2020-2021 / MECA0445-2

Heat transfer

Duration

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

Number of credits

 Bachelor of Science (BSc) in Architectural Engineering5 crédits 
 Bachelor of Science (BSc) in Engineering5 crédits 
 Master of Science (MSc) in Aerospace Engineering5 crédits 
 Master of Science (MSc) in Electromechanical Engineering5 crédits 
 Master of Science (MSc) in Mechanical Engineering (EMSHIP+, Erasmus Mundus)5 crédits 
 Master of Science (MSc) in Engineering Physics5 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 11 lectures. 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 has two components. The theoretical course, taught in English by the instructors, introduces and develops the general concepts and their mathematical formulation. Theoretical results are also discussed in details and illustrated through practical examples. This theory part is in the form of weekly podcasts that the students have to watch at home.
The podcasts are complemented with weekly problem sets in which the theoretical concepts are applied to solve practical problems. The problem sets include short exercises requiring direct applications of formulas, more complex exercises, and recommended further exercises. Final answers or detailed solutions are provided depending on the type of exercice.  
In order to ensure sufficient interaction between the students and the instructors, an informal discussion is organized on Mondays at 9h00 in the classroom and/or over videoconference, during which students can ask questions. The first part of the discussion is led by the instructors and focuses on theoretical aspects; in the second part the problem sets are discussed with the course assistants. 
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 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, hybrid learning)

Due to the sanitary situation, the course is offered mostly as distance-learning. 
The theory lectures are in the form of weekly podcasts that students have to watch at home. Problem sets are also posted weekly on the course website. Students are expected to solve them on their own. The solution is distributed one week later. Nonetheless, a forum is available for students to ask questions regarding theory, exercises or homework. 
Additional help is provided during the informal discussions every Monday at 9h00. To ensure sufficient social distancing, the class is divided into two groups. Each week alternately, one of the two groups takes part in the informal discussion in person (face-to-face), the other group can participate over videoconference. 
Depending on the evolution of the sanitary situation, the course might need to be reorganized.

Organisational adjustments related to the current health context

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.
Other course material (lecture slides, podcasts, problem sets, solutions, ...) are posted weekly on the course website: www.mtfc.uliege.be/Heat-transfer.

Assessment methods and criteria

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

  • Final 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 final exam of the 2nd session.
Depending on the sanitary situation, the final exam is either
  • [green/yellow level] a written exam, closed-book but with a summary of all important correlations (taken from the textbook) provided, that typically includes a series of shorter questions and one or two longer exercises, or
  • [orange/red level] an online exam on eCampus, open-book, that typically includes multiple choice questions, multiple answer questions and short questions with a final numerical result.

Work placement(s)

Organizational remarks

The course is jointly taught by Prof. Dewallef and Prof. Terrapon. The exact schedule, the deadlines and all organizational aspects are communicated during the first session.
The introduction session takes place on the first Monday of the quadrimester. It is organized in two groups, based on the first letter of the students last name:

  • group A => A to L
  • group B => M to Z
Students of group A should be present at 8h30 in the classrom, while students of group B should come at 9h15. The same groups are defined for the weekly informal sessions. 
Depending on the sanitary situation, some organizational changes might be necessary.

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.uliege.be).
  • Always address emails to both lecturers (or to all the assistants) and not only to one.
  • Follow the elementary rules of politeness.
  Instructors:
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.uliege.be