• Energy Research

AbstractWe considered the magnetized micro polar fluid with hybrid nanomaterial flow over a curved stretching surface. We discussed the effects of single wall carbon nanotube and multiwall carbon nanotube with base fluids (water and propylene glycol). Under the flow assumptions, we developed the mathematical model and applied the boundary layer approximations to reduce the system of partial differential equations. Further, the suitable similarity transformations are applied on the partial differential equations to make dimensionless system. The dimensionless system solved by means of numerical scheme via bvp4c shooting methods. Involving the dimensionless physical parameters effects are highlighted in the form of graphs and tables. Additionally, significant physical quantities i.e. Nusselt number, Couple stress coefficient and Skin friction coefficient are also presented and evaluated numerically. These results are more important which may use in the field of engineering and industrial.

Abstract A transient two-dimensional ISPH method based on the time-fractional derivative was applied for emulating thermosolutal convection of the nano-encapsulated phase change material (NEPCM) embedded in an annulus between an inner wavy shape and outer hexagonal-shaped cavity. The impacts of a magnetic field and double rotations amongst an inner wavy shape and outer hexagonal-shaped cavity on the heat and mass transmission of NEPCM in an annulus have been conducted. Effects of a time parameter τ (0.01 − 1), frequency parameter ω (1 − 7), fractional time derivative α (0.95 − 1), Darcy parameter Da (10−2 − 10−4), Hartmann number Ha (0 − 100), fusion temperature θf (0.05 − 0.8), and Rayleigh number Ra (103 − 105) on the contours of temperature, heat capacity, concentration, and velocity field as well as profiles of Nu ¯ and Sh ¯ are investigated. The main findings signaled that the double rotations plays effectively in speed up the nanofluid movements, and changing the features of temperature, concentration, and heat capacity inside an annulus. An augmentation in a frequency parameter boosts the nanofluid speed by 128.57%. A decline in α from 1 to 0.95 enhances the maximum nanofluid velocity by 13.73%. The nanofluid movements within an annulus are reduced according to an increase in Ha and a decrease in Da. The power in the Rayleigh number enhances the nanofluid movements within an annulus.

This paper discusses the magnetic powers on the thermosolutal convection of nano-encapsulated phase change material (NEPCM) inside a porous annulus by using the ISPH method. A novel annulus is constructed between an exterior hexagonal-shaped and inner shape of the dual curves having varying lengths (a&b). The heat/mass source is put in the left-top and right-bottom parts of a hexagonal-shaped and the other parts are adiabatic. The inner dual curves are maintained at Tc and Cc. The effects of the inner dual curve lengths (a=0.1−0.4&b=0.2−1), a fusion temperature (θf=0.05−0.95), Darcy parameter (Da=10−2−10−5), Hartmann number (Ha=0−100), solid volume fraction (ϕ=0.01−0.06), time parameter (τ=0−0.8), and Rayleigh number (Ra=103−106) on the contours of heat capacity, concentration, streamlines, temperature, and nanofluid velocity are researched. The results revealed that an increase in a fusion temperature shifts a phase change zone from the dual curves towards the heater source positions. The lengths of the inner dual curves are controlling the contours of the heat capacity, temperature, streamlines, and concentration in an annulus. Thus, the velocity's maximum boosts by 26.92% as length b shrinks from 1 to 0.2. Increasing Ra expands the contours of temperature, concentration, and heat capacity Cr across an annulus.

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.