20.2. Derivations of Energy Losses

Try these first

1. 1.

   Define energy losses in a fluid system.

   Hint

   Think about how fluids interact with surfaces.

2. 2.

   What are the two types of flow mentioned?

   Hint

   Consider how the velocity affects flow behavior.

3. 3.

   What is the primary cause of energy losses in fluid systems?

   • Friction
   • Weight
   • Temperature

   Hint

   Consider what slows down the fluid.

4. 4.

   True or False: Turbulent flow has less energy losses than laminar flow.

   • True
   • False

   Hint

   Think about the orderly nature of laminar flow.

5. 5.

   A fluid flows through a pipe with a sudden contraction from diameter 0.2m to 0.1m. Using Bernoulli's equation, calculate the expected pressure drop due to energy losses if the flow velocity before the contraction is 3m/s.

   Hint

   Use continuity equation to find velocity after contraction.

6. 6.

   A globe valve experiences a pressure drop of 15 kPa while managing a flow of 0.5 m³/s. If the K factor for this valve is 0.18, calculate the approximate energy loss attributed to the valve.

   Hint

   Recall the head loss relationship: h = K(v²/2g).