Computational study of the thermal performance of water/Fe3O4 nanofluid in an oscillating heat pipe: A molecular dynamics approach

Recently, oscillating heat pipes (OHPs) filled with nanofluid (NF) as the operating fluid has drawn researchers’ attention because of their improved thermal conductivity, and heat/mass transfer (HT/MT) characteristics. An OHP is an HT device based on a two-phase fluid flow that transfers heat between heat sources and heat sinks which is applicable in industries in terms of its highly effective thermal conductivity. According to previous research, in previous experimental and computational studies, the effect of adding metal oxide NPs into the operating fluid of an OHP was not studied. Therefore, adding Fe3O4 NPs to the operating fluid of the water flowing into an OHP with nano dimensions will be the research work ahead that can increase the efficiency of designed structures. The maximum density, velocity, temperature, and heat flux after 20 ns are examined to determine the effects of NP size and an external magnetic field (EMF). The numerical findings show that heat flux increased from 1561 to 1602 W/m2 when the NPs' size grew from 5 to 10. Therefore, the HT/MT of Fe3O4-H2O simulated NF showed enhanced thermal behavior as NP's radius increases. Furthermore, the results show that the presence of an EMF enhanced the thermal behavior of NF in the OHP. The heat flux increased from 1563 to 1586 W/m2 when the magnetic field magnitude increased from 1 to 5 T

Investigation of mechanical properties and transparency of spark plasma sintered Mg2+ and Y3+ codoped α-Al2O3 nanoparticles synthesized via coprecipitation

This research aims to investigate the effect of different amounts of doping elements (magnesium and yttrium ions) on the hardness, elastic modulus, flexural strength, and transparency of alumina ceramics. For this purpose, different amounts of Mg2+ and Y3+ doped α-Al2O3 nanoparticles were synthesized via the co-precipitation method. The results revealed that the majority of Mg2+ and Y3+ doped α-Al2O3 nanoparticles have a particle size of 300–400 nm. Furthermore, the density and transparency (60% in-line transmittance at a wavelength of 5 μm, with a sample thickness of 2.4 mm) of the bulk materials prepared with doping of 100 ppm Mg2+and 400 ppm Y3+ (100M400Y) presented the best performance compared with other samples. Furthermore, the hardness and Young modulus of this sample were 28 GPa and 349 GPa, respectively. The flexural strength of the 100M400Y sample reached the highest value, 193 MPa, due to the smaller grain size and minimal porosity