| Affiliations: | College of Sciences |
| Team Leader: |
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| Faculty Mentor: |
Adrienne Dove, PhD
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Team Size:
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5 |
| Open Spots: | 5 |
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Team Member Qualifications:
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REQUIRED SKILLS: Students should have some familiarity with nozzle design basics (or be willing to self-study), CAD modeling of nozzles for 3D printing, and basic familiarity with computer-based analysis techniques. There is additional opportunity for exploring methods of data collection and analysis using computer science techniques for image analysis such as edge detection and particle tracking; students with existing experience in this area would also be good fits for this project. Background in plume physics, fluid mechanics, granular mechanics, and PSI are encouraged but not required. |
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Description:
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BACKGROUND: When landing on a lunar surface, damage occurs due to the impact of the nozzle plume on the granular surface material. The reduced gravity (0.166 g or 1.625 m/s2) environment of the moon and the absence of significant atmospheric pressure (10-10 Torr or below) complicate these physics. Understanding the physics of the rarefied and transition flow, and the influence on the surface material, is vital for enabling technology which will allow for repeated co-located landings. RESEARCH PROBLEM: Landers can have under-, over-, or perfectly-expanded nozzle designs which correspond to over-, under-, or perfectly-expanded plumes, respectively. The shape of the plume is also influenced by the atmospheric pressure of the landing site – in higher ambient pressure regimes, plumes can become collimated, ‘concentrating’ down, for example, a plume that would have been over-expanded into a perfectly-expanded plume. We propose that the process of collimation likely changes the structure of the plume itself, and that we should work to isolate the plume shape and atmospheric pressure variables. APPROACH: Our lab has an existing experimental setup – the Gas-Regolith Interaction Testbed (GRIT) – which is a drop-tower (microgravity) vacuum chamber experiment. GRIT has a solenoid-controlled opening which allows atmosphere to enter the chamber (creating our nozzle plume), and we place regolith simulants to replicate the granular lunar surface material. We will design and install a set of nozzles so that we can study over-, perfectly-, and under-expanded plumes in a range of atmospheric conditions. Since our nozzle does not have to support a lander, we can purposely design inefficient nozzles that would not be used in real missions to experimentally explore the parameter space. STUDENT BENEFIT: One of the best ways to explore what makes for an efficient nozzle design is to purposely design many inefficient nozzles. This project could be the basis for a great engineering senior design project and will give students experience with designing and constructing nozzles, then collecting and analyzing experimental data regarding the nozzle performance in different environments. |