Thermal performance investigation of SWCNT and graphene quantum dots nanofluids in a shell and tube heat exchanger by using fin blade tubes

The experimental study, thermal performance, and pressure drop of single-walled carbon nanotube (SWCNT) and graphene quantum dot (GQD) nanofluids in shell and tube heat exchanger with fin blade tubes are evaluated. The effects of the working fluid (water) volume flow rates ($\dot{V}=$ 2.5–10 L/min), volume concentration of nanoparticles ($\omega =$ 0.0%, 1%, 3%, and 5%), Reynolds number of working fluid (Re = 850–3300), and tube building (heat exchanger with fin blade tubes and without fin blade tube) have been analyzed. Results represent that with augmentation of volume concentration of SWCNT nanoparticle up to 1%, heat transfer rate increases by ∼5% and then up to 5% volume concentration of SWCNT nanoparticle decreased about 17%, also this calculation for GQD nanoparticle conducted and results represented decreasing 6% and approximately unchanged heat transfer rate, respectively. With regard to obtained results, heat transfer rate of heat exchanger can be improved by using the fin blades by 188%, compered without fin blade heat exchanger also most related increase for pressure drop of heat exchanger was recorded about 80% for 5% SWCNT of nanofluid. At the end, the mean enhancement in effectiveness of heat exchanger with various concentrations of SWCNT and GQD nanofluids and using the fin blades is about over 100% and 85%, respectively. In fact, the present study shows that applying the new finned tubes in the heat exchanger has more impact, related to the mentioned nanoparticles on the thermal properties of heat exchanger.