Heat Transfer
Objectives
Know the three modes of heat transfer -- conduction, convection and radiation -- the corresponding laws and models.
Acquire skills to formulate and solve common problems concerning heat transfer in various engineer situations such as insulation and heat exchange.
Learn to manage the limited time available to solve exercises, be it in the study or in examination.
General characterization
Code
10505
Credits
6.0
Responsible teacher
Daniel Cardoso Vaz, José Fernando de Almeida Dias
Hours
Weekly - 4
Total - 83
Teaching language
Português
Prerequisites
It is assumed the knowledge of the matters dealt with in: «Física II», «Análises Matemáticas», «Mecânica dos Fluidos» and «Termodinâmica Aplicada».
The written and laboratory work evaluations have implicit that the student is able to express his/hers train of thought intelligibly, either in portuguese or english, know how to use spreadsheet or another computational aid, and to apply the tools that were used in the course.
Bibliography
1. Carvalho, J. L. (2017), "Transferência de Calor e Eficiência Energética", NOVA Editorial - FCT/UNL.
2. Incropera e DeWitt (2011), "Fundamentals of Heat and Mass Transfer", John Wiley & Sons.
3. Holman, J. P. (2010), "Heat Transfer", McGraw-Hill.
4. Çengel, Yunus A. (2006), "Heat and Mass Transfer: A Practical Approach", McGraw‑Hill.
5. Bejan, Adrian (2013), "Heat Transfer", John Wiley & Sons.
6. Figueiredo, Rui (2015), "Transmissão de Calor - Fundamentos e Aplicações", Ed. Lidel.
Teaching method
There are theorectical (1.5 h) and problem-solving (2.5 h) classes, as well as a laboratory session. In the theorectical classes the study matter is presented while giving space for students'' questions. In the problem-solving sessions, the approach is centrered in the application of concepts, by proposing exercises and seeking the active participation of the students in solving them.
With the reduction of contact hours there are parts of the programme that are consolidated by means of two works to be solved individually and autonomously by the students, using spreadheet or another computational means.
Evaluation method
Translation to appear soon.
Subject matter
1- Heat transfer modes: Fourier, Newton and Stefan-Boltzmann laws. Heat diffusion equation. Thermal diffusivity. Isotherms and heat flux. Electrical analogy.
2 - Steady-state conduction: mathematical and numerical methods (finite differences).
3- Dynamic conduction: Biot and Fourier numbers. The Heisler charts. Periodic regime.
4- Forced convection: revision of fluid dynamics concepts. Differential quation of energy conservation in the thermal boundary layer. Prandtl and Nusselt numbers. Empirical correlations.
5- Heat exchangers: configurations; thermal design; Logarithmic Mean Temperature Difference.
6- Natural convection: Grashof number. Empirical correlations (laminar and turbulent regimes).
7- Radiation: properties. The black and grey bodies. Kirchhoff and Wien laws. Monochromatic and total emissivities. Shape factors. Applications to environmental radiation.