Conference Paper

Liquid Rocket Engine Design for Additive Manufacturing

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Abstract

This paper discusses the processes involved in the additive manufacturing of a regenerative and film-cooled liquid rocket engine with a thrust of 10 kN using Inconel 718, while detailing validation techniques. A description of the objectives and design constraints provide the context and motivations. Computational Fluid Dynamics (CFD) models were developed and provided the expected pressure and thermal regimes under regenerative and film cooling. Additionally, Finite Element (FE) models were used to predict the capabilities of the engine structure. A description of 3D printing methods highlights the benefits and limitations of the technology, specifically the influence the design of liquid rocket engines. A pintle injector is used, printed as a separate, easily removable and replaceable component. Issues related to overhangs, surface roughness, and shrinkage; aspects related to post-print processing and the need to minimize machining are discussed. Results from the CT scans of the engine and its components are presented. The paper also outlines the series of tests that will be performed on this engine to verify its performance and provide design basis for future works This engine will be used to power the reusable flight vehicle that is under development at the Kyushu Institute of Technology in Japan. The student-led Liquid Propulsion Laboratory at the University of Southern California is responsible for the work detailed below.

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... Dressler [1], Mercieca [7] or Vasques [16], T M R can also be found as the inverse radialto-axial ratio, such as in Sakaki [17], Austin [18] or Fessla [19]. ...
Thesis
The pintle injector is distinguished by its unique geometry and injection characteristics, compared to the impinging or coaxial distributed-element injectors typically used on liquid bipropellant rocket engines. The pintle injector design can deliver high combustion efficiency (typically 96-99%) and enables some unique operating features, such as deep throttling and injector face shut-off. Its design simplicity makes it ideally suited for use on low cost engines [1]. The thesis work is focused on the development and validation of analytical models and software for the design of a pintle injector for a LOX-CH4 liquid rocket engine. A numerical tool has been developed to preliminary design the injector and give insights on the achievable performance of the system. It defines a layout of the injector orifices then provides the thermal analysis of the components exposed to the heat of the combustion chamber. Once defined a configuration that achieves both high performance and withstands the thermal loads, computational fluid dynamics has been employed to support the detailed design of the components, to identify weaknesses in the flow field and to optimize its topology. A technology demonstrator has been designed and manufactured, to be ready for a cold flow characterization campaign. Significantly lower development costs has been achieved optimizing the model for additive layer manufacturing, which is imposing as a major breakthrough in propulsion technology and allows to realize complex systems near net shape and with a lower number of parts.
... Fessl et al. 11 used additive manufacturing (AM) to print the liquid rocket engine they had designed. They used an EOS M290 metal printer that uses Selective Laser Sintering (SLS) to print with materials such as Inconel 718. ...
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Liquid rocket thrust chambers aspects of modeling, analysis, and design
  • M Habiballah
  • V Yang
Habiballah, M., & Yang, V. (2004). Liquid rocket thrust chambers aspects of modeling, analysis, and design. Reston, Va.: American Institute of Aeronautics and Astronautics, Inc.
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