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At least 19 records

Rocket Engine Thrust Chamber Assembly

A thrust chamber assembly for liquid fueled rocket engines and the method of making it wherein a two-piece mandrel having the configuration of an assembly having a combustion chamber portion connected to a nozzle portion through a throat portion is wrapped with a silica tape saturated with a phenolic resin, the tape extending along the mandrel and covering the combustion chamber portion of the mandrel to the throat portion. The width of the tape is positioned at an angle of 30 to 50 deg. to the axis of the mandrel such that one edge of the tape contacts the mandrel while the other edge is spaced from the mandrel. The phenolic in the tape is cured and the end of the wrap is machined to provide a frusto-conical surface extending at an angle of 15 to 30 deg. with respect to the axis of the mandrel for starting a second wrap on the mandrel to cover the throat portion. The remainder of the mandrel is wrapped with a third silica tape having its width positioned at a angle of 5 to 20 deg. from the axis of the mandrel. The resin in the third tape is cured and the assembly is machined to provide a smooth outer surface. The entire assembly is then wrapped with a tow of graphite fibers wetted with an epoxy resin and, after the epoxy resin is cured, the graphite is machined to final dimensions.

Cornelius, Charles S.↗

Rocket Engine Thrust Chamber Assembly

A thrust chamber assembly for liquid fueled rocket engines and the method of making it wherein a two-piece mandrel wrapped with a silica tape saturated with a phenolic resin, the tape extending along the mandrel and covering the combustion chamber portion of the mandrel to the throat portion. The phenolic in the tape is cured and the end of the wrap is machined. The remainder of the mandrel is wrapped with a third silica tape. The resin in the third tape is cured and the assembly is machined. The entire assembly is then wrapped with a tow of graphite fibers wetted with an epoxy resin and, after the epoxy resin is cured, the graphite is machined to final dimensions.

Cornelius, Charles S.↗

Design of a GRCop-42 Regeneratively Cooled Thrust Chamber Assembly and Feed System

An additively manufactured thrust chamber assembly was designed and printed using laser powder bed fusion. The NASA-developed material GRCop-42 was used for its high strength and high temperature characteristics. The combustion chamber and nozzle utilize regenerative coolant channels to achieve long duration hot fire tests. Design for additive manufacturing was used to create geometries not easily attainable with traditional machining. The thrust chamber assembly was post processed to ensure print quality and verify for testing. A feed system – encompassing all propellant lines, valves, sensors, and tanks – was designed and built to enable steady state, pressure regulated testing. Pressure transducers, thermocouples, and load cells were placed to enable measurements of the propellant properties and engine performance. Venturis and orifices were used throughout the system to control the flow rates to the thrust chamber. Aside from providing propellants, the feed system provides pressure using nitrogen, and purges the lines during shutdown. The design process for this testing platform is described. A testing campaign on the hardware will be conducted by the Akronauts Rocket Design Team at the University of Akron in Spring 2023.

Dillon M. Petty↗

Design of a GRCop-42 Regeneratively Cooled Thrust Chamber Assembly and Feed System

An additively manufactured thrust chamber assembly was designed and printed using laser powder bed fusion. The NASA-developed material GRCop-42 was used for its high strength and high temperature characteristics. The combustion chamber and nozzle utilize regenerative coolant channels to achieve long duration hot fire tests. Design for additive manufacturing was used to create geometries not easily attainable with traditional machining. The thrust chamber assembly was post processed to ensure print quality and verify for testing. A feed system – encompassing all propellant lines, valves, sensors, and tanks – was designed and built to enable steady state, pressure regulated testing. Pressure transducers, thermocouples, and load cells were placed to enable measurements of the propellant properties and engine performance. Venturis and orifices were used throughout the system to control the flow rates to the thrust chamber. Aside from providing propellants, the feed system provides pressure using nitrogen, and purges the lines during shutdown. The design process for this testing platform is described. A testing campaign on the hardware will be conducted by the Akronauts Rocket Design Team at the University of Akron in Spring 2023.

Dillon M. Petty↗

Development of an Integrated Rocket Thrust Chamber Assembly Analysis and Design Toolkit (TCAT)

There are many individual computational tools and methods used to analyze and design components of a rocket engine thrust chamber assembly (TCA) 11,21. To analyze and design a thrust chamber assembly these tools are usually used in sequence while communication of information between these tools is usually done manually. Each component of a TCA is usually designed and optimized individually with limited considerations on system optimized design. This approach is often iterative and can be prone to error. Also at present, expert knowledge of each tool is required. The objective of this software development effort is to select, integrate and automate the best tools into an easy-to-use computational package, the Thrust Chamber Analysis Toolkit (TCAT). This tool will provide a seamless process to analyze and design all or individual components of a thrust chamber assembly. This paper describes the current status of the MAT software development. The selected component codes and their capabilities are briefly described. User and module interfaces and integration status are presented. MAT pre- and post-processing added options are presented and overall MAT capabilities are demonstrated with the results of sample cases. Ongoing and planned model validation efforts are also described. Finally, the MAT future plan options are discussed.

Farhangi, S.↗

The NASA Constellation University Institutes Project: Thrust Chamber Assembly Virtual Institute

This paper documents key aspects of the Constellation University Institutes Project (CUIP) Thrust Chamber Assembly (TCA) Virtual Institute (VI). Specifically, the paper details the TCA VI organizational and functional aspects relative to providing support for Constellation Systems. The TCA VI vision is put forth and discussed in detail. The vision provides the objective and approach for improving thrust chamber assembly design methodologies by replacing the current empirical tools with verified and validated CFD codes. The vision also sets out ignition, performance, thermal environments and combustion stability as focus areas where application of these improved tools is required. Flow physics and a study of the Space Shuttle Main Engine development program are used to conclude that the injector is the key to robust TCA design. Requirements are set out in terms of fidelity, robustness and demonstrated accuracy of the design tool. Lack of demonstrated accuracy is noted as the most significant obstacle to realizing the potential of CFD to be widely used as an injector design tool. A hierarchical decomposition process is outlined to facilitate the validation process. A simulation readiness level tool used to gauge progress toward the goal is described. Finally, there is a description of the current efforts in each focus area. The background of each focus area is discussed. The state of the art in each focus area is noted along with the TCA VI research focus in the area. Brief highlights of work in the area are also included.

Tucker, P. Kevin↗

NASA's Composite Overwrap Lessons Learned on 40k Thrust Chamber Assemblies

Filament wound carbon fiber/polymer composite overwraps combined with additively manufactured (AM) copper alloy combustion chambers are a critical part of NASA’s Rapid Analysis and Manufacturing Propulsion Technology (RAMPT) project. The composite overwrap is a high strength-to-weight material and allows for significant weight reduction of the high-pressure thrust chamber assembly, reduction of overall cost, and reduced fabrication time while offering structural robustness. Integrated AM/composite overwrap chamber assemblies using 2,000 lbf (2k) and 7,000 lbf (7k) thrust were successfully hot fire tested at NASA Marshall Space Flight Center (MSFC). These assemblies allowed the team to learn lessons related to the design, analysis, and manufacturing of these integrated assemblies. A final goal of the RAMPT project is to design and test a 40,000 lbf (40k) thrust chamber assembly. The40k chamber presented the team several new challenges including an integral inlet port in the main body of the composite overwrap. Through multiple iterations of manufacturing techniques, varied materials, and Non-Destructive Evaluations (NDE), many lessons were learned to obtain a final design solution that would not only allow for the interrupted port inlet but also allow for sufficient material margins for the most critically stressed part of the chamber. This paper will cover the manufacturing techniques exploring fabric designs to help subsidize the coverage in the areas left bare by the inlet port during the filament winding process and custom tooling needed for the final full chamber processing. The original material choice of bismaleimide (BMI) 5250-4 from the 7k chamber performed well for the extreme environment of hot fire testing but proved to be difficult with the increased scale and interrupted port design of the 40kchamber. Discussion in this paper will cover these changes, including evaluation of the design, comparison to the prior 2k and 7k designs, and show the final hardware that will be tested. One primary goal of this work and RAMPT project is to provide this development process and data to industry for infusion into future engine designs.

Filament Wound↗

Orbital transfer vehicle 3000 LBF thrust chamber assembly hot fire test program

The Aerojet Orbital Transfer Vehicle (OTV) Thrust Chamber Assembly (TCA) concept consists of a hydrogen cooled chamber, and annular injector, and an oxygen cooled centerbody. The hot fire testing of a heat sink version of the chamber with only the throat section using hydrogen cooling is documented. Hydraulic performance of the injector and cooled throat were verified by water flow testing prior to TCA assembly. The cooled throat was proof tested to 3000 psia to verify the integrity of the codeposited EF nickel-cobalt closeout. The first set of hot fire tests were conducted with a heat sink throat to obtain heat flux information. After demonstration of acceptable heat fluxes, the heat sink throat was replaced with the LH2 cooled throat section. Fourteen tests were conducted with a heat sink chamber and throat at chamber pressures of 85 to 359 psia. The injector face was modified at this time to add more face coolant flow. Ten tests were then conducted at chamber pressures of 197 to 620 psia. Actual heat fluxes at the higher chamber pressure range were 23 percent higher than the average of 10 Btu/in 2 predicted.

Schneider, Judy↗

Computer Tomography Analysis of Fastrac Composite Thrust Chamber Assemblies

Computed tomography (CT) inspection has been integrated into the production process for NASA's Fastrac composite thrust chamber assemblies (TCAs). CT has been proven to be uniquely qualified to detect the known critical flaw for these nozzles, liner cracks that are adjacent to debonds between the liner and overwrap. CT is also being used as a process monitoring tool through analysis of low density indications in the nozzle overwraps. 3d reconstruction of CT images to produce models of flawed areas is being used to give program engineers better insight into the location and nature of nozzle flaws.

Beshears, Ronald D.↗

Design and fabrication of a hydrogen/oxygen thrust chamber assembly

The combustion system for the Advance Expander Test Bed engine consists of a thrust mount, an injector with a H2-O2 torch igniter, a combustion chamber, and a conical nozzle extension. These components constitute the thrust chamber assembly. The design, fabrication, and testing of these components are described in detail.

Hernacki, Thomas R.↗

Lightweight Thrust Chamber Assemblies using Multi-Alloy Additive Manufacturing and Composite Overwrap

Additive Manufacturing (AM) has brought significant design and fabrication opportunities for complex components with internal features such as liquid rocket engine thrust chambers not previously possible. This technology allows for significant cost savings and schedule reductions in addition to new performance optimization through weight reduction and increased margins. Specific to regeneratively-cooled combustion chambers and nozzles for liquid rocket engines, additive manufacturing offers the ability to form the complex internal coolant channels and the closeout of the channels to contain the high pressure liquid propellants with a single operation. Much of additive manufacturing development has focused on monolithic alloys using Laser Powder Bed Fusion (L-PBF), which do not allow for complete optimization of the structure. The National Aeronautics and Space Administration (NASA) completed feasibility of an AM bimetallic L-PBF GRCop-84 copper-alloy combustion chamber with an AM electron beam freeform Inconel 625 structural jacket under the Low Cost Upper Stage Propulsion (LCUSP) Project. A follow-on project called Rapid Analysis and Manufacturing Propulsion Technology (RAMPT) is under development to further expand large-scale multi-alloy thrust chambers while maturing composite overwrap technology for significant weight savings opportunities. The RAMPT project has three primary objectives: 1) Advancing blown powder Directed Energy Deposition (DED) to fabricate integral-channel large scale nozzles, 2) Develop composite overwrap technology to reduce weight and provide structural capability for thrust chamber assemblies, and 3) Develop bimetallic and multi-metallic additively manufactured radial and axial joints to optimize material performance. In addition to these primary manufacturing developments, analytical modeling efforts compliment the process development to simulate the AM processes to reduce build failures and distortions. The RAMPT project is also maturing the supply chain for various manufacturing processes described above in addition to L-PBF of GRCop-42. This paper will present an overview of the RAMPT project, the process development and hardware progress to date, material and hot-fire testing results, along with future developments.

Additive Manufacturing↗

Design verification test matrix development for the STME thrust chamber assembly

This report presents the results of the test matrix development for design verification at the component level for the National Launch System (NLS) space transportation main engine (STME) thrust chamber assembly (TCA) components including the following: injector, combustion chamber, and nozzle. A systematic approach was used in the development of the minimum recommended TCA matrix resulting in a minimum number of hardware units and a minimum number of hot fire tests.

Dexter, Carol E.↗

RS-88 Pad Abort Demonstrator Thrust Chamber Assembly Testing at NASA Marshall Space Flight Center

This paper documents the effort conducted to collect hot-tire dynamic and acoustics environments data during 50,000-lb thrust lox-ethanol hot-fire rocket testing at NASA Marshall Space Flight Center (MSFC) in November-December 2003. This test program was conducted during development testing of the Boeing Rocketdyne RS-88 development engine thrust chamber assembly (TCA) in support of the Orbital Space Plane (OSP) Crew Escape System Propulsion (CESP) Program Pad Abort Demonstrator (PAD). In addition to numerous internal TCA and nozzle measurements, induced acoustics environments data were also collected. Provided here is an overview of test parameters, a discussion of the measurements, test facility systems and test operations, and a quality assessment of the data collected during this test program.

Farr, Rebecca A.↗

Development of an Efficient CFD Model for Nuclear Thermal Thrust Chamber Assembly Design

The objective of this effort is to develop an efficient and accurate computational methodology to predict both detailed thermo-fluid environments and global characteristics of the internal ballistics for a hypothetical solid-core nuclear thermal thrust chamber assembly (NTTCA). Several numerical and multi-physics thermo-fluid models, such as real fluid, chemically reacting, turbulence, conjugate heat transfer, porosity, and power generation, were incorporated into an unstructured-grid, pressure-based computational fluid dynamics solver as the underlying computational methodology. The numerical simulations of detailed thermo-fluid environment of a single flow element provide a mechanism to estimate the thermal stress and possible occurrence of the mid-section corrosion of the solid core. In addition, the numerical results of the detailed simulation were employed to fine tune the porosity model mimic the pressure drop and thermal load of the coolant flow through a single flow element. The use of the tuned porosity model enables an efficient simulation of the entire NTTCA system, and evaluating its performance during the design cycle.

Cheng, Gary↗

Combustion Dynamics and Stability Modeling of a Liquid Oxygen/RP-2 Oxygen-Rich Staged Combustion Preburner and Thrust Chamber Assembly with Gas-Centered Swirl Coaxial Injector Elements

The Combustion Stability Tool Development (CSTD) project, funded by the Air Force Space and Missile Systems Center, began in March 2015 supporting a renewed interest in the development of a liquid oxygen/hydrocarbon, oxygen-rich combustion engine. The project encompasses the design, assembly, and hot-fire testing of the NASA Marshall Space Flight Center 40-klbf Integrated Test Rig (MITR). The test rig models a staged-combustion configuration by combining an oxygen-rich preburner (ORPB), to generate hot gas, with a thrust chamber assembly (TCA) using gas-centered swirl coaxial injector elements. There are five separately designed interchangeable injectors in the TCA that each contain 19- or 27- injector elements. A companion paper in this JANNAF conference describes the design characteristics, rationale, and fabrication issues for all the injectors. The data acquired from a heavily instrumented rig encompasses several injectors, several operating points, and stability bomb tests. Another companion paper in this JANNAF conference describes this test program in detail. In this paper, dynamic data from the hot-fire testing is characterized and used to identify the responses in the ORPB and TCA. A brief review of damping metrics are discussed and applied as a measure of stability margin for damped acoustic modes. Chug and longitudinal combustion stability models and predictions are described which includes new dynamic models for compressible flow through an orifice and a modification to incorporate a third feed line for inclusion of the fuel-film coolant. Flow-acoustics finite element modeling is used to investigate the anticipated TCA acoustics, the effects of injector element length on stability margin, and the potential use of an ORPB orifice trip ring for improving longitudinal stability margin.

Casiano, M. J.↗