A numerical study on thermal performance evaluation of a parabolic trough collector with ZrO2/water nanofluid and combination of twisted tape and perforated plate inserts

The heat transfer coefficient, Nusselt number, friction factor, and thermal performance factor of ZrO 2 /water nanofluids flow in a parabolic through collector (PTC) equipped with combination of different twisted tape (TT) and perforated plate (PP) inserts have been studied numerically. The studies were performed in the Reynolds number range from 4000 to 10000, different volume loadings of 0.2%, 0.6%, and 1.0%, different twisted tape ratios y / w of 4, 5, and 6, and different perforated plate pitch distance of 12.78, and 23.32, respectively. The ANSYS-CFD (computational fluid dynamics) with turbulence– ε model and semi-implicit method for pressure linked equations (SIMPLE) algorithm was used to discretize the problem. Results indicated that, the with 1.0% vol. of nanofluid in a plain absorber tube, the heat transfer, and Nusselt number is enhanced over 36.65%, and 23.73%, with a friction factor penalty of 11.04%, at a Reynolds number of 10000, compared to base fluid data. The results also show that, Nusselt number increase of 233.65%, and 211.37% for 1.0% vol. of nanofluid in absorber tube with twisted tape twist ratio of 4, and perforated plate pitch distance of 12.78, over the same nanofluid in a tube without inserts. The thermal performance factor is increased by 2.02-times at 1.0% vol of nanofluid and with twisted tape insert of 4 and PP pitch distance of 12.78 at a Reynolds number of 10000, over the same nanofluid without inserts in a tube.