CN2125 Heat and Mass Transfer is a 4 MC module that is like a sequel to CN2122 but it is tougher in my opinion. Tougher in the sense that there is more content per week. It was pretty mind-blowing in the beginning as we were flooded with formulas and new terms but it got better in the later weeks as we kinda got used to it plus similarities can be drawn between heat transfer and mass transfer.
Assessment
15% 3 Homework Assignments, 1 Mini-Project Assignment, 1 Industry Lecture Report (How the 15% is divided among these 3 segments is not known)
25% Quiz 1 (1 hour, Open Book)
+ Quiz 2 (35 mins, Open Book)
60% Finals (2.5 hours, Open Book)
25% Quiz 1 (1 hour, Open Book)
+ Quiz 2 (35 mins, Open Book)
60% Finals (2.5 hours, Open Book)
Lecturer:
First half: A/Prof Wang Chi-Hwa
Second half: A/Prof Praveen Linga
First half: A/Prof Wang Chi-Hwa
Second half: A/Prof Praveen Linga
Tutor:
First half: A/Prof Wang Chi-Hwa
Second half: A/Prof Praveen Linga
First half: A/Prof Wang Chi-Hwa
Second half: A/Prof Praveen Linga
Textbooks/Readings
Welty, James R., Charles E. Wicks, and Robert E. Wilson (WWWR). Fundamentals of momentum, heat, and mass transfer, 5th ed. There is another textbook that is catered just for CN2125 (like the title of the textbook is CN2125). BUT, the content of the lecture notes prepared by the profs were taken from the WWWR book, so that's why I recommend that textbook. CN2125 covers Chapter 15 - 29 of WWWR textbook while CN2122 covers Chapters 1 - 14 of the very same textbook. Yes, this textbook is that powerful such that its contents have to be split into two modules.
I would highly recommend having at least an online pdf version of the textbook as some parts of the textbook will help to reinforce what the profs have taught. Sometimes, I would be unsure of the units of some terms in certain formulas given in the lecture notes and I would refer to the textbook to double confirm. Plus there are extra questions in the textbook to practice as well (which tbh I didn't have time to practice hahaha).
Lectures
Welty, James R., Charles E. Wicks, and Robert E. Wilson (WWWR). Fundamentals of momentum, heat, and mass transfer, 5th ed. There is another textbook that is catered just for CN2125 (like the title of the textbook is CN2125). BUT, the content of the lecture notes prepared by the profs were taken from the WWWR book, so that's why I recommend that textbook. CN2125 covers Chapter 15 - 29 of WWWR textbook while CN2122 covers Chapters 1 - 14 of the very same textbook. Yes, this textbook is that powerful such that its contents have to be split into two modules.
I would highly recommend having at least an online pdf version of the textbook as some parts of the textbook will help to reinforce what the profs have taught. Sometimes, I would be unsure of the units of some terms in certain formulas given in the lecture notes and I would refer to the textbook to double confirm. Plus there are extra questions in the textbook to practice as well (which tbh I didn't have time to practice hahaha).
Lectures
There were 2 lectures per week. One lecture is one hour long and the other is 2 hours long, just like CN2122. The lectures lasted for 12 weeks straight; there wasn't one on week 13 as one lecture was taken up by Quiz 2 and the other by Good Friday. This module has webcast but again, I would recommend going for the lectures as the Profs for this module teach well in my opinion.
Soooo, in the beginning of CN2125 lectures, prepare to be a little mindblown because Prof Wang tends to talk pretty fast sometimes and he rarely has breaks in between his sentences. A lot of parts of the lecture notes are also just copied straight from the textbook, so you have to listen to him well in order to understand what the notes are trying to explain. In my opinion, I feel that Prof Wang does explain the content well but since the content is new, it took a while for me to understand what he was trying to explain. I had to re-read the lecture notes a few times, especially for convective heat-transfer correlations and boiling/condensation before I could understand them. Prof Wang took the lectures from Weeks 1 - 8 which covered steady/unsteady state conduction, natural/forced convection and fundamentals of mass transfer/diffusion.
Prof Linga then took the lectures from Weeks 9 - 12 which covered steady/unsteady state molecular diffusion, convection mass transfer and radiation. In my opinion, Prof Linga teaches the content very well too and I feel that he is better in explaining the concepts as compared to Prof Wang. I rarely referred to the textbook as well for Prof Linga's portion, as compared to Prof Wang's portion. Prof Linga also brought up real life applications of what we learn to help us better understand how the content we covered can be applied. Overall, I have no complaints for the two Profs in CN2125 (as compared to CN2121 and CN2122) and I am rather satisfied with my experience in their lectures.
Soooo, in the beginning of CN2125 lectures, prepare to be a little mindblown because Prof Wang tends to talk pretty fast sometimes and he rarely has breaks in between his sentences. A lot of parts of the lecture notes are also just copied straight from the textbook, so you have to listen to him well in order to understand what the notes are trying to explain. In my opinion, I feel that Prof Wang does explain the content well but since the content is new, it took a while for me to understand what he was trying to explain. I had to re-read the lecture notes a few times, especially for convective heat-transfer correlations and boiling/condensation before I could understand them. Prof Wang took the lectures from Weeks 1 - 8 which covered steady/unsteady state conduction, natural/forced convection and fundamentals of mass transfer/diffusion.
Prof Linga then took the lectures from Weeks 9 - 12 which covered steady/unsteady state molecular diffusion, convection mass transfer and radiation. In my opinion, Prof Linga teaches the content very well too and I feel that he is better in explaining the concepts as compared to Prof Wang. I rarely referred to the textbook as well for Prof Linga's portion, as compared to Prof Wang's portion. Prof Linga also brought up real life applications of what we learn to help us better understand how the content we covered can be applied. Overall, I have no complaints for the two Profs in CN2125 (as compared to CN2121 and CN2122) and I am rather satisfied with my experience in their lectures.
Tutorial
Tutorials took place once a week, and they were 1 hour long. For all the tutorials for CN2125, the tutorial answers are uploaded on the same document together with the questions. In my opinion, this is actually very good because it provided me with a better understanding of the topic before attending the tutorial itself. Sometimes, I would not be able to understand the phrasing of the question or what the question is actually asking me to find. Referring to the answer as a reference can help me A LOT in this aspect. Even with answers provided, tutorials are still worth going as more often than not, I would not be able to understand every single part of the answer sheet. (There are sometimes errors in the answer sheet as well.) Also, the Profs would usually give tips and "shortcuts" about certain concepts, which is real good. Do take note of everything the Profs say as it may just be a clue for one of the questions for your final exam. The Profs taught well for the tutorials, just like the lectures.
One thing to note, although we ballot for our tutorials, we may not need to attend the exact tutorial slot given to us since attendance is not taken. Thus, people jump around tutorial slots (including me). Sooooo, do reach early as there might not be enough seats for tutorials sometimes (applies to CN2116 as well). (This occurred for my batch but may not occur for yours, so no worries if it doesn't apply to you hahaha.)
Homework Assignments
There were 3 homework assignments in total for CN2125. The first one (due on week 5) covers steady/unsteady conduction, the second one (due on week 8) covered condensation and mass diffusivity, the third one (due on week 13) covered steady/unsteady molecular diffusion. Each assignment contained 2 - 3 questions. They were all rather do-able and since they are homework assignments, you can discuss with your friends. So, the homework assignments aren't a hugh problem and is actually a form of bonus marks for us. So, do them well and get those marks.
Mini-Project Report and Industry Lecture Report
We had to form a group of 3-4 students and write a 2 page mini project report. How the report works is that we have to come up with our own heat transfer problem that occurs in real life (yes, we become Profs for one time and come out with a problem statement) and then solve the problem. It is rather interesting in my opinion. It wasn't that big of a problem writing the report as there were many concepts in this module to choose from. My group decided to work on a critical radius problem. There are also sample reports provided by Prof Wang so you shouldn't worry too much about it.
As for the industry lecture report, the lecture, which is actually a webcast lecture, is given by a chemical engineer from Shell. His talk is mainly about applications of different types of heat exchangers in the oil refinery and LNG industry. We had to write a 1 page report summarizing what we learnt from the lecture. The funny part about this was that the lecture is webcasted and was recorded in 2015, instead of actually inviting the person himself down to give a talk. This actually means that this webcast video has been used for four batches of chemical engineering undergraduates taking CN2125. But I do gain insights after listening to his talk so I am not in a position to complain here.
Quizzes
Quiz 1 was based on the first 5 weeks of lecture content and was held on Week 7. All the tests and exams for CN2125 were open book, thankfully. The first quiz wasn't too tough in my opinion; no large/complicated formulas were required and hints were even given for all the questions. If you have revised well, Quiz 1 shouldn't be a big problem.
For Quiz 2, it covered the first 2 weeks of lecture taught by Prof Linga and was held on Week 13. There was only 1 question on steady state diffusion (with heterogeneous reaction) but it can be a little tricky and tedious. Prof Linga likes to tweak his questions slightly differently from the lecture examples so we require a little more thinking in order to understand what the problem statement is asking for (this applies for his portion in the final exam as well).
One thing to note, although we ballot for our tutorials, we may not need to attend the exact tutorial slot given to us since attendance is not taken. Thus, people jump around tutorial slots (including me). Sooooo, do reach early as there might not be enough seats for tutorials sometimes (applies to CN2116 as well). (This occurred for my batch but may not occur for yours, so no worries if it doesn't apply to you hahaha.)
Homework Assignments
There were 3 homework assignments in total for CN2125. The first one (due on week 5) covers steady/unsteady conduction, the second one (due on week 8) covered condensation and mass diffusivity, the third one (due on week 13) covered steady/unsteady molecular diffusion. Each assignment contained 2 - 3 questions. They were all rather do-able and since they are homework assignments, you can discuss with your friends. So, the homework assignments aren't a hugh problem and is actually a form of bonus marks for us. So, do them well and get those marks.
Mini-Project Report and Industry Lecture Report
We had to form a group of 3-4 students and write a 2 page mini project report. How the report works is that we have to come up with our own heat transfer problem that occurs in real life (yes, we become Profs for one time and come out with a problem statement) and then solve the problem. It is rather interesting in my opinion. It wasn't that big of a problem writing the report as there were many concepts in this module to choose from. My group decided to work on a critical radius problem. There are also sample reports provided by Prof Wang so you shouldn't worry too much about it.
As for the industry lecture report, the lecture, which is actually a webcast lecture, is given by a chemical engineer from Shell. His talk is mainly about applications of different types of heat exchangers in the oil refinery and LNG industry. We had to write a 1 page report summarizing what we learnt from the lecture. The funny part about this was that the lecture is webcasted and was recorded in 2015, instead of actually inviting the person himself down to give a talk. This actually means that this webcast video has been used for four batches of chemical engineering undergraduates taking CN2125. But I do gain insights after listening to his talk so I am not in a position to complain here.
Quizzes
Quiz 1 was based on the first 5 weeks of lecture content and was held on Week 7. All the tests and exams for CN2125 were open book, thankfully. The first quiz wasn't too tough in my opinion; no large/complicated formulas were required and hints were even given for all the questions. If you have revised well, Quiz 1 shouldn't be a big problem.
For Quiz 2, it covered the first 2 weeks of lecture taught by Prof Linga and was held on Week 13. There was only 1 question on steady state diffusion (with heterogeneous reaction) but it can be a little tricky and tedious. Prof Linga likes to tweak his questions slightly differently from the lecture examples so we require a little more thinking in order to understand what the problem statement is asking for (this applies for his portion in the final exam as well).
Final Exam
Well, the final exam was really different from how the Profs described it. It consists of "5 structured questions" and was 2.5 hours long. The reason for the quotation marks was that there were actually 11 questions that were divided into "5 parts" and the worse part is that the questions in each part were not even related to each other. Thus, there were actually 11 questions to be completed in 2.5 hours, meaning about 13 - 14 minutes per question. I have prepared my own notes on all the chapters which were very helpful to me in my opinion. My notes can be accessed here.Some questions are rather straight forward wheareas some are rather tricky and require you to read between the lines to understand what they are asking for. This is because sometimes, the question sounds as if they're asking a concept of a certain topic but what you're required to solve is actually a concept from another topic. An example would be question 3 below because that question sounded like a natural convection question but it turns out it was asking about unsteady state conduction. So, be very careful and think for a while before you answer the questions.
Here are the lists of questions for the final exam I took. They may not be in the correct order as I am just remembering them from the top of my head (we can't bring the scripts back). Here we go:
1. Steady state conduction (summation of resistances, total heat transfer rate)
2. Natural convection of air flow over a horizontal cylinder
3. Usage of Bi modulus and lumped-parameter analysis to calculate h, heat transfer coefficient
4. Forced convection laminar flow through a pipe, log mean temperature difference
5. Condensation on horizontal pipe + banks of horizontal tubes
6. Liquid mass diffusivity (Stokes-Einstein Theory)
7. Critical radius of plastic insulation around an electrical wire
8. Double pipe heat exchanger, Log mean temperature difference
9. Steady state diffusion for heterogeneous reactions (Carbon + oxygen to give carbon dioxide and carbon monoxide)
10. Two phase mass transfer (mass transfer coefficient, k, expressed in terms of mole fractions for both the liquid and vapour phase)
11. Radiation energy balance (Fraction functions, Gray surface analogy)
Questions 1-8 were on Prof Wang's portion while questions 9 - 11 were on Prof Linga's portion. I managed to complete the paper jusstttt on time as the last 2 questions were rather tricky (Prof Linga's questions hahaha). Overall, I feel that with sufficient revision and going through the tutorials, the final exam should be conquerable. But time management can be an issue, as compared to CN2116, so do take note of that.
Expected Grade: A
Final Grade: A+
Final Comments
CN2125 was a rather heavy content module but I felt I did gain quite a lot from this module. Not an easy module to study at first but it gets better once you get used to the style of content. I felt that I did well for this module because I kept reading through the lecture notes and my own notes again and again until I really understand the concepts presented to me. So, do allocate some time for this module every week to revise its concepts.
Stay tuned for more updates.
- Alan
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