Propulsion Projects

How do we propel the rocket? With the thrust chamber! The thrust chamber is where combustion occurs and generates the thrust that propels our rocket into the sky: after the liquid oxidizer (N2O) is injected into the chamber, it mixes and burns with melted and vaporised solid fuel (paraffin wax + carbon black). This generates high temperature (up to 3200 K) and pressure (up to 600 psi) gas that then passes through the nozzle to create thrust.

The following parts integrate together to fulfil this mission reliably and efficiently:

• The middle connector, which connects to the runline and injector to provide oxidizer to the chamber
• The injector*, which vaporizes the liquid oxidizer as it enters the chamber
• The casing, which contains the high pressures of combustion
• The liner*, which thermally insulates the thrust chamber to prevent other part failures
• Spacers* which provide thermal protection and improve mixing of fuel and oxidizer
• The nozzle, which accelerates combustion products to supersonic speeds, creating thrust
• The rear interface, which retains the nozzle and transfers the thrust it produces

*This year, liners and spacers will primarily be under Engine Heat Shields (AE5). The injector is its own standalone project (PR3).

In the Thrust Chamber project, you will learn how to:

• CAD in Siemens NX
• Redesign components to better optimize them
• Create drawings for manufacturing
• Perform FEAs for structural or heat transfer analysis
• Perform Computational Fluid Dynamics analysis (CFDs)
• Assemble our system and validate designs via hydrostatic testing and the MRT test site!

We look forward to having you on the team!

The injector plays an important role in the delivery of oxidizer to our combustion chamber during combustion. Simply put the injector is a plate with a precise hole pattern drilled into it. Not only does the injector atomize the incoming liquid oxidizer allowing for more complete combustion but it also plays an important role in the safety of the engine by ensuring an adequate pressure drop between the oxidizer tank and the combustion chamber,

Currently, the injector on our rocket is known as a shower head, and as the name suggests, it delivers the oxidizers in a flow pattern similar to what you'd see in your shower. However, over the past year we have had the opportunity to develop many new injector geometry, including:

• Hollow cone
• Impinging
• Vortex
• Swirl

While the first three are similar to the shower head as they are holes in a plate, they incorporate various hole geometries to improve combustion stability, regression rates and combustion efficiency. Swirl is a slightly more complex design similar to what you’d see for an overhead fire sprinkler, and acts as a hybrid that incorporates some of the flow characteristics featured in the previously mentioned designs.

This year we plan on running a rigorous experimental campaign to characterize and hopefully optimize our injector design for our combustion chamber, with the help of this data and potentially CFDs (Computational Fluid Dynamics). This will include many trips to our test site on Macdonald campus to use our dedicated injector testing set up, an opportunity to work on many design iterations and development of new manufacturing methods to help accelerate the iteration process. To top it all off, this year, the past injector project lead will be writing a paper, using these results, to present at an aerospace conference in Florida this January! All in all, on the injector project you’ll get an opportunity to learn a lot about experimental methods, data analysis, machining, fluid flow characteristics and CADing. So if you're interested in participating in all aspects of the design process, this is the project for you!

Thorondor is a hybrid rocket. In the combustion chamber, liquid nitrous oxide flows through the solid paraffin wax fuel (candle wax) with carbon black powder added for better radiative heat transfer. The fuel is a hollow cylinder that we produce by melting, and then either mould-casting (using 3D printed moulds) or spincasting. Spincasting is the method that the team has used for years where the molten fuel is spun for two hours in the rocket’s combustion chamber as it solidifies in a hollow cylinder shape (see the pic below!) We are developing our mould-casting setup because it’s safer and easier than spincasting. You just pour the melted wax into the mould! We have also vacuum-sealed the fuel while it’s solidifying to avoid bubbles in the fuel grain.

This design cycle, we will manufacture the fuels for hot fires and for competition, along with innovating new techniques, additives and fuel sizes. The big challenge is to scale up the fuels for the bigger long-term project, the Ancalagon rocket.

There’s gonna be 3D printing and CADing the moulds, research, designing new jigs and melting the wax to cast the fuel! We will be looking into compression moulding, vacuum sealing the mould, and methods for hot-wire-cutting the fuel.

By joining this project you will have the opportunity to:

• Have hands-on participation in fuel casting,
• Learn about our fuel manufacturing process, and how it contributes to the performance of the rocket,
• Research new additives and fuel casting methods, while testing the validity of mould-casting for larger scale fuel grains,
• Gain experience with CAD (computer aided design) software and 3D printing,
• Attend hotfire engine tests at the team’s testsite.