Lesson 10-Head Loss in Conduit Flow

A conduit is a pipe, tube, or duct that is completely full of flowing fluid ….

## Why Take this Lesson?

Picture yourself with ability to design millions of real world products (e.g. fuel system in a car, water filter for the third world) or to design systems (e.g. beautiful water fountain in hotel lobby, hydroelectric power, solar heating, heat exchangers). Visualize that you can easily

• Explain why and where head loss occurs
• Predict head loss or predict pressure drop
• Predict power requirement
• Size pipes (i.e. recommend a diameter)
• Size pumps (i.e. recommend flow rate and head requirements)
• Estimate the power that can be produced by a energy system
• Determine flow rates

## Goals of This Lesson

• Concepts. Laminar flow, turbulent flow, developing flow, fully-develop flow, resistance coefficient, minor-loss coefficient
• Derivations
• Derive the Darcy-Weisbach equation
• Derive the Poiseuille flow solution
• Procedural knowledge
• Use pi-groups to classify flow (developing, fully developed, laminar flow)
• Determine values of the friction factor using the Moody diagram or eqns.
• Facts.
• Sketch the Moody diagram and label the main features.
• Describe how to specify a pipe size using the NPS system
• Applications—Solve typical engineering problems (see "Typical Applications" on p. 135).

## Requirements to Complete this Lesson

1. Create OMC's for laminar flow, turbulent flow, developing flow, fully developed flow. Using your OMCs, teach the ideas to 1 to 2 people. Write down your findings.

2. Create a half-page handout1 for use by the design engineer. Address the following topics:
- a. How to find Reynolds number, meaning of Re, why various formulas are equivalent.
- b. How to classify flow in a conduit (developing, fully developed, laminar, turbulent).
- c. Why flow classification is important in design.

3. Using your own approach, derive the Darcy-Weisbach eqn. Hit the requirements for quality given in the derivation article under the heading Quality (what a great derivation looks like!).

4. Prove that you can solve problems involving the Darcy-Weisbach eqn (f is given) by solving problems 10.6 and 10.7.

5. Using your own approach, derive Eq. (10.15). Then derive Eq. (10.27). Hit the requirements for quality given in the derivation article under the heading Quality (what a great derivation looks like!).

6. Create a one-page handout2 for use by the design engineer. Address the following topics:
- a. Moody diagram. Main features, how to use, definition of symbols
- b. Meaning of "smooth pipe", "fully rough flow", "sand-roughness" height.
- c. Equations that can be used to predict the curves on the Moody diagram.

7. Prove that you can solve problems involving the Darcy-Weisbach eqn. & the Moody diagram (or eqns) by solving 2 problems from the following list: 10.16, 10.27, 10.40, 10.54, 10.56.

8. Create a one-page handout3 for use by the design engineer. Address the following topics:
- a. Combined Head Loss Equation. How to use, how/where to find f, how/where to find K
- b. Minor loss coefficient. Meaning, how to measure, how to look up. Key facts.

9. Prove that you can solve application problems involving the combined head loss equation by
- a. Solving 2 problems from the following list. 10.63, 10.66, 10.75
- b. Solving two real world problems of your choice (examples = design a cool fountain, predict the flow rate out of a tank draining with syphon, design a "water-fall" for a party, …).

10. Apply Reflective Thinking to your work on this lesson.