2019-2020 / MECA0445-2

Heat transfer

Duration

28h Th, 24h Pr, 4h Labo., 9h Proj.

Number of credits

 Bachelor in engineering : architectural engineering5 crédits 
 Bachelor in engineering5 crédits 
 Master in aerospace engineering (120 ECTS)5 crédits 
 Master in electro-mechanical engineering (120 ECTS)5 crédits 
 Master in mechanical engineering (120 ECTS)5 crédits 
 Master in physical engineering (120 ECTS)5 crédits 

Lecturer

Pierre Dewallef, Vincent Terrapon

Language(s) of instruction

English language

Organisation and examination

Teaching in the second semester

Schedule

Schedule online

Units courses prerequisite and corequisite

Prerequisite or corequisite units are presented within each program

Learning unit 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 transfer

Learning outcomes of the learning unit

At the end of the course, students should be able to quantify the heat transfer 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 transfer 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 in two parts. The second part, 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 preceded by an exercise session of two hours, during which the students are invited to apply the techniques introduced during the previous theory sessions in order to solve practical problems. This session is chaired by the course assistants, and is done in smaller groups, either in French or in English.
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.
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 or in English depending on the choice of the student.

Recommended or required readings

The mandatory reference book is:
"Incropera's Principles of Heat and Mass Transfer" Incropera, Dewitt, Bergman & Lavine Global Edition John Wiley & Sons (2017) ISBN: 978-1-119-38291-1

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 also distributed.

Assessment methods and criteria

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

  • Written exam: 80%
  • 3 individual homework: 20%
For the 2nd session, the global contribution of the 3 homework problems 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.
The written exam 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 and in English.

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 (or to all the assistants) and not only to one.
  • Follow the elementary rules of politeness.
  Lecturers:
Prof. Pierre DEWALLEF; Laboratoire de Thermodynamique; B49, R2; +32(0)4 366 9995; p.dewallef@uliege.be
Prof. Vincent E. TERRAPON; MTFC research group; B52, 0/415; +32(0)4 366 9268; vincent.terrapon@uliege.be; http://www.mtfc.ulg.ac.be