Example $6\mathrm{.}4.$ In Example $6\mathrm{.}1,$ Fig. $6\mathrm{.}6,$ we have decided that we wish to transport $300ga\frac{l}{m}in,$ instead of the $50ga\frac{l}{m}in$ in that example. Now what is the required pressure in Tank $A?$

This is six times the required volumetric flow rate in Example $6\mathrm{.}1$ ; the average velocity is $V=2\mathrm{.}17f\frac{t}{s}*6=13\mathrm{.}0f\frac{t}{s}.$ If the flow here were laminar, as it was in that example, then we could simply multiply the required pressure by $6.$ But in that example the Reynolds number $R=1028.$ Here we have the same pipe diameter, viscosity, and density, but six times the velocity, so we must have $R=1028+6=6164.$ This is $>4000,$ so the flow is sure to be turbulent.

To use Fig. $6\mathrm{.}10$ or Eq$.6\mathrm{.}22,$ we need a value of $\frac{}{D}.$ Reading the value for commercial steel pipe from Table $6\mathrm{.}2,$ we have

$\frac{}{D}=\frac{0\mathrm{.}0018in}{3\mathrm{.}068in}=0\mathrm{.}0006$

Then we enter Fig. $6\mathrm{.}10$ at the right at $\frac{}{D}=0\mathrm{.}0006$ and follow that curve to the left to $R=6164,$ finding $($as best wt can read that crowded part of the chart$)f=0\mathrm{.}009.$ We may check that value from Eq$.6\mathrm{.}22,$ finding $0\mathrm{.}00905.$ We wil discuss later the uncertainties in friction factor values, so for now we accept $0\mathrm{.}0091$ as a good estimate of $f.$

Excel Assignment

Solve Examples $6\mathrm{.}4,6\mathrm{.}5$ and $6\mathrm{.}6$ in Excel. You should use the Goal seek method for Examples $6\mathrm{.}5$ and $6\mathrm{.}6.$ After submission, you should arrange a $10$min meeting to discuss your solutions.