25.3. Mechanical Energy and Efficiency

Try these first

1. 1.

   What is a hydraulic gradient line?

   Hint

   Consider where the free surface of the liquid is.

2. 2.

   Explain the role of a pump in a fluid system.

   Hint

   Think about the direction of energy transfer.

3. 3.

   What does the hydraulic gradient line represent?

   • Kinetic Energy
   • Pressure Head
   • Fluid Velocity

   Hint

   Think about what you measure at the free surface.

4. 4.

   False or True: A turbine decreases fluid pressure by converting mechanical energy into fluid energy.

   • True
   • False

   Hint

   Consider the direction of energy transfer.

5. 5.

   A pump rated at 2000 Watts boosts water pressure from 50 kPa to 150 kPa. Calculate the water flow rate if the pump is 80% efficient.

   Hint

   Consider how much energy is actually being used after accounting for efficiency.

6. 6.

   Using Bernoulli’s equation, calculate the velocity of water flowing through a pipe at point A with a pressure of 80 kPa, at an elevation of 5 m, if at point B the pressure is 40 kPa with a height of 2 m.

   Hint

   Ensure elevation differences and pressure changes are reflected correctly.