Enhancing thermal conductivity of fluids with nano-particles
01 Jan 1995-Vol. 231, pp 99-105
About: The article was published on 1995-01-01 and is currently open access. It has received 7263 citations till now. The article focuses on the topics: Thermal conductivity & Nanoparticle.
Citations
More filters
TL;DR: In this paper, the authors summarized the existing alternative designs of PTC and suggested the future trends in this area, as well as the use of concentrating thermal photovoltaic collectors.
225 citations
TL;DR: In this paper, the Brinkman model was used to study the onset of convection in a horizontal layer of a porous medium saturated by a nanofluid, and it was found that the critical thermal Rayleigh number can be reduced or increased by a substantial amount depending on whether the basic nanoparticle distribution is top-heavy or bottom-heavy, by the presence of the nanoparticles.
Abstract: The onset of convection in a horizontal layer of a porous medium saturated by a nanofluid is studied analytically. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. For the porous medium, the Brinkman model is employed. Three cases of free–free, rigid–rigid, and rigid–free boundaries are considered. The analysis reveals that for a typical nanofluid (with large Lewis number), the prime effect of the nanofluids is via a buoyancy effect coupled with the conservation of nanoparticles, whereas the contribution of nanoparticles to the thermal energy equation is a second-order effect. It is found that the critical thermal Rayleigh number can be reduced or increased by a substantial amount, depending on whether the basic nanoparticle distribution is top-heavy or bottom-heavy, by the presence of the nanoparticles. Oscillatory instability is possible in the case of a bottom-heavy nanoparticle distribution.
224 citations
TL;DR: The relative change in burning rate from neat nitromethane increased with increasing concentrations of fuel additives and decreased with increasing pressure until at high pressures no enhancement was found.
Abstract: We have compared the combustion of the monopropellant nitromethane with that of nitromethane containing colloidal particles of functionalized graphene sheets or metal hydroxides. The linear steady-state burning rates of the monopropellant and colloidal suspensions were determined at room temperature, under a range of pressures (3.35−14.4 MPa) using argon as a pressurizing fluid. The ignition temperatures were lowered and burning rates increased for the colloidal suspensions compared to those of the liquid monopropellant alone, with the graphene sheet suspension having significantly greater burning rates (i.e., greater than 175%). The relative change in burning rate from neat nitromethane increased with increasing concentrations of fuel additives and decreased with increasing pressure until at high pressures no enhancement was found.
223 citations
Cites background from "Enhancing thermal conductivity of f..."
...Furthermore, the heat sink properties of the liquid may be significantly enhanced by low concentrations of nanoparticle additives in the liquid.(9) 12 A colloidal catalyst dispersed in the fuel is particularly appealing because it can be readily integrated into existing and future liquid combustion systems....
[...]
TL;DR: In this article, a hybrid solar distillation system comprising of corrugated and wick absorbers of solar stills is integrated with an external condenser to examine their performance, and the performance of CrWSS with internal reflectors, integrated with external condensor and using different types of nanomaterials is investigated and compared with the conventional still.
223 citations
TL;DR: In this article, the authors investigated the viscosity and thermal conductivity of ZnO nanofluids with nanoparticle shapes of nearly rectangular and of sphere, under various volume concentrations of the nanoparticles, ranging from 0.05 to 5.0 vol.
Abstract: The viscosity and thermal conductivity of ZnO nanofluids with nanoparticle shapes of nearly rectangular and of sphere, were experimentally investigated under various volume concentrations of the nanoparticles, ranging from 0.05 to 5.0 vol.%. The viscosity of the nanofluids increased with increases in the volume concentration by up to 69%. In addition, the enhancement of the viscosity of the nearly rectangular shape nanoparticles was found to be greater by 7.7%, than that of the spherical nanoparticles. The thermal conductivity of the ZnO nanofluids increased by up to 12% and 18% at 5.0 vol.% for the spherical and the nearly rectangular shape nanoparticles, respectively, compared to that of the base fluid (water). The shape of the particles is found to have a significant effect on the viscosity and thermal conductivity enhancements.
223 citations
Cites background from "Enhancing thermal conductivity of f..."
...The main advantages of these nanofluids are their higher stability, compared to that of fluids containing micro- or milli-sized particles, and their enhanced thermal conductive capability, comparedwith that of base fluids (Choi, 1995; Zussman, 2002)....
[...]