Volume fraction

About: Volume fraction is a research topic. Over the lifetime, 16312 publications have been published within this topic receiving 374181 citations.

Experimental evaluation of dynamic viscosity of ZnO–MWCNTs/engine oil hybrid nanolubricant based on changes in temperature and concentration

Abstract: In this work, an experimental investigation on the effects of temperature and concentration of nanoparticles on the viscosity of ZnO–MWCNTs/engine oil (SAE 10W40) hybrid nanolubricant is presented The experiments were repeated at volume fractions of 005%, 01%, 02%, 04%, 06%, and 08%, temperature range of 5–55 °C, and shear rates from 6665 to 13,330 s−1 The viscosity of hybrid nanolubricant was measured using the Brookfield digital viscometer (CAP2000) We found that the nanofluid has a Newtonian behavior at all volume fractions and temperatures Also, by increasing the volume fraction of nanoparticles and nanotubes at a constant temperature the nanofluid viscosity is increased Nanofluid viscosity decreases with increasing the temperature at a constant volume fraction

The effect of velocity and dimension of solid nanoparticles on heat transfer in non-Newtonian nanofluid

Abstract: In this investigation, the behavior of non-Newtonian nanofluid hydrodynamic and heat transfer are simulated. In this study, we numerically simulated a laminar forced non-Newtonian nanofluid flow containing a 0.5 wt% carboxy methyl cellulose (CMC) solutionin water as the base fluid with alumina at volume fractions of 0.5 and 1.5 as the solid nanoparticle. Numerical solution was modelled in Cartesian coordinate system in a two-dimensional microchannel in Reynolds number range of 10≤Re≤1000. The analyzed geometrical space here was a rectangular part of whose upper and bottom walls was influenced by a constant temperature. The effect of volume fraction of the nanoparticles, Reynolds number and non-Newtonian nanofluids was studied. In this research, the changes pressure drop, the Nusselt number, dimensionless temperature and heat transfer coefficient, caused by the motion of non-Newtonian nanofluids are described. The results indicated that the increase of the volume fraction of the solid nanoparticles and a reduction in the diameter of the nanoparticles would improve heat transfer which is more significant in Reynolds number. The results of the introduced parameters in the form of graphs drawing and for different parameters are compared.

High-strength aluminum alloys containing nanoquasicrystalline particles

Abstract: By the use of homogeneous dispersion of nanoscale quasicrystalline particles in fcc-Al phase, new Al-based alloys with useful mechanical properties were developed. The structure consists of nanoscale icosahedral particles with a size of 30–50 nm surrounded by fcc-Al with a thickness of about 5–10 nm and no high-angle grain boundary is observed in the Al phase. The icosahedral phase has a high volume fraction of 60–70%. The unique structure is formed by the unique solidification mode in which the icosahedral phase precipitates as a primary phase followed by solidification of Al phase from the remaining liquid. The features of mechanical properties for the nanoquasicrystalline alloys are classified into three types, i.e. high tensile strength type of 800 MPa in Al–Cr–Ce–Co and Al–Mn–Ce–Co systems high elongation type of 30% in Al–Mn–Cu–Co system and high elevated temperature strength type of 500 MPa at 473 K and 350 MPa at 573 K in Al–Fe–Cr–Ti system. These mechanical properties are superior to those for the conventional Al-based crystalline alloys and the extension of the new Al-based alloys to practical application has also been described.

Linear static response of nanocomposite plates and shells reinforced by agglomerated carbon nanotubes

Abstract: The static response of composite plates and shells reinforced by agglomerated nanoparticles made of Carbon Nanotubes (CNTs) is investigated in the present paper. A two-parameter agglomeration model is taken into account to describe the micromechanics of such particles, which show the tendency to agglomerate into spherical regions when scattered in a polymer matrix. From the macro mechanical point of view, the structures under consideration are characterized by a gradual variation of their mechanical properties along the thickness direction, since various distributions are employed to describe the volume fraction of the reinforcing phase. Several Higher-order Shear Deformation Theories (HSDTs) are taken into account and compared. The fundamental equations which govern the static problem in hand are solved numerically by means of the Generalized Differential Quadrature (GDQ) method. The variation of the agglomeration parameters, as well as the through-the-thickness profiles which describe the CNT volume fraction, are investigated to show the effect of the reinforcing phase on the static response of these nanocomposite plates and shells. In particular, a posteriori stress and strain recovery procedure is developed for these purposes. The current approach is validated through the comparison with the results available in the literature or obtained by a three-dimensional finite element model.

Giant magnetic coercivity and percolation effects in granular Fe(SiO2) solids

Abstract: We demonstrate a novel method for enhancing the coercivity of magnetic materials. Granular Fe‐(SiO2) solids have been fabricated over a wide volume fraction range from 15% to 100%. Giant magnetic coercivity, as high as 2500 Oe, has been observed in granular solids in which the isolated Fe granules are only nanometers in size. Across the whole volume fraction range magnetic coercivity experiences dramatic variations due to the change of granular size and percolation effects.