Impact of variable magnetic fields on bioconvection in Fe₃O₄–blood suspension under hyperthermia: Insights from Artificial Neural Network analysis

This study investigates the unsteady, fully developed bioconvective flow within a duct subjected to hyperthermia, influenced by a uniform or non-uniform Lorentz force. The motivation stems from the growing importance of understanding heat and mass transfer mechanisms in bioengineering applications, particularly in targeted hyperthermia treatments. The bioconvection is driven by motile microorganisms in a Fe₃O₄–blood suspension, with the magnetic force generated by an electric current in a wire. The effects of Joule heating and viscous dissipation are also considered, while the Langevin magnetization model is employed to analyze weak and strong magnetization situations. The study employs the Finite Volume Method (FVM) to solve the governing equations under constant axial pressure gradients. Additionally, an artificial neural network (ANN) is integrated to accurately predict critical physical quantities such as Nusselt numbers. Key findings reveal that the highest heat transfer rates are observed with pure blood, whereas Fe₃O₄–blood suspension with weak magnetization shows the lowest rates. Magnetic bioconvection is enhanced with increasing Reynolds number or magnetic field strength. However, a rise in the Péclet number consistently reduces microorganism distribution across all cases. These insights provide valuable guidance for optimizing thermal and flow control in biomedical and industrial applications

Non-homogenous nanofluid model for 3D convective flow in enclosures filled with hydrodynamically and thermally heterogeneous porous media

The non-homogenous two-phase Buongiorno's nanofluids model is applied to investigate the convection process within cubic enclosures filled with homogenous/heterogeneous porous medium. The homogenous/heterogeneous properties are considered in the overall permeability and thermal conductivity of the porous elements. Different cases upon the type of the medium are considered, namely, homogeneous porous domain, heterogeneous porous domain in all directions, heterogeneous cavity with stratification in X-Y plane, heterogeneous cavity with stratification in X-Z plane and heterogeneous cavity with stratification in Y-Z plane. The worked mixture is Al2O3ewater nanofluid and the Brownian motion parameters, the thermophores parameter and the dynamic viscosity are variables. The SIMPLE algorithm together with the finite volume method are extended to the three dimensional case and applied to treat the governing equations. It is remarkable that the heterogeneous case in all directions (η1=η2=η3=1.5) gives the largest values of the average Nusselt coefficient while the homogenous case has the lowest rate of the heat transfer. In all the considered porous cases, the growing in the Rayleigh and Darcy numbers enhances the average Nusselt number

MHD Casson flow over a solid sphere surrounded by porous material in the presence of Stefan blowing and slip conditions

Flow around a solid sphere finds utility in numerous single- and two-phase engineering applications, such as sport balls, combustion systems, silt conveyance in waterways, hydraulic conveying, pneumatic equipment, food and chemical manufacturing. Therefore, this paper aims to examine the Casson nanofluids flow and heat transfer over a solid sphere that is saturated in an isotropic porous material in the presence of Stefan blowing and slip conditions. The forced situation is due to the presence of a stagnation point while the surface of the sphere is subjected to thermal slip conditions. Besides, various significant impacts are taken into account such as Lorentz force, thermal radiation, heat source/sink, and activation energy. The solution technique is based on non-similar transformations and implicit finite difference method with the Blottner algorithm. It is remarkable that, for all values of the activation parameter, the growth of Stefan number reduces the gradients of the velocity, temperature, and nanoparticle concentration. Also, the presence of the thermal slip factor reduces the temperature distributions. Additionaly, an increase in either the Casson parameter or Darcy number enhances the flow while both temperature and concentration are diminishing. Furthermore, there is an improvement in values of the Nusselt number up to 50.57 % when the magnetic parameter is varied from 0 to 6

Fractional melting process in inclined containers using (NePCM) and hybrid nanoparticles

Using substances of high latent heat such as phase change materials is a perfect technique in the energy storage units. Additionally, examining the heat transport and melting process for these materials is beneficial for a wide variety of solar-related applications. Therefore, this study aims to examine the time-dependent fractional melting process within inclined containers filled with Nanoparticles-enhanced Phase-Change Materials (NePCM) via the model of the enthalpy-porosity. The used NePCM is octadecane and the fractional derivatives are considered for all the time-dependent variables, namely, velocities, temperature and liquid fraction. The Caputo definition is applied to estimate the non-integer derivatives and the fractional order takes the values between 0.75 and 0.95. The solution methodology is depending on the Finite Volume technique with SIMPLE approach. The range of the Fourier number is between 0.05 and 0.4 and the resulting data is presented in terms of melting interface, liquid fraction, streamlines, isotherms and heat transfer rate. The main findings revealed that the influences of order of the fractional derivatives more significant at the higher values of the Fourier number and the melting interface points move towards the heated wall as order of the fractional derivatives is reduced. Also, at higher values of the fractional derivative's order (0.9), the maximizing of inclination angle causes a diminishing in the rate of the heat transfer