Heat transfer and pressure drop characteristics of MgO nanofluid in a double pipe heat exchanger

The present work aims to investigate the plausible application of MgO-ethylene glycol as a heat transfer fluid in a double-pipe heat exchanger. The nanofluid was prepared using a two-step method at weight concentrations of 0.1, 0.2 and 0.3%. The test rig provided conditions to measure the convective heat transfer coefficient, pressure drop and friction factor of the system. Influence of the different operating parameters such as flow rate, mass concentration of nanoparticles and inlet temperature of nanofluid to the heat exchanger on the heat transfer coefficient and pressure drop was experimentally investigated. Results showed that the heat transfer coefficient within the heat exchanger can be enhanced by 27% for wt.% = 0.3 in comparison with the base fluid (ethylene glycol). It was also found that the presence of MgO nanoparticles increased the pressure drop by 35% at wt.% = 0.3. The friction factor of the system decreased nonlinearly with an increase in the Reynold number and it followed the trend of 64/Re equation. An increase in the mass concentration of nanoparticles increased the friction factor and the maximum friction factor enhancement was 32% belonging to the nanofluid with mass concentration of wt.% = 0.3. Likewise, inlet temperature was found to have a very slight influence on the heat transfer coefficient and no effect on the friction factor and pressure drop of the system. The thermo-physical properties of MgO-ethylene glycol nanofluid was also experimentally measured at various temperatures.