MECA0445-2 : Heat transfer

Study Programmes 2015-2016

MECA0445-2

Heat transfer

Duration :

30h Th, 26h Pr, 4h Labo., 9h Proj.

Number of credits :

Bachelor in engineering : architecture		5
Bachelor in engineering		5
Master in aerospace engineering (120 ECTS)		5
Master in electro-mechanical engineering (120 ECTS)		5
Master in mechanical engineering (120 ECTS)		5
Master in physical engineering (120 ECTS)		5

Lecturer :

Pierre Dewallef, Vincent Terrapon

Language(s) of instruction :

English language

Organisation and examination :

Teaching in the second semester

Units courses prerequisite and corequisite :

Prerequisite or corequisite units are presented within each program

Course contents :

The transfer of energy as heat plays a key role, not only in technical applications (energy production, engines, cooling of electronic components, buildings, ...), but also in our daily life (climate and weather, cooking, human body, ...). It is almost impossible to find examples where heat transfer is absent. It is also directly linked to today's challenges of energy and environment. Heat transfer is therefore a key subject in the curriculum of engineers and architects.
Heat transfer represents the transfer of thermal energy from a warm body to a colder one. The objective of the course is thus to quantitatively relate heat fluxes to temperature gradients.
There are three main heat transfer modes: conduction, convection and radiation. The course focuses first on each mode separately, and then on multimode heat transfers. For each mode, the underlying physical processes are described and quantitative laws are developped. Theoretical notions are illustrated through numerous practical examples from our daily life.
In particular, following topics are covered:

Physical origin of the different heat transfer mechanisms (conduction, convection, radiation) and key definitions (flux, heat, temperature...), conservation equations, relation to thermodynamics, general solution methodology.
Conduction: Fourier's law, heat diffusion equation (1D, 2D, unsteady), shape factor, analogy with electrical circuits
Convection: velocity and thermal boundary layer, convection coefficient, Nusselt number, laminar vs. turbulent, natural vs. forced, external vs. internal
Boiling and condensation: critical point, nucleate pool boiling, film condensation
Heat exchangers: analysis of different types (parallel, counter-flow) and definition of performance parameters (number of transfer units NTU, log mean temperature difference)
Radiation: emission, irradiation, black body, gray surface, real surfaces, view factors
Multimode heat transfers

Learning outcomes of the course :

At the end of the course, students should be able to quantify the heat transfers in a large range of practical applications. This involves the following skills:

to decompose the problem into smaller parts
to identify the relevant heat transfer processes
to evaluate the non-dimensional numbers characterizing the different heat transfer modes
to relate the non-dimensional numbers to the physics
to select and apply the appropriate principles of conservation and constitutive laws
to identify the appropriate empirical correlations
to use the appropriate resolution method and quantify the heat transfers and/or temperatures
to critically assess and discuss the results

Prerequisite knowledge and skills :

To efficiently follow this course, it is preferable to have some basic knowledge of Thermodynamics (e.g., "CHIM0286 "Elements de thermodynamique") and mathematics (e.g., MATH0007 "Analyse mathématique II").

Planned learning activities and teaching methods :

The course is divided into 13 lectures that take place each Monday morning. The material covered in each lecture corresponds to one or two chapters of the textbook, successively covering the three main parts of the course: conduction, convection and radiation.
Each lecture is divided into two parts. A first part of two hours, taught in English by the instructors, corresponds to the theoretical course, where the general concepts and their mathematical formulation are exposed. Theoretical results are also discussed in details and illustrated through practical examples.
The theory part is then followed by an exercise session of two hours in French, during which the students are invited to apply the techniques introduced during the theory sessions in order to solve practical problems. This session is chaired by the course assistants.
The last lecture of the course is dedicated to solving more complex problems, where different heat transfer modes are present. It also serves as questions-answers session for the final exam.
Learning activities also include three homework (at the end of each part of the course) to be solved individually at home. These homework are evaluated and count towards the final grade. Their objective is to ensure a continuous learning of the subject, to allow a self-evaluation for the students, and to help the instructors in identifying the difficulties encounted by the students.
Finally, a laboratory work is also organized to illustrate the use of numerical techniques in solving heat transfer problems. It is evaluated based on a written report to hand in a week later. This laboratory is performed in groups of two outside of normal class hours. Different time slots are available (more details will be given during the quadrimester). The attendance at the laboratory is mandatory to take the exam in the 1st and 2nd session.
A detailed calendar of the course material and deadlines will be presented during the first lecture et distributed electronically to all registered students.

Mode of delivery (face-to-face ; distance-learning) :

Both the theoretical lectures and the exercise sessions are face-to-face.
The theoretical lectures are taught in English and the exercise sessions in French.

Recommended or required readings :

The mandatory reference book is:
"Foundations of Heat Transfer" Incropera, Dewitt, Bergman & Lavine 6th edition (International Student Version) John Wiley & Sons ISBN: 978-0-470-64616-8

This reference is one of the best textbook on the topic of heat transfer. It is in English, so that students can familiarize themselves with the technical notions in English. Moreover, numerous practical examples are developed and a large number of additional exercises is proposed for the students to practice. The course faithfully follows the textbook.
It can be obtained

through the Centrale des Cours (please reserve your copy in advance),
in different bookshops (it might be necessary to order it),
as electronic version (e-book) on the editor website.

A copy is available for consultation at the library.
Slides used in the lectures are not distributed.

Assessment methods and criteria :

For the 1st session, the final grade is obtained from 2 contributions:

Written exam: 80%
3 homework problems and 1 laboratory report (4 x 5%): 20%

For the 2nd session, the global contribution of the 3 homework problems and of the laboratory only counts if it improves the final grade. If not, the final grade corresponds to the grade of the written exam of the 2nd session.
In all cases, the attendance at the laboratory is mandatory to take the exam in the 1st and 2nd session.
The written exam generally consists in three parts:

Theory
Multiple-choice questions
Exercises

It is a closed-book exam. However, the objective is not that students learn all correlations by heart. Therefore, a summary of all important correlations (taken from the textbook) is distributed at the exam.
Students must bring an official identification to take the exam. A calculator can be used, but any GSM, tablet, PC or similar are forbidden.

Work placement(s) :

Organizational remarks :

The course is jointly taught by Prof. Dewallef and Prof. Terrapon. The exact schedule and the deadlines are communicated during the first lecture.
The theoretical lectures will be taught in English and the exercise sessions in French.

Contacts :

Students are encouraged to actively interact with the professors, also outside of the lectures. It is highly recommended to set up an appointment first. For questions regarding the exercise sessions and the laboratory, the students can contact directly the assistants.
It is expected that the students follow a few basic rules when communicating by email:

Indicate as subject "MECA0445: ...".
Only use ULg addresses (xxx@student.ulg.ac.be).
Always address emails to both lecturers and only to one (or to all the assistants).
Follow the elementary rules of politeness.

Lecturers:
Prof. Pierre DEWALLEF; Laboratoire de Thermodynamique; B49, R2; +32(0)4 366 9995; p.dewallef@ulg.ac.be
Prof. Vincent E. TERRAPON; MTFC research group; B52, 0/415; +32(0)4 366 9268; vincent.terrapon@ulg.ac.be; http://www.mtfc.ulg.ac.be
Assistants:
Bertrand DECHESNE; B49, 23; +32(0)4 366 4823; bdechesne@ulg.ac.be