Search NASA⌕ Search

SEARCH · Search NASA

Results for “Liquid Rocket Engines”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Signal Processing Methods for Liquid Rocket Engine Combustion Stability Assessments

The J2X Gas Generator engine design specifications include dynamic, spontaneous, and broadband combustion stability requirements. These requirements are verified empirically based high frequency chamber pressure measurements and analyses. Dynamic stability is determined with the dynamic pressure response due to an artificial perturbation of the combustion chamber pressure (bomb testing), and spontaneous and broadband stability are determined from the dynamic pressure responses during steady operation starting at specified power levels. J2X Workhorse Gas Generator testing included bomb tests with multiple hardware configurations and operating conditions, including a configuration used explicitly for engine verification test series. This work covers signal processing techniques developed at Marshall Space Flight Center (MSFC) to help assess engine design stability requirements. Dynamic stability assessments were performed following both the CPIA 655 guidelines and a MSFC in-house developed statistical-based approach. The statistical approach was developed to better verify when the dynamic pressure amplitudes corresponding to a particular frequency returned back to pre-bomb characteristics. This was accomplished by first determining the statistical characteristics of the pre-bomb dynamic levels. The pre-bomb statistical characterization provided 95% coverage bounds; these bounds were used as a quantitative measure to determine when the post-bomb signal returned to pre-bomb conditions. The time for post-bomb levels to acceptably return to pre-bomb levels was compared to the dominant frequency-dependent time recommended by CPIA 655. Results for multiple test configurations, including stable and unstable configurations, were reviewed. Spontaneous stability was assessed using two processes: 1) characterization of the ratio of the peak response amplitudes to the excited chamber acoustic mode amplitudes and 2) characterization of the variability of the peak response's frequency over the test duration. This characterization process assists in evaluating the discreteness of a signal as well as the stability of the chamber response. Broadband stability was assessed using a running root-mean-square evaluation. These techniques were also employed, in a comparative analysis, on available Fastrac data, and these results are presented here.

Kenny, R. Jeremy↗
NASA NTRS2014

Designing Liquid Rocket Engine Injectors for Performance, Stability, and Cost

NASA is developing the Space Launch System (SLS) for crewed exploration missions beyond low Earth orbit. Marshall Space Flight Center (MSFC) is designing rocket engines for the SLS Advanced Booster (AB) concepts being developed to replace the Shuttle-derived solid rocket boosters. One AB concept uses large, Rocket-Propellant (RP)-fueled engines that pose significant design challenges. The injectors for these engines require high performance and stable operation while still meeting aggressive cost reduction goals for access to space. Historically, combustion stability problems have been a critical issue for such injector designs. Traditional, empirical injector design tools and methodologies, however, lack the ability to reliably predict complex injector dynamics that often lead to combustion stability. Reliance on these tools alone would likely result in an unaffordable test-fail-fix cycle for injector development. Recently at MSFC, a massively parallel computational fluid dynamics (CFD) program was successfully applied in the SLS AB injector design process. High-fidelity reacting flow simulations were conducted for both single-element and seven-element representations of the full-scale injector. Data from the CFD simulations was then used to significantly augment and improve the empirical design tools, resulting in a high-performance, stable injector design.

Westra, Douglas G.↗
NASA NTRS2017

Development and Testing of Carbon-Carbon Nozzle Extensions for Upper Stage Liquid Rocket Engines

Carbon-carbon (C-C) composite nozzle extensions are of interest for use on a variety of launch vehicle upper stage engines and in-space propulsion systems. The C-C nozzle extension technology and test capabilities being developed are intended to support National Aeronautics and Space Administration (NASA) and Department of Defense (DOD) requirements, as well as those of the broader Commercial Space industry. For NASA, C-C nozzle extension technology development primarily supports the NASA Space Launch System (SLS) and NASA's Commercial Space partners. Marshall Space Flight Center (MSFC) efforts are aimed at both (a) further developing the technology and databases needed to enable the use of composite nozzle extensions on cryogenic upper stage engines, and (b) developing and demonstrating low-cost capabilities for testing and qualifying composite nozzle extensions. Recent, on-going, and potential future work supporting NASA, DOD, and Commercial Space needs will be discussed. Information to be presented will include (a) recent and on-going mechanical, thermal, and hot-fire testing, as well as (b) potential future efforts to further develop and qualify domestic C-C nozzle extension solutions for the various upper stage engines under development.

Valentine, Peter G.↗
NASA NTRS2018

Hybrid Additive Manufacturing Deposition and Selective Laser Melting Techniques Applied to Copper-Alloy Liquid Rocket Engine Combustion Chambers

Virgin Orbit and the NASA Marshall Space Flight Center have partnered to fabricate a small, multi-metallic, regeneratively cooled thrust chamber by leveraging the strengths of two different types of additive manufacturing: Direct Metal Laser Sintering (DMLS) for the copper alloy liner and blown powder Directed Energy Deposition (DED) for the Inconel structural jacket. The DED is being developed using Virgin Orbit's DMG Mori Seiki hybrid additive/subtractive machining center to further enable unique processing and further cost savings. The materials chosen are preferred for high performance thrust chamber applications, representing a significant advancement from the compromises typically made in the production of metal 3D printed thrust chambers for rocket engines. The 1.2K-lbf thrust article is a 16" tall, 3" diameter design modified for this effort to be regeneratively cooled with water and hot fired using a RP-1/LOX pintle-style development injector from Virgin Orbit's NewtonFour upper stage engine. The thrust chamber was tested at Virgin Orbit's Necker test site in Mojave, California. Results from this test campaign are reported in addition to information characterizing the liner, jacket, and bimetallic diffusion layer materials. This paper will also highlight some of the future bimetallic thrust chamber developments that MSFC and Virgin Orbit will complete under a recently awarded NASA contract.

Zagorski, Kevin↗
NASA NTRS2018

Additive Manufacturing of Liquid Rocket Engine Combustion Devices: A Summary of Process Developments and Hot-Fire Testing Results

Additive Manufacturing (AM) is an emerging technology with a focus on complex metallic component fabrication: Enables complex shapes and internal features that were not possibly with traditional manufacturing techniques, and significant schedule and overall lifecycle cost reductions. To date at the NASA Marshall Space Flight Center (MSFC), combustion devices component hardware ranging in size from 100 - 35,000 lbf has been designed and manufactured using AM and many of these pieces have been hot-fire tested.

Gradl, Paul↗
NASA NTRSDate not supplied

Mechanisms of Interfacial Mixing in the Blown Powder Deposition of Inconel 625 to Copper Alloy for Liquid Rocket Engine Applications

There is an increasing need for functional materials to support high heat flux applications and optimize weight by using bimetallic additive manufacturing (AM). While one promising fabrication technology is the use of blown powder directed energy deposition (DED) AM, challenges remain with bi-metallic combinations. Prominent among these challenges is the need to understand mixing of materials at the bimetallic interface for forming stronger, more durable and reliable joints to extend the versatility of AM into critical applications. One application is the manufacturing of combustion chambers with copper-alloy liners and Superalloy structural jackets. In this application, material combinations are selected for effective heat dissipation, using copper, and retention of strength at high temperatures using Inconel 625. Currently, the dominant problem with this configuration is the highly variable strength of the interface and its correlation with deposition parameters. In this study, samples were fabricated at several vendors with Inconel 625 deposited onto wrought C-18150 (Cu-Cr-Zr) to form a bimetallic interface. Characterization of the interfaces were achieved through optical and electron microscopy, mechanical testing of mini tensile specimens, and electron dispersion spectroscopy to understand diffusion and bulk mixing behaviors at the joint. A theoretical framework was constructed in the context of solidification and mixing mechanisms to explain the resulting differences in the interface. This qualitative approach utilized a fluid dynamics perspective to sum the order of magnitudes of the various acting forces on the weld pool during deposition to predict convection trends based off known parameters. The predicted trends for each vendor are compared to obtain a better understanding of how mixing in the molten pool varied based on deposition parameters.

Additive Manufacturing↗