Resetting model heat exchanger for another testing with the acoustic emission sensor.

Author: Jackson Marsh | Major: Mechanical Engineering | Semester: Spring 2023

My name is Jackson Marsh, and I am a mechanical engineering major in the college of engineering. I have been doing research for the past three semesters with Dr. Han Hu in the mechanical engineering department. The spring 2023 semester has been very exciting, as I have been working towards creating a multimodal acoustic sensing array. To do this, I have been assisted on two projects and led a project. As I continue research next year, I will continue working towards the multimodal acoustic sensing array while polishing up the smaller projects I have been a part of.

My research towards a multimodal acoustic sensing array utilizes the fact that sound and acoustic waves (also known as acoustic emissions) make up the world around us. These emissions can be characterized by their frequencies, lengths, amplitudes, and patterns. Learning what characteristics are associated with certain events can be useful for real life non-intrusive sensing. Non-intrusive sensing means that the process that makes the acoustic emissions isn’t influenced by the sensors used. For example, this semester I used an acoustic emissions sensor to characterize the flow of sand through a mock heat exchanger. In real applications to know this flow speed, sensors are put into the heat exchanger itself. I have also used acoustic emission sensors to help characterize the activity of different circuit components.

All of the projects where I have helped characterize things have been to further my understanding of using acoustic emissions. My mentor has helped me find other projects in the lab where acoustic sensors could be utilized. It was then my job to figure out the best way to implement them. We then realized that many of the projects used the same sensors, but that the sensors did not all run through the same program. Because of this, my project became focused on combining all of the sensors into the same program. With this, the program and sensors could be taken to any application to test the acoustics. While at first, I thought this may be easy, the integration of each individual sensor to the program has proven very difficult. The multimodal array I am creating utilizes four different types of acoustic sensors: acoustic emission sensors, hydrophones, microphones, and ultrasonic microphones. Each of these sensors comes from a different manufacturer and has its own native software with it. To combine all of these sensors, I have been trying to use NI’s LabVIEW. To get the most out of this technology, my mentor purchased the most current version. A graduate student showed me the basics of LabVIEW, however I quickly learned that I was going to need a deep understanding of the program to create a successful array. The most trouble comes because the same code architecture must be used for each sensor, but the needs from each sensor are different. This has resulted in going through each individual sensor and a time and getting it to work. The semester cut this work short, as I was just starting to get comfortable with LabVIEW at the end, however, I know that next semester I will be able to continue the work and finish getting through all of the challenges.

All of the projects that have used the sensors when learning about acoustic emissions had applications themselves. The heat exchanger project that I mentioned earlier was conducted as part of a team. Because of the outcomes of this project, I will be travelling to the ASME Energy Sustainability conference to represent my team. We are very proud of the work we have done and are excited to showcase it. This could not have been done without the help of our mentor who procured all of the resources we needed and helped us find this specific topic. As go into my senior year, I look forward to wrapping up the work I am doing. I expect to write a conference paper or two, or maybe even a journal article about the work I am doing. I hope that the demonstration of an acoustic array can lead to more innovation with non-intrusive sensing.