Numerical Analysis Of Mass Transfer Research Articles

Simultaneous in situ measurements and numerical analysis of mass transfer in polymer electrolyte fuel cell electrode slurries during drying

Simultaneous in situ measurements and numerical analysis of mass transfer in polymer electrolyte fuel cell electrode slurries during drying

Numerical Analysis of Mass Transfer in MHD Nanoparticle Based Crude Oil Flow on a Flat Plate under Various Slip Condition

This work analyzed of crude oil based nanofluid of Al2O3, Cu, SWCNTs (single walled carbon nanotubes) the mass transfer in two dimensional MHD of incompressible steady, viscous and electrically conducting in the presence of magnetic field over a flat plate under various slip conditions. The result was obtained using similarity transformation and the fourth-fifth order Runge Kutta Fehlberg technique with shooting method using Maple 18. The velocity profile and the nanoparticle concentration were plotted for both low and high velocity slip conditions. Various effects of parameters were tested on the rate of skin friction and mass transfer. The effect that involves the magnetic parameter M, buoyancy ratio G, Schmidt number Sc, velocity slip parameter and nanoparticle volume fraction were analyzed. It was found that magnetic field with Grashof number and Schmidt number parameters are dominant on momentum and concentration dimensionless parameters. Copper with velocity slip 0.1 was higher shear stress then other materials as well as, for SWCNT with velocity slip 1.0 was lower shear stress. Furthermore, copper with velocity slip 0.1 is higher of mass transfer than other materials as well as oxide aluminium is lower compared to other materials with velocity slip 1.0.

Numerical analysis of mass transfer and material mixing in friction stir welding of aluminum/magnesium alloys

A computational fluid dynamics model was developed for numerical simulation of heat & mass transfer and material mixing in friction stir welding of dissimilar aluminum and magnesium alloys. It considered the stress reduction caused by the recrystallization around the tool, the local composition liquefaction due to eutectic reaction between the aluminum/magnesium solid solution and the intermetallic compounds as well as the local turbulence below the tool pin. With comparison of the calculated and experimentally observed material mixing and distribution, it was found that the local turbulence is a key factor influencing the formation of the severe intercalated zone and the mixing zone and the widening of the mixing zone at trailing side. The model was also validated by comparing the predicted and measured thermal cycles at both advancing and retreating sides.

Non-dispersive solvent extraction of p-toluic acid from purified terephthalic acid plant wastewater with p-xylene as extractant

Non-dispersive solvent extraction (NDSE) with p-xylene as extractant was employed as a novel separation method to recover both p-toluic (PT) acid and water from purified terephthalic acid (PTA) wastewater. The mass transport behavior of PT acid from aqueous solution to p-xylene was investigated by experiments and numerical simulation. Experiments showed that NDSE is feasible and effective. Residual PT acid in the raffinate can be reduced to lower than the permitted limit of wastewater re-use (100 g/m3) with extraction time longer than 60 s in industrial conditions. A mathematical model of PT acid mass transport was developed to optimize the membrane module performance. The model was validated with the experimental results with relative errors of less than 6%. Numerical analysis for mass transfer through the lumen side, the porous membrane layer, and the shell side showed that PT acid transport in the aqueous solution is the rate determining step. The effects of the membrane and operating parameters on membrane module performance were investigated by means of computational simulations. The key parameters suggested for industrial NDSE design are: fiber inner radius r1=200–250 µm, extraction time te=50–60 s, aqueous/organic volumetric ratio a/o=9.0, and temperature T=318 K.

Experimental and numerical analysis of mass transfer in a binary mixture with Soret effect in the presence of weak convection.

One of the targets of the experiment IVIDIL (Influence Vibrations on Diffusion in Liquids) conducted on-board ISS was to study the response of binary mixtures to vibrational forcing when the density gradient results from thermal and compositional variations. Compositional variations were created by the Soret effect and can strengthen or weaken the overall density gradient and, consequently, the response to vibrational forcing. We present the results of two experimental runs conducted on-board ISS in the frame of the experiment IVIDIL for low and strong vibrational forcing. The experimental observations revealed that a significant mean flow is set within 2 minutes after imposing vibrations and later in time it varies weakly and slowly due to the Soret effect. A mathematical model has been developed to compute the thermal and concentration fields in the experiment IVIDIL and verify the accuracy of picture processing based on the classical approach used in non-convective systems with the Soret effect. The effect of temperature and concentrations perturbations by joint action of vibrational convection and Soret effect on long time scale are carefully examined. The model demonstrates that image processing used for non-convective systems is suitable for the systems with vibration-affected thermodiffusion experiment.

Numerical analysis of mass transfer in packed-bed reactors with irregular particle arrangements

Packed bed reactors with moderate tube-to-particle diameter ratios are studied numerically using the computational fluid dynamics approach. Irregular particle arrangements within the reactors are generated by a modified ballistic deposition method. The study is focused on mass transfer phenomena in the reactors, while two different case studies are selected for numerical analysis, basically imitating the relevant experimental procedures. The first one is the dissolution of benzoic acid particles in water, the second one is the sublimation of naphthalene particles in air. To validate the simulation results, experimental mass transfer correlations from literature are used and a good agreement between numerical and experimental results is found. The numerical analysis provides useful data that can be applied for the improvement of the packed bed performance as well as for a deeper understanding of the fundamental transport phenomena in such reactors.

Numerical analysis of mass transfer in double-pass parallel-plate dialyzers with external recycle

The effect of external recycle on the performance of dialysis in double-pass rectangular membrane modules was investigated. Theoretical analysis of mass transfer in parallel-flow dialyzers is analogous to heat transfer in parallel-flow heat exchangers. In contrast to a single-pass device without recycle, improvement in mass transfer of about 30% is achievable if parallel-flow dialysis is operated in a double-pass device of same size with external recycle which provides the increase of fluid velocity, resulting in reduction of mass-transfer resistance.

Analysis of mass transfer in dissipative nonideal systems: Numerical simulation

The results of a numerical analysis of mass transfer in extended quasi-two-dimensional and three-dimensional dissipative nonideal systems are presented. Pair interaction between particles is modeled by isotropic repulsive potentials represented by combinations of power laws and exponentials. Simulations are performed for parameter values characteristic of laboratory dusty plasmas. It is shown that short-time particle dynamics in nonideal liquid systems is similar to evolution of thermal oscillations at crystal lattice sites.

Simulation of mass transfer in systems with isotropic pair correlation of particles

Results of a numerical analysis of mass transfer in systems of macroscopic particles with various isotropic interaction potentials are presented. Parameters that determine transport properties of nonideal dissipative systems are obtained for a broad class of model potentials. An approximate expression for the diffusivity of interacting particles is proposed. The relationship between diffusivity and viscosity is analyzed for strongly nonideal systems.

Numerical Analysis of Mass Transfer from an Evaporating or Condensing Binary Solution Drop under High Mass Flux Condition.

Numerical analyses for mass transfer from a binary solution drop with surface mass ejection or suction are made by using a finite difference method for diagonal Schmidt number Sc AA =1-3, Sc BB =1-2, Reynolds number Re p =10-100 and surface mass ejection or suction ratios Φ=-0.23∼0.21 at nondiagonal Schmidt number Sc AB =5, Sc BA =5 and driving force ratios Δω B /Δω A =5. The average diffusion fluxes of a binary solution drop after due consideration of the effect of interaction between diffusion fluxes are affected by Re p , Sc AA and Φ. A new correlation for the average diffusion fluxes of a binary solution drop with surface mass ejection or suction is proposed in terms of multicomponent transfer numbers.

Mass Transfer at a Microelectrode in Channel Flow

Several recent papers have been devoted to numerical analysis of mass transfer from rectangular microband or circular microdisk electrodes placed in a parabolic channel flow. The numerical calculations typically show good agreement with experimental results. Frequently, the geometry and flow conditions are such that all the mass transfer occurs in a thin layer adjacent to the electrode, and such confinement simplifies the characterization of the transport to the problem of mass transfer in a shear flow. Analytical formulas are available for strip-shaped and disk-shaped geometries for both low and high Peclet numbers (the dimensionless wall shear rate) and are shown here to be in good agreement with the published experimental electrochemical results.

Numerical Analysis of Mass Transfer with Graphite Oxidation in a Laminar Flow through a Circular Tube.

Mass transfer has been numerically studied in a laminar flow through a circular graphite tube at high temperature. Homogeneous (carbon monoxide combustion) and heterogeneous (graphite oxidation) chemical reactions occur in the multicomponent gas mixture : helium, oxygen, carbon monoxide and carbon dioxide. The effects of carbon monoxide combustion and graphite oxidation on the mass transfer coefficients were quantitatively and qualitatively clarified in the range of 50 to 1000 of inlet Reynolds number, 0 to 0.5 of inlet oxygen mass fraction and 800 to 1600°C of temperature.

A numerical analysis of mass transfer in a plane shear layer.

The two-dimensional unsteady motion of a plane shear layer and its mass transfer process were numerically simulated by using the discrete vortex method, combined with the third-order upwind finite difference method. A visualized distribution of the mass concentrations showed that the occurrence of entrainment corresponded to large eddy motion. The distribution profiles of the average concentration and the fluctuation intensity showed self-similarities. The distribution profile of the average concentration had a stepwise shape, and that of the fluctuation had two peaks. The entrainment of the fluid of the high-speed side proved to be larger than that of the low-speed side.

A numerical analysis of mass transfer in a plane shear layer.

The unsteady motion of a two-dimensional incompressible shear layer and its mass transfer process were numerically simulated by using the Discrete Vortex Method combined with the third-order Upwind Finite Difference Method. The visualized distribution of mass concentration showed that the occurrence of entrainment corresponded to the large eddy motion. The distribution profiles of the average concentration and the fluctuation intensity showed similarities. The distribution profile of the average concentration had a stepwise shape and that of the fluctuation had two peaks. The entrainment of the fluid of the high speed side proved to be larger than that of the low speed side.