Experimental investigation of heat transfer and flow analysis of artificially roughened solar air heater by using double arc reverse shaped roughness with gap on the absorber plate. (2023)

• Record Type: Journal Article
• Authors: Agrawal, Yogesh; Yugbodh, Kshitij; Faisal Ahmed, Syed; Jain, Ekta; Bhagoria, JL; Gautam, Atul; Mishra, Anuprita
• Is Part Of: Materials today. Volume 78(2023)Part 3
• Page Start: 403
• Page End: 413
• Publication Date: 2023
• Subjects: Discrete double arc ribs -- Friction factor -- Nusselt Number -- Solar air heater -- Thermo-hydraulic performance; Materials science -- Congresses -- Periodicals; 620.1
• DOI: 10.1016/j.matpr.2022.10.180
• Languages: English
• ISSNs: 2214-7853

Abstract

Abstract: Artificial roughness in the form of ribs is a convenient method for the enhancement of heat transfer coefficient in a solar air heater. In the present paper, an indoor experimental examination of Nusselt number (Nu) and friction factor (f) characteristics of a Solar air heater using novel discrete double arc reverse form roughness bottom side of the absorber plate was carried out. The range for criterion, relative roughness pitch (p/e) of 6.67, relative roughness height (e/Dh ) of 0.027, angle of arc (α) of 30°, 45°, 60°, 75°, Reynolds number (Re) of 3000 to 14000, aspect ratio (W/H) of 8 were applied in between the laboratory test. It has been found that the performance of roughened solar air heater duct is better than the performance of a smooth duct for the range of roughness parameters investigated. Enhancement of heat transfer coefficient (h) was noticed 266% more than a smooth channel. Increments of Nusselt number (Nu) and friction factor (f) were found at 268% and 221% more than smooth channel respectively. Maximum thermal efficiency was found 137% more than a smooth channel. Thermo-hydraulic concepts have been used to identify the ideal design and operating conditions. Depending on the insolation, it has been discovered that systems running within a certain Reynolds number range operate better thermo-hydraulically. The range of Thermo-hydraulic performance (THP) improved along with the increment of the Reynolds number. At a relative roughness pitch (p/e) of 6.67, a relative roughness height of 0.027, along the angle of arc (α) of 60°, the highest improvement of Thermo-hydraulic performance (THP) was noticed 2.22.