Abstract
A parabolic trough collector (PTC) with internal helical axial fines is considered as a turbulator and is analyzed numerically. This research aims to plan a new geometry of absorbent pipes containing axial helical fines, which leads to enhancing solar collector efficiency (η) by increasing Nusselt number (Nu) and decreasing pressure drop (ΔP), especially at higher Reynolds numbers (Re). For numerical simulation, finite volume method and SIMPLEC algorithm are used. The heat transfer rate (HTR) and operating properties of ((CH2OH)2)/Cu-SWCNT hybrid nanofluid (NF) with different volume fractions and Reynolds numbers are investigated. The results are obtained for two cases of axial helical fins with a different number of turns along the pipe. The results show that the maximum efficiency of 78.197% is related to the pipe with the highest number of turns when Re = 12000 and φ = 1%, while η = 71.4785% for the pipe with the lowest number of turns under the same conditions. The maximum PEC value is 4.7 and belongs to Re = 12000 for a pipe with a lower number of turns (case 2) in which φ = 1%. Therefore, using more turns is more desirable from the point of view of thermal fluid dynamics.