60 min, 1 to 24 hours, 1 to 30 days, 1 to 12 months, greater than 1 year

Non-expert summaryBroad review of the fluid mechanics involved in the cleaning and decontamination of surfaces using liquid flows. Three main phases are reviewed: the contacting phase, which requires the liquid cleanser to reach the soil; the action phase, which studies the various physico-chemical effects of the cleanser on the soil; and the removal phase, where the cleanser transports the soil away from the surface through various phenomena.

[... Show more]

Article

Mathematical modelling of chemical agent removal by reaction with an immiscible cleanser

Dalwadi, M.P., O'Kiely, D., Thomson, S.J., Khaleque, T. S., Hall, C. L.

2017SIAM Journal on Applied Mathematics77(6)1937-1961

Keywordsasymptotic analysis, decontamination, moving boundary problem, Stefan problem, surface reaction

DisciplinesApplied Mathematics, Fluid Mechanics

CategoryTheoretical modelling

Non-expert summaryModelling study of the decontamination of a porous material. An immiscible cleanser react with a contaminant, producing reactants which can be partially soluble in either phases. The diffusive-reactive transport problem is solved taking into account the moving boundary through asymptotic analysis and compared with numerical simulations. It is found that the partition coefficient of the product is more important in determining the removal rate than the reaction rate, as products of the reaction can prevent further reaction if they accumulate at the interface.

[... Show more]

Article

Homogenisation problems in reactive decontamination

Luckins, E., Breward, C.J.W., Griffiths, I.M., Wilmott, Z.

2020European Journal of Applied Mathematics31782-805

Keywordsdecontamination, homogenisation, porous material, reaction

DisciplinesApplied Mathematics, Fluid Mechanics

CategoryTheoretical modelling

Non-expert summaryTheoretical study of the decontamination of a 2D porous material. The decontaminant is immiscible with the contaminant and neutralize it through interfacial reaction. Two scenarios are considered with either the contaminant filling partially the pore space, or fully. This reactive-diffusive problem is solved using a homogenisation technique that separates the local pore-scale dynamics from the macro-scale temporal evolution. The effect of the porous material is accounted for by the model.

[... Show more]

Article

Movement of chemical warfare agent simulants through porous media

Jenkins, R.A., Buchanan, M.V., Merriweather, R., Ilgner, R.H., Gayle, T.M., Watson, A.P.

1994Journal of Hazardous Materials37(2)303-325

Keywordschemical warfare agent simulant, decontamination, permeation, porous material, risk

DisciplinesChemical Engineering, Chemistry, Fluid Mechanics

CategoryLaboratory experiments

Scale1e-3 to 1 m / 1 to 60 min, 1 to 24 hours

Non-expert summaryExperimental study of the permeation of CWA simulants through different layers of porous building materials: brick, cinder block, wall board, wood. The breakthrough time is measured in a specially designed cell. Anisotropy of the permeation is observed for anisotropic material such as wood. Surface decontamination is tested and shown effective.

[... Show more]

Review article

Hydrodynamic systems for assessing surface fouling, soil adherence and cleaning in laboratory installations

Detry, J.G., Deroanne, C. and Sindic, M.

2009Biotechnol. Agron. Soc. Environ.13(3)427-439

Keywordscleaning, decontamination, hydrodynamics

DisciplinesChemical Engineering, Chemistry, Fluid Mechanics

CategoryReview

Scale1e-6 to 1e-3 m, 1e-3 m, 1e-3 to 1 m / 1 to 60 s, 1 to 60 min

Non-expert summaryThis is a short review presenting and comparing five apparatuses that are used in laboratory scale investigations of cleaning: the parallel plate flow cell, the impinging jet, the radial flow cell, the rotating disk and fluid dynamic gauging. These systems are of particular relevance to the study of surface fouling, surface cleaning or adhesion on solid surfaces in laboratory environment. The key features of their hydrodynamics, as well as their practical advantages and drawbacks, are discussed. Examples of applications fields are also listed. A useful introduction to these devices.

[... Show more]

Article

Mass transfer from a flat surface to an impinging turbulent jet

Rao, V.V., Trass, O.

1964Canadian Journal Chemical Engineering42(3)95-99

Keywordscleaning, decontamination, impinging turbulent jet, mass transfer

DisciplinesChemical Engineering, Fluid Mechanics

CategoriesLaboratory experiments, Theoretical modelling

Scale1e-6 to 1e-3 m, 1e-3 to 1 m / 1e-3 to 1 s, 1 to 60 s

Non-expert summaryThis is a relatively early experimental study of mass transfer of a sparingly soluble material from a flat, solid surface when it is exposed to a normally impinging turbulent jet of water. The nozzle Reynolds numbers ranged from 25,000 to 125,000. The surface was coated with trans-cinnamic acid, and thickness profiles were measure over time to determine the local rate of mass transfer. The mass transfer flux is used to calculate the local Sherwood number (dimensionless mass transfer coefficient). In the wall-jet region these were found to be independent of the nozzle to plate distance, and were correlated as Sh = 1.3*Re^0.84*(x/d)^- 1.27. The authors found reasonable agreement with published heat transfer data . The average Sherwood numbers in the impingement region were found to decrease rapidly beyond a transition zone of 6.5 diameters from the nozzle: mass transfer rates are thus weak beyond this zone.

[... Show more]

Article

Local wall shear stress variations predicted by computational fluid dynamics for hygienic design

Jensen, B.B.B., Friis, A., Bénézech, T., Legentilhomme, P., Lelièvre, C.

2005Food Bioproducts Processing83(C1)53-60

Keywordscleaning, decontamination, shear flow, turbulence

DisciplinesChemical Engineering, Fluid Mechanics

CategoryNumerical simulations

Scale1e-3 to 1 m / 1e-3 to 1 s, 1 to 60 s

Non-expert summaryThe prediction of flow behaviour in complex geometries representative of industrial and other practical systems often requires the use of computational fluid dynamics (CFD) simulations. Two important pipe geometries are considered in this paper: a sudden and a gradual expansion or contraction. Steady state simulations using the STAR-CD package were used to predict the distribution of the mean shear stress imposed by a turbulent liquid flow from 1 inch to 2 inch cylindrical geometries (Reynolds number in the 1 inch pipe of 50,000), and the fluctuations in the shear stress. These calculated values are compared with estimates based on electrochemical mass transfer measurements. The data sets provide useful benchmarking results for other studies.

[... Show more]

Article

Hydrodynamic cleaning of a viscous film from the inside of a long tube

Mickaily, E.S. and Middleman, S.

1993AIChE Journal39(5)885-893

Keywordscleaning, decontamination, immiscible flow, thin film

DisciplinesChemical Engineering, Fluid Mechanics

CategoriesLaboratory experiments, Theoretical modelling

Scale1e-6 to 1e-3 m / 1e-3 to 1 s, 1 to 60 s

Non-expert summaryA simple, dynamic model, supported by experiments, is presented for the thinning (removal) of a viscous liquid film from the inside of the smooth interior surface of a long cylindrical tube. The model is based on the motion of the film generated by the shear stress imposed on it by the turbulent flow of air through the tube. The model gives estimates of the mean thickness of the film (an olive oil and a castor oil). The authors extend the investigation to include removal from roughened surfaces, modelling these as regularly spaced triangular cavities.

[... Show more]

Article

Convective mass transfer from a submerged drop in a thin falling film

Landel, J.R., Thomas, A.L., McEvoy, H., Dalziel, S.B.

2016J. Fluid Mech.789630-668

Keywordsdecontamination, drop, film flow, interfacial dynamics, mass transfer

DisciplinesChemical Engineering, Fluid Mechanics

CategoriesLaboratory experiments, Theoretical modelling

Scale1e-6 to 1e-3 m, 1e-3 m / 1e-3 to 1 s, 1 to 60 s, 1 to 60 min

Non-expert summaryThis is an experimental and modelling study of the removal of a passive tracer contained in small, thin, viscous drops attached to a flat inclined substrate using the flow of a thin gravity-driven film. The drop cannot be detached either partially or completely from the surface by the mechanical forces exerted by the cleaning fluid on the drop. Convective mass transfer is established across the interface between the drop and the flowing liquid film and the (dilute) tracer diffuses into the film flow, which takes it away. The Peclet number, comparing the rate of mass transfer in the drop to the rate in the liquid film, is small (< 1) . Two models are presented: a simple empirical model based on film mass transfer coefficients; and a fuller theoretical model solving the quasi-steady two-dimensional advection–diffusion equation in the film, coupled with a time-dependent one-dimensional diffusion equation in the drop. A range of values of the Peclet number (0.01 to 1) is considered in the fuller model. Good agreement is observed between the experimental data and the models.

[... Show more]

« Previous 1 2