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[en] Computation of fluid solid flow requires an accurate scheme to capture the moving boundary problems for solid objects moving in a fluid. In this paper, a multi-relaxation time lattice Boltzmann method is coupled with the Newton's second law to predict the flow characteristics around obstacle placed in a channel. The treatment of the curved boundary is based on the conventional bounce-back boundary scheme and interpolations. Good agreement with the previous studies by other methods indicates good applicability of the present scheme
[en] Nanofluid that made up of fluid and solid nanoparticles has gained attention from diverse fields due to its superior thermophysical properties to enhance the performance of different systems which require flowing medium with excellent heat transfer behavior. Many past researchers have proven that conventional heat transfer fluid can be replaced by the rising nanotechnology–nanofluid which showed astonishing performance under different circumstances. In this paper, we attempt to present a recent review on the consequences of implantation of nanofluid, especially in vehicle engine cooling system and other heat transfer applications such as solar collector, electronics cooling system, flow boiling and thermal energy storage system. Thermophysical properties and heat transfer performance of nanofluids obtained in simulation, test rigs and even real vehicle engine experiments are discussed thoroughly. Models and correlations used by past researchers to compute thermophysical properties are also included. In the last part, various advantages from using nanofluid are summarized, and suggestions for research gap between past studies are discussed to further improve the investigation work in the future.
[en] The current investigation has presented a new synthesis technique to prepare pentaethylene glycol-treated graphene nanoplatelets (PEG-GnP) and pentaethylene glycol thermally treated graphene (PEG-TGr). The covalently functionalized (PEG-GnP and PEG-TGr) at various mass concentrations were dispersed in distilled water by ultrasonication for preparing nanofluids. The functionalization process effectiveness was established by using the surface characterization and morphology analysis with FTIR, Raman spectroscopy, FE-SEM, and TEM. The thermo-physical properties and stability of functionalized nanofluids were investigated utilizing numerous measuring devices. Dispersion stabilities of the functionalized nanofluids were observed for a long period of time (30 days). Water-based functionalized nanofluids revealed very Newtonian behavior with the increment in the experimental values of dynamic viscosity as temperature decreases and mass concentration of sample increases. Thermal conductivity of GnP and TGr dispersed in distilled water nanofluids show the enhancement of 32 and 31%, respectively, at 50 °C and 0.1% mass concentration.
[en] Recently, solar energy research popularity has been growing rapidly due to its pollutant-free renewable energy source. As an alternative energy to the existing conventional fossil resources, solar energy is projected to drive the future research to a new level in renewable energy field. One of the methods to harvest the solar energy is through the solar thermal collector, which utilizes heat transfer fluid to capture the solar radiation. In this paper, a recent development of application using concentrated direct absorption solar collector on nanofluids is comprehensively discussed. Our emphasis is on concentrating solar collector including parabolic trough, parabolic dish, heliostat field collector and Fresnel solar collector. To accomplish this, an inclusive review on the analytical, numerical and experimental studies in this field is prepared. Finally, some issues related to the concentrated direct absorption solar collector using nanofluid are also presented.
[en] Nanotechnology has emerged to be an essential aspect of science and technology. The growth of this field has been enormous specifically in the development of nanomaterials. Till date, numerous nanomaterials have been developed and designed to suit various applications from mechanical to biomedical. Among the developed nanomaterial, alumina (Al) has been subject of interest due to its notable chemical and physical properties. Specifically, in thermal properties, Al has been shown to have superior thermal conductivity, convective heat transfer coefficient and heat transfer coefficient properties. As such, Al has been utilized in different forms in various fields of applications and verified for its importance, significance and efficiency. Though it had shown outstanding results in the field engineering and sciences, their effect towards the environment and human health is yet to be explored extensively. The present paper aims to review the significance of Al nanoparticle addition in mono- and hybrid nanofluids. Also, this paper intends to provide the reader with an overview of the works that have been carried out using Al nanoparticles and their findings.
[en] A pioneer idea for increasing the thermal performance of heat transfer fluids was the use of ultrafine solid particles suspension in the basefluid. Nanofluids, synthesized by mixing solid nanometre-sized particles at low concentrations with the basefluid, were used as a new heat transfer fluid which developed a remarkable effect on the thermophysical properties and heat transfer coefficient. For any nanofluid to be usable in heat transfer applications, the main concern is its long-term stability. In this investigation, pentaethylene glycol-treated graphene nanoplatelets (PEG-GnP), pentaethylene glycol-thermally treated graphene (PEG-TGr), Al2O3 and SiO2 were synthesized. The thermophysical properties of PEG-GnP, PEG-TGr, Al2O3 and SiO2 were measured experimentally by using different devices and equipment. Dispersion stabilities of carbon-based nanofluids and metallic oxides nanofluids were observed for 30 days, and the results showed the higher dispersibility of the nanofluids in an aqueous media with very low sedimentation. Thermal conductivity, viscosity and density were increased, while specific heat decreased as mass concentration increased. The temperature effect on the nanofluids was directly proportional to their thermal conductivity and inversely to the viscosity, density and specific heat.