Increasing heat transfer in flat plate solar collectors using various forms of turbulence-inducing elements and CNTs-CuO hybrid nanofluids

In this research, hybrid nanofluids and various turbulence-inducing elements were utilized to raise the convective heat transfer coefficient. To achieve this goal, three different creatively turbulence-inducing elements cases with equal pipe lengths in the flat plate solar collector have been simulated using CFD software. This article can be divided into three parts. In the first part, the heat transfer coefficient (HTC) in different forms of turbulence-inducing elements was compared with the BASE case of the pipe, and the results showed that CASE 3 has a better heat transfer than the others. For instance, at Reynolds numbers 10000 and 4000, the heat transfer coefficient of the CASE 3 is 31.31% and 31.06% higher than the BASE case. In the second part, different hybrid nanofluids and pure water were studied in the best case obtained from the first stage (CASE 3), and the results showed that SWCNT-CuO/H2O hybrid nanofluids had a better heat transfer coefficient. In the third part, hybrid nanofluids with a concentration of 1–5% in different Reynolds numbers were evaluated, and the outcomes demonstrated that the most extreme impact of concentration was at Reynolds number 4000 at the concentration of 5%, which increased the HTC by 8.79%. [Display omitted]