In the recent years, great interest has been devoted to the unique properties of nanofluids. The dispersion process and the nanoparticle suspension stability have been found to be critical points in the development of these new fluids. For this reason, an experimental study on the stability of water-based dispersions containing different nanoparticles, i.e. single wall carbon nanohorns (SWCNHs)...

An overview of systematic studies that address the complexity of nanofluid systems and advance the understanding of nanoscale contributions to viscosity, thermal conductivity, and cooling efficiency of nanofluids is presented. A nanoparticle suspension is considered as a three-phase system including the solid phase (nanoparticles), the liquid phase (fluid media), and the interfacial phase, whic...

Experimental investigation of heat transfer during pool boiling of two nanofluids, i.e., water-Al2O3 and water-Cu has been carried out. Nanoparticles were tested at the concentration of 0.01%, 0.1%, and 1% by weight. The horizontal smooth copper and stainless steel tubes having 10 mm OD and 0.6 mm wall thickness formed test heater. The experiments have been performed to establish the influence ...

This paper presents an experimental investigation of convective heat transfer coefficient for nanofluids using spiral pipe heat exchanger. The aim of this study is to investigate experimentally flow and convective heat transfer characteristics of water-based nanofluids flowing through a spiral pipe. The test section consist of spiral pipe with ratio pitch per diameter is 7.0 and mean hydraulic ...

In this work we investigated the scattering and absorption properties of nanofluids consisting in aqueous suspensions of single wall carbon nanohorns. The characteristics of these nanofluids were evaluated in order to use them as direct sunlight absorber fluids in solar devices. The investigation was carried our for nanohorns of different morphologies and for suspensions prepared with different...

Nanofluids are a new class of thermal vectors potentially able to drastically increase the heat transfer properties of base fluids such as water, glycol and oil. Nanoparticles of various materials, size (<100 nm), shapes and concentrations can be added to the base fluid to enhance the transport properties. In particular, the knowledge of thermal conductivity and viscosity is essential to study ...

The heat transfer enhancement and entropy generation of Al2O3-water nanofluids laminar convective flow in the microchannels with flow control devices (cylinder, rectangle, protrusion, and v-groove) were investigated in this research. The effects of the geometrical structure of the microchannel, nanofluids concentration φ(0%–3%), and Reynolds number Re (50–300) were comparatively studied by mean...

The cooling system of an Automobile plays an important role in its performance, consists of two main parts, known as radiator and fan. Improving thermal efficiency of engine leads to increase the engine's performance, decline the fuel consumption and decrease the pollution emissions. Water and ethylene glycol as conventional coolants have been widely used in radiators of an automotive industry ...

The entropy generation analysis of fully turbulent convective heat transfer to nanofluids in a circular tube is investigated numerically using the Reynolds Averaged Navier–Stokes (RANS) model. The nanofluids with particle concentration of 0%, 1%, 2%, 4% and 6% are treated as single phases of effective properties. The uniform heat flux is enforced at the tube wall. To confirm the validity of the...

Magnetic nanofluids (known also as ferrofluids or magnetic fluids) are a special category of smart nanomaterials, in particular magnetically controllable nanofluids [1]. These types of nanofluids are colloids of magnetic nanoparticles, such as Fe3O4, γ-Fe2O3, CoFe2O4, Co, Fe or Fe-C, stably dispersed in a carrier liquid [2]. Consequently, these nanomaterials manifest simultaneously fluid and ma...