Liquid Rocketry: Project Liquid

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Project Liquid is Yale's Liquid Rocketry team, in which I'm a member of the Propulsion sub-team (more details below). To the left is an assembly from a previous iteration of our engine, the Yengine 1.0. This was an IPA and Nitrous Oxide-powered ablative-cooled engine pressurized with Nitrogen. We are currently working on the next in the line of future iterations: the Yengine 2.0. This will be a regenerative and film-cooled engine using self-pressurizing ethane and nitrous oxide.

Augmented Spark Ignitor

Project Goal:

Design and manufacture an Augmented Spark Ignitor (ASI) that will serve as the primary source of ignition for an ethane and nitrous oxide powered rocket engine.

Skills Used:

CAD (OnShape)
Mechanical design
Machining (lathe, mill, drill press)
Testing & troubleshooting

Specifications:

Thrust: 0-3 lbf
O/F: 4
Chamber pressure: 100 PSI
Chamber temperature: ~2300 K
Maximum burntime: 3 sec

Results and Significance:

The team saw successful design, manufacture, assembly, and testing of the ASI with 1 and 3 second burn times. The chamber successfully withstood the high pressure (100 PSI) and temperature (2300 K) conditions.
Despite an overall successful product, the ASI exhibited inconsistencies in tests conducted in close proximity to one another, providing the team with exciting work in the future to refine our design.
This marks the first set of hot fires of any kind for the team and sets a fantastic precedent for future tests!

ASI Chamber Subassembly

Design/Methodology:

After obtaining target combustion parameters such as the ASI chamber pressure and thrust based on the requirements of our main engine, we worked to characterize the combustion properties of our propellants, ethane and nitrous oxide, using NASA's chemical equilibrium analysis (CEA). Using the isentropic flow relationships, we characterized the chamber and throat cross sectional areas. We selected a chamber length that would allow for satisfactory propellant mixing and to avoid unwanted thrust, we omitted the diverging section of the nozzle.

My subteam lead (in blue) and I (in black) manufacturing ASIs on the lathe.

Manufacture:

Copper was selected as the chamber material for its thermal conductivity, in the hopes that this would allow heat on the chamber walls to dissipate to its surroundings. I cut, lathed, milled, and drill pressed two ASIs from a copper rod, and preformed quality testing on both these two ASIs as well two more.

ASI and test stand subassembly.

Assembly:

The chamber was mated to the fluids supply system using two o-ring boss (ORB) fittings followed by 1/4 inch teflon-lined NPT fittings. The ASI was mated with a standoff to a pressure transducer so that we could monitor the chamber pressure during testing. The outside of the chamber is threated so that it can screw into the injector plate. A spark plug screws into the back of the ASI, sealed with a built-in crush gasket. The ASI was mounted to the test-stand with four screws.

Testing:

Leak Test: A leak test cap was manufactured to screw over the end of the ASI and plug the nozzle. Using an air compressor, the ASI was pressurized to 150 PSI to ensure that any leaky seals were corrected.

Static Fire: A series of static fire tests were conducted in February and May of 2024. Our second attempt was a successful, 1-second burn, as is seen in the montage on the left. The May test supported a successful 3 second burn.

Yengine 2.0: Stress Analysis

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