Abstract
Abstract Drying agricultural food products in an indirect type solar dryer (ITSD) is a topic of frequent research. Heat transfer rate to the fluid flow in the solar collector can be enhanced by providing artificial roughness on the surface of the absorber plate. The present work concentrates on air flow and heat transfer characteristics in a solar air collector provided with roughness of square shaped rib over the absorber of ITSD. 2D numerical simulations are performed for flow through the solar air collector for relevant Reynolds number (Re) which ranges from 3800 to 18,000. The Re, relative roughness pitch (P/e), relative roughness height (e/D) and thermo-hydraulic performance parameter (THPP) are chosen as design variables. The governing equations for turbulent flow field are solved using RNG k–ɛ turbulence model. The simulation results are compared with smooth duct which shows that the duct with roughened surface enhances the heat transfer and friction factor (fr) by 2.13 and 3.54 times, respectively. The solar air collector with roughness of square shaped rib with P/e = 7.14 gives better THPP of 1.45 at Re of 15000. It is found that the additional drying chamber temperature of 4 K and heat gain of 106% when the dryer is upgraded to roughened surface from smooth surface. The present simulation model is validated with experimental outcomes of existing literature and good agreement is noticed.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
