Numerical and experimental study on the optimization of a ribbed-petaled pattern absorber pipe with spiral twisted tapes enhancements

• The study develops a new absorber tube using passive cooling techniques. • The effect of mass flow rate and geometrical parameters is examined. • A rib pitch of 16 mm, width of 1.75 mm, and height of 0.1 mm are optimal. • The tube using all passive cooling methods achieved a 48.3% THPF increase. • The difference between experimental and numerical results is 3.01%. Low thermal efficiency remains one of the most critical challenges in absorber tube designs. Therefore, Thermohydraulic Performance Factor (THPF) analysis was performed for a newly designed absorber tube featuring ribs and petal arrays on its surfaces. Three key parameters were studied: rib pitch numbers of (8, 10, 12, 14, and 16), rib width (1, 1.25, 1.50, 1.75, and 2) mm, and rib height (0.1, 0.2, 0.3, 0.4, and 0.5) mm. Also, petal arrays are incorporated to enhance thermal performance. Once the effects of geometrical parameters were optimized, the study experimentally revealed the impact of flow enhancers including a coil, a twisted tape, and their combination. The study examined flow rates of (0.01, 0.03, 0.05, and 0.07 kg/s) with a constant heat flux of 1000 W/m². The optimal rib tube geometry was a rib pitch of 16, a rib width of 1.75 mm, and a rib height of 0.1 mm, achieving the highest THPF enhancement of 14.07%. The best-ribbed tube design with petal arrays resulted in 18.79% increase in THPF. The results were experimentally validated, with a variation of 3.01%. Finally, the combination of coiled twisted tape with the best absorber tube design yielded the highest THPF enhancement of 43.80%.