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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Investigation into the pH and Electrical Conductivity Enhancement of Mgo-Ethylene Glycol Nanofluids

Get access (open in a dialog) DOI: 10.1615/IHTC15.tpp.008604
pages 8917-8926

Аннотация

The revolution of the industrial and manufacturing sector witnessed with the design and production of high capacity, compact size, portable and light weight devices such as microelectronics and transportation systems is currently posing a critical challenge of thermal management. In order to maintain the compactness of these devices, the conventional method of increasing surface area of heat exchangers by extended surfaces is often ruled out. Recently, researches on the option of using nanofluids as alternative thermal fluids without necessarily increasing the size of heat transfer devices are increasing. However, the issue of its stability is still of a great concern. Actually, stability is essential to the development of technologies that will thrive with the use of this newly formulated heat transfer fluid. Systematic studies on these fluids have shown that pH and electrical conductivity are two interrelated properties which are critical and essential because of their key roles on their stability status. Nevertheless, there has been no detailed research on the pH and electrical conductivity enhancement regarding the ultrasonication energy, temperature variation, nanoparticles size and volume fraction (especially pH). Therefore, in the present work, three different sizes (20, 40 and 100 nm) of MgO nanoparticles at volume fraction up to 2% were prepared using ultrasonication assisted two-step method for 30 and 60 minutes respectively. The pH and electrical conductivity of the prepared samples were studied between the temperature ranges of 20–70 °C. From the available results, the pH and electrical conductivities of MgO-EG nanofluids strongly depend on temperature and volume fraction. On the contrary, it was established that MgO nanoparticles size does not have control on the measured pH and electrical conductivity. However, the patterns obtained were the same for the two ultrasonication times which does not only serve to show the effect of ultrasonication time but also buttresses the repeatability and correctness of the results in this case. It was also found that as low as 0.1% volume fraction produces pH enhancement above 40% and electrical conductivity more than 3000%.