MkII Cooling
Hi everyone! The development of MkII is rounding the corner, and we are excited to share with you our recent progress. One big challenge to our design was how we were going to prevent the thrust chamber assembly from melting during a hot fire. Our student engineers determined two methods to choose from: installing an ablative lining or regenerative cooling. After careful consideration, we have decided to go with an ablative lining. Let’s dive into how we attacked this challenge and what led to our decision.
The LRI’s main design philosophy is to establish a set of requirements for a product, and to design only to those requirements. Any time spent optimizing anything that isn’t a requirement is time wasted! For the challenge of avoiding melting of our engine during a hot-fire, we had established a few requirements for our cooling system. They are as follows:
The cooling system shall…
Prevent our chamber and nozzle from reaching a certain temperature during a 15 second hotfire on a test stand
Not extend manufacturing complexity and time beyond what is already slated for MkII
Remain under a defined budget amount
With regards to the first point, both regenerative cooling and an ablative lining satisfy this requirement based on literature. It is the second and third points that start to differentiate the two methods. Regenerative cooling requires you to drill channels inside the walls of our chamber and nozzle to allow fluids to travel at high flow rates through them. When talking to our network of machinists, they have told us that this would increase manufacturing complexity and time of MkII. Also, with this increased complexity, we would need to pay them more for this added service. This is where the ablative lining starts to look a lot better.
Notice that we are only worrying about a 15 second test stand hotfire. MkII is being made to demonstrate the capabilities of our new test-stand. This is important because we are not optimizing MkII for a flight vehicle. Simplicity is key here so we need to have an engine ready when our test-stand is built. An ablative lining would not extend manufacturing time, and it would remain well under-budget as we have obtained sponsors for ablative procurement.
Overall, an ablative lining for our engine will best suit our goals. MkII development has been a very exciting process for me because of the fast-paced iterations going on with the project. I hope you all share this excitement around the Liquid Rocket Initiative as I do. If you want to be in-the-know about our projects, follow our Instagram and keep and eye out for more blog posts!
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