Introduction to Heat Transfer in a First-year Mechanical Engineering Course

Dani Fadda; Oziel Rios

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Conference: 2018 ASEE Annual Conference & Exposition
Location: Salt Lake City, Utah
Publication Date: June 23, 2018
Start Date: June 23, 2018
End Date: July 27, 2018
Conference Session: First-year Programs Division: Design
Tagged Division: First-Year Programs
Page Count: 9
DOI: 10.18260/1-2--30719
Permanent URL: https://peer.asee.org/30719
Download Count: 844

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Paper Authors

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Dani Fadda University of Texas, Dallas

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Dr. Fadda is Clinical Associate Professor of Mechanical Engineering. His background includes two decades of professional engineering practice in the energy industry where he has held numerous positions. Dr. Fadda has worked in product research and developed patented products for chemical, petrochemical, and nuclear applications. He is involved with professional organizations and was named the 2016 ASME North Texas Engineer of the Year.

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Oziel Rios University of Texas, Dallas

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Dr. Oziel Rios earned his Ph.D. in mechanical engineering from the University of Texas at Austin in 2008 where his research focused on design of robotic systems with an emphasis on kinematic and dynamic modeling for analysis and control. Dr. Rios teaches the first-year and CAD courses in the Mechanical Engineering Department at the University of Texas at Dallas. Dr. Rios has also taught kinematics and dynamics of machines and graduate-level CAD courses. Dr. Rios’ research and teaching interests include: robotics, design, kinematics and dynamics of machines and engineering education.

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Abstract

An activity is described in this paper to introduce freshman students to the concept of heat loss due to convection heat transfer. The activity is part of an introductory course to mechanical engineering. The overall goal of the introductory course is to help students learn concepts in mechanical design, forces and stresses, engineering materials, motion and power transmission, and thermal and energy systems. The course has several different activities. The goal of the particular activity described in this paper is to cover the thermal systems portion of the class. In the activity, a ball bearing (sphere) is specified to have a given diameter and initial temperature. A tutorial is given to help students draw the sphere in SolidWorks and define its material. The thermal utility of SolidWorks is used to set initial conditions, a convection heat transfer coefficient, an ambient temperature, and run a transient heat transfer simulation. The numerical simulation is treated as a lab experiment and emphasis is placed on the results while only basic instructions are given to manage mesh independence and numerical convergence. As they run the simulation, the students can visually see the color of the sphere change, indicating it is cooling over time. The students also create cuts through the sphere at different simulation times to discover that the temperature in the middle of the sphere is typically higher than the temperature at the surface. When the ball bearing is steel and the cooling fluid is air (Bi < 1), the temperature gradient can be a very small fraction of one degree Celsius. The students plot the average temperature of the sphere versus time as calculated using SolidWorks. Since cooling a sphere due to convection has an analytical solution for Bi < 1, the analytical equation is provided to the students. They are asked to generate a plot of temperature versus time using the analytical equation. Comparing the temperature versus time curve obtained by SolidWorks to that obtained using the analytical equation can show quite a difference when there is an error in the calculations. However, when the calculations are correct, the curves are found to have excellent agreement. The students are given a lecture on heat transfer before doing this activity. The physics of cooling a sphere using convection is described in the lecture. When the students come to perform the activity in the lab, they are paired into teams and each two students are asked to work together. They generate an engineering report showing their input data, results, and conclusions. The teams are assessed based on their ability to run the simulation, use the analytical equation, make the comparison, and provide a meaningful conclusion. A rubric is developed and teaching assistants (TA) are asked to grade. Grading the reports indicate a high level of attainment of the project goals. The TA’s load will be described and examples of the conclusions will be provided in the paper. The activity is implemented in classes of 48 students (Fall Semester) and other classes of over 200 students (Spring Semester). The project is scalable and can be applied in any mechanical engineering freshman class. It is found to have no limitations based on the class size as long as computers are available with the SolidWorks or equivalent software. A survey is used to capture the student’s perception of the activity. Results of the survey indicate the activity is well appreciated by the students. Results of the survey will be included in the paper.

Citation
Format

Fadda, D., & Rios, O. (2018, June), Introduction to Heat Transfer in a First-year Mechanical Engineering Course Paper presented at 2018 ASEE Annual Conference & Exposition , Salt Lake City, Utah. 10.18260/1-2--30719

TY - CPAPER
AB - An activity is described in this paper to introduce freshman students to the concept of heat loss due to convection heat transfer. The activity is part of an introductory course to mechanical engineering. The overall goal of the introductory course is to help students learn concepts in mechanical design, forces and stresses, engineering materials, motion and power transmission, and thermal and energy systems. The course has several different activities.
The goal of the particular activity described in this paper is to cover the thermal systems portion of the class. In the activity, a ball bearing (sphere) is specified to have a given diameter and initial temperature. A tutorial is given to help students draw the sphere in SolidWorks and define its material. The thermal utility of SolidWorks is used to set initial conditions, a convection heat transfer coefficient, an ambient temperature, and run a transient heat transfer simulation. The numerical simulation is treated as a lab experiment and emphasis is placed on the results while only basic instructions are given to manage mesh independence and numerical convergence. As they run the simulation, the students can visually see the color of the sphere change, indicating it is cooling over time. The students also create cuts through the sphere at different simulation times to discover that the temperature in the middle of the sphere is typically higher than the temperature at the surface. When the ball bearing is steel and the cooling fluid is air (Bi &lt; 1), the temperature gradient can be a very small fraction of one degree Celsius. The students plot the average temperature of the sphere versus time as calculated using SolidWorks.
Since cooling a sphere due to convection has an analytical solution for Bi &lt; 1, the analytical equation is provided to the students. They are asked to generate a plot of temperature versus time using the analytical equation. Comparing the temperature versus time curve obtained by SolidWorks to that obtained using the analytical equation can show quite a difference when there is an error in the calculations. However, when the calculations are correct, the curves are found to have excellent agreement.
The students are given a lecture on heat transfer before doing this activity. The physics of cooling a sphere using convection is described in the lecture. When the students come to perform the activity in the lab, they are paired into teams and each two students are asked to work together. They generate an engineering report showing their input data, results, and conclusions.
The teams are assessed based on their ability to run the simulation, use the analytical equation, make the comparison, and provide a meaningful conclusion. A rubric is developed and teaching assistants (TA) are asked to grade. Grading the reports indicate a high level of attainment of the project goals. The TA’s load will be described and examples of the conclusions will be provided in the paper.
The activity is implemented in classes of 48 students (Fall Semester) and other classes of over 200 students (Spring Semester). The project is scalable and can be applied in any mechanical engineering freshman class. It is found to have no limitations based on the class size as long as computers are available with the SolidWorks or equivalent software.
A survey is used to capture the student’s perception of the activity. Results of the survey indicate the activity is well appreciated by the students. Results of the survey will be included in the paper.

AU - Dani Fadda
AU - Oziel Rios
CY - Salt Lake City, Utah
DA - 2018/06/23
PB - ASEE Conferences
TI - Introduction to Heat Transfer in a First-year Mechanical Engineering Course
UR - https://peer.asee.org/30719
DO - 10.18260/1-2--30719
ER -