Marshall Space Flight Center
June 1 – August 6, 2021
Goals of your project/s:
The overall goal of this current project is to design the concept of a coilgun based 3D printer for in space manufacturing. This 3D printer would heat up metal to melting temperature, and above using Ohmic heating, and launch droplets of the fluid metal using the magnetic coils to print metal structures. This concept still needs many aspects investigated to validate feasibility of concept.
Describe what you did during the internship:
I worked on the droplet physics modeling to understand if printing was possible by launching liquid droplets onto a solid, cool surface. I first determined the heat loss of the droplet due to radiation within the timespan of being launched by the coilgun and hitting the surface. Then, I determined the time it would take for the droplet to solidify upon impacting on the cold surface. This was done by a 1D approximation of the Stefan problem. Afterward, the motion of the droplet impacting was investigated using computational fluid dynamics algorithms, within MATLAB and COMSOL. Both models were pitted against one another, attempting to verify any inaccuracies with either model. I used several methods within the MATLAB algorithm to see if any would create results similar to COMSOL.
Did you achieve your goals? What were the results and conclusions?
The project ran out of time before I could fully finish the model comparison. The algorithms build in MATLAB were not the same as the COMSOL model, nor were most of them running the simulation properly without creating an infinite pressure instability and crashing the code. The conclusion is that instead of using the Navier-Stokes equations to solve the problem, the van der Waals state equations needed to be used in the MATLAB solver, most likely in a smoothed particle hydrodynamics model.
Describe positive lessons learned from this experience:
I learned more numerical methods for computational fluid dynamics and how to better utilize COMSOL for fluid motion, including more refined meshing methods. I also learned that over explaining is always better than underexplaining, especially with research.
Describe negative lessons learned from this experience:
I need to work on my report writing. My first drafts tend to have nonuniform structure and are scattered when describing the story.