Heat Transfer

Mechanical Engineering, Publication in the Diário da República - Despacho nº 14312/2015 - 02/12/2015

5 ECTS; 2º Ano, 2º Semestre, 15,0 T + 15,0 PL + 30,0 TP + 3,50 OT

- Flávio Rodrigues Fernandes Chaves

Not applicable.

An initial approach to Heat Transfer is presented from the point of view of the Mechanical Engineer. The application examples address situations encountered by Mechanical Engineers in their daily work. Previous concepts are reviewed, and the contents of the course aim to provide a solid foundation for subsequent courses.

1. Introduction.
1.1 Areas of application of heat transfer.
1.2 Heat transfer by conduction.
1.3 Convection.
1.4 Radiation.
1.5 Conservation of energy principle.
1.6 Simultaneous heat transfer mechanisms.

2. Heat conduction equation.
2.1 Introduction.
2.2 One-dimensional heat conduction equation.
2.3 General heat conduction equation.
2.4 Boundary and initial conditions.
2.5 Solution of heat conduction problems.
2.6 Heat sources.

3. Steady heat conduction.
3.1 Conduction of heat in plane walls.
3.2 Thermal resistance.
3.3 Conduction of heat in cylinders and spheres.
3.4 Critical radius of insulation.
3.5 Fins.

4. Transient heat conduction.
4.1 Introduction.
4.2 Biot Number.
4.3 Lumped system analysis.
4.5 Transient heat conduction in walls, cylinders and spheres.

5. Heat convection.
5.1 Nusselt number.
5.2 Classification of flows.
5.3 Velocity and temperature boundary layers.
5.4 Laminar and turbulent regime.
5.5 Finding the convection coefficient h.
5.6 Natural and forced convection.

6. Heat exchangers.
6.1 Introduction.
6.2 Types of heat exchangers.
6.3 Overall heat transfer coefficient.
6.4 Analysis of heat exchangers: LMTD method.
6.5 Analysis of heat exchangers: e-NTU method.
6.6 Comparison between LMTD and e-NTU methods.
6.7 Compact heat exchangers.

Evaluation Methodology
Two tests during the semester (50% + 50%) or a final exam (100% of final grade).
Minimum pass grade of 10/20.

- Çengel, Y. e Ghajar, A. (2015). Heat and mass transfer: fundamentals & applications. EUA: McGraw-Hill
- Figueiredo, R. (2015). Transmissão de Calor. Lisboa: Lidel

Method of interaction
Theoretical, practical and laboratory classes.

Software used in class
Not applicable.