Energy and Nuclear Engineering

ALESSANDRO TASSONE

The students who complete this course will be able to:

1. Recognize the terminology and physical principles associated with heat transfer and thermofluid dynamics.
2. Identify the relevant transport phenomena for any process or system involving heat transfer.
3. Use the available information to calculate transport coefficients for a flow regime (friction factor and heat transfer coefficient).
4. Explain the momentum transfer mechanisms for flow inside conduits and around solid bodies and how these mechanisms influence heat transfer.
5. Specify and explain the fundamental transport equations that describe steady-state and unsteady-state heat transfer, along with specifying initial and boundary conditions.
6. Develop simple analytical models capable of describing industrial processes and systems, drawing conclusions related to their design or operation.
7. Identify and describe the main phenomena related to two-phase flow and the presence of liquid-vapor phase change (evaporation and boiling) and vice versa (condensation).

It is required a basic knowledge of thermodynamics and heat transfer, as provided by Fisica Tecnica - 1022052.

Fundamental and energy units; Units conversion; Review on Thermodynamics; Thermo-physical and transport properties; Dimensionless Numbers; Conduction heat transfer - The heat equation; Steady heat conduction in special conditions and geometries; Transient conduction; General conservation equations - Conservation of mass; Conservation of momentum; Conservation of energy; Radiation heat transfer; Two-phase flows: characteristic variables and properties; Two-phase flows: momentum and energy equations; Convection transfer - Boundary Layers; External Flows in forced convection; Internal flows: Friction and heat transfer in forced convection; Turbulent flows; Natural convection; Heat Exchangers; Two-phase flow regimes; Boiling: introduction - Bubble equilibrium, nucleation, dynamics; Pool boiling - The boiling curve; Subcooled and saturated flow boiling; Critical heat flux and Post dry-out heat transfer; Condensation - The Nusselt's theory.

Fundamentals of Heat and Mass Transfer, 7th Edition, by T.L. Bergman, A.S Lavine, F.P. Incropera and S. P. Dewitt. John Wiley and Sons, 2011

Convective Boiling and Condensation, 3rd Ed., by J.G. Collier and J.R. Thome. Oxford University Press, 1994.

Course Notes

A Heat Transfer Textbook, 5th ed, John H. Lienhard - Available here: https://ahtt.mit.edu/

Lectures and workshops are delivered in-person.

Attending lectures is not compulsory, but strongly advised. Interaction with the teacher is warmly encouraged.

The student will be evaluated during the semester and at the end of the course by a written test (compulsory) and an oral one (facultative, depending on conditions). Minimum passing grade is 18/30, which is equivalent to achieving 36 points.
Semester evaluations
During the semester, student progress is evaluated using questionnaires and lab activities. To ensure a proper monitoring, the participation to some of these activities is compulsory. Performance in the semester evaluation can be valid to determine part of its final grade up to a maximum of 25 points, following the guidelines reported below.
Three kinds of semester evaluations are foreseen:
• Self-Evaluation tests (SET): these multiple choice and short exercise tests are distributed through the course website and are representative of the questions you could face during the written examination. They are dedicated to a single topic and are going to be released according to the course schedule. They will stay available throughout the semester (and afterwards) for practice. A limited number of attempts (5) is possible for each test. Please note that passing SET-0 (Fundamental concepts) is compulsory to attend the written examination.
• Progress Evaluation Tests (PET): these multiple-choice tests are distributed through the course website. Participation to all PETs is compulsory. They are going to be available only for a limited time, which will be disclosed by the teacher, typically one week after the last lesson on the relevant topic. Only one (1) attempt is possible for each test.
o Single-phase heat transfer (conduction/convection) and heat exchanger PET (PET-1Phase): average grade can be converted into bonus points (up to a maximum of 10 and only above a minimum threshold). Result is going to be communicated at the end of the semester and the student may elect to use these bonus points to substitute the multiple-choice questionnaire during the written exam. This can be done only for the first three exam sessions, 2 ordinary and 1 extraordinary (until March).
o Two-phase flow and phase change PET (PET-2Phase): average grade is converted into bonus points (up to a maximum of 10 and only above a minimum threshold). Result is going to be communicated at the end of the semester and used to calculate the preliminary grade after the written exam. This can be done only for the first three exam sessions, 2 ordinary and 1 extraordinary (until March).
• Laboratory practise session (LPS): a short experimental experience performed in the teaching thermal-hydraulic lab at Palazzo Baleani. A group of maximum two (2) students will gather experimental data and write a short report describing the experiment performed and perform some basic calculations using these data. The report is going to be graded and will award up to 5 bonus points. Result is going to be used to calculate the preliminary grade after the written exam. Lab session schedule is going to be communicated by the teacher and will be limited to the period December-March.
Written exam
The written test is intended to evaluate the student preparation on the topics of single-phase heat transfer and heat exchangers (Unit 1 to 13). To attempt the test, the student must have passed the SET-0. The test will last 150 minutes (2.5 hours) and will consist of:
1. A multiple-choice questionnaire of 20 questions on all topics considered for the test, up to 10 points (which can be substituted by the average PET grade if certain conditions are met).
2. Three numerical exercises, one (1) short question and two (2) longer problems, up to 15 points.
a. Long problems are like those presented in the exercise sessions, both those where I show you the solution procedure and those with just the answer.
b. Short problems are typically much simpler and require one or two calculations to be solved. Some are discussed during regular lectures (look in the lesson notes).
3. Two short-essay style open questions on theoretical topics, up to 16 points.
a. Examples of open questions can be found in the Syllabus within the folder “Written test examples”
Minimum passing grade is 24 points out of the 41 available in the test. Examples of past exam question sheets can be found in the Syllabus within the folder “Written test examples”
Preliminary grade
Once the written test has been completed, points achieved there will be summed to those accumulated during the semester evaluation. A preliminary grade will be calculated according to the formula: (Total points of written examination + lab activity + PET two-phase flow)/2.
If the preliminary grade is >= 18 (36 points), the student may elect to transform it into its final grade. If your preliminary grade is <18, you must attend the oral examination. To improve the preliminary grade, the student must attend the oral examination.
• Example/1: Andrea passed their written test with 24/40 (minimum score) and has 5 points from LPS and 0 points from PET-2Phase. Their preliminary grade is (24 +5 + 0)/2 = 29/2 = 14.5. Andrea must attend the oral examination to achieve a passing grade.
• Example/2: Jessie passed their written test with 33/40 and has 3 points from LPS and 8 points from PET-2Phase. Their preliminary grade is (33 +3 + 8)/2 = 44/2 = 22. Jessie can transform their preliminary grade. Their final grade would be 22/30. Jessie can elect to attempt the oral examination to get a better grade.
Preliminary grade can be kept between two exam sessions belonging to the same exam period: for instance, a preliminary grade obtained in January can be improved in the oral examination of February, but not in the one of June.
Oral examination
The oral examination is composed of either 1 or 2 questions pertaining the topics of two-phase flows (basic concepts, pool boiling, flow regimes and flow boiling, condensation) and can award up to 20 points (possibly including up to 10 points from two-phase flow PET). Examples of exam questions can be found in the Syllabus within “Oral test examples”.
Depending on the semester evaluation:
• If the student PET is still valid, this will be valid for 50% of the oral examination grade. The exam will consist of one (1) question (Reduced Oral) that will award the remaining 50%, from 0 to 10 points.
o At the beginning of the oral examination, the student may elect to discard the PET grade.
• If the student PET is no longer valid or has been discarded, the exam will be composed of two (2) questions (Full Oral), that may award between 0 and 20 points.
Please note that a passing grade (6/10 and above for reduced oral or 12/20 and above for full oral) is still required to pass the oral examination, regardless of the preliminary grade.
If the performance during the oral examination is deemed to be gravely insufficient by the teacher, the oral examination is failed. The written exam grade will be maintained for a second attempt at oral examination in a successive exam session (please note that the rules for PET score validity applies in this case).
If the second attempt also fails, the written exam grade is voided and the student has to attend another written examination.
Explicative scenarios:
• Example/1: Andrea has a preliminary grade of 32 points, of which 5 from the PET-2Phase. If they choose to discard the PET, the maximum grade they can achieve (with two questions) is: [(Preliminary grade – PET-2Phase)+Max Full Oral Score]/2 = [(32-5)+20]/2 = 47/2 = 24. If they choose to keep the PET score, the maximum grade they can achieve with one question is: (Preliminary grade + Max Reduced Oral Score)/2 = (32 + 10)/2 = 42/2 = 21.
• Example/2: Jessie has a preliminary grade of 44 points, of which 8 from the PET-2Phase. If they choose to discard the PET, the maximum grade they can achieve (with two questions) is: [(Preliminary grade – PET-2Phase)+Max Full Oral Score]/2 = [(44-8)+20]/2 = 56/2 = 28. If they choose to keep the PET score, the maximum grade they can achieve with one question is: (Preliminary grade + Max Reduced Oral Score)/2 = (44 + 10)/2 = 54/2 = 27.
Final grade
Final grade will be calculated according to the formula: (Preliminary grade + oral examination grade)/2. The minimum passing grade is 18 (equivalent to 36 points). If the total number of points is above 60, the student will be awarded the course honors.

Examples for the written and oral exams are available on the course website.

• Course introduction - Elements of heat transfer


• The General Heat Conduction Equation


• Steady-state conduction in special conditions and geometries


• Steady-state conduction problems 


• Transient conduction


• General Conservation Equation - Introduction and mass conservation equation


• Transient conduction problems


• General Conservation Equation - Momentum conservation equation


• General Conservation Equation - Energy conservation equation


• Application of General Conservation Equations and similarity


• Boundary Layers


• External forced convection flows


• External flow problems


• Internal flows - momentum balance and pressure drop


• Internal flows - energy balance and heat transfer
  coefficient


• Internal flow problems


• Turbulent flows - turbulent boundary layer


• Turbulent flows - turbulent heat transfer


• Natural convection - Boussinesq approximation and vert.
  Plate


• Natural convection - horizontal plate and enclosures


• Natural convection problems


• Heat Exchangers - Generality and LMTD method


• Heat Exchangers - Epsilon-NTU method


• Heat exchanger problems


• Thermal-hydraulic lab at Palazzo Baleani


• Two phase flows - introduction and GCE


• Bubble nucleation, growth, dynamics


• Pool Boiling - I


• Pool Boiling - II


• Pool boiling problems


• Two phase flows - regimes


• Flow boiling - 
  subcooled and saturated boiling


• Flow boiling - critical heat flux and post chf


• Condensation - Nusselt's Theory


• Condensation problems