Relative roughness pitch is an important parameter considered for designing artificial roughness to enhance the heat transfer coefficient.
2.
Relative roughness is not a parameter in any of the equations because the friction factor of Bingham plastic fluids is not sensitive to pipe roughness.
3.
It was observed that increasing the relative roughness height above the laminar sub layer gives the optimum thermo hydraulic performance by creating local wall turbulence and thus enhancing heat transfer.
4.
Moody diagram showing the Darcy-Weisbach friction factor " f " " D " plotted against Reynolds number Re for various relative roughness ? / " D"
5.
Prasad and Saini [ 1988 ] conducted experiments by varying the relative roughness pitch in the absorber plate and observed that the flow pattern downstream the ribs was a function of the relative roughness pitch.
6.
Prasad and Saini [ 1988 ] conducted experiments by varying the relative roughness pitch in the absorber plate and observed that the flow pattern downstream the ribs was a function of the relative roughness pitch.
7.
This dimensionless coefficient will be a combination of geometric factors such as, the Reynolds number and ( outside the laminar regime ) the relative roughness of the pipe ( the ratio of the roughness height to the hydraulic diameter ).
8.
The chart plots Darcy Weisbach friction factor against Reynolds number Re for a variety of relative roughnesses, the ratio of the mean height of roughness of the pipe to the pipe diameter or ? / " D ".
9.
Furthermore, research performed at the University of North Carolina revealed that scanning velocity did not have an effect on relative roughness because the roughness for all surfaces increase by the same amount as scanning velocity increases in accordance with Weber's Law.
10.
Relative roughness plays a vital role in the design of the artificial roughness elements . Prasad and Saini [ 1988 ] conducted experiments by varying the relative roughness height and observed its corresponding effect on the flow pattern downstream the ribs and the laminar sub layer.
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