The impact of viscosity on the combined heat, mass and momentum transfer in laminar liquid falling films

Mittermaier, M.; Ziegler, Felix

doi:10.1007/s00231-017-2219-9

Cited by 7 publications

(4 citation statements)

References 25 publications

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“…In contrast, when 1D diffusion was supposed, the mass balance at the interface changes. Similar to Mittermaier and Ziegler [49], the absorbed mass flux was determined with: (15) For penetration theory of Higbie [29], notably, some studies used the expression suggested to calculate the average absorbed mass flux over a given flow length to consider the local mass flux. The original formulation of the local mass flux assumes 2D diffusion [50], as (16) as where is the maximum velocity at the interface, is the flow length, and and are the equilibrium mass fraction at the interface and the mass fraction of the solution adjacent to the wall, respectively.…”

Section: Source Termsmentioning

confidence: 99%

Numerical analysis of different mass transfer models for falling film absorbers

Arroiabe

Martinez‐Agirre

Bou-Ali

2022

International Journal of Heat and Mass Transfer

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Section: Source Termsmentioning

confidence: 99%

Numerical analysis of different mass transfer models for falling film absorbers

Arroiabe

Martinez‐Agirre

Bou-Ali

2022

International Journal of Heat and Mass Transfer

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“…The hydrodynamic model results in longitudinal and transversal velocity components and their evolution in the entrance region. The numerical solution is obtained by utilising a Newton-Raphson method to solve the finite difference formulation of the governing equations and is described in Mittermaier and Ziegler (2015). Parts of the description are repeated here:…”

Section: Model Descriptionmentioning

confidence: 99%

Theoretical evaluation of absorption and desorption processes under typical conditions for chillers and heat transformers

Mittermaier

Ziegler

2015

International Journal of Refrigeration

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Highlights • Comparison of absorption and desorption for absorption chillers & heat transformers• Absorption chiller: thin film leads to higher transfer rate during desorption • Heat transformer: favourable properties lead to higher transfer rate for absorption • Various assumptions have been evaluated to substantiate the effects Abstract A comparison of absorption and desorption is conducted using a detailed model describing heat and mass transfer. First, the influences of various assumptions have been evaluated. Second, typical conditions for both absorption chillers and heat transformers have been defined. The performance of absorption and desorption processes have been analysed for a flow length of 0.1m. In an absorption chiller, during desorption, the viscosity is lowered and the mass diffusivity is increased. These circumstances cause a 46% higher transfer rate as compared to absorption. Thus, the overall performance of the process is determined by the absorber component. In a heat transformer, during absorption at an elevated pressure and temperature level, the viscosity is lower and mass diffusivity is higher as compared to desorption. Therefore, the transfer rate of during absorption is 10% higher as compared to desorption. Hence, the desorber performance is somewhat more influential to the overall system performance. Nomenclature c pHeat capacityLongitudinal velocity (m s −1 )x Longitudinal coordinate, streamwise (m) y Transversal coordinate (m) Greek letters   Mass flow per unit length (kg m −1 s −1 ) sor h  Heat of sorption (J kg −1 ) δ Film thickness (m) λ Thermal conductivity (W m −1 K −1 ) μ Dynamic viscosity (Pa s) ξ Mass fraction (−) Page 2 of 25 ρ Density (kg m −3 ) Subscripts 0 Inlet condition abs Absorption avg Average A Absorbate e.g. water in liquid state des Desorption eq Equilibrium if Interface S Solution of absorbent e.g. LiBr − H 2 O V Vapour e.g. steam W Wall

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“…Most interesting applications of this phenomenon include food processing, absorption, thermal wadding, diffusion of nutrition in tissues heat oil, heterogeneous catalysis in suspension cooling of nuclear reactors, and geothermal reservoir. Such valuable applications insist the researchers discuss such effects by using different fluids models under different flow features …”

Section: Introductionmentioning

confidence: 99%

“…Such valuable applications insist the researchers discuss such effects by using different fluids models under different flow features. [1][2][3][4][5] Indeed, the rheology and interdisciplinary nature of non-Newtonian fluids led researchers to suggest various fluid models. The flow of non-Newtonian fluids brings a broader range of applications in the chemical and allied processing industries.…”

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confidence: 99%

Significance of the nonlinear radiative flow of micropolar nanoparticles over porous surface with a gyrotactic microorganism, activation energy, and Nield's condition

Waqas

Khan

Shehzad

et al. 2019

Heat Trans. Asian Res.

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Current continuation presents the numerical study regarding stretched flow micropolar nanofluid over moving the sheet in the existence of activation energy and microorganisms. Furthermore, nonlinear aspects of thermal radiation are also utilized in the energy equation which results in the energy equation becomes highly nonlinear. This investigation has been performed by using convective Nield boundary conditions. First, useful dimensionless variables are implemented to reduce the partial differential into ordinary ones. Later on, the approximate solution of the transformed physical problem is computed by using the shooting scheme. A detailed physical interpretation of obtained results is also presented for velocity, temperature, motile microorganisms density, and mass concentration profiles. A detailed graphical explanation for each engineering parameter has been discussed for some specified range like 0 goodbreakinfix≤ K 1 goodbreakinfix≤ 1.5 , 0.1 goodbreakinfix≤ m goodbreakinfix≤ 0.7 , 0.1 goodbreakinfix≤ K goodbreakinfix≤ 0.7 , 0.1 goodbreakinfix≤ N t goodbreakinfix≤ 2.4 , 0.1 goodbreakinfix≤ γ goodbreakinfix≤ 0.4 , 1.0 goodbreakinfix≤ italicPr goodbreakinfix≤ 1.8 , 0.4 goodbreakinfix≤ R d goodbreakinfix≤ 1.0 , 0.2 goodbreakinfix≤ N b goodbreakinfix≤ 0.8 , 0.1 goodbreakinfix≤ E goodbreakinfix≤ 7.0, and 0.4 goodbreakinfix≤ L b goodbreakinfix≤ 1.0 . The theoretical computations based presented here can be more proficient to attain the maximum efficiency of various thermal extrusion systems and microbial fuel cells.

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The impact of viscosity on the combined heat, mass and momentum transfer in laminar liquid falling films

Cited by 7 publications

References 25 publications

Numerical analysis of different mass transfer models for falling film absorbers

Numerical analysis of different mass transfer models for falling film absorbers

Theoretical evaluation of absorption and desorption processes under typical conditions for chillers and heat transformers

Significance of the nonlinear radiative flow of micropolar nanoparticles over porous surface with a gyrotactic microorganism, activation energy, and Nield's condition

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