Course Outline

Heat Transfer

1. Introduction to Heat Transfer

OBJECTIVES:

1. Discuss the relationship between Thermodynamics and Transport Processes
2. Describe the physical meaning of each of the terms within a general thermal energy balance
3. Explain and give examples of the three primary modes of heat transfer
4. Calculate the thermal resistance and magnitude of conductive heat flow/flux through a planar wall
5. Calculate the thermal resistance and magnitude of heat flow in convective and radiative systems
6. Calculate the resistance and magnitude of heat flow in systems in which multiple modes of heat transfer are present

• Relation to Thermodynamics
• Balances and Rate Expressions[Ch 6.1, 16.1-16.3]
• Modes of Heat Transfer [Ch 15]
  • Conduction[Ch 15.1]
    • Example 1
    • Example 2
    • Resistance
  • Convection [Ch 15.3]
  • Radiation [Ch 15.4]
• Combined Modes [Ch 15.5]

HW #1 (Solutions) 15.3, 15.9, *15.23, 15.27, *17.4

HW #2 (Solutions) 17.5, 17.6, 17.10, 17.13, 17.14

Group Exercise 1(solutions)

Quiz 1(solutions)

Group Exercise 2(solutions)

Quiz 2(solutions)

2. Steady 1D Conduction

OBJECTIVES:

1. Simplify the general thermal energy equation (identifying assumptions)
2. Identify reasonable boundary conditions in a conduction problem (explain when each is most useful)
3. Calculate temperature profiles within planar, cylindrical, and spherical solids
4. Determine the heat flow through these solids from their temperature profiles
5. Determine the conductive resistance in more complex geometries
6. Show how thermal energy "generation" affects temperature profiles
7. Derive the "fin equation"
8. Calculate the temperature profile within a fin
9. Determine the heat flow through a fin from the temperature profile
10. Determine the efficiency of a fin
11. Calculate the heat flow through a fin from the fin's efficiency

• Conduction through a slab[Ch 17.1]
• ...a pipe
• ...a pipe with convection
• ... a sphere
• A catalytic "slab"[Ch 17.2]
• Electricity through a wire
• What are fins (extended surfaces)?[Ch 17.3]
• Deriving the fin equation
• Fin Boundary Conditions
• Solving the fin equation
• Using the fin efficiency (tables)
• Really using the fin efficiency

HW #3 (Solutions) 17.15, 17.18, 17.21, 17.25, *17.28

Group Exercise 3(solutions)

Quiz 3(solutions)

Group Exercise 4(solutions)

3. Steady Multi-D Conduction

OBJECTIVES:

1. Simplify the general thermal energy equation (identifying assumptions)
2. Identify reasonable boundary conditions in a conduction problem
3. List the possible methods of solution of multi-d problems and when they are applicable
4. Outline the procedure for analytically solving a multi-d conduction problem (both temperature profile and heat flow)
5. Draw flux plots for strange geometries
6. Explain the connection between flux plots and the shape factor
7. Use shape factors to calculate heat flow in multi-d geometries

• How to solve multi-d problems [Ch 17.4]
• An analytical solution technique
• Flux plotting
• Shape factors

HW #4 (Solutions) 17.27, 17.32, 17.44, 17.50, 17.52

In Class Exercise(solutions)

Group Exercise 5(solutions)

Exam I on Tuesday June 1 (Example Test)

4. Unsteady Conduction

OBJECTIVES:

1. Simplify the general thermal energy equation (identifying assumptions)
2. Identify reasonable boundary conditions in a conduction problem
3. Explain the utility of the Biot number
4. Identify "regimes" of transient response based on the value of the Biot number
5. Use the "lumped" equation to solve "1D" transient problems
6. Outline the procedure for analytically solving a non-"1D" conduction problems (both temperature profile and heat flow)
7. Make the general thermal energy equation dimensionless
8. Use temperature/time charts to obtain temperature (profiles) for non-"1D" problems
9. Identify and "solve" semi-infinite media problems

• Biot Number: Lumped parameter model [Ch 18.1]
• An analytical solution technique[Ch 18.1]
• A dimensionless equation
• Using temperature/time charts[Ch 18.2]
• Semi-infinite media[Ch 18.1]

HW #5 (Solutions) 18.2*, 18.10, 18.13 (assume "lumped" is OK and then check your assumption), 18.13 (use charts), 18.14

5. Convection

OBJECTIVES:

1. Simplify the general thermal energy equation (identifying assumptions)
2. Identify reasonable boundary conditions
3. Explain the physical meaning of the Pe and Pr numbers
4. Calculate the heat transfer coefficient from the temperature profile in the fluid

• Convective conduction equation [Ch 19.4]
• Boundary layer and dimensionless numbers[Ch 19.1-19.4]
• Heat transfer coefficient[Ch 19.6]
• Convective Dimensionless Recap

6. Heat Exchangers

OBJECTIVES:

1. Solve the "thermodynamic" problem
2. Calculate the "average" driving force from the heat flow and resistance
3. Calculate the heat flow in an exchanger from the exchanger's effectiveness

• Heat Transfer Equipment [Ch 22.1]
• Log mean temperature difference [Ch 22.2]
• Extending the T_lm difference [Ch 22.3]
• heat exchanger effectiveness

HW #6 (Solutions) 18.24, 18.27, 22.2, *22.7, 22.8 (a and c only)

HW #7 (Due 6/18) (optional: 19.9c, 20.18), 22.16 (T's may be backward, use comon sense), 22.17

Quiz 4(solutions)

Quiz 5(solutions)

Group Exercise 6(solutions)

Group Exercise 7(solutions)

(not) Quiz 6(solutions)

Review Notes

Practice Final