Enhancement of Heat Transfer in Counter Flow Shell and Helical Coil Tube Heat Exchanger (SHCHE) Using Ni-Cu Hybrid Nano Fluid Under Turbulent Flow Regime by Varying Volume Concentration, Pitch, Flow Rate and Coil Material

Experiments under this study were conducted under turbulent flow conditions. The Cu-Ni nanoparticles are prepared using the Sol-Gel method and further surface-treated to reduce sedimentation after suspending these nanoparticles in pure water. The impact of pitch (0.032, 0.042 and 0.052m), mass flow rate, coil material (Aluminium (Al) and Copper (Cu), and volume concentration (0.02, 0.04 and 0.06) on heat transfer rate was computed. Reynolds number (Re), Nusselt number (Nu) were calculated to evaluate the thermal performance of a counter-flow helical coil heat exchanger. It was noticed that the moderate heat transfer rate increased by employing Cu-Ni-distilled water hybrid nanofluid for a 12-turn copper coil with 0.06% volume concentration under turbulent flow conditions compared to distilled water. Further, it was evident that the pressure drop is also compounded by an increase in flow rate and a decrease in the pitch of the helical coil. In turbulent regions, the pressure drop increased by 12.5, 17.64 and 26.3% for 0.02, 0.04 and 0.06 Cu-Ni nano particle volume concentrations, respectively, when related to pure water at Re equal to 14150. Major Findings: In the case of a 12-turn copper coil, the overall heat transfer coefficient(U) is improved by 43.71, 52.196 and 60.782 % for 0.02, 0.04 and 0.06 % vol, respectively, compared to distilled water at Re=14150. It is found that the ideal condition to run the shell and helical coil heat exchanger at Re=14150 with 0.06% vol of Cu-Ni hybrid nanofluid. *