Department of Mechanical and Vehicle Engineering, Adama Science and Technology University, Adama, Ethiopia; Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
Bekele, A., Department of Mechanical and Vehicle Engineering, Adama Science and Technology University, Adama, Ethiopia; Mishra, M., Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, India; Dutta, S., Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, India
The performance of conventional solar air heaters (SAHs) can be improved by providing obstacles on the heated wall (i.e. on the absorber plate). Experiments have been performed to collect heat transfer and flow-friction data from an air heater duct with delta-shaped obstacles mounted on the absorber surface and having an aspect ratio 6:1 resembling the conditions close to the solar air heaters. This study encompassed for the range of Reynolds number (Re) from 2100 to 30,000, relative obstacle height (e/H) from 0.25 to 0.75, relative obstacle longitudinal pitch (Pl/e) from 3/2 to 11/2, relative obstacle transverse pitch (Pt/b) from 1 to 7/3 and the angle of incidence (α) varied from 30° to 90°. The thermo-hydraulic performance characteristics of SAH have been compared with the previous published works and the optimum range of the geometries have been explored for the better performance of such air-heaters compared to the other designs of solar air heaters. © 2014 Elsevier Ltd. All rights reserved.
