Investigation of the effect of ultrasonic waves on heat transfer and nanofluid stability of MWCNTs in sono heat exchanger: an experimental study

The precipitation of nanoparticles is one of the most important barriers in the industrial application of nanofluids. The common method for stabilizing nanofluids is imposing ultrasonic waves on the nanofluid before using it in the heat exchangers. The problem with this method is that after a short time, the nanoparticles start to settle. In this study, the effect of using a novel heat exchanger equipped with ultrasonic transducers on increasing the stability and heat transfer coefficient of exchanger is investigated. The results indicated that using ultrasonic transducers has increased the heat transfer coefficient as well as increasing the stability of nanofluids. The effect of ultrasonic waves on the heat transfer coefficient increased with increasing the concentration of nanofluid but reduced with increasing the flow rate. In the range covered by these results, the simultaneous use of nanofluid and ultrasonic waves could increase the heat transfer coefficient by 300%.