This paper deals with the magnetohydrodynamic （MHD） flow of an Oldroyd 8-constant fluid in a porous medium when no-slip condition is no longer valid. Modified Darcy＇s law is used in the flow modelling. The non-line...This paper deals with the magnetohydrodynamic （MHD） flow of an Oldroyd 8-constant fluid in a porous medium when no-slip condition is no longer valid. Modified Darcy＇s law is used in the flow modelling. The non-linear differential equation with non-linear boundary conditions is solved numerically using finite difference scheme in combination with an iterative technique. Numerical results are obtained for the Couette, Poiseuille and generalized Couette flows. The effects of slip parameters on the velocity profile are discussed.展开更多
The sluggish kinetics of oxygen evolution reaction(OER)have seriously obstructed the industrial application of water electrolysis and rechargeable metal-air batteries.Intrigued by the molecular orbital bonding of O2 i...The sluggish kinetics of oxygen evolution reaction(OER)have seriously obstructed the industrial application of water electrolysis and rechargeable metal-air batteries.Intrigued by the molecular orbital bonding of O2 in a spin triplet state,magnetic field-assisted strategies are widely explored to boost OER electroctalytic activities such as magnetohydrodynamic(MHD)effect,magnetoresistance effect,magnetothermal effect,and spin effect.Here,we investigated the impact of magnetic fields on ferromagnetic catalysts,demonstrating that magnetic fields enhance OER activity by aligning spins and improving mass transfer;then we proposed reasonable verification methods for spin alignments.Subsequently,the possibilities of both mass diffusion and surface conditions besides the spin effect were analyzed sufficiently.Finally,we highlighted the importance of distinguishing spin effects from MHD influences.展开更多
The unique chemical mechanical, and thermodynamic properties of nanofluids make them a subject of great interest for scientists from all domains. Such fluids are of particular significance in biomedical engineering ow...The unique chemical mechanical, and thermodynamic properties of nanofluids make them a subject of great interest for scientists from all domains. Such fluids are of particular significance in biomedical engineering owing to their vast and novel applications in modern drug delivery systems; for example, mixed convective peristaltic flow of water-based nanofluids under the influence of an externally applied magnetic field is of particular significance. Hence, a lot of research has focused on peristalsis in the presence of velocity and thermal slip effects. An empirical relation for the effective viscosity of the nanofluid is proposed here for the first time. The viscosity of the nanofluid varies with temperature and nanoparticle volume fraction. Numerical simulation of the resulting nonlinear system of equations is presented for different quantities of interest. The results indicate that the maximum velocity and temperature of the copper-water nanofluid increase for larger variable viscosity parameter. The pressure gradient in the wider part of the channel is also found to increase as a function of the variable viscosity parameter. The variable viscosity parameter also influences the size of the trapped bolus. An increase in the nanoparticle volume fraction reduces the reflux phenomenon in a peristaltic flow.展开更多
文摘This paper deals with the magnetohydrodynamic （MHD） flow of an Oldroyd 8-constant fluid in a porous medium when no-slip condition is no longer valid. Modified Darcy＇s law is used in the flow modelling. The non-linear differential equation with non-linear boundary conditions is solved numerically using finite difference scheme in combination with an iterative technique. Numerical results are obtained for the Couette, Poiseuille and generalized Couette flows. The effects of slip parameters on the velocity profile are discussed.
基金supported by the National Natural Science Foundation of China(grant no.52172226)the Innovation Program of Shanghai Municipal Education Commission,China(grant no.2023FGS3).
文摘The sluggish kinetics of oxygen evolution reaction(OER)have seriously obstructed the industrial application of water electrolysis and rechargeable metal-air batteries.Intrigued by the molecular orbital bonding of O2 in a spin triplet state,magnetic field-assisted strategies are widely explored to boost OER electroctalytic activities such as magnetohydrodynamic(MHD)effect,magnetoresistance effect,magnetothermal effect,and spin effect.Here,we investigated the impact of magnetic fields on ferromagnetic catalysts,demonstrating that magnetic fields enhance OER activity by aligning spins and improving mass transfer;then we proposed reasonable verification methods for spin alignments.Subsequently,the possibilities of both mass diffusion and surface conditions besides the spin effect were analyzed sufficiently.Finally,we highlighted the importance of distinguishing spin effects from MHD influences.
文摘The unique chemical mechanical, and thermodynamic properties of nanofluids make them a subject of great interest for scientists from all domains. Such fluids are of particular significance in biomedical engineering owing to their vast and novel applications in modern drug delivery systems; for example, mixed convective peristaltic flow of water-based nanofluids under the influence of an externally applied magnetic field is of particular significance. Hence, a lot of research has focused on peristalsis in the presence of velocity and thermal slip effects. An empirical relation for the effective viscosity of the nanofluid is proposed here for the first time. The viscosity of the nanofluid varies with temperature and nanoparticle volume fraction. Numerical simulation of the resulting nonlinear system of equations is presented for different quantities of interest. The results indicate that the maximum velocity and temperature of the copper-water nanofluid increase for larger variable viscosity parameter. The pressure gradient in the wider part of the channel is also found to increase as a function of the variable viscosity parameter. The variable viscosity parameter also influences the size of the trapped bolus. An increase in the nanoparticle volume fraction reduces the reflux phenomenon in a peristaltic flow.
