scholarly journals Heat and Mass Transfer in a Thin Liquid Film over an Unsteady Stretching Surface in the Presence of Thermosolutal Capillarity and Variable Magnetic Field

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Yan Zhang ◽  
Min Zhang ◽  
Shujuan Qi
Keyword(s):  
Magnetic Field ◽  
Mass Transfer ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Capillary Number ◽  
Thin Liquid Film ◽  
Perturbation Expansion ◽  
Expansion Method ◽  
Variable Magnetic Field ◽  
Unsteady Stretching Surface

The heat and mass transfer characteristics of a liquid film which contain thermosolutal capillarity and a variable magnetic field over an unsteady stretching sheet have been investigated. The governing equations for momentum, energy, and concentration are established and transformed to a set of coupled ordinary equations with the aid of similarity transformation. The analytical solutions are obtained using the double-parameter transformation perturbation expansion method. The effects of various relevant parameters such as unsteady parameter, Prandtl number, Schmidt number, thermocapillary number, and solutal capillary number on the velocity, temperature, and concentration fields are discussed and presented graphically. Results show that increasing values of thermocapillary number and solutal capillary number both lead to a decrease in the temperature and concentration fields. Furthermore, the influences of thermocapillary number on various fields are more remarkable in comparison to the solutal capillary number.

Entropy Minimization in an Evaporating Thin Liquid Film in Capillary Tubes

2007 ◽  
Author(s):  
Rama Subba Reddy Gorla ◽  
Thamilselvan Nallappan ◽  
Larry W. Byrd ◽  
David M. Pratt
Keyword(s):  
Mass Transfer ◽  
Fluid Flow ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Flow Resistance ◽  
Capillary Tube ◽  
Thin Liquid Film ◽  
Thermodynamic Optimization ◽  
Transfer Rates ◽  
Driven Systems

An analysis has been provided for the entropy generated for the micro/nano scale heat and mass transfer in a capillary tube in terms of the gradients of velocity, temperature and concentration as well as the physical properties of the fluid. The heat and mass transfer rates are assumed to be uniform on the surface of the capillary tube. The optimum tube diameter that corresponds to the minimization of entropy generated and minimization of fluid flow resistance is about one millimeter. We have applied the method of thermodynamic optimization to capillary driven systems.

scholarly journals Numerical study of heat and mass transfer during evaporation of a thin liquid film

2015 ◽  
Vol 19 (5) ◽  
pp. 1805-1819 ◽  
Author(s):  
M’hand Oubella ◽  
M’barek Feddaoui ◽  
Rachid Mir
Keyword(s):  
Mass Transfer ◽  
Liquid Film ◽  
Heat And Mass Transfer ◽  
Numerical Study ◽  
Thin Liquid Film ◽  
Simple Algorithm ◽  
Liquid Films ◽  
Inlet Temperature ◽  
Transfer Rates ◽  
Film Evaporation

A numerical study of mixed convection heat and mass transfer with film evaporation in a vertical channel is developed. The emphasis is focused on the effects of vaporization of three different liquid films having widely different properties, along the isothermal and wetted walls on the heat and mass transfer rates in the channel. The induced laminar downward flow is a mixture of blowing dry air and vapour of water, methanol or acetone, assumed as ideal gases. A two-dimensional steady state and elliptical flow model, connected with variable thermo-physical properties, is used and the phase change problem is based on thin liquid film assumptions. The governing equations of the model are solved by a finite volume method and the velocity-pressure fields are linked by SIMPLE algorithm. The numerical results, including the velocity, temperature and concentration profiles, as well as axial variations of Nusselt numbers, Sherwood number and dimensionless film evaporation rate are presented for two values of inlet temperature and Reynolds number. It was found that lower the inlet temperature and Re, the higher the induced flows cooling with respect of most volatile film. The better mass transfer rates related with film evaporation are found for a system with low mass diffusion coefficient.

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