Second law of thermodynamic analysis of 40:60% propylene glycol and water mixture based nanodiamond nanofluid under transition flow

Second law efficiency (exergy) was studied experimentally for transition flow in a tube of 40:60% (weight) p4ropylene glycol and water mixture based nanodiamond nanofluid. Prior to prepare the stable nano-diamond (ND) nanofluid, its soot was rinsed by strong chemicals. The experiments were carried out for several values of particle loading (0.2% to 1.0%) and of Reynolds number (2000 to 8000). The experimental analysis was also conducted for the heat transfer, friction factor and pumping power characteristics of the ND nanofluid. By increasing the values of particle concentration and Reynolds number, the results indicate an increase of heat transfer, Nusselt number, friction factor, pumping power and thermal performance factor, and a decrease of the thermal entropy generation. In comparison with the base fluid data, the heat transfer coefficient, Nusselt number, pressure drop, pumping power, friction factor and the thermal performance factor of the ND nanofluid augment by 36.83%, 24.16%, 15.38%, 13.18%, 19.9%, and 16.94%, respectively, and the thermal entropy generation decreases by 26.92% for 1.0 vol% and Reynolds number of 5321.16.

Automated summary

Experimental study on the second law efficiency of a transition flow in a tube containing 40:60% weight ratio of propylene glycol and water mixture based nanodiamond nanofluid showed improvements in heat transfer, friction factor, pumping power, and thermal performance as the particle concentration and Reynolds number increased. Compared to the base fluid, the nanofluid exhibited significant enhancements in heat transfer coefficient, Nusselt number, pressure drop, pumping power, friction factor, and thermal performance factor, along with reduced thermal entropy generation.