Experimental investigation of the effects of water-hBN nanofluids on the thermal performance and pressure drop of concentric tube heat exchanger

In this study, the effects of nanofluids prepared with hexagonal boron nitride (hBN) nanoparticles on thermal performance and pressure drop by using a nested pipe heat exchanger were investigated. The experiments were carried out in parallel and counter flow with different flow rates and Reynolds numbers with stable and suspended 0.01%, 0.1% and 1% volumetric concentrations of waterhBN nanofluids. The results showed that the counter-flow heat exchanger using water-hBN nanofluid improved 16.7% of total heat transfer coefficient compared to pure water. In the parallel flow heat exchanger, when the results were examined, the preference of hexagonal boron nitride nanofluid as cold fluid was higher than the counter current heat exchanger in terms of increase in heat transfer compared to pure water. The change in the total heat transfer coefficient calculated for the counter-flow heat exchanger according to the different nanofluid flow rate reached the highest value in the 1.5 lt / min flow rate compared to the pure water and the improvement was 16.7%. In addition, exergy analysis of the system at different concentrations and different Reynold numbers was performed.