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Swordfish II-a
Regeneratively-cooled liquid bipropellant engine
Swordfish II-a is a regeneratively-cooled liquid bipropellant engine I'm developing with a peer. We're treating this project as a means to learn the necessary thermo/fluids concepts not included in our university coursework. As such, all design decisions are based on first-principles calculations. We expect to fire this engine for the first time over the summer of 2024.
Specs
Fuel
Liquid kerosene
Oxidizer
Liquid nitrous oxide
Thrust
400lbf
Chamber pressure
440psi
Burn time
10 seconds max (bounded by tank size)
O/F (Isp-optimized)
8.9
Expansion ratio
8.85
Isp
224s
Chamber pressure
440psi
Injector
Pintle (ox-centric)
Feed system
Pressure-fed, blowdown (ox) and regulated-pressure (fuel)
Cooling
Regeneratively-cooled nozzle, YSZ thermal coating in chamber
Chamber/nozzle
As a pedagogical exercise, a peer and I decided to design this engine from the most basic principles of fluid mechanics and thermodynamics. We arrived at the optimal nozzle contour via an original Method of Characteristics script. As you can see from our preliminary ANSYS Fluent run, the nozzle appears to be barely overexpanded.
Method of Characteristics (MoC) output
MoC nozzle contour
CC and nozzle with regen coolant channels
Method of Characteristics (MoC) output
1/4
Injector
Semi-final CAD of pintle injector
Semi-final CAD of pintle injector
1/1
Swordfish will have an oxidizer-centric pintle injector. We are still iterating total momentum ratios (TMRs) to arrive at reasonable pressure drop/injector stiffness values, but we expect to have a full design completed in the coming weeks.
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