Ethan at his desk looking at a slide from his presentation alongside one of the numerical temperature fields.

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

My name is Ethan Weems, and I am a senior in the Department of Mechanical Engineering within the College of Engineering. For the past year or so, I have been conducting research on the development of advanced air-cooled heat sink designs under the guidance of Dr. Han Hu, also from the Department of Mechanical Engineering. This blog post will focus on my work completed during the Summer 2023 term. Going forward, my intention is to take the skills I have developed on this project and apply it towards a graduate-level thesis project and pursue a master’s degree after my graduation.

The purpose of generating new heat sink designs is to improve the heat transfer efficiency of electronic devices. This is critically important as electronic chips get smaller over time and the existing limitations of cooling capabilities become further pronounced. Air-cooling technologies are not the best method of effective heat transfer. However, because it is low-cost, easy to implement, and allows for smaller form factors, it remains one of the most important directions in heat transfer research.

This is an update to a previous blog post in which I described the experimental characterization facility that was developed for my project. Since then, I have primarily been interested in developing computational simulations and producing modified designs based on those numerical results. For the simulations, I used the COMSOL Multiphysics Conjugate Heat Transfer module to couple the fluid (air) flow with the heat transfer within the virtual testing chamber of the heat sink and the heater source. As expected, the temperatures were found to be the lowest on the side of the heat sink exposed to the oncoming cool air being pulled across, while the device was warmest at its baseplate where the heater was located. From there, a system was proposed in which the heat sink temperature field was imported as a point map into a topology optimization program called nTop. The dimensions of the heat sink were rescaled to the temperature of the original design. As a result, the fins were thinner at the location of the cooling air and thicker where the temperature was higher. The benefit of this is that the weight of the device is reduced, and the temperature performance is improved, based on the computational results of the subsequent design. This demonstrates a potentially advantageous pathway through which this field-driven design procedure could be used to further improve the designs of current heat sink geometries.

I was fortunate to be given the opportunity to present my work at the 2023 American Society of Mechanical Engineers Summer Heat Transfer Conference in July. This gave me the chance to receive feedback from experts within my research field. There was some interest from the audience, but they offered some advice that will be important to consider going forward: the contraction of the air channels might force some of the airflow out of the channel which is where the heat from the bottom of the device is built up. Further exploration of this should be considered, and my method for geometry modification adjusted accordingly. The conference was a tremendous learning experience for me as well. It demonstrated what a career in academia looks like, while also introducing numerous new ideas and projects within the research community. I was able to meet a dozen or so individuals and had discussions with them about different topics. One of these conversations brought to my attention an annual heat sink design competition hosted by the ITHERM conference. This is a direction that I may end up pursuing this coming year, as it is directly relevant to much of the work that I have already completed.

The experience also helped me work with others. Throughout the summer, I was able to interact with my advisor, who provided general guidance as well as resources for reaching the outcomes of the project. Working directly with two other undergraduate students (Grant Resler and Joshua Mora) helped me to hone my interpersonal skills in an academic/professional setting. Because each of us had different levels of understanding, we had to truly collaborate in ensuring that each of our strengths were maximized while minimizing our weaknesses. Due to the multi-faceted nature of this project, Grant and Joshua developed complementary skills that they can use in pursuit of their own future research projects. The efforts of these three individuals specifically were invaluable. I am grateful to each of them.

Going forward, I will use much of the knowledge that I gained through working on this project on a separate project being worked on in my lab in which we are designing an immersion cooling system which has used air-cooling to dissipate the buildup of heat in our device. This represents a unique application of what I have learned in developing a comprehensive synergy between the multiple layers of the cooling device.