TY - JOUR
N2 - Providing roughness is an effective method to heat fluids to high temperature. Present paper make use of concave dimple roughness on one and three sides of roughened ducts aimed at determining rise in heat transfer and friction of three sides over one side roughened duct. Three sides roughened duct produces high heat transfer compared to one side roughened. Results are shown as a rise in Nusselt number and friction factor of three sides over one side roughened duct. Experimental investigation was conducted under actual outdoor condition at National Institute of Technology Jamshedpur, India to test various sets of roughened collectors. Roughness parameter varied as relative roughness pitch 8–15, relative roughness height 0.018–0.045, dimple depth to diameter ratio 1–2, Reynolds number 2500–13500 at fixed aspect ratio (width/hight) 8. Highest enhancement in Nusselt number for varying relative roughness pitch, height, and diameter ratio was respectively found as 2.6 to 3.55 times, 1.91 to 3.42 times and 3.09 to 3.94 times compared to one side dimple roughened duct. Highest rise in friction for three sides over one side roughened duct for these varying parameters was respectively found as 1.62 to 2.79 times, 1.52 to 2.34 times and 2.21 to 2.56 times. To visualize the effect of roughness parameter on heat transfer and friction factor, variation in Nusselt number and friction factor for varying roughness parameters with Reynolds number is shown.
L1 - http://www.journals.pan.pl/Content/117611/PDF/03_paper.pdf
L2 - http://www.journals.pan.pl/Content/117611
PY - 2020
IS - No 3
EP - 89
DO - 10.24425/ather.2020.134572
KW - Dimple roughened
KW - Relative roughness pitch
KW - Relative roughness height
KW - Dimple depth to diameter ratio
KW - Nusselt number
KW - Friction factor
A1 - Kumar, Vikash
PB - The Committee of Thermodynamics and Combustion of the Polish Academy of Sciences and The Institute of Fluid-Flow Machinery Polish Academy of Sciences
VL - vol. 41
DA - 2020.09.25
T1 - Augmentation in heat transfer and friction of three sides over one side dimple roughened solar duct
SP - 57
UR - http://www.journals.pan.pl/dlibra/publication/edition/117611
T2 - Archives of Thermodynamics
ER -