Author: Ethan Weems | Major: Mechanical Engineering | Semester: Spring 2023

My name is Ethan Weems, and I am a Junior Honors Mechanical Engineering student. My research focuses on ways to improve current electronic cooling methods. Specifically, I have been investigating air cooling because it is often the easiest to implement while not being cost prohibitive. I have been working under the guidance of Dr. Han Hu of the Mechanical Engineering department in his research lab.

My project involves the generative development of heat sink designs. To assess the quality of an air-cooled heat sink, we needed an experimental facility. So, that is where I began. From my review of the relevant literature and the input of my advisor, I found that the most relevant metrics for describing the performance of a heat sink are its pressure drop and its convective heat transfer coefficient. Thus, I created a system in which measurements can be collected allowing for the calculation of these values. The system, which is essentially a miniature 3D printed wind tunnel, contains three thermocouples, two pressure transducers, and contains ports allowing for the measurement of the airspeed using a handheld anemometer at different locations throughout the facility. There is a simple DC fan that pulls air through the system and across the heat sink fins. Additionally, I can control a small heater beneath the heat sink. This heat source represents the electronic device that would be generating heat in a real-world application. Separately, there is an Arduino board that is used to control the airspeed of the fan. All the measurement data are collected using a National Instruments DAQ.

I first began working on this project during my sophomore year, when I was presented with the opportunity to begin working with Dr. Hu. At the time, two friends and I worked on the project and honestly didn’t know very much about what we were doing. Yet, with our advisor’s suggestions and references, we were able to develop a preliminary design for the system that I described above. That summer, I was fortunate enough to work in the lab and improve the system significantly. During that time, I also began developing numerical simulations that could be used to validate my eventual experimental results. The lab environment is unique in that there are numerous unrelated projects being worked on simultaneously, but the skills being used often overlap. I owe much of my learning to other students within the lab. The graduate students especially have been extremely helpful in explaining technical tasks that I struggled with learning on my own.

So far, I have been able to conduct tests on several aftermarket heat sinks. Now that this baseline has been established, the next step is to generate new designs. The software nTop allows for the optimization of model geometries through parameterization of several key aspects of the design. Using this, I will be able to maximize the rate of convective heat transfer from the heat sink. I am currently gaining experience and confidence with the software and will be able to produce models that we will send off for manufacturing. Then, I will be able to test the new heat sinks in my characterization facility and compare the performance to the aftermarket designs. It serves as a proof of concept that could potentially be utilized by an electronics company.

The biggest issue that I ran into was encountered when I began running tests on the original heat sinks. The fan wasn’t working right and when I substituted it for the backup fan, its motor started smoking. Unsure of the issue after double- and triple-checking everything, I ordered replacement fans. I blamed myself for the issue because while the fans are rather cheap, I am working with much more expensive hardware that I do not want to be responsible for damaging. When the new fans arrived, I asked fellow lab members to independently wire and power the fan after I had walked them through the circuit and explained how it was to be assembled. The result was the same. After getting in touch with the manufacturer of the device and learning that the “fried” component on the system board regulated excessive input voltages, I began investigating the power supply unit that I was using for my system. As it turns out, the PSU was outputting twice the voltage of what it displayed on its monitor! This experience, albeit frustrating, taught me an important lesson; in research, there are lots of things that can go wrong but that does not mean one should blame oneself. Setbacks are frequent and arguably necessary for success.

I plan to present my work at the American Society of Mechanical Engineers (ASME) Summer Heat Transfer Conference (SHTC) this July in Washington, DC. I anticipate receiving lots of feedback that will help me better understand the physics involved as well as how to improve my technical writing and presentation abilities. Although my career goals reside outside of academia, I believe that the skills I’ve developed through this experience will benefit me immensely in an industrial setting. Even with this seemingly simple project, I have made use of these technical software applications (among others): SolidWorks, MATLAB, LabVIEW, COMSOL, and nTop. I would encourage all students to get involved in research, even if it is something that they may not pursue long-term. The experience itself improves analytical, problem-solving, and interpersonal skills at a rate which I have not witnessed elsewhere.