Second law analysis on an elliptical twisted tube for a heat exchanger

This works presents a second law analysis on heat exchanger tube configurated as circular smoot (CST), elliptical smooth (EST) and twisted (ETT) with different aspect ratios pitch lengths. The ETTs were ratio (AR) of 1.5 2.0 twist length (PL) 50, 100 200 mm. hydraulic diameter was kept constant for all cases, since the results are influenced by change in diameter. CFD analyzes run to perform considered cases. carried out considering that thermo-physical properties water fluid depending temperature. Besides, under steady state condition turbulent flow which corresponds Reynolds number ranging from approximately 4000 27,000. evaluated discussed terms thermal, frictional total entropy generation, Bejan number, generation exergy destruction efficiency. It is resulted increase AR decrease PL show better As result, case ETT_AR=2.0_PL=50 at minimum mass rate study, highest efficiency obtained 0.45, value greater than 80% CST.