Atmospheric surface plasma across Kapton and Aluminum layered DBD.

Author: Ethan Graef | Major: Mechanical Engineering and German | Semester: Spring 2023

Electric transportation is the future of human society, but why do we not have many electric aircraft yet? When we’re talking about electric aircraft development, a typical idea that comes to mind is to use a battery instead of a fossil fuel engine. However, using a big heavy battery to meet the power demands of an aircraft is not ideal for a weight-sensitive system. They lack the efficiency needed to power a plane, and they heat up quickly, and if untreated, these high temperatures can lead to battery corrosion and loss of battery life. Another proposed solution to electric aircraft is the concept of ionic wind propulsion. Ionic wind propulsion is a propulsion system powered by the movement of ions which requires no moving parts. While ionic wind propulsion is also limited by battery efficiency, it’s an appealing concept that would help reduce noise pollution in aircraft, and in recent studies, ionic wind propulsion has yielded some promising results

I’ve always been interested in aircraft design. I grew up hearing stories of the advanced aeronautical design of the Spitfire, P-51 Mustang, and Zero aircraft that dominated WWII. As a Freshman, I met Dr. Huang while participating in an RC airplane senior design team called Design Build Fly. The team captain that year, Mike Fredricks, was researching ionic wind propulsion with Dr. Huang, and I found it interesting, so I picked up where he left off.

During the Spring of 2023, as a Junior Mechanical Engineering and German major, I had the pleasure of working with Dr. Adam Huang of the Mechanical Engineering Department on my research topic on ionic wind propulsion. This semester, we focused on developing a power supply to generate plasma in our flexible dielectric barrier discharge devices (DBDs). Our next steps include testing the thrust outputs of different flexible DBD geometries and cell densities coupled with various fixed neodymium magnets and choosing an optimal configuration for an ionic wind-powered aircraft.

This semester of research had its obstacles but still brought about some fruitful results. We had hoped to buy a dc-ac power supply over Winter break to power the plasma generation of our DBDs, but the power supply needed was out of our budget. Despite this hiccup, we developed a circuit that utilizes four IGBTs in an H-bridge configuration to convert dc to ac voltage. Dr. Huang designed the initial circuit for testing, and I integrated the circuit with the high voltage dc power supply. Using this dc-ac converter circuit in conjunction with our high dc voltage power supply, we generated plasma on Kapton aluminum foil layered DBD at around 1.7 kV at a max frequency of 5.2 kHz. This power supply circuit allowed us to conduct more tests on different geometries of DBDs and different DBD cell densities, but during the midst of these tests, some circuit components degraded and eventually failed under continuous high-voltage loads. Mattie McLellan, a freshman who joined our research team, helped me conduct tests of different DBDs and manufacture new DBDs. The ladder half of the semester was used to diagnose the degraded components of the dc-ac converter circuit. During this time, I learned so much about the circuit theory behind plasma generation, and I was able to familiarize myself with the various components of our dc-ac converter circuit and their role in plasma generation. While we have replaced many of the circuit components to be resistant to long high-voltage exposure, we are still having trouble with a couple of transistors degrading. We hope that replacing these faulty transistors will allow us to finally do prolonged testing of the DBDs with differing cell densities and geometries at sustained high-voltage loads.

While I’m away for my internship, our research will continue through the Summer with the help of Dr. Huang and Mattie. We plan to have the circuit back in working order by the end of the Summer so that we can record concrete plasma generation data of different DBD geometries and cell densities. We also want to swing a magnet in front of the DBD while it’s generating plasma to see if the plasma can be contorted by the moving magnetic field produced by the magnet. During the Fall of 2023, I plan to continue my research while studying abroad in Darmstadt, Germany. Back home, our team will work on the physical plasma generation of the DBDs while I perform numerical simulations of the DBD plasma generation using COMSOL, a multi-physics simulation software. We hope to use the COMSOL simulation data to confirm our physical findings of DBD plasma generation.