Hi i'm doing an analysis on pipe flow where the initial design of pipe mention that friction factor to be 0.015 around, but when I apply Bernoulli's equation based on the two points measurement, I computed f is around 0.03.
We also consider there is an increase in f but my colleague conveys that friction factor is fixed 0.03 from initial design stage and it wont change because of very high turbulent flow (i.e) high turbulent flow might not cause corrosion or increase in roughness.
Whereas I'm of thought, high turbulent flow slowly ruptures the pipe inner diameter that cause the roughness to increase. Reynolds number is of range 1e6 to 1e7.
Just thinking about the stresses at the wall, tau_wall appears greater in turbulent regime than in laminar, however I cannot say for sure if and in how much time that affects the roughness.
However, I am not sure how you applied Bernoulli for the case of viscous flows (it cannot be applied). Are you considering the integral corrected by the viscous loss?
first of all, consider the content of the liquid. Does it include hard particles, does it consist of agressive agents?
Filippo Maria Denaro hi thanks, it is normal pipe flow analysis and I'm not sure why you say Bernoulli's principle cannot be applied between two points in a pipe flow. http://www-mdp.eng.cam.ac.uk/web/library/enginfo/aerothermal_dvd_only/aero/fprops/cvanalysis/node40.html
Vladyslav Demenko thank u so much, yes due to excessive turbulence, there will be wear and tear and hence there will be increase in roughness. Also in our analysis we are not considering any particles in the flow.
Ijaz Fazil Syed Ahmed Kabir
The Bernoulli'integral requires that the flow is incompressible and ideal, that is no viscosity and no conducibility of the fluid are considered. It is wrong to use it for viscous flow in pipe, just consider as example what happens to the pressure for the Hagen-Poiseulle flow. Otherwise you have to consider the Fanno flow where dissipative terms can be included in quasi one-dimensional flows.
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