Dimidium

Overview

The Regeneratively Cooled Engine (Dimidium) project aims to develop a liquid bipropellant rocket engine using E98 ethanol and nitrous oxide (N₂O) as its fuel and oxidizer, respectively. E98 not only serves as the fuel, but as the engine's coolant, flowing through regenerative cooling channels during startup and operation to enable extended burn times without disposable components such as ablative liners. These channels are machined into the nozzle and combustion chamber walls and then enclosed using an additive manufacturing process called electroforming. Dimidium is designed for a 16.3-second burn with a peak thrust of approximately 1,000 lbf.

Key Systems

• Machining: The engine’s injector, nozzle–chamber assembly, and regenerative coolant channels are manufactured in-house, with the major components then welded together to form the final copper assembly.
• Electroforming Using an additive manufacturing technique demonstrated by NASA in the 1960s, we use electrochemical baths to deposit copper and nickel onto the engine, closing the coolant channels and forming the outer wall with a 0.1-inch-thick nickel layer.
• Computational Analysis: Employing both CONVERGE CFD and ABAQUS FEA softwares, we have developed and are refining models to predict the engine’s structural and thermal performance both at startup and steady-state operation.
• Propulsion and Testing: Using a pressure-fed nitrous oxide and E98 ethanol system, we are developing and testing the engine’s injector, feed system, and regenerative coolant channels in preparation for hot-fire testing.