Reimagining Orbital Transfer Vehicle Propulsion

“NIKOLA Y. VAPTSAROV” NAVAL ACADEMY

Engineering Faculty - Department of Electronics

A case for Rotating Detonation Engines

Created by: Emil Dimov Raychev

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Introduction

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Bridging Orbits – What is an OTV?

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Spinning Fire – What is a Rotating Detonation Engine?

• Up to 25% more efficient.
• No moving parts, hence less complex.
• More room for larger payloads.

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Spinning Fire – What is a Rotating Detonation Engine?

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DDT is not a well understood phenomenon, therefore it cannot accurately be predicted. Still,

several critical conditions need to be met before it occurs:

1. Dimension of the tube diameter must correspond to the detonation cell size of the mixture.
2. The shock needs to be initiated either via a pre-detonator or a spark plug.
3. The DDT tube needs to have periodic obstacles to rapidly accelerate the flame front.
4. CJ velocity – Needs to be around 1500 – 2500 m/s

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Taming Detonation – Critical DDT Conditions

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“For dealing with this situation, I have always recommended a good pair of running shoes.”

– John D. Clark

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Taming Detonation - Fuel & Oxidizer

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In order for the detonation wave to be maintained, several key factors need to be taken

into consideration:

1. Fuel/Oxidizer injection must be axial, as opposed to radial (up to 15% better performance).
2. Fuel/Oxidizer needs to be stored as liquid for density purposes, but vaporized prior to injection for performance.
3. The injector plate form plays a huge part with impinging/shearing jets performing best for gas/gas systems.

Taming Detonation – Geometry

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Rotating detonation engines need to withstand both intense pressure and heat (up to 3000K).

Some of the following materials were tested for these purposes with varying levels of success:

1. Stainless Steel 304 🡪 Total failure. Exceeded tensile limit and melting point (1725 K).
2. Inconel 625 🡪 Improved survivability, however melting still occurred in longer test runs.
3. Inconel 718 🡪 Not a great heat conductor, retains a lot of the temperature.
4. GRCop-42/GRCop-84 🡪 Higher fatigue strength, but lower thermal conductivity.
5. CuCrZr 🡪 High thermal conductivity, but moderate tensile strength.

Taming Detonation – RDE Stability

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Ignition! – Putting it all together

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Ignition! – Putting it all together

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Ignition! – Putting it all together

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What’s next?

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Thank you for your attention!

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