Baumeister, Joseph F.

NASA NTRS2015

RL10 Engine Ability to Transition from Atlas to Shuttle/Centaur Program

A key launch vehicle design feature is the ability to take advantage of new technologies while minimizing expensive and time consuming development and test programs. With successful space launch experiences and the unique features of both the National Aeronautics and Space Administration (NASA) Space Transportation System (Space Shuttle) and Atlas/Centaur programs, it became attractive to leverage these capabilities. The Shuttle/Centaur Program was created to transition the existing Centaur vehicle to be launched from the Space Shuttle cargo bay. This provided the ability to launch heaver and larger payloads, and take advantage of new unique launch operational capabilities. A successful Shuttle/Centaur Program required the Centaur main propulsion system to quickly accommodate the new operating conditions for two new Shuttle/Centaur configurations and evolve to function in the human Space Shuttle environment. This paper describes the transition of the Atlas/Centaur RL10 engine to the Shuttle/Centaur configurations; shows the unique versatility and capability of the engine; and highlights the importance of ground testing. Propulsion testing outcomes emphasize the value added benefits of testing heritage hardware and the significant impact to existing and future programs.

Launch Vehicle↗

NASA NTRS2014

RL10 Engine Ability to Transition from Atlas to Shuttle/Centaur Program

A key launch vehicle design feature is the ability to take advantage of new technologies while minimizing expensive and time consuming development and test programs. With successful space launch experiences and the unique features of both the National Aeronautics and Space Administration (NASA) Space Transportation System (Space Shuttle) and Atlas/Centaur programs, it became attractive to leverage these capabilities. The Shuttle/Centaur Program was created to transition the existing Centaur vehicle to be launched from the Space Shuttle cargo bay. This provided the ability to launch heaver and larger payloads, and take advantage of new unique launch operational capabilities. A successful Shuttle/Centaur Program required the Centaur main propulsion system to quickly accommodate the new operating conditions for two new Shuttle/Centaur configurations and evolve to function in the human Space Shuttle environment. This paper describes the transition of the Atlas/Centaur RL10 engine to the Shuttle/Centaur configurations; shows the unique versatility and capability of the engine; and highlights the importance of ground testing. Propulsion testing outcomes emphasize the value added benefits of testing heritage hardware and the significant impact to existing and future programs.

Propulsion Testing↗

NASA NTRS1999

Comparison Analysis Between Nevada and TSS Using a Jet Engine Exhaust Nozzle Test Rig

Thermal analysis in both simple and complex models can require calculating the propagation of radiant energy to and from multiple surfaces. This can be accomplished through simple estimation techniques or complex computationally intense computer modeling simulations. Currently there are a variety of computer analysis techniques used to simulate the propagation of radiant energy, each having advantages and disadvantages. The major objective of this effort was to compare two ray tracing radiation propagation analysis programs (NEVADA and TSS) Net Energy Verification and Determination Analyzer and Thermal Synthesizer System with experimental data. Results from a non-flowing, electrically heated test rig was used to verify the calculated radiant energy propagation from a nozzle geometry that represents an aircraft propulsion nozzle system. In general the programs produced comparable overall results, and results slightly higher then the experimental data. Upon inspection of individual radiation interchange factors, differences were evident and would have been magnified if a more radical model temperature profile was analyzed. Bidirectional reflectivity data (BRDF) was not used do to modeling limitations in TSS. For code comparison purposes, this nozzle geometry represents only one case for one set of analysis conditions. Since each computer code has advantages and disadvantages bases on scope, requirements, and desired accuracy, the usefulness of this single case study may be limiting.

Baumeister, Joseph F.↗

NASA NTRS1995

Combining Comparison Functions and Finite Element Approximations in CFD

In a variety of potential flow applications, the modal element method has been shown to significantly reduce the numerical grid, employ a more precise grid termination boundary condition, and give theoretical insight to the flow physics. The method employs eigenfunctions to replace the numerical grid over significant portions of the flow field. Generally, a numerical grid is employed around obstacles with complex geometry while eigenfunctions are applied to regions in the flow field where the boundary conditions can easily be satisfied. To handle a wider class of computational fluid dynamics (CFD) problems, the present paper extends the modal element to include function approximations which do not satisfy the governing differential equation. To accomplish this task, a double modal series approximation and weighted residual constraints are developed to force the comparison functions to satisfy the governing differential equation and to interface properly with the finite element solution. As an example, the method is applied to the problem of potential flow in a channel with two-dimensional cylindrical like obstacles. The calculated flow fields are in excellent agreement with exact analytical solutions.

Baumeister, Kenneth J.↗

NASA NTRS1994

Radiant Energy Measurements from a Scaled Jet Engine Axisymmetric Exhaust Nozzle for a Baseline Code Validation Case

A non-flowing, electrically heated test rig was developed to verify computer codes that calculate radiant energy propagation from nozzle geometries that represent aircraft propulsion nozzle systems. Since there are a variety of analysis tools used to evaluate thermal radiation propagation from partially enclosed nozzle surfaces, an experimental benchmark test case was developed for code comparison. This paper briefly describes the nozzle test rig and the developed analytical nozzle geometry used to compare the experimental and predicted thermal radiation results. A major objective of this effort was to make available the experimental results and the analytical model in a format to facilitate conversion to existing computer code formats. For code validation purposes this nozzle geometry represents one validation case for one set of analysis conditions. Since each computer code has advantages and disadvantages based on scope, requirements, and desired accuracy, the usefulness of this single nozzle baseline validation case can be limited for some code comparisons.

Baumeister, Joseph F.↗

NASA NTRS1994

Modal element method for potential flow in non-uniform ducts: Combining closed form analysis with CFD

An analytical procedure is presented, called the modal element method, that combines numerical grid based algorithms with eigenfunction expansions developed by separation of variables. A modal element method is presented for solving potential flow in a channel with two-dimensional cylindrical like obstacles. The infinite computational region is divided into three subdomains; the bounded finite element domain, which is characterized by the cylindrical obstacle and the surrounding unbounded uniform channel entrance and exit domains. The velocity potential is represented approximately in the grid based domain by a finite element solution and is represented analytically by an eigenfunction expansion in the uniform semi-infinite entrance and exit domains. The calculated flow fields are in excellent agreement with exact analytical solutions. By eliminating the grid surrounding the obstacle, the modal element method reduces the numerical grid size, employs a more precise far field boundary condition, as well as giving theoretical insight to the interaction of the obstacle with the mean flow. Although the analysis focuses on a specific geometry, the formulation is general and can be applied to a variety of problems as seen by a comparison to companion theories in aeroacoustics and electromagnetics.

Baumeister, Kenneth J.↗

NASA NTRS1993

Application of ray tracing in radiation heat transfer

This collection of presentation figures displays the capabilities of ray tracing for radiation propagation calculations as compared to an analytical approach. The goal is to introduce the terminology and solution process used in ray tracing, and provide insight into radiation heat transfer principles and analysis tools. A thermal analysis working environment is introduced that solves demanding radiation heat transfer problems based on ray tracing. This information may serve as a reference for designing and building ones own analysis environment.

Baumeister, Joseph F.↗

NASA NTRS1993

Jet Engine hot parts IR Analysis Procedure (J-EIRP)

A thermal radiation analysis method called Jet Engine IR Analysis Procedure (J-EIRP) was developed to evaluate jet engine cavity hot parts source radiation. The objectives behind J-EIRP were to achieve the greatest accuracy in model representation and solution, while minimizing computer resources and computational time. The computer programs that comprise J-EIRP were selected on the basis of their performance, accuracy, and flexibility to solve both simple and complex problems. These programs were intended for use on a personal computer, but include the ability to solve large problems on a mainframe or supercomputer. J-EIRP also provides the user with a tool for developing thermal design experience and engineering judgment through analysis experimentation, while using minimal computer resources. A sample jet engine cavity analysis demonstrates the procedure and capabilities within J-EIRP, and is compared to a simplified method for approximating cavity radiation. The goal is to introduce the terminology and solution process used in J-EIRP and to provide insight into the radiation heat transfer principles used in this procedure.

Baumeister, Joseph F.↗

NASA NTRS1991

Relationship of optical coating on thermal radiation characteristics of nonisothermal cylindrical enclosures

A numerical ray tracing technique was applied to simulate radiation propagating from various non-isothermal cylindrical cavities to determine the effect of optical coating (surface emissivity). In general, the analysis showed that the optical coating and temperature within a cavity have a significant effect on emitted radiation based on cavity dimension. Temperature thresholds were found to exist where the same optical coating may either reduce or increase cavity performance (apparent emissivity). Parametric values of apparent emissivity results are presented over a wide range of variables to correlate cylindrical cavity radiation for non-uniform cavity emissivity values. A universal curve was developed to aid in selecting wall emissivity values for design considerations.

Baumeister, Joseph F.↗

NASA NTRS1990

Thermal radiation characteristics of nonisothermal cylindrical enclosures using a numerical ray tracing technique

Analysis of energy emitted from simple or complex cavity designs can lead to intricate solutions due to nonuniform radiosity and irradiation within a cavity. A numerical ray tracing technique was applied to simulate radiation propagating within and from various cavity designs. To obtain the energy balance relationships between isothermal and nonisothermal cavity surfaces and space, the computer code NEVADA was utilized for its statistical technique applied to numerical ray tracing. The analysis method was validated by comparing results with known theoretical and limiting solutions, and the electrical resistance network method. In general, for nonisothermal cavities the performance (apparent emissivity) is a function of cylinder length-to-diameter ratio, surface emissivity, and cylinder surface temperatures. The extent of nonisothermal conditions in a cylindrical cavity significantly affects the overall cavity performance. Results are presented over a wide range of parametric variables for use as a possible design reference.

Baumeister, Joseph F.↗

NASA NTRS1989

Comparative thermal analysis of the space station Freedom photovoltaic deployable boom structure using TRASYS, NEVADA, and SINDA programs

The proposed Space Station Photovoltaic Deployable Boom was analyzed for operating temperatures. The boom glass/epoxy structure design needs protective shielding from environmental degradation. The protective shielding optical properties (solar absorptivity and emissivity) dictate the operating temperatures of the boom components. The Space Station Boom protective shielding must also withstand the effects of the extendible/retractable coiling action within the mast canister. A thermal analysis method was developed for the Space Station Deployable Boom to predict transient temperatures for a variety of surface properties. The modeling procedures used to evaluate temperatures within the boom structure incorporated the TRASYS, NEVADA, and SINDA thermal analysis programs. Use of these programs led to a comparison between TRASYS and NEVADA analysis methods. Comparing TRASYS and NEVADA results exposed differences in the environmental solar flux predictions.

Baumeister, Joseph F.↗

NASA NTRS1989

Comparative thermal analysis of the Space Station Freedom photovoltaic deployable boom structure using TRASYS, NEVADA, and SINDA programs

The proposed Space Station Photovoltaic Deployable Boom was analyzed for operating temperatures. The boom glass/epoxy structure design needs protective shielding from environmental degradation. The protective shielding optical properties (solar absorptivity and emissivity) dictate the operating temperatures of the boom components. The Space Station Boom protective shielding must also withstand the effects of the extendible/retractable coiling acting within the mast canister. A thermal analysis method was developed for the Space Station Deployable Boom to predict transient temperatures for a variety of surface properties. The modeling procedures used to evaluate temperatures within the boom structure incorporated the TRASYS, NEVADA, and SINDA thermal analysis programs. Use of these programs led to a comparison between TRASYS and NEVADA analysis methods. Comparing TRASYS and NEVADA results exposed differences in the environmental solar flux predictions.

Baumeister, Joseph F.↗

NASA NTRS1988

Thermal distortion analysis of the space station solar dynamic concentrator

A method was developed to evaluate the thermal distortion of the Space Station Solar Dynamic Concentrator and the effects of thermal distortion on concentrator optical performance. The analytical method includes generating temperature distributions with TRASYS and SINDA models, interfacing the SINDA results with the SINDA-NASTRAN Interface Program (SNIP), calculating thermal distortion with a NASTRAN/PATRAN finite element model, and providing flux distribution maps within the receiver with the ray tracing OFFSET program. Temperature distributions, thermally induced slope errors, and flux distribution maps within the receiver are discussed. Results during a typical orbit indicate that temperatures of the hexagonal panels and triangular facets range between -18 and 99 C (-1 to 210 F), facet rotations are less than 0.2 mrad, and a change in facet radius due to thermal flattening is less than 5 percent. The predicted power loss with thermal distortion effects was less than 0.3 percent. The thermal distortion of the Solar Dynamic concentrator has negligible effect on the flux distribution within the receiver cavity.

Trudell, Jeffrey J.↗

NASA NTRS1988

Thermal distortion analysis of the Space Station solar dynamic concentrator

A method was developed to evaluate the thermal distortion of the Space Station Solar Dynamic Concentrator and the effects of thermal distortion on concentrator optical performance. The analytical method includes generating temperature distributions with TRASYS and SINDA models, interfacing the SINDA results with the SINDA-NASTRAN Interface Program (SNIP), calculating thermal distortion with a NASTRAN/PATRAN finite element model, and providing flux distribution maps within the receiver with the ray tracing OFFSET program. Temperature distributions, thermally induced slope errors, and flux distribution maps within the receiver are discussed. Results during a typical orbit indicate that temperatures of the hexagonal panels and triangular facets range between -18 and 99 C (-1 to 210 F), facet rotations are less than 0.2 mrad, and a change in facet radius due to thermal flattening is less than 5 percent. The predicted power loss with thermal distortion effects was less than 0.3 percent. The thermal distortion of the Solar Dynamic concentrator has negligible effect on the flux distribution within the receiver cavity.

Trudell, Jeffery J.↗