By Julian O’Connor, Copy Editor
The Rocket Development Lab (RDL), one of the largest student run groups on campus, has many subgroups. Each group works on its own project to support the club’s goals of teaching students more about the different aspects of rocketry, as well as developing technology for a space-shot cumulative effort, called the Mountain Spirit Program.
One of these groups is the Test Cell 3 (TC3) Liquid Oxygen (LOX) Tanks Redesign Group, which is, according to group sensors expert Hoa Nguyen, is developing a “new design for LOX tanks for future testing that will fix the problems we currently have with our LOX tanks.” Problems the group aims to solve include “leaks, boil-off, accurate DAQ [Data Acquisition] readings,” and more. The LOX tanks being replaced are the ones currently installed in TC3, the RDL’s third and most impressive standing rocket test cell, used for the testing of liquid fueled rockets.
The current tanks are the same ones that were installed when the Test Cell was first built three years ago by Capstone Team Tiber Designs, and are starting to show their age, as Nguyen mentioned. The current tanks’ issues result in an inefficiency of LOX usage during testing campaigns The goal of the Tanks Redesign Group is to eliminate those issues, thus reducing testing costs due to improved efficiency of LOX supply.
One of the biggest changes that the group is planning for their new tanks is the addition of a capacitive level sensor to measure LOX levels more accurately. Nguyen mentions that “this will be a big step for the test cell because this instrument is so far only used in the industry.”
For background, a capacitive level sensor is a device that uses an electrical component known as a capacitor to measure the amount of liquid in a container. A capacitor is a device made of two parallel, electrically charged plates, which are separated by a non-conducting material, known as a dielectric. Capacitors are generally used to store power. The power that can be stored by a capacitor is determined by the size and separation of the plates, as well as the dielectric constant of the dielectric.
A capacitive level sensor works, in essence, by having a large capacitor that runs the primary dimension of a container, that, when the container is empty, has one material, such as air, acting as the dielectric, and when the container fills with another material, such as LOX, the new material also fills the space between the capacitor plates, displacing the old material and replacing it as the dielectric. The two materials have different dielectric constants, and so the sensor where one material ends and the other begins.
This device is, understandably, rather complicated to manufacture, and so far has not been used in any RDL project, making the use of one in the new tanks a milestone for the rocketry program at ERAU. The device is also expensive to purchase from industry manufacturers.
Nguyen says that “the project is important because this is our way of improving on-campus liquid engines testing,” and also says that it will “set a better foundation” for understanding how tanks are made in the industry. For the RDL, the benefit will be improved LOX tanks, allowing them to conduct better tests using less LOX. For the students working on the project, it is an opportunity “to solve different problems that we may not see in classes and practice engineering skills on a high level.” For the Prescott campus community as a whole, improving the equipment of the RDL will improve the educational experience for students who either join the RDL or take one of the classes that makes use of the same equipment – such as Boost Lab, an elective taken mostly by mechanical engineering majors .
The team is still on the preliminary design state,” because of the complex calculations that need to be finished, according to Nguyen, who does believe, however, that the project is in a good place, saying that while “there are also some studies that need to be done for purchasing parts and materials ,” the team is “set” on the preliminary design phase.
