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ISSN Online: 2688-7231

ISBN Online: 978-1-56700-524-0

Proceedings of the 26thNational and 4th International ISHMT-ASTFE Heat and Mass Transfer Conference December 17-20, 2021, IIT Madras, Chennai-600036, Tamil Nadu, India
December, 17-20, 2021, IIT Madras, Chennai, India

Experimental analysis on performance of solar air heater combined with staggered element in inclined rib using liquid crystal thermography technique

Get access (open in a dialog) DOI: 10.1615/IHMTC-2021.2870
pages 1899-1906

Abstract

An experimental investigation have been conducted for the analysis of local convective heat transfer coefficient of an artificially roughened rectangular duct of SAH using LCT technique having inclined rib geometry with staggered arrangement over absorber surface. Along with the optimization of thermal performance of the devices, it is also critical to get an accurate phenomenon of heat transfer distribution inside the system. One of the most precise methods for mapping temperature distribution is LCT. LCT uses TLCs to give a visual representation of the temperature distribution based on the changing colors of the TLC when heated. The color pattern is recorded by a CCD video camera and the recorded image is digitized and converted from the RGB to HSI domain using MATLAB program. The investigated parameters considered for the present study are relative P⁄e=10, α=60°, e⁄Dh=0.0303, d⁄W=0.25, g⁄e=2, and variations in p'⁄P and r/e are taken as 0.2-0.8 & 1-4, and Reynolds number in the rage of 4000-12500. The enhancement in Nu & ƒ has been determined and compared to a smooth surface and THPP is evaluated at the optimum relative staggered rib position and relative staggered rib size. Nu increases with an increase in Re. The maximum augmentation in Nu and f is observed to be 4.01 times and 4.28 times respectively against smooth surface and obtained at optimum value of, p'⁄P =0.6 and r⁄e = 2. The maximum value of THPP occurred is 2.47 at Re of 12400.