Analysis of flow pattern characteristics and strengthening mechanism of co-rotating and counter-rotating mixing with double impellers on different string shafts

Based on two cases of the double impellers on different shafts in the co-rotating and counter-rotating, the distribution of the velocity, streamline, turbulent kinetic energy, and turbulent energy dissipation rate are obtained through three-dimensional unsteady numerical simulation. Very good agreements between experimental and numerical results have been obtained. The hydrometallurgy purification experimental platform was built with the size of one third of the simulated. The results show that the mechanical string mixing system with double impellers on different shafts can form a more obvious convection effect in the central area of the double impellers, which can effectively break the mixing isolation region and improve the mixing effect. In the co-rotating case, the two impellers can generate strong convection in the central area and form an interactive vortex and a high-speed flow channel between the two impellers. while the convection formed by counter-rotating case is weaker and the vortex structures are independent of each other. The counter-rotating system performs better in the macro momentum transfer and the co-rotating system performs better in the micro-mixing level. In the experiments of hydrometallurgy purification, 7.93% more energy is used in the co-rotating system than that of the counter-rotating system. The average energy consumed by co-rotating in the process of purifying every one percent of Cd2+ ions are 8.65% lower than that of counter-rotating. The co-rotating system can improve microscopic mass transfer effect and finally save energy and time compared to the counter-rotating system.

Heat and Mass Transfer Effect on an Infinite Vertical Plate in the Presence of Hall Current and Thermal Radiation with Variable Temperature

MHD and radiated heat flow on a rotating system of an electrically conducting fluid in the presence of Hall current under the influence of variable temperature is studied analytically. An exact solution of a non-dimensional form of coupled partial differential equations is obtained by the technique of Laplace transform. The effect of temperature, velocity and concentration is analyzed for various parameters like the Hall parameter (m), thermal radiation (R), rotation parameter (Ω), Hartmann number (M) and results are discussed in detail with the help of graphs. A mixed analysis of a rotating fluid with Hall current and thermal radiation plays a very essential role in the research area such as plasma physics, MHD generator, fluid drift sensor, cosmological and geophysical level, etc.

Numerical Simulation for Convective Heat and Mass Transfer Effect of Micropolar Nanofluid Flow with Variable Viscosity and Radiation

The present work gives out the heat and mass transfer effect of micropolar nanofluid flow. The fluid viscosity is assumed as temperature dependent and it varies linearly. The radiative heat flux and the viscous dissipation are also considered in the energy equation. The partial differential equations governing the flow have been transformed into system of ordinary differential equation and explained numerically through fourth order Runge-Kutta method with shooting technique. Fluid properties such as velocity, angular velocity, temperature, and concentration are analyzed graphically for a range of solid volume fraction (0<ɸ<2) of nanosolid particles.

Mass Transfer Effect on a Rotating MHD Transient Flow of Liquid Lead Through a Porous Medium in Presence of Hall and Ion Slip Current with Radiation

A problem of unsteady MHD convective flow of liquid lead through an impulsively started semi infinite vertical porous plate in presence of a transversely applied uniform magnetic field under the effects of Hall current, ion slip current and chemical reaction is investigated. The fluid is considered to be incompressible while the magnetic Reynolds number is assumed to be very small. An exact solution to the flow model is obtained adopting Laplace Transform Technique in closed form. The effects of the relevant physical parameters on the velocity field, temperature field and concentration field are displayed graphically and the effects on skin friction, Nusselt number and Sherwood number are presented in tabular form.

SYNTHESIS OF HIGHLY DISPERSED MOLYBDATE OF COBALT IN THE MELT SYSTEM (Na2MoO4 - NaCl)EVT – CoSO4

The paper presents a new computational and experimental material for the development of a rational method for obtaining one of the significant representatives of the elements of the d-family-cobalt molybdate in melts of the system (Na2MoO4 - NaCl)evt-CoSO4 in a highly dispersed state at a relatively low temperature and high process performance. It contains extensive material on the properties and applications of cobalt molybdenum, a critical analysis of which indicates the need to develop new approaches to the synthesis of such a unique compound. Along with experimental problems, the article also solves a number of theoretical issues. In particular, we are talking about the application of the mass transfer effect between Mn(Fe,Co)MoO4 – Na2CO3 systems and the environment for the first time revealed by the authors to the analysis of the drug CoMoO4 synthesized in the work. The mechanism of manifestation of this phenomenon, which, as shown by theoretical analysis and experimental data, due to polyvalences cobalt. Therefore, this is due to the possibility of leakage in the system CoMoO4–Na2CO3 exchange reaction CoMoO4+Na2CO3→CoCO3+Na2MoO4, dissociation CoCO3=CoO+CO2 and redox of хCoO+1/2О2→CoхOу, where y=x+1, leading to the loss of CO2 and the transformation of CoO – product of the decomposition of CoCO3 at the expense of the oxygen environment to the oxide type CoхOу, the composition of which is determined by the process temperature. The experimental data obtained in this work confirm the effectiveness of the mass transfer effect in the analysis of molybdenum and tungstates of polyvalent d-elements. Much attention is paid to the comprehensive study of the obtained cobalt molybdate in the system (Na2MoO4 - NaCl)evt–CoSO4 by a complex of physical and chemical methods (thermodynamic, x-ray phase, dispersion, chemical kinetic (thermogravimetric)).

Heat and mass transfer effect on a radiative second grade MHD flow in a porous medium over a stretching sheet

A study on heat and mass transfer of a steady laminar boundary layer flow of an electrically conducting fluid of second grade in a porous medium subject to a uniform magnetic field past a semi-infinite stretching sheet with power law surface temperature or power law surface heat flux. The variations in fluid velocity, fluid temperature and species concentration are displayed graphically whereas the numerical values of skin friction, Nusselt number and Sherwood number are presented in tabular form for various values of the pertinent flow parameters. The asymptotic expansions of the solutions for large Prandtl number are also given for the two heating conditions. The temperature distribution decreases with the increase in thermal radiation parameter in case of PST and PHF. The rate of mass transfer at the solid surface increases in the presence of magnetic field and decreases with heavier diffusing species.