A computational study of the effect of viscoelasticity on slot coating flow of dilute polymer solutions

Bajaj, Mohit; Prakash, J. Ravi; Pasquali, Matteo

doi:10.1016/j.jnnfm.2007.05.013

Cited by 27 publications

(35 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Previous studies have shown that the breakdown of viscoelastic computations coincides with the smallest eigenvalue becoming negative in some regions of the flow domain [29,37,39,40].…”

Section: Mesh Convergence and The Limiting Weissenberg Numbermentioning

confidence: 93%

See 1 more Smart Citation

Viscoelastic flow in a two-dimensional collapsible channel

Chakraborty¹,

Bajaj²,

Yeo³

et al. 2010

Journal of Non-Newtonian Fluid Mechanics

Self Cite

View full text Add to dashboard Cite

“…Previous studies have shown that the breakdown of viscoelastic computations coincides with the smallest eigenvalue becoming negative in some regions of the flow domain [29,37,39,40].…”

Section: Mesh Convergence and The Limiting Weissenberg Numbermentioning

confidence: 93%

“…(1), (2), (5), (8) and (11), yields a large set of coupled non-linear algebraic equations, solved by Newton's method with analytical Jacobian, frontal solver, and first order arc length continuation in parameters [29,36,37]. …”

Section: Boundary Conditions and Discretisationmentioning

confidence: 99%

Viscoelastic flow in a two-dimensional collapsible channel

Chakraborty¹,

Bajaj²,

Yeo³

et al. 2010

Journal of Non-Newtonian Fluid Mechanics

Self Cite

View full text Add to dashboard Cite

“…Further analysis of visco-elastic fluid flow includes the work of Romero et al [36] and Bajaj et al [37] who studied the slot coating of visco-elastic fluids onto a moving substrate as well as the work of Quintella et al [38] who examined both computationally and experimentally the displacement of a visco-elastic fluid filled capillary tube by a semi-infinite slug of air. This work complements the experimental study of Huzyak and Koelling [39] who undertook an experimental investigation of the penetration of a bubble through a viscoelastic fluid and found that as the fluid becomes more viscoelastic the fractional coverage of fluid left on the tube increases.…”

Section: Introductionmentioning

confidence: 99%

A model for film-forming with Newtonian and shear-thinning fluids

Hewson

Kapur

Gaskell

2009

Journal of Non-Newtonian Fluid Mechanics

View full text Add to dashboard Cite

The formation of a thin film by (i) the slow penetration of a gas bubble into a liquid filled tube, (ii) the withdrawal of a planar substrate from a liquid filled gap, is investigated theoretically for the cases of both Newtonian and shear thinning liquids; the latter conforming to either a power law or Ellis model. Formulated as a boundary value problem underpinned by lubrication theory, the analysis gives rise to a system of ordinary differential equations which are solved numerically subject to appropriate boundary conditions. For Newtonian liquids comparison of the predicted residual film thickness for a wide range of capillary number, Ca ∈ 10 −4 , 10 , is made with others obtained using existing expressions, including the classical one of Bretherton, in the region of parameter space over which they apply. In the case of (i), prediction of the behaviour of the residual fluid fraction and gap-to-film thickness ratio, for a Newtonian liquid and one that is shear-thinning and modelled via a power-law, is found to be in particularly good agreement with experimental data for Ca < 0.2. For (ii), both shear thinning models are utilized and contour plots of residual film thickness generated as a function of Ca and the defining parameters characteristic of each model.

show abstract

“…A análise destes valores mostram que o aumento do número de capilaridade acarreta em uma diminuição da espessura de filme adimensional ‫,)ݐ/ܪ(‬ e por consequência um aumento da espessura de filme ‫.ݐ‬ Este comportamento é também relatado por Bajaj et al (2008) e Tsuda (2010.…”

Section: Cenários Consideradosunclassified

Redução da espessura de filme na fabricação de células fotovoltaicas

Romero

Garuzzi

2016

Cieng

View full text Add to dashboard Cite

. RESUMOA energia solar fotovoltaica é uma alternativa interessante para a geração de energia elétrica, entretanto, ainda é cara se comparada com as fontes tradicionais. Uma forma de aumentar sua competitiva é diminuindo a quantidade de material utilizado. No método de revestimento por extrusão, a diminuição da vazão resulta em camadas cada vez mais finas. Entretanto, a diminuição da espessura encontra limites físicos e operacionais, um deles é o limite de vazão mínima. Este fenômeno verifica-se quando o menisco à jusante invade a separação barra/substrato originando defeitos indesejados, que podem ocorrer para vazões muito baixas ou velocidades do substrato elevadas. Este trabalho apresenta a simulação numérica do processo de revestimento por extrusão de fluidos Newtonianos utilizando a técnica Volume de Fluido (VOF) para determinar o limite de vazão mínima. O domínio de solução das equações 2D se restringe à parte a montante da barra de revestimento. Os resultados mostram que a espessura mínima de filme aumenta com o número de capilaridade, isto significa que, para obter filmes mais finos, a velocidade do processo produtivo deve ser baixa. Além da discussão sobre os limites operacionais é incluída uma revisão bibliográfica referente ao petróleo, células fotovoltaicas e métodos de revestimento. Palavras-chave: Escoamento bifásico, Limite de vazão mínima, Revestimento por extrusão, Volume de fluido. ABSTRACTPhotovoltaic solar cells are an attractive option to electric energy generation, but is still expensive if compared with traditional sources. One way to reduce the cost of solar cells is to use a thinner coating thickness. In the slot coating process, lower flow rates results in lower film thickness. However, there are physical and operational limits related with the method. One of them is the low-flow limit. This phenomena is observed at low film thickness, the downstream meniscus invades the gap between downstream slot die lip and the substrate creating a permanent and undesirable defect in the substrate. This work presents the numerical simulation of the slot coating process of Newtonian fluids, with the volume of fluid technique in order to determine the low-flow limit. The solution domain of the 2D governing equations is restricted to the downstream section of the slot coating die. It is verified that the minimal wet coating thickness increase with the capillary number, which means that thinner films will be obtained at lower substrate velocity. Further on the discussion about operational limits, highlighting the low flow limit, it is included a bibliographic revision about the oil production, photovoltaic solar cells and coating methods.

show abstract

A computational study of the effect of viscoelasticity on slot coating flow of dilute polymer solutions

Cited by 27 publications

References 40 publications

Viscoelastic flow in a two-dimensional collapsible channel

Viscoelastic flow in a two-dimensional collapsible channel

A model for film-forming with Newtonian and shear-thinning fluids

Redução da espessura de filme na fabricação de células fotovoltaicas

Contact Info

Product

Resources

About