Concept explainers
Suppose that the free surface of the inlet reservoir in Prob. 13-39 is 3.0 m higher in elevation, such that Z2- z1= 4.85 m. All the constants and parameters are identical to those of Prob. 14-39 except for the elevation difference. Calculate the volume flow rate for this case and compare with the result of Prob. 14-39. Discuss.
The volume flow rate by the pump.
Answer to Problem 41P
The volume flow rate by the pump is
Explanation of Solution
Given information:
The diameter of pipe is
Write the expression for head required.
Here, pressure at exit is
Write the expression for coefficient of total minor head loss.
Here, coefficient of entrance loss is
Write the expression for head loss.
Here, length of pipe is
Write the expression for
Here, shutoff head is
Write the expression for Reynolds number.
Here, density of water is
Write the expression for Colebrook equation.
Here, coefficient of friction is
Write the expression for volume flow rate.
Calculation:
Substitute
Substitute
Substitute
Substitute
Refer Table-A-3 "Properties of saturated water" at
Substitute
Substitute
Substitute
Here, apply hit and trial to obtain velocity of flow.
Trial-(1)
Substitute
Since the values on both sides are not equal, so assumption
Trial-(2)
Substitute
Here, the values on both sides are equal, so velocity of flow is
Substitute
Here, the volume flow rate for elevation difference of
Since the volume flow rate for the for the elevation difference of
Hence on decreasing elevation difference between the reservoir the volume flow rate increases.
Conclusion:
The volume capacity delivered by the pump is
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Chapter 14 Solutions
Fluid Mechanics: Fundamentals and Applications
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