In this study, we conducted a numerical simulation to examine the cooling performance of an aluminum finned heat sink attached to a silicon chip, placed in a chamber of a rectangular cross‐section. The heat sink is cooled by convective heat transfer utilizing nine commercially available gaseous coolants, namely air, hydrogen, helium, nitrogen, oxygen, carbon dioxide, freon12 vapor, propane, and ammonia. To select an appropriate coolant for electronic devices in terms of thermal–hydraulic performance, the maximum temperature on the chip domain and the associated pressure drop in the cooling channel as a function of coolant velocity are analyzed for the aforementioned fluids. It has been found that the minimum temperature is recorded for propane and freon12 vapor, which is approximately 31.1°C, for a coolant velocity of 0.5 m/s, but freon12 vapor shows the highest pressure drop, approximately 900 mPa, among all coolants. In the overall velocity regime, hydrogen shows the best cooling performance in terms of both cooling capacity and hydrodynamic characteristics. But considering safety issues, helium can be a better alternative. This comprehensive study provides a better understanding of different coolant performances, which will aid engineers to develop an effective cooling technique to accommodate the inexorably rising power demand.

Natural convection inside a triangular solar collector is investigated numerically for different nanofluids and hybrid nanofluids in this study. The individual effects of Al2O3–water, carbon nanotubes (CNT)–water, and Cu–water nanofluids are observed for different solid volume fractions of nanoparticles (0%–10%). Three types of hybrid nanofluids are prepared using different ratios of Al2O3, CNT, and Cu nanoparticles in water. A comparison is made varying the Rayleigh numbers within laminar range (103–106) for different tilt angles (0°, 30°, 60°, and 90°) of the solar collector. The inclined surface of the triangular solar collector is isothermally cold and the bottom wall (absorber plate) is isothermally hot, whereas the vertical wall with respect to the absorber plate is considered adiabatic. Average Nusselt numbers along the hot wall for different parameters are observed. Streamlines and isotherm contours are also plotted for different cases. Dimensionless governing Navier–Stokes and thermal energy conservation equations are solved by Galerkin weighted residual finite element method. Better convective heat transfer is found for higher Rayleigh number, solid volume fraction, and tilt angle. In the case of hybrid nanofluid, increasing the percentage of the nanoparticle that gives better heat transfer performance individually results in enhancing natural convection heat transfer inside the enclosure.

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A numerical study on natural convection heat transfer in a right triangular solar collector filled with CNT-water and Cuwater nanofluids has been conducted. The inclined wall and the bottom wall of the cavity are maintained at a relatively lower temperature (Tc), and higher temperature (Th), respectively, whereas the vertical wall, is kept adiabatic. The governing non-dimensional partial differential equations are solved by using the Galerkin weighted residual finite element method. The Rayleigh number (Ra) and the solid volume-fraction of nanoparticles (ϕ) are varied in the range of 103 ≤ Ra ≤ 106, and 0 ≤ ϕ ≤ 0.1, respectively, to carry out the parametric simulations within the laminar region. Corresponding thermal and flow fields are presented via isotherms and streamlines. Variations of average Nusselt number as a function of Rayleigh number have been examined for different solid volume-fraction of nanoparticles. It has been found that the natural convection heat transfer becomes stronger with the increment of solid volume fraction and Rayleigh number, but the strength of circulation reduces with increasing nanoparticles’ concentration at low Ra. Conduction mode dominates for lower Ra up to a certain limit of 104. It is also observed that when the solid volume fraction is increased from 0 to 0.1 for a particular Rayleigh number, the average Nusselt number is increased to a great extent, but surprisingly, the rate of increment is more pronounced at lower Ra. Moreover, it is seen that Cu-water nanofluid offers slightly better performance compared to CNT-water but the difference is very little, especially at lower Ra.