The experimental investigations were consisting of two parts. The first part was carried out to study the effect of corner geometry on the steady-state forced convection inside horizontal isosceles triangular ducts with sharp corners. The electrically-heated triangular duct was used to simulate the triangular passage of a plate-fin compact heat exchanger. The isosceles triangular ducts were manufactured with duralumin, and fabricated with the same length of 2.4 m and hydraulic diameter of 0.44 m, but five different apex angles (i.e. θa= 15°, 30°, 40°, 60°, and 90°) respectively. The investigation was performed under turbulent flow condition covering a wide range of Reynolds number (i.e. 7000 ≤ ReD≤ 20000). It was found that the best thermal performance is achieved with the apex angle of 60°. The second part was performed to investigate the effect of surface roughness on the forced convection of the same system. Horizontal equilateral triangular ducts with an apex angle of 60° were fabricated with the same length and hydraulic diameter, but different average surface roughnesses of 1.2 μm, 3.0 μm and 11.5 μm respectively. It was concluded that the duct with a higher surface roughness will have a better heat transfer performance. Non-dimensional expressions for the determination of the heat transfer coefficient of the triangular ducts with different apex angles and surface roughnesses were also developed.
|Number of pages||6|
|Journal||Heat and Mass Transfer/Waerme- und Stoffuebertragung|
|Publication status||Published - 1 Jan 1998|
ASJC Scopus subject areas
- Condensed Matter Physics
- Fluid Flow and Transfer Processes