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The pursuit of superior working fluids for heat and mass transfer systems in the industry is on the rise, inspired by not only to maximize revenue but also to accommodate heat dissipation or chemical separation under extreme conditions. The addition of a small amount of nanoparticle, a product called nanofluid, has been initiated over the last decade. In particular, researchers have employed carbon nanotubes (CNTs) into conventional fluids as their preferred nanoparticles due to the merits of having a remarkable thermal conductivity compared to other nanoparticles. Here, we present a comprehensive and up to date review of this incredible fluid being applied in various heat transfer (convective and boiling) and mass transfer systems such as heat exchangers and separators. Other critical parameters associated with the practicality of the CNT nanofluids such as pumping power and efficiency are also discussed. We surveyed a remarkable range of results of some of the heat and mass transfer studies that strongly depend on the inherent CNT nanofluid characteristics and operating conditions such as CNT treatment, size, concentration, Reynolds number, and so on. A major conclusion that can be drawn from this review is the significantly higher heat transfer coefficient at lower pressure drop or pumping power of the CNT nanofluid compared to other nanofluids, which implied better thermal performance of the heat transfer system. Besides that, the concentration of CNT is the influential factor to achieve optimum boiling heat transfer while the mass transfer performance of the CNT nanofluid is moderately good against other nanofluids. Additionally, CNT treatment using covalent functionalization is crucial for the overall stability and performance of the CNT nanofluid. However, several issues that inhibit their widespread use such as possible corrosion-erosion in systems, lack of risk assessments, and high cost of CNT nanofluid must be thoroughly addressed in future studies. [ABSTRACT FROM AUTHOR]

This paper reviewed the application of nanofluids in vehicle engine cooling system. So far, nanoparticles have been used in engine oil, transmission oil, and radiator coolant to enhance heat transfer removal from vehicle engine. The heat transfer performance of nanofluids has been reported to perform better compared to pure fluid. This review focused on the experimental and numerical studies by previous researchers and their suggested amount of nanoparticles for optimum performance in vehicle engine cooling system. Finally, the conclusions and important summaries were presented according to the data collected. [ABSTRACT FROM AUTHOR]

The performance of friction drag, heat transfer rate, and mass transfer is illustrated the in boundary layer flow region via density of motile microorganisms. Magnetic dipole in presence of Curie temperature and density of motile microorganisms plays important role in stabilizing and controlling the momentum and thermal boundary layers. In this direction, the characteristics of the magnetic dipole on the suspensions of motile microorganisms in the flow of ferrofluid are incorporated. Heat flux in the suspensions of motile microorganisms and at the surface is computed via Fourier's law of heat conduction. Characteristics of sundry physical parameter on the ferrohydrodynamic, thermal energy, mass transfer, and bioconvection are computed numerically and analytically. It is depicted that an enhancement in thermal Rayleigh number results in the reduction of friction drag, thereby enhances the heat transfer rate and Sherwood number at the surface, while the local density of motile microorganisms enhance for larger values of bioconvection Lewis number. Further, it is characterized that bioconvection Rayleigh number has increasing behavior on the heat transfer in the boundary layer. Comparison with available results are found in an excellent agreement. • Heat transport phenomenon is depicted in motile micro-organisms. • Thermal Rayleigh number results in the reduction of friction drag. • Velocity reduces and the temperature field enhances for β_{f}. • The wall shear stress of the motile micro-organisms reduces. • The fast reduction in heat transfer rate is observed. [ABSTRACT FROM AUTHOR]