Propulsion Projects

The thrust chamber project involves designing, testing, and validating the two different thrust chambers which are currently in development within MRT. Regardless of the type of engine, the thrust chamber is where the combustion occurs! Our current hybrid engine provides around 6 kN of thrust to propel the rocket into the air. Liquid oxidizer (N2O) is injected into the chamber where it mixes with the solid fuel (paraffin wax and carbon black). This generates gas at high temperature and pressure (up to 3200 K and 600 psi) which leaves the chamber through the nozzle, creating thrust.

Many different components come together to create the system we call the thrust chamber:

• The engine block transfers thrust and connects the thrust chamber to the rest of the rocket
• The injector (PR3) vaporizes the incoming liquid oxidizer
• The front and rear spacers (AE5) hold the fuel in place and provide additional space for recirculation and mixing during combustion
• The nozzle accelerates the combustion gasses to supersonic speeds, creating thrust
• The casing contains the high pressure gasses
• The liner (AE5) provides thermal insulation against hot gasses to protect other components

By joining this project you will have the opportunity to:

• Learn to use Computer Aided Design (CAD) in Siemens NX
  • Create drawing for manufacturing
  • Design/redesign components of the Thrust Chamber
• Learn to use Finite Element Analysis (FEAs) to simulate how parts will react to real world forces
• Run Computational Fluid Dynamics (CFDs) to simulate flow from the nozzle
• Assemble and test our system both on campus and at the MRT test site!
  • Hydrostatic testing
  • Hotfire testing

We look forward to welcoming those with any level of experience!

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, in an attempt to gather benefits from each of them.

This year, our goal is to prove that an alternative-geometry injector is viable on the rocket. We have used the showerhead for all of our past hybrid rockets, and want to capture lost performance. We plan to do this through 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. The data collected would then be input into models using custom-built code.

We also plan on making workflow more efficient for the team. Whether it be CADing tools, automating CAD process for injector design or novel machining methods, joining the injector project will give you an opportunity to learn a lot about experimental methods, data analysis, machining, fluid flow characteristics, CADing(and potentially other analysis tools such as CFD or FEA-Finite Element Analysis-) and programming. So if you're interested in participating in all aspects of the design process, this is the project for you!