University of Rochester

Problems and Solutions:

ME 223 Heat Transfer taught by Hesam Askari


Department of Mechanical Engineering
University of Rochester
Spring 2017

Required for ME majors. 4 credits, 5 contact hours.


Course Goals

This course is an introduction to the principal concepts and methods of heat transfer. The knowledge ere will be an integral part to your career as a mechanical engineer. The objectives of this integrated subject are to develop the fundamental principles that allow analysis of problems involving generation of heat and transfering heat. The implicaitons in real-world applicaitons are many. To name a few would be design of radiators, heat exchangers, printed circuit boards, packaging and biological systems. You will learn to formulate the models necessary to study, analyze and design heat transfer mechanisms. Then you will link your knowledge of Thermodynamics and Fluid mechanics to analyze complicated cases such as irregular shapes, heat transfer in flow over/inside objects, biling and condensation applications. You will also learn about numerical methods that are used in Heat Transfer analysis. Successful students in this course will gain

  • an ability to apply knowledge of mathematics, science, and engineering (ABET outcome a);
  • an ability to design a system, component, or process to meet desired needs within realistic constraints such as economic, environmental, social, political, ethical, health and safety, manufacturability, and sustainability (ABET outcome c);
  • an ability to identify, formulate, and solve engineering problems (ABET outcome e);
  • and an ability to use the techniques, skills, and modern engineering tools necessary for engineering practice (ABET outcome k);
Course Specific Outcomes (Click to expand)

Prerequisites

Successful completion of ME 123, ME 225, MTH 163 or MTH 165 is required.

Materials

***Required textbook***: Y. A. Cengel, Heat and Mass Transfer, Fundamentals and Applications, 5th, 4th, or 3rd edition, McGraw Hill. ANY of the three editions will do.

Assignments & Grading

All assignments and activities associated with this course must be performed in accordance with the University of Rochester's Academic Honesty Policy. In this course, students are allowed to collaborate on homework — provided that each collaborator takes the time to fully understand the material and write a separate copy of the assignment. Mere copying is an act of academic dishonesty. On exams, the students are allowed to consult the textbook and their class notes. Using any other sources such as quizzes, homework or recitation materials will be a violation of Academic Honesty Policy. Students must write and sign the Honor Pledge on all exams: “I affirm that I will not give or receive any unauthorized help on this exam, and that all work will be my own.” Facilitating dishonesty is dishonesty. Procrastination is a major source of dishonesty, so start assignments early and keep yourself organized.

Reading Quizzes - 10%
About half of class meetings will begin with a reading quiz consisting of three or four short questions taken directly from the textbook. No reference material is allowed during the quizzes. See the course Schedule.
Homework - 20%
Homework is due about once a week, at the start of class. Our late homework policy is NONE! See the course Schedule for due dates.
Exams - 55%
There will be three non-cumulative(Chapterwise, not subjectwise) exams during the semester. Each exam constitutes 20% of your overall grade. Each student is allowed to retry ONE of the exams during the final examinations week in an attempt to improve their lowest grade. Attempting a retry is optional, but prior arrangement is required.
Midterm 1: Wednesday, February 15, 5:30-8:30 PM - Dewey 1101
Midterm 2: Wednesday, March 8, 5:30-8:30 PM - Dewey 1101
Midterm 3: Wednesday, April 26, 5:30-8:30 PM - Dewey 1101
Final exam: During the allocated final exam date and time, you can attempt to repeat ONE of the above three exams. If you did better, your grade will be replaced for that one exam. A form will be sent out after the third midterm to sign up for a repeat attempt, indicating which exam you want to retake. Completion of this form prior to the deadline is absolutely necessary to sit in the final exam.
Design Project - 15%
Design project is a teamwork between groups of 3 students. Further details about the due dates will be posted laterthrough BlackBoard. Check back the course Schedule for due dates.

Grading:

If you have a question about the grade you've received on an assignment, please speak first with the teaching assistant who graded it as they can help you the best.

Lectures and Recitations Schedule:

Lectures 11:50-12:40 Mondays, Wednesdays and Fridays (Dewey 2162).
Workshops 12:30-13:45, 14:00-15:15, 15:25-16:40 on Thursdays (Respectively in Hylan 203, Gavett 301 and Dewey 2110D).

Feedback & Availability

I will distribute evaluations periodically to collect feedback. Announcements will occasionally be made by email. I typically check email frequently but cannot guarantee immediate response at all times. Quick questions can be effectively and efficiently addressed by email, but for in-depth questions a face-to-face discussion usually works better, so consider requesting a meeting. Or, come to regular office hours with the professor or teaching assistants:

Name & Mailto link Office hours Location Name & Mailto link Office hours Location
Prof. Askari
ML

MW 1530-1630 Hopeman 343 Xinyi Fang
XF


F 1700-1800 TBA
Xuchen Gong
XG


F 1600-1700 Hopeman TA Room Florence Yip

FY

T 1700-1800 Hopeman TA Room
Jiacheng Sun
JS
R 1830-1930 Upper ITS Jacky Li
JL
M 1730-1830 Upper ITS
Muxi Li
ML
T 1030-1130 ITS Ziyan Chen
ZC
M 1300-1400 ITS


Course Schedule

This schedule may evolve as the course progresses. Reading assignments specified as section numbers below come from the fifth edition of Cengel's book. The first workshop will meet Jan 26.

Date Topic Reading Due
Wed, Jan 18 Course Overview, Engineering heat transfer, First Law of Thermomechanics 1.1-1.4
Fri, Jan 20 Heat transfer Mechanisms, Conduction, Convection and Radiation 1.5-1.8
Mon, Jan 23 Simultaneous mechanisms, Heat conduction equation, General 3D conduction equation 1.9, 2.1-2.3 Quiz 1
Wed, Jan 25 Boundary conditions and Initial conditions 2.4 HW1
Fri, Jan 27 Solution to steady 1D conduction, Heat generation, Variable thermal conductivity 2.5-2.7 Quiz 2
Mon, Jan 30 Steady heat conduction in walls, Thermal resistance 3.1-3.2
Wed, Feb 1 Generalized thermal resistance networks, Conduction in spheres and cylinders 3.4-3.5 HW2
Fri, Feb 3 Critical radius of insulation, Fin equation 3.5,3.6 Quiz 3
Mon, Feb 6 Finned surfaces, Effectiveness, Proper length 3.6
Wed, Feb 8 Project Annoncement, Transient Heat Conduction, Lumped System Analysis, Criteria and remarks 4.1 HW3
Fri, Feb 10 Transient heat conduction in walls, long cylinders and spheres 4.2 Quiz 4
Mon, Feb 13 Semi-infinite solids, Multidimensional Systems 4.3,4.4
Midterm#1 - Wednesday Feb 15 - 5:30-8:30 PM - Dewey 1101
Wed, Feb 15 Fundamentals of Convection, Mechanism, Knowing the flow, Velocity boundary layer 6.1-6.3 Project team list
Fri, Feb 17 Thermal boundary layer, Prandtle number, Laminar vs. Turbulent flow 6.4-6.5 HW4
Quiz 5
Mon, Feb 20 Heat and momentum transfer, Convection equations, Solutions for flat plate. 6.6-6.8
Wed, Feb 22 Nondimensionalized equations, Friction and convection coefficients, Analogies between heat and momentum transfer 6.9-6.11 Quiz 6
Fri, Feb 24 External forced convection, Drag and heat transfer, Parallel flow over plates 7.1-7.2
Mon, Feb 27 Flow across cylinders and spheres, Flow over tube banks 7.3-7.4 HW 5
Wed, Mar 1 Flow over tube banks 7.4 Quiz 7
Fri, Mar 3 Internal forced convection, Average quantities, Entrance region 8.1-8.3 HW6
Mon, Mar 6 General thermal analysis 8.4 Quiz 8
Midterm#2 - Wednesday Mar 8 - 5:30-8:30 PM - Dewey 1101
Wed, Mar 8 Laminar flow in tubes 8.5
Fri, Mar 10 Turbulent flow in tubes 8.6 Quiz 9
Mon, Mar 13 Spring recess
Wed, Mar 15 Spring recess
Fri, Mar 17 Spring recess
Mon, Mar20 Natural Convection, Equations of motion, Convection over surfaces 9.1-9.3 HW7
Wed, Mar 22 Convection over surfaces, Natural convection of finned surfaces 9.4 Quiz 10
Fri, Mar 24 Convection inside enclosures 9.5
Mon, Mar 27 Combined natural and forced convection 9.6 Quiz 11
Wed, Mar 29 Heat Exchangers, Overall heat transfer coefficient 11.1-11.2 HW8
Fri, Mar 31 Analysis of heat exchangers 11.3
Mon, Apr 3 Log Mean Temperature Difference Method 11.4 Quiz 12
Wed, Apr 5 Effectiveness NTU method 11.5
Fri, Apr 7 Effectiveness NTU method, Selection of heat exchangers 11.5-11.6 Quiz 13
Mon, Apr 10 Boiling heat transfer, Pool boiling 10.1-10.2 HW9
Wed, Apr 12 Flow Boiling
Fri, Apr 14 Condensation heat transfer Quiz 14
Mon, Apr 17 Numerical methods, Finite difference formulation, 1D Steady state conduction 5.1-5.3 HW10
Wed, Apr 19 2D Steady state conduction 5.4
Fri, Apr 21 Transient heat conduction 5.5 Quiz 15
Mon, April 24 Transient heat conduction 5.5
Midterm #3 - Wednesday Apr 26 - 5:30-8:30 PM - Dewey 1101
Wed, Apr 26 Sustainability lecture #1 TBA Numerical Homework
Fri, Apr 28 Sustainability lecture #2 TBA
Mon, May 1 Semester Review
Wed, May 3 Semester Review
Finals period (TBA) Final Exam


Grading Responsibilities

Quizzes and homework are graded by the course teaching assistants who rotate duties.The initials stated on your work indicates who has been assigned as grader. Please contact the grader first for any concerns over grading because they can address it best.