Design of Regeneratively Cooled Bi-Propellant Rocket Engine Using Additive Manufacturing

Empirical heat transfer values and thermodynamic models were verified and expanded for a uni-element film-cooled liquid rocket engine operating on a gaseous oxygen and RP-1 mixture. This effort was motivated by the likely reduction of the overall engine mass by integrating regenerative cooling channels directly into the combustion chamber and nozzle walls through the use of additive manufacturing. The data was collected for a range of operating conditions from 1.77 to 2.29 oxidizer-to-fuel mass mixture ratio and 9.65% to 19.69% film cooling. The combustion chamber of the engine experienced damage at heat flux values of 4.54 MW/m2 that occurred at a chamber pressure of 6.96 MPa, a mixture ratio of 2.0, and 9.59% film cooling. The data collected was used with computational tools to develop a novel integrated chamber-nozzle engine design for both regenerative cooling and film cooling conditions. The final design possessed less than 6% variation of flow though the 18 regenerative liner passages and was predicted to be able to handle the current and expected heat transfer values. The unit was printed using Stainless Steel 17-4PH with additive manufacturing techniques but will need to be qualified with future open and closed-loop testing to evaluate the delivered regenerative cooling effectiveness.