Irreversibility characteristics of a mini shell and tube heat exchanger operating with a nanofluid considering effects of fins and nanoparticle shape

Abstract

The second law of thermodynamics is assessed for a water/Ethylene Glycol–boehmite nanofluid in a mini shell and tube heat exchanger (MSTHE). The nanofluid with five particle shapes is considered as the hot fluid in the pipe-side, whilst the water is selected as the cold fluid in the shell-side. For whole MSTHE, as Reynolds number (Re) raises, the thermal entropy generation (TEG) and Bejan number (Be) diminish, whilst the frictional entropy generation (FEG) heightens. The platelet-shaped particles cause the most significant TEG, FEG, and total entropy generation, while they result in the most minor Be. For whole MSTHE, the TEG, total entropy generation, and Be for the MSTHE with fin are lower than those for the MSTHE without fin, whilst the FEG demonstrates a opposite trend. In the platelet-based nanofluid for the case with fin, the total entropy generation decreases 4.9% by increasing the Re from 500 to 2000.