Problem Solving Using Moody Diagram
Problem - A Hydraulic fossil oil has the kinematic viscosity of fifty cS . The fossil oil flows through a commercial steel pipage of one inch diameter. Find the friction part for the next weather condition -
a. Velocity of the menstruum - ten ft/s
b. Velocity of the menstruum - xl ft/s
Solution
At offset nosotros convey to notice Raynolds Number from this formula, (This formula is optimized for kinematic viscosity inwards cS = Centistokes)
NR
=
=
Putting the values of all the parameters nosotros larn -
a . Raynolds Number is 1548. So the menstruum is laminer (Raynolds release < 2000 )
So hither nosotros don't need the relative roughness as well as so nosotros don't need the Moody Chart. Simply nosotros volition purpose the formula for friction factor, f
By using this formula nosotros larn friction part , f = 0.042 (ans)
b. Raynolds Number is 6192 . So the menstruum is Turbulent (Raynolds Number > 4000)
Now for turbulent menstruum nosotros volition convey to use moody diagram for getting the friction factor. For that argue nosotros convey to calculate the relative roughness. Here is the equation for relative roughness.
For getting the value of epsilon nosotros volition purpose this nautical chart -
From the nautical chart nosotros run into that- for commercial steel actual roughness epsilon = 0.0018
So Relative roughness = 0.0018 inwards / one inwards = 0.0018
Now larn in to the moody chart
Locate Raynolds Number = 6192 inwards the Raynolds Number axis inwards the chart. And directly larn upwards vertically to larn the value of relative roughness = 0.0018 . Now projection horizontally for getting the value of f . Which is f = 0.036 (ans) . For your assistance the necessary points are shown inwards the diagram.
Thank you. If you lot convey whatever query almost the occupation or the Moody Diagram as well as so contact me or only exit a comment. Cheers ! Hope this volition hold upwards helpful .