Computational study of heat transfer and fluid flow in a solar trough collector with a ribbed surface and an MWCNT— A l 2 O 3 /water-based hybrid nanofluid

Abstract

The parabolic trough solar collector (PTSC) is renowned for its impressive ability to harness solar energy effectively. Nevertheless, it does suffer from a low thermal efficiency $({\eta }_{\mathrm{th}})$ , which presents an exciting opportunity for its performance enhancement using novel coolant hybrid nanofluids (NFs) and reconfigured receiver tubes. This study performs computational simulations to analyze the thermal and hydraulic performance of PTSC equipped with a V-ribbed receiver tube for MWCNT— $\mathrm{A}{\mathrm{l}}_2{\mathrm{O}}_3$ /water hybrid. All turbulent flow simulations are performed for different values of parameters (relative rib height $({\mathrm{R}}_{\mathrm{h}}/{\mathrm{D}}_{\mathrm{t}})$ , relative streamwise pitch ratio $({\mathrm{P}}_{\mathrm{stm}}/{\mathrm{R}}_{\mathrm{h}})$ and relative spanwise pitch ratio $({\mathrm{P}}_{\mathrm{spn}}/{\mathrm{R}}_{\mathrm{h}})$ of V-ribbed receiver tube with different Reynolds number $(\mathrm{Re})$ (10,000–50,000). Various performance indicators (Nusselt number $(\mathrm{Nu})$ , friction factor $(\mathrm{f})$ , and performance evaluation criterion) had been investigated to assess the collector's performance. The results indicate that the highest Nu achieved of 760 with ${\mathrm{P}}_{\mathrm{spn}}/{\mathrm{R}}_{\mathrm{h}}=11.11$ . Additionally, the maximum $\mathrm{f}$ of 0.29 was observed at ${\mathrm{P}}_{\mathrm{spn}}/{\mathrm{R}}_{\mathrm{h}}=7.78$ with ${\mathrm{R}}_{\mathrm{h}}/{\mathrm{D}}_t=0.0135$ and ${\mathrm{P}}_{\mathrm{stm}}/{\mathrm{R}}_{\mathrm{h}}=56.67$ . Furthermore, the peak enhanced ${\eta }_{\mathrm{th}}$ of 1.9 was attained with ${\mathrm{P}}_{\mathrm{spn}}/{\mathrm{R}}_{\mathrm{h}}=11.11$ , specifically at $\mathrm{Re}$ of 50,000. The findings indicate that using a V-ribbed receiver tube augments the heat transfer of the solar collector by 134.57% at Re of 50,000 with hybrid NF.