Application of reflux classifier with closely spaced inclined channels in pre-concentrate process of fine antimony oxide particles

In this work,the reflux classifier with closely spaced inclined channels is used as the pre-concentration facility to improve the separation efficiency before the shaking table separation.Three operating parameters of reflux classifier(RC)to pre-concentrate fine(0.023−0.15 mm)tailings of antimony oxide were optimized by response surface methodology(RSM)using a three-level Box-Behnken design(BBD).The parameters studied for the optimization were feeding speed,underflow,and ascending water speed.Second-order response functions were produced for the Sb grade and recovery rate of the concentrate.Taking advantage of the quadratic programming,when the factors of feeding,underflow and ascending water are respectively 225,30 and 133 cm^3/min,a better result can be achieved for the concentrate grade of 2.31% and recovery rate of 83.17%.At the same time,70.48% of the tailings with the grade of 0.20% were discarded out of the feeding.The results indicated that the reflux classifier has a good performance in dealing with fine tailings of antimony oxide.Moreover,second-order polynomial equations,ANOVA,and three-dimensional surface plots were developed to evaluate the effects of each parameter on Sb grade and recovery rate of the concentrate.

Irreversibility investigation of Casson fluid flow in an inclined channel subject to a Darcy-Forchheimer porous medium:a numerical study

The heat transfer and entropy generation characteristics of the magnetohydrodynamic Casson fluid flow through an inclined microchannel with convective boundary conditions are analyzed.Further,the effects of the viscous forces,Joule heating,heat source/sink,and radiation on the flow are taken into account.The non-dimensional transformations are used to solve the governing equations.Then,the reduced system is resolved by the fourth-fifth order Runge-Kutta-Fehlberg method along with the shooting technique.The effects of different physical parameters on the heat transfer and entropy generation are discussed in detail through graphs.From the perspective of numerical results,it is recognized that the production of entropy can be improved with the Joule heating,viscous dissipation,and convective heating aspects.It is concluded that the production of entropy is the maximum with increases in the Casson parameter,the angle of inclination,and the Hartmann number.Both the Reynolds number and the radiation parameter cause the dual impact on entropy generation.

Adopting inclined channel to decline the salinity mixing for rotary energy recovery device:Simulation and optimization

After years of research,the energy efficiency of energy recovery device has been raised to a high level,but the salinity mixing has not been effectively improved.Mixing will lead to a rise of highpressure seawater salinity,which will increase the operating cost.In this paper,the computational fluid dynamics(CFD)simulation of the rotary energy recovery device(RERD)is carried out.It is found that the unstable flow caused by the nonparallel between the channel and the flow direction of fluid is an important reason for mixing.After the inclined channel structure is adopted,the nonparallel problem is improved.The formation of unstable flow is effectively controlled.Under the commercial product operating conditions,the volumetric mixing of the optimized device is reduced from 3.34%to 1.29%,showing the effectiveness of the structure.

Optimization and Simulation of Inclined Channel Area Lining for CDQ Ovens

The mechanical force borne by the lintel and“brackets”in the inclined channel area of CDQ and the thermal stress generated by the top-down temperature gradient were simulated by ANSYS software.The following conclusions are drawn.(1)The mechanical force has very mild effect on the damage of the“brackets”.(2)The temperature gradient caused by the uneven temperature distribution of CDQ oven is the key factor affecting the“bracket”damage.The different expansion of refractory materials in various parts results in the thermal stress concentration which tears the“brackets”.(3)The structure adjustment of the“brackets”has very little effect on the thermal stress distribution.(4)The multi-phase nitride bonded silicon carbide for CDQ can effectively alleviate the stress concentration at the“brackets”,realizing the long-life and stable operation.

Influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel

The influence of variable viscosity and double diffusion on the convective stability of a nanofluid flow in an inclined porous channel is investigated.The DarcyBrinkman model is used to characterize the fluid flow dynamics in porous materials.The analytical solutions are obtained for the unidirectional and completely developed flow.Based on a normal mode analysis,the generalized eigenvalue problem under a perturbed state is solved.The eigenvalue problem is then solved by the spectral method.Finally,the critical Rayleigh number with the corresponding wavenumber is evaluated at the assigned values of the other flow-governing parameters.The results show that increasing the Darcy number,the Lewis number,the Dufour parameter,or the Soret parameter increases the stability of the system,whereas increasing the inclination angle of the channel destabilizes the flow.Besides,the flow is the most unstable when the channel is vertically oriented.

Numerical Investigation of"Frog-Leap"Mechanisms of Three Particles Aligned Moving in an Inclined Channel Flow

Intrigued by our recent experimental work(H.Yamaguchi and X.D.Ni-u,J.Fluids Eng.,133(2011),041302),the present study numerically investigate theflow-structure interactions(FSI)of three rigid circular particles aligned moving in an inclined channelflow at intermediate Reynolds numbers by using a momentum-exchanged immersed boundary-lattice Boltzmann method.A"frog-leap"phenomenon observed in the experiment is successfully captured by the present simulation and flow characteristics and underlying FSI mechanisms of it are explored by examining the ef-fects of the channel inclined angles and Reynolds numbers.It is found that the asym-metric difference of the vorticity distributions on the particle surface is the main cause of the"frog-leap"when particle moves in the boundary layer near the lower channel boundary.

MHD peristaltic flow in an inclined channel with heat and mass transfer

This paper addresses the peristaltic flow of magnetohydrodynamic viscous fluid in an inclined compliant wall channel. Different wave amplitudes and phases ensure asymme- try in the channel flow configuration. Simultaneous effects of heat and mass transfer are also considered. Viscous dissipation effect is present. The flow and heat transfer are investigated under long wavelength and low Reynolds number assumption. The expres- sions for stream function, axial velocity, temperature and concentration are obtained. The solution expressions for physical quantities are sketched and discussed. It is found that Brinkman and Hartman numbers have reverse effect on the temperature.

Hybrid Effects of Thermal and Concentration Convection on Peristaltic Flow of Fourth Grade Nanofluids in an Inclined Tapered Channel: Applications of Double-Diffusivity

This article brings into focus the hybrid effects of thermal and concentration convection on peristaltic pumping of fourth grade nanofluids in an inclined tapered channel.First,the brief mathematical modelling of the fourth grade nanofluids is provided along with thermal and concentration convection.The Lubrication method is used to simplify the partial differential equations which are tremendously nonlinear.Further,analytical technique is applied to solve the differential equations that are strongly nonlinear in nature,and exact solutions of temperature,volume fraction of nanoparticles,and concentration are studied.Numerical and graphical findings manifest the influence of various physical flow-quantity parameters.It is observed that the nanoparticle fraction decreases because of the increasing values of Brownian motion parameter and Dufour parameter,whereas the behaviour of nanoparticle fraction is quite opposite for thermophoresis parameter.It is also noted that the temperature profile decreases with increasing Brownian motion parameter values and rises with Dufour parameter values.Moreover,the concentration profile ascends with increasing thermophoresis parameter and Soret parameter values.

Peristaltic transport of MHD Williamson fluid in an inclined asymmetric channel through porous medium with heat transfer

The intention of this investigation is to study the effects of heat transfer and inclined magnetic field on the peristaltic flow of Williamson fluid in an asymmetric channel through porous medium. The governing two-dimensional equations are simplified under the assumption of long wavelength approximation. The simplified equations are solved for the stream function, temperature, and axial pressure gradient by using a regular perturbation method. The expression for pressure rise is computed numerically. The profiles of velocity, pressure gradient, temperature, heat transfer coefficient and stream function are sketched and interpreted for various embedded parameters and also the behavior of stream function for various wave forms is discussed through graphs. It is observed that the peristaltic velocity increases from porous medium to non-porous medium, the magnetic effects have increasing effect on the temperature, and the size of the trapped bolus decreases with the increasing of magnetic effects while the trend is reversed with the increasing of Darcy number. Moreover, limiting solutions of our problem are in close agreement with the corresponding results of the Newtonian fluid model.

Mixed convective flow of a hybrid nanofluid between two parallel inclined plates under wall-slip condition

The mixed convection flow of a hybrid nanofluid in an inclined channel with top wall-slip due to wall stripe and constant heat flux conditions is studied.Explicit analytical solutions are given to the flow velocity,temperature,as well as the pressure in non-dimensional forms.The flow regime domain,the velocity and temperature distributions,and the dependence of various physical parameters such as the hybrid nanoparticle volume fractions,the wall-slip,the Grashof number,the Reynolds number,and the inclined angle are analyzed and discussed.It is found that the hybrid nanofluid delays the appearance of flow reversal on both walls and the wall-slip postpones the flow reversal on the top wall.

Development and Application of Multi-phase Nitrides Bonded Silicon Carbide Lintel Blocks for Dry Quenching Furnaces

Multi-phase nitrides bonded silicon carbide lintel blocks were prepared using industrial SiC(SiC≥98 mass%,3-0.5,≤0.5 and≤0.044 mm),Si powder(Si≥98 mass%,≤0.044 mm),and SiO2 micropowder(SiO2≥96 mass%,d50=0.15 pm)as raw materials,and calcium lignosulfonate as the additive,batching,mixing,and molding on a vibration pressure molding machine,drying and then firing at 1420℃for 10 h in high-purity N2.The apparent porosity,the bulk density,the cold modulus of rupture,the hot modulus of rupture,and the linear expansion coefficient of the samples were tested.The phase composition and the microstructure of the samples at different nitriding depths(50,100,and 150 mm)were analyzed by XRD and SEM.The field application effects of the blocks were studied.The results show that:(1)the multi-phase nitrides bonded silicon carbide refractories can dynamically adjust their own phase composition and minimize structural and thermal stresses,improving the service life of key parts of dry quenching furnaces;(2)calcium lignosulfonate can improve the nitriding micro-environment of multi-phase nitrides bonded silicon carbide lintel blocks,successfully increasing the effective nitriding thickness of the blocks to 300 mm;(3)Sinosteel LI RR provides a unique concept in the design of materials and block types as well as the stable and scientific overall structure,promoting the industrialization process of dry quenching furnaces with long service life in China.

Analytical analysis of inclined three-layered composite channel with cobalt ferrite nanoparticles and Hall current in Darcy medium

The present study explores the influence of electromagnetic effects on the flow of a nanofluid in a saturated permeable medium,confined between a clear viscous fluid in an inclined channel.The nanofluid consists of cobalt ferrite nanoparticles dispersed in ethylene glycol.The governing equations are derived considering Darcy's law for the permeable medium and Tiwari's model for fluids containing nano-sized particles.Additionally,radiation and dissipation effects are incorporated into the energy equation.The equations are transformed into dimensionless form and solved analytically using the perturbation technique.The results are analyzed through graphs and tables for different material parameters.The findings reveal that higher electric and magnetic strengths have a significant impact on the fluid velocity at the interface of the two fluids,resulting in reduced shear both at the clear fluid surface and the interface between them.This highlights the crucial role played by electric and magnetic strengths in modifying flow phenomena.Consequently,combining electric and magnetic strengths with nanofluids can be utilized to achieve desired qualities in multi-fluid flow and enhance heat transfer characteristics.

EFFECT OF SLIP AND MAGNETIC FIELD ON PERISTALTIC FLOW IN AN INCLINED CHANNEL WITH WALL EFFECTS

Peristaltic transport of a Newtonian incompressible fluid in the presence of applied mag netic field in an inclined channel with slip is investigated. A perturbation method of solu tion is obtained in terms of wall slope parameter and analytical expressions are derived for average velocity and stream function using Saffman slip condition. The effects of var ious relevant parameters on average velocity and stream line pattern have been studied. It is found that average velocity increases with slip and decreases with permeability and magnetic parameter.

Motion characteristics of binary solids in a liquid fluidised bed with inclined plates

Rectangular inclined channels prove promising for solid classification based on the principle of parti- cle differential sedimentation. In the present work, we investigated the motion characteristics of binary solids in a modified fluidised bed （mFB） with inclined plates. We developed a theoretical model for the particle motion behaviour that accounts for the average solid volume fraction in the inclined channel and interactions between binary solids. The experimental system was designed to be consistent with the idealised theoretical arrangements to maximise the measurement accuracy. The experimental particles were mixtures of silica sand particles of sizes 425-710 i^m and 710-880/~m, respectively. Specifically, we investigated the flow hydrodynamics of the binary suspension in terms of the settling length of both par- ticle species and the bed expansion behaviour. We also analysed the utilisation factor and the separation efficiency of the mFB. The results showed that the average solid volume fraction in the inclined channel fluctuated slightly for a given total solid inventory. The utilisation factor and separation efficiency of the system decreased when increasing either the fluidisation velocity or the solid inventory. The prediction results were in good agreement with the experimental data with an absolute deviation of less than 15%.