Document Type : Article
Authors
1
Department of Mechanical Engineering, Faculty of Electrical and Computer Mechanics, Islamic Azad University, Science and Research Unit, Tehran, Iran
2
Mechanical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
3
Department of Mechanical Engineering,/Faculty of Mechanics, Electricity and Computer (Islamic Azad University of Science and Research), Tehran , Iran
Abstract
The development of microchannel manufacturing technology has led to a growing interest in using them as heat exchangers. Devices like microchannel are used to control the temperature of equipment and components that generate high heat flux. Use of microchannels can be explored in various applications i.e. turbine blades, rocket engine, hybrid vehicle, hydrogen storage, refrigeration cooling, thermal control in microgravity and capillary pump loops. Another method for increasing heat transfer is to disperse nanoparticles with a low volume fraction into the base fluid. Nanofluids have been found to possess enhanced thermophysical properties such as thermal conductivity, thermal diffusivity, viscosity, and convective heat transfer coefficients compared to those of base fluids like oil or water. It has demonstrated great potential applications in many fields. In this research, an experimental study on the heat transfer characteristics of oil-based nanofluid inside wavy microchannels with series and parallel arrangement has been carried out. In order to examine the performance of each microchannel separately and to make it easier to draw their diagrams, they are named as 1 and 2. Experiments were performed on TiO2 and SiO2 oil-based nanofluids in volume fractions of 0.05 and 0.1, flow rates of 0.5, 1.0 and 1.5 lit/min and inlet temperatures of 40°C, 45°C, 50°C, 55°C. The results show an increase in the Nusselt number of the base fluid up to 41.8% in the series arrangement and also a decrease in the surface temperature in the series arrangement compared to the parallel arrangement. Also, TiO2 and SiO2 nanofluids with volume fraction of 0.1 caused the highest increase in heat transfer up to 56% and 52.7% in parallel arrangement and up to 45.8% and 42% in series arrangement compared to the base fluid, respectively. The pressure drop of the test section in series arrangement was up to 82.1% higher than parallel.
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