Performance and entropy production analysis of angle blade turbulators used to increase heat transfer

In this study, the effects on thermal performance and entropy production of new type turbulators with different blade angles and numbers, which are placed in a circular shaped pipe and manufactured in a 3D printer, were investigated experimentally. According to the experiments performed in the Reynolds number (Re) range of 7007–13,982, the Nusselt numbers of the 60°, 70° and 80° fin angle turbulators are, respectively, compared to the supported plain pipe; increased by 82.09%, 98% and 105.83%. Due to the increase in the blade angle, the maximum thermal performance was obtained as 1.542 for the 80° blade angle turbulator for Re = 12,538. The thermal performance factors of the 80° and 70° blade angle turbulators were found to be 1.048 and 1.039 times higher than the 60° blade angle turbulators, respectively. It was determined that the thermal improvement factor of the 80° blade angle turbulator is 1.008 times higher than the 70° blade angle turbulator. In terms of the second law, the maximum entropy production increase of the finned turbulators compared to the supported plain pipe was 153.96% at Re = 8387, in 3 turbulators with 80° fin angles. It has been determined that 1 turbulator model with 60° blade angles is more advantageous compared to the turbulators with 70° and 80° blade angles, since it produces the lowest entropy. In addition, it has been concluded that the most suitable turbulator model in terms of thermal performance is 3 turbulators with 80° blade angles. Graphic abstract: [Figure not available: see fulltext.] © 2023, Akadémiai Kiadó, Budapest, Hungary.