IMPROVEMENT OF STABILITY AND THERMAL CONDUCTIVITIES OF OIL-BASED NANOFLUIDS IN OPTIMUM ACID-BASE ADMIXTURE VALUES

Abstract

In this work, it has been aimed to improve the stability and thermal conductivity of the nanofluids that use the heat transfer oil, which is frequently used in the industry, as the base fluid. For this purpose, the nanofluids were synthesized by using Al₂O₃ (alumina) and TiO₂ (titanium dioxide) nanoparticles in the mass ratios of 1%, 2% and 3% and the heat transfer oil as the base fluid. H₂SO₄ (sulphuric acid) or KOH (potassium hydroxide) at 5 N (normality) valence solutions were added separately to the prepared nanofluids at the determined volumetric ratios (10^-3%, 3.5×10^-3%, 5.3×10^-3% and 8×10^-3%). By being prepared nanofluids separately with acid and base, the highest enhancement rates in the stability appeared were about 24% for 2% Al₂O₃ by mass and 3.5x10^-3% H₂SO₄ by volume mixture in the alumina-acid case and about 50% for 1% Al₂O₃ by mass and 5.3x10^-3% KOH by volume mixture in the alumina-base case. Similarly, the highest enhancement rates in the stability of the nanofluids were about 75% for 3% TiO2 by mass and 10^-3% H₂SO₄ by volume mixture in the titanium dioxide-acid case and about 77% for 2% TiO₂ by mass and 10^-3% KOH by volume mixture in the titanium dioxide-base case.