Repeat Prob. 8-93 for cast lion pipes of the same diameter.
(a)
The electric power consumption of the system for pumping of water.
Answer to Problem 94P
The electric power consumption of the system for pumping of water is
Explanation of Solution
Given information:
The temperature of the water is
Write the expression for the Reynolds number.
Here, Reynolds number is
Write the expression for the volume flow rate of the water.
Here, the volume flow rate of the water is
Write the expression for the friction factor for turbulent flow.
Here, friction factor for turbulent flow is
Write the expression for the head loss through the pipe.
Here, length of the pipe is
Write the expression for the pressure drop through the pipe.
Here, the pressure drop through the pipe is
Write the expression for the electric power consumption of the system for pumping of water.
Here, electric power consumption of the system for pumping of water is
Write the expression for the Bernoulli Equation.
Here, pressure at point
Write the expression for the motor-pump efficiency.
Here, the motor-pump efficiency is
Calculation:
Substitute
Substitute
Since value of the Reynolds number is greater than
Substitute
Substitute
Substitute
Substitute
Substitute
Conclusion:
The electric power consumption of the system for pumping is
(b)
The daily cost of the power consumption of the system.
Answer to Problem 94P
The daily cost of the power consumption of the system is
Explanation of Solution
Calculation:
The unit cost of the electricity is
Write the expression for the amount of daily cost of the power consumption.
Here, amount of daily cost of the power consumption is
Substitute
Conclusion:
The daily cost of the power consumption of the system is
(c)
The frictional heating during flow will make up drop in temperature or not.
Answer to Problem 94P
The frictional heating during flow will make up drop in temperature.
Explanation of Solution
Given information:
The drop-in temperature of geothermal water during flow is
Write the expression for the rise in temperature of geothermal water.
Here, rise in temperature of geothermal water during flow is
Calculation:
Substitute
Since rise in temperature of geothermal water due to frictional heating is greater than the drop in temperature of geothermal water during flow, therefore the frictional heating during flow will make up drop in temperature.
Conclusion:
The frictional heating during flow will make up drop in temperature.
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Chapter 8 Solutions
FLUID MECHANICS CONNECT ACCESS
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- Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning