Experimental study of heat transfer enhancement using hybrid nanofluid and twisted tape insert in heat exchangers

The study presented an experimentally investigating the effect of (Al₂O₃ +CuO /water) hybrid nanofluid on the heat transfer enhancement inside the tube heat exchanger at constant heat flux. hybrid nanofluid with volume concentration (0.6, 1.2, 1.8 %) has been used at different inlet velocities. The experimental setup consisted copper tube heat exchanger with hybrid nanofluid and two types of twisted tape was used in turbulent regime with Reynolds number ranging from 3560 to 8320. The twisted tape, manufactured from polylactic acid (PLA) by 3-dimensional printer device, was inserted inside the tube. The results showed that the maximum increase in Nusselt number 47.17%with plain twisted tape insert when compared to horizontal plain pipe. Also, the enhancement in heat transfer (Nusselt ratio) is about 29%. And the maximum thermal performance of double v-cut twisted tape is about (1.69) was achieved at (∅︀=1.8%) with (TR=9.25) for double v-cut tape with hybrid nanofluid.