A novel ultrasonic approach to determine thermal conductivity in CuO-ethylene glycol nanofluids

CuO-ethylene glycol nanofluids of various concentrations have been synthesized using ultrasonically assisted two step method. Ultrasonic and thermal investigations are made on the nanofluids at different temperatures ranging from 308 K to 328 K. The intermolecular interactions in CuO-ethylene glycol nanofluids are realized through the ultrasonic velocity and it is found that the CuO-ethylene glycol interactions surpass the CuO-CuO interactions. The variations of ultrasonic velocity with respect to temperature confirm the weakening of the intermolecular adhesive forces at elevated temperatures. In addition to the interaction studies, a new methodology is proposed to find thermal conductivity of nanofluids using ultrasonic velocity. The results, thus obtained through ultrasonic method, are found to agree well with those obtained through the transient line heat source technique, which confirms the aptness of the proposed method. (C) 2014 Elsevier B.V. All rights reserved.