Preparation of nanofluid is of prime importance to obtain better thermal and physical properties. Different preparation parameters used in nanofluid preparation sometimes perform contrarily even if prepared with same nanoparticles and base fluid. Stability, thermal conductivity, and viscosity of the nanofluid are significantly affected by the cluster (agglomerate) size of nanoparticles in the base fluid which deteriorate thermal performance. In order to break the agglomerates and improve the dispersion of nanoparticles, ultrasonication is a more prevalent method. Nanofluids react differently for different sonication time and the reaction of the nanofluid with the change in sonication time varies for different nanofluids, which is dependent on various factors. In this regard, research works pertinent to the effect of ultrasonication on different properties of nanofluids are confined. In this paper, review of investigations carried out on experimentally evaluated ultrasonication effects on thermal properties and various physical properties of nanofluid. It is found that with an increased sonication time/energy, reduces the particle size and thus aids in obtaining a better dispersion leading to enhancement of stability, thermal conductivity and reducing viscosity. However, the longer ultrasonication duration was not found to be better in all cases where best performance was obtained for an optimum duration of ultrasonication.

An overview on the effect of ultrasonication duration on different properties of nanofluids

Nusselt number analysis from a battery pack cooled by different fluids and multiple back-propagation modelling using feed-forward networks

With the growing demand of economically feasible, clean, and renewable energy, the use of solar photovoltaic (PV) systems is increasing. The PV panel performance to generate electrical energy depends on many factors among which tilt angle is also a crucial one. Among hundreds of research work performed pertinent to solar PV panels performance, this work critically reviews the role of tilt angles and particularly locating the optimum tilt angle using different methods. The past data collected for analysis can be categorized mainly into mathematical model based, experimental based, simulation based, or combination of any of these. Single-axis tracking, dual-axis tracking, simple glass cover, hydrophobic glass cover, soiled glass, clean glass, partial shadow, use of phase-change material, computational fluid dynamic analysis, etc., are the novel methods found in the literature for analysis and locating the optimum tilt angle. For illustration purpose, few figures are provided in which the optimum tilt angle obtained on monthly, seasonally, and annual basis is shown. Research works are growing in the field of computations and simulations using online software and codes. Pure mathematical-based calculations are also reported but the trend is to combine this method with the simulation method. As the PV panel performance is found to be affected by number of parameters, their consideration in any single study is not reported. In future, work is required to carry out the experiment or simulation considering the effect of soiling, glass material, temperature, and surrounding ambience on the location of optimum tilt angle. As a whole, the optimum tilt angles reported for locations exactly on the equator line, i.e., 0° latitude, ranges between − 2.5° and 2.5°, for locations just above the equator line, i.e., latitude 2.6°–30° N ranges between 5° and 28°, for 40°–70° N, it is 29°–40°, and for 71°–90° N, it is 41°–45°. For locations at 2.6°–30° S, optimum tilt angles range between − 4° and − 32°, 30°–46° S, it is − 33° to − 36°, 47°–65° S, it is − 34° to − 50°, and for 66°–90° S it is − 51° to − 62°.

Optimum location and influence of tilt angle on performance of solar PV panels

Role of ultrasonication duration and surfactant on characteristics of ZnO and CuO nanofluids

Growth in electronic devices comes with a challenge to engineers to provide proficient cooling mechanism in order to evade performance decline. Minichannel heat sinks are one among type of cooling ...

Thermal analyses of minichannels and use of mathematical and numerical models

This paper presents an experimental comparative thermal analysis of CuO-W nanofluid in circular minichannels. Under steady state forced convection and constant heat flux of 3.4 KW/m CuO-W nanofluid and water are passed through the minichannel. The flow rates chosen are 0.4 lpm (litre per minute), 0.6 lpm, 0.8 lpm and 1 lpm and with hydraulic diameter of 2mm of the minichannel. Variation in Nusselt number (Nu), Convective heat transfer coefficient (h), friction factor, pressure drop and pumping power along with flow rates for CuO-W nanofluid are compared with water. For all the flow rates considered in present investigation, an increase in all the thermal parameters is observed. % enhancement in actual heat transfer rate is upto 89%, 20% for convective heat transfer coefficient and 26% in case of Overall heat transfer coefficient are obtained compared to water. However, the pumping power required for CuO-W nanofluid is more compared to water.

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Abdul K

Papers

Experimental Thermal Investigation of CuO-W Nanofluid in Circular Minichannel