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The transient hydrodynamics and thermal behavior of free convection flow over an isothermal vertical flat plate is investigated.

The study focuses on the role of the local acceleration term in the magnetohydrodynamic (MHD) momentum equation. A finite difference method based on a second‐order differential equation is used to solve the differential equations.

It is found that the local acceleration term has insignificant effect on the flow behavior especially at large values of magnetic forces. Also, it is found that the effect of the magnetic forces on the flow hydrodynamics behavior is significant but its effect on the thermal behavior is insignificant. It has been realized that the local acceleration term is usually small compared to the magnetic retarding force, and hence can be neglected.

A quantitative description of the operating and geometrical parameters within which the local acceleration term may be significant is not available in the literature yet. Also, the authors' intention is to improve physical understanding of the hydrodynamic and thermal behaviors of the present problem.

The study provides results concerning the thermal behavior of free convection flow.

The purpose of this paper is to investigate the impact of time-periodic thermal boundary conditions on natural convection flow in a vertical micro-annulus.

Analytical solution in terms of Bessel’s function and modified Bessel’s function of order 0 and 1 is obtained for velocity, temperature, Nusselt number, skin friction and mass flow rate.

It is established that the role of Knudsen number and fluid–wall interaction parameter is to decrease fluid temperature, velocity, Nusselt number and skin friction.

No laboratory practical or experiment was conducted.

Cooling device in electronic panels, card and micro-chips is frequently cooled by natural convection.

In view of the amount of works done on natural convection in microchannel, it becomes interesting to investigate the effect that time-periodic heating has on natural convection flow in a vertical micro-annulus. The purpose of this paper is to examine the impact of time-periodic thermal boundary conditions on natural convection flow in a vertical micro-annulus.

The purpose of this paper is to further extend the work of Weng and Chen (2009) by considering heat generation/absorption nature of fluid.

Exact solution of momentum equation is derived separately in terms of Bessel’s function of first and second kind for heat-generating fluid and modified Bessel’s function of first and second kind for heat absorbing fluid.

During the course of numerical computations, it is found that skin friction and rate of heat transfer at outer surface of inner cylinder and inner surface of outer cylinder increases with the increase in heat generation parameter while the reverse trend is found in the case of heat absorption parameter.

In view of the amount of works done on natural convection with internal heat generation/absorption, it becomes interesting to investigate the effect of this important activity on natural convection flow in a vertical annular micro-channel. The purpose of this paper is to further extend the work of Weng and Chen (2009) by considering heat generation/absorption nature of fluid.

This investigation has been carried out for thermal-diffusion (Dufour) and diffusion-thermo (Soret) effects on the boundary layer flow of Jeffrey fluid in the region of stagnation-point towards a stretching sheet. Heat transfer occurring during the melting process due to a stretching sheet is considered. The paper aims to discuss these issues.

The authors convert governing partial differential equations into ordinary differential equations by using suitable transformations. Analytic solutions of velocity and temperature are found by using homotopy analysis method (HAM). Further graphs are displayed to study the salient features of embedding parameters. Expressions of skin friction coefficient, local Nusselt number and local Sherwood number have also been derived and examined.

It is found that velocity and the boundary layer thickness are increasing functions of viscoelastic parameter (Deborah number). An increase in the melting process enhances the fluid velocity. An opposite effect of melting heat process is noticed on velocity and skin friction.

The boundary layer flow in non-Newtonian fluids is very important in many applications including polymer and food processing, transpiration cooling, drag reduction, thermal oil recovery and ice and magma flows. Further, the thermal diffusion effect is employed for isotope separation and in mixtures between gases with very light and medium molecular weight.

Very scarce literature is available on thermal-diffusion (Dufour) and diffusion-thermo (Soret) effects on the boundary layer flow of Jeffrey fluid in the region of stagnation-point towards a stretching sheet with melting heat transfer. Series solution is developed using HAM. Further, the authors compare the present results with the existing in literature and found excellent agreement.

The purpose of this paper is to investigate numerically the thermal and hydrodynamics performance of circular microchannel heat exchanger (CMCHE) using various nanofluids.

The three‐dimensional steady, laminar developing flow and conjugate heat transfer governing equations of a balanced MCHE are solved using finite volume method.

The results are shown in terms of temperature profile, heat transfer coefficient, pressure drop, wall shear stress, pumping power, effectiveness and performance index. The addition of nanoparticles increased the heat transfer rate of the base fluids. The temperature profiles of the fluids have revealed that higher average bulk temperatures were obtained by the nanofluids compared to water. The addition of nanoparticles also increased the pressure drop along the channels slightly. The increase in nanoparticle concentrations yielded better heat transfer rate while the increase in Reynolds number decreased the heat transfer rate.

The tested nanofluids are Ag, Al₂O₃, CuO, SiO₂, and TiO₂. Reynolds number range varied from 100 to 800 and the nanoparticle concentration varied from 2 per cent to 10 per cent.

Parallel flow in CMCHEs is used in thermal engineering applications and the design and performance analysis of these CMCHE are of practical importance.

This paper provides the details of the thermal and hydrodynamics performance analysis of flow heat exchangers using nanofluids, which can be used for heat transfer augmentation in thermal design.

The purpose of this paper is to present the development of a cost-effective acrylonitrile butadiene styrene (ABS)-rice straw (RS) composite filament for use in fused deposition modelling (FDM) and the effect of RS content on the mechanical properties of the developed filament.

RS and ABS were processed and mixed at varying fibre content (5-15 per cent). Filament using each mixture was produced using a single screw extruder. Tensile, flexural and water absorption specimens were prepared using a FDM machine. The mechanical properties were then tested following ASTM standards. Scanning electron microscope images of the specimens were also taken.

Tensile properties decreased as the RS content increased. However, specimens with a 0° raster angle showed better tensile properties than the 45° raster angle specimens, indicating that tensile properties of FDM parts are anisotropic. Flexural properties decreased as fibre content increased but increased at 15 per cent fibre content. Water absorption of the composite increased as the fibre content increased.

This paper highlights a new method of disposing of rice straw waste, by producing an ABS-RS filament for FDM. The resultant filament is cost-effective and can be used to produce cheap prototypes. This paper is the first that studies ABS-RS composites in FDM.