On the entropy analysis and hydrothermal behavior of buoyancy-driven magnetized hybrid nanofluid flow within a semi-circular chamber fitted with a triangular heater: Application to thermal energy storage for energy management

The present investigation is on examination of the natural convection and entropy generation considering the heatlines visualization of nanofluid I‐shaped enclosure with two corrugated walls considering inner rectangular heater of three different heights. The influence of Brownian motion along with thermophoresis had been implemented using Inhomogeneous two‐phase model of nanofluid. The governing equations were solved numerically using COMSOL software. Influence of Rayleigh number , Buoyancy ratio number , Lewis number , heater length . The results indicate that the influence of Lewis number on heat transfer bettering is stronger at high Rayleigh number while its impact is negligible at a lower value of Rayleigh number (conduction mode). In addition, the total entropy generation gets its highest value at Lewis number . Bejan number, fluid flow strength and heat rate increase as the rectangular heater height increases. Also, higher heat transfer augmentation is taken when the heater height is while increasing the heater height to leads to more total entropy generation. The impact of heater height on total entropy generation is highly affected by Rayleigh number as increasing the heater height from into , total entropy generation increases by at while it increases by at .

Inhomogeneous flow model of natural convection, entropy generation, and heatlines visualization in wavy I‐shaped enclosure with rectangular heater

Abdulkadhim,

Abed,

Hamzah

et al. 2024

Exact solutions of hydromagnetic convective flow in a microchannel with superhydrophobic slip and temperature jump: Microfluidics applications

Sajjan,

Raju

2024

The researchers explored the free convective flow of a hybrid nanofluid in a vertical microchannel with a rectangular cross‐section. Notably, both channel walls were heated alternately, and a transverse magnetic field was applied across the channel. The channel walls had unique properties, one of which was nonslip and the other was exceedingly hydrophobic. The major purpose was to investigate the effects of magnetism and superhydrophobicity on important flow parameters. The differential equations in the investigation were solved, producing accurate results. The study yielded some significant discoveries. First, when heated, the magnetic parameter reduced skin friction on both sides. Second, in both heating conditions, the magnetic field reduced flow rate and velocity. The flow rates in the two reported situations were similar at a crucial temperature jump coefficient. Furthermore, for low‐temperature jump coefficients, heating the superhydrophobic side reduced the Nusselt number whereas heating the nonslip side had no magnetic effect. The percentage change in the value of Nusselt number and velocity decreases continuously with increase in nonlinear density variation with temperature (NDT) parameter and magnetic parameter. The percentage increases in the value of skin friction with increase in temperature jump and slip length but decrease in the percentage of skin friction for the effect of magnetic term and NDT parameter. As the NDT parameter increases, the velocity percentage rises to 50.59% when the superhydrophobic surface is heated and to 84.30% when the nonslip surface is heated. The temperature jump is statistically significant for the value of the Nusselt number and skin friction for the no‐slip surface condition. These discoveries have practical consequences for the design and management of both tiny and large‐scale systems, with possible applications in microfluidics, microelectronics, nanoscience, and nanotechnology.

Improving the natural convection of the heat sink inside an enclosure by fin perforation for electronic applications

Abdulsahib,

Alkhafaji,

Albayati

2024

The present study aims to enhance the natural convection in the heat sink inside an enclosure by perforating fins for power electronic applications. The enclosure is a cube that is manufactured in such a way that the upper and lower surfaces, as well as the front and back surfaces, are thermally insulated. The right surface is hot, while the left surface is cold at a temperature difference ∆T of (4°C, 8°C, 10°C). The heat sink used consists of five fins that are attached to the heated surface. The heat sink fins are perforated with perforation number NP (4, 8, 12, and 16) and perforation diameter DP (0.5 and 1 cm). Temperatures are measured using 13 thermocouples placed within the enclosure and the temperature distribution is determined using a FLIR E30BX IR thermal camera, while velocity contours are obtained using numerical software. The main results showed improvement in heat transfer with an increase in the number of perforations and (DP = 1 cm) was found to be more efficient than (DP = .5 cm), for instance, when (∆T = 10°C) for (NP = 16) and (DP = .5 cm). There is a 2.9% improvement in temperature reduction on the fins' tip, while at =(DP = 1 cm), the percentage of improvement was 3.5% and showed a greater expansion of the velocity lines between the fins at (∆T = 10°C), where the rate of increase in the velocity contours from (∆T = 4 and 8°C) reaches 20% and 7% respectively. In addition, heat sinks with perforated fins are both lighter and more cost‐effective in terms of metal usage during the manufacturing process.