Experimental and numerical investigation on irregular spacing of the ribs in the entry length of a solar air heater channel. (20th October 2020)

• Record Type: Journal Article
• Authors: Ansari, Mohammad; Bazargan, Majid
• Is Part Of: Science and technology for the built environment. Volume 26:Number 9(2020)
• Page Start: 1231
• Page End: 1240
• Publication Date: 2020-10-20
• Subjects: Heating -- Periodicals; Ventilation -- Periodicals; Air conditioning -- Periodicals; Refrigeration and refrigerating machinery -- Periodicals; Indoor air quality -- Periodicals; Indoor air quality; Air conditioning; Heating; Refrigeration and refrigerating machinery; Ventilation; Periodicals; 697
• DOI: 10.1080/23744731.2020.1793639
• Languages: English
• ISSNs: 2374-474X

Abstract

Abstract : An experimental test rig is utilized to measure the effects of the flow configuration and particularly the rib geometry, on the thermal performances of solar air heaters. Since the heat transfer rate within the entry length is relatively high, the implementation of the ribs needs to be justified. Computational fluid dynamics simulations are also conducted to support the experiments and to provide detailed visualization of the flow field. The experimental data approves that the numerical simulation can estimate the heat transfer and pressure drop with reasonable accuracy. It appears from the results that achieving a particular spacing between the first ribs within the entry length, greater than the normal spacing in the fully developed region, yields a better performance. It is shown that in relatively short channels where the ratio of channel length to hydraulic diameter is small, the application of wider spacing in the entry length results in almost the same heat transfer rates, while it benefits from a much smaller pressure drop. In a presented case study, the application of irregular spacing improves the thermal performance of a flat plate solar collector by 11% compared to the collectors having ribs with regular spacing.