Numerical investigation of fluid flow and heat characteristics of a roughened solar air heater with novel v-shaped ribs
2022
Allauddin, Usman | Khan, Waqar | Ali, Saim E. | Haider, Syed Muhammad Mehdi | Ahmed, Abdul S. | Rehman, Abdur | Verdin, Patrick G.
Solar air heaters convert clean solar energy into useful heat and have a wide range of applications. Computational Fluid Dynamics (CFD) can aid in the design and development of solar air heaters with optimized thermal efficiency. A detailed numerical study was conducted to investigate the fluid flow and heat transfer characteristics of a roughened solar air heater with novel V-shaped ribs having staggered elements. Three dimensional steady-state numerical simulations were performed using the k– RNG turbulence model, and results were found in excellent agreement with experimental data. The effect of ribs spacing were studied through varying the rib pitch to rib height ratio P/e= 6 to 14, for Reynolds numbers (Re) in the range of 4000-14,000. A significant enhancement in the ribs-roughened solar air heater’s thermal performance was observed. It was also established that an increment in P/e from 6 to 10 increases the Nusselt number (Nu) for all Re values investigated. About 72.6% Nu enhancement was predicted for P/e=10 at Re = 12,000. It was further observed that an increment in p/e from 10 to 14 decreases Nu for all Re values considered.
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