Nusselt number and flow distribution analysis over the roughened surface in a rectangular channel of a solar air heater
| Main Authors: | Amit Kumar, Apurba Layek |
|---|---|
| Format: | Article Journal |
| Bahasa: | eng |
| Terbitan: |
, 2020
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/5969763 |
Daftar Isi:
- National Institute of Technology Durgapur, Durgapur-713 209, West Bengal, India E-mail: amit4310@rediffmail.com Manuscript received online 16 June 2020, revised and accepted 02 September 2020 This paper provides the experimental investigation on the latest development of the optical method primarily based on liquid crystals thermography (LCT) method, which is understood to be a vital tool to obtain surface temperature distribution and assessment of heat transfer coefficients of a rectangular channel using artificial rib roughness. The LCT approach makes use of thermo chromic liquid crystals, an organic material applied at heated surface in an effort to get the color response, which is snapped by a CCD Camera on the premise of temperature modifications. The acquired color sample is digitized and decoded into its HSI (hue, saturation, and intensity) value by the RrGgBb (red, green, blue) response. The effect of roughness parameters taken into consideration encompasses relative roughness pitch (Pi/e) values of 6 - 12, attack angle (α) of 30o - 75o and relative roughness width (W/w) of 3 – 6 on the improvement of heat transfer are investigated over by varying Reynolds number (Re) levels from 13500 - 20500. The objective is to get the Nusselt number variety distribution over the artificially roughened surface with uniform heat flux conditions. It is noted that relative roughness pitch (Pi/e) of 8, W/w of 5 at an attack angle (α) of 600 suggests its most beneficial value of heat transfer as compared to smooth absorber surface.