This document summarizes test results from simulating loss-of-lubrication conditions for aerospace spur gears. Tests were conducted at NASA's Glenn Research Center using a contact fatigue test facility. Instrumentation was added to measure temperatures during testing, including thermocouples embedded in gear shrouding and on a test gear. Testing was performed at different load levels until gear failure occurred. Higher loads resulted in faster failure times. Testing provides data to validate models of gear temperature and failure during lubrication loss.
05 probabilistic assessment of cladding hoop stresses in spent nuclear fuel r...leann_mays
This document summarizes research presented at the SFWST Annual Meeting on probabilistic assessments of cladding hoop stresses in spent nuclear fuel rods. It describes objectives to assess structural integrity of fuel rods and canisters during cask transportation after extended storage. It outlines the development of models to predict rod conditions, including regression models relating burnup to rod void volume and internal pressure. The models account for factors like integral fuel burnable absorbers and consider uncertainties. Results are presented comparing models and considering effects of temperature profiles during drying.
This document provides standards for crimping, interconnecting cables, harnesses, and wiring for NASA. It establishes requirements for personnel training and certification programs. The document defines terms and applicable specifications. It covers general principles for reliable cabling and wiring, documentation, and rework procedures. Personnel must be trained and certified to perform crimping and cabling work for NASA according to the specifications in this document.
Evaluation of Over-speed, Burst Margin and Estimation of Low-cycle Fatigue Li...AM Publications
Aero engine rotor burst evaluation is one of the most important problems to be taken care off, whenever it comes to designing a turbo machinery disc. The consequences of a fiasco can be intense, since the disc disintegrates into multiple pieces and they are hurled away in all the possible direction at high speeds. Due to high thermo-mechanical loading conditions the disc is subjected to varying degrees of temperature from bore to rim. However, the centrifugal force dominates in the disc which ranges from 85%-90% and the rest can be treated as thermal and gas loads. The challenge lies at designing a disc for off design conditions with their varying loads and duty cycles. In present work evaluation of safety margins and low-cycle fatigue (LCF) estimation of an aero engine disc through classical methods and blending the terminologies with simulation engineering to arrive at a probable interpretation of number of duty cycles is carried out. The methodology compares the fatigue parameters involved in evaluation of disc life. The design tool closely connects the flight certification requirement, namely Flight Readiness Certification, Federal Aviation Administration and European Aviation Safety Agency the regulating agencies for safety in air transportation vehicles. Speed regulations through API and MIL handbook for material specification using finite element analysis approach.
The document discusses the testing of an additively manufactured monopropellant thruster called Callan. It describes ground testing of the Callan engine at Purdue University to characterize startup procedures and long duration burns. It also describes testing of the propellant feed system at Open Source Maker Labs to verify the design. The thruster aims to promote Cube Quest by enabling the Triteia 6U CubeSat mission to achieve lunar orbit. The propulsion system uses additively manufactured components and hydrogen peroxide propellant.
The document discusses the testing of an additively manufactured monopropellant thruster called Callan. It describes ground testing of the Callan engine at Purdue University to characterize startup procedures and long duration burns. It also describes testing of the propellant feed system at Open Source Maker Labs to verify the design. The thruster aims to promote Cube Quest by enabling the Triteia 6U CubeSat mission to achieve lunar orbit. The propulsion system uses additively manufactured components and hydrogen peroxide propellant.
The document summarizes a CFD analysis of NASA's ADP fan geometry conducted by Yidi Tang. The analysis included constructing computational grids of over 5.5 million cells and simulating three operating conditions (SLTO, approach, cutback). The computed flow rates and bypass ratios showed good agreement with NASA's test data. The validated CFD model could be used to analyze the fan performance and validate a body force model.
Use of Wind Tunnel Refinements in the Dispersion Modeling Analysis of the Ala...Sergio A. Guerra
The proposed Alaska LNG Gas Treatment Plant project required dispersion modeling to evaluate impacts on ambient air quality standards. Initial modeling found inconsistent results due to complex building arrangements of two nearby facilities. Wind tunnel testing was used to determine equivalent building dimensions to refine building inputs, which significantly reduced predicted concentrations. The environmental regulator approved the wind tunnel analysis approach. The modeling now demonstrates operations will not cause exceedances of air quality standards.
Mass transfer studies in an agitated vessel with radial axial impeller combin...eSAT Journals
Abstract The effect of radial-axial impeller combination in dual configuration was tested for gas liquid mass transfer coefficient (KLa) and compared with that of dual axial impeller (30º Pitched blade) combination. The trials were conducted at gas rates of 2litre/min to 10litre/min and agitation rates of 180rpm to 360rpm.Good mass transfer coefficient was obtained by replacing the lower axial impeller with a radial impeller. Rushton Turbine and Curved blade (half pipe) impeller were used in replacing the lower axial impeller. Amongst the two radial impellers, curved blade resulted in higher KLa than Rushton Turbine at highest gassing rate tested. About 15-35% and 20-48% increase in KLa was observed by replacing lower pitched blade impeller with Rushton and Curved blade impeller each. The results from the present study shows the capability of replacing lower axial impeller with Radial impeller and retrofitting existing lower Rushton Turbine with Curved blade impeller. Keywords: Mass transfer coefficient, Rushton, Axial, agitated vessel.
05 probabilistic assessment of cladding hoop stresses in spent nuclear fuel r...leann_mays
This document summarizes research presented at the SFWST Annual Meeting on probabilistic assessments of cladding hoop stresses in spent nuclear fuel rods. It describes objectives to assess structural integrity of fuel rods and canisters during cask transportation after extended storage. It outlines the development of models to predict rod conditions, including regression models relating burnup to rod void volume and internal pressure. The models account for factors like integral fuel burnable absorbers and consider uncertainties. Results are presented comparing models and considering effects of temperature profiles during drying.
This document provides standards for crimping, interconnecting cables, harnesses, and wiring for NASA. It establishes requirements for personnel training and certification programs. The document defines terms and applicable specifications. It covers general principles for reliable cabling and wiring, documentation, and rework procedures. Personnel must be trained and certified to perform crimping and cabling work for NASA according to the specifications in this document.
Evaluation of Over-speed, Burst Margin and Estimation of Low-cycle Fatigue Li...AM Publications
Aero engine rotor burst evaluation is one of the most important problems to be taken care off, whenever it comes to designing a turbo machinery disc. The consequences of a fiasco can be intense, since the disc disintegrates into multiple pieces and they are hurled away in all the possible direction at high speeds. Due to high thermo-mechanical loading conditions the disc is subjected to varying degrees of temperature from bore to rim. However, the centrifugal force dominates in the disc which ranges from 85%-90% and the rest can be treated as thermal and gas loads. The challenge lies at designing a disc for off design conditions with their varying loads and duty cycles. In present work evaluation of safety margins and low-cycle fatigue (LCF) estimation of an aero engine disc through classical methods and blending the terminologies with simulation engineering to arrive at a probable interpretation of number of duty cycles is carried out. The methodology compares the fatigue parameters involved in evaluation of disc life. The design tool closely connects the flight certification requirement, namely Flight Readiness Certification, Federal Aviation Administration and European Aviation Safety Agency the regulating agencies for safety in air transportation vehicles. Speed regulations through API and MIL handbook for material specification using finite element analysis approach.
The document discusses the testing of an additively manufactured monopropellant thruster called Callan. It describes ground testing of the Callan engine at Purdue University to characterize startup procedures and long duration burns. It also describes testing of the propellant feed system at Open Source Maker Labs to verify the design. The thruster aims to promote Cube Quest by enabling the Triteia 6U CubeSat mission to achieve lunar orbit. The propulsion system uses additively manufactured components and hydrogen peroxide propellant.
The document discusses the testing of an additively manufactured monopropellant thruster called Callan. It describes ground testing of the Callan engine at Purdue University to characterize startup procedures and long duration burns. It also describes testing of the propellant feed system at Open Source Maker Labs to verify the design. The thruster aims to promote Cube Quest by enabling the Triteia 6U CubeSat mission to achieve lunar orbit. The propulsion system uses additively manufactured components and hydrogen peroxide propellant.
The document summarizes a CFD analysis of NASA's ADP fan geometry conducted by Yidi Tang. The analysis included constructing computational grids of over 5.5 million cells and simulating three operating conditions (SLTO, approach, cutback). The computed flow rates and bypass ratios showed good agreement with NASA's test data. The validated CFD model could be used to analyze the fan performance and validate a body force model.
Use of Wind Tunnel Refinements in the Dispersion Modeling Analysis of the Ala...Sergio A. Guerra
The proposed Alaska LNG Gas Treatment Plant project required dispersion modeling to evaluate impacts on ambient air quality standards. Initial modeling found inconsistent results due to complex building arrangements of two nearby facilities. Wind tunnel testing was used to determine equivalent building dimensions to refine building inputs, which significantly reduced predicted concentrations. The environmental regulator approved the wind tunnel analysis approach. The modeling now demonstrates operations will not cause exceedances of air quality standards.
Mass transfer studies in an agitated vessel with radial axial impeller combin...eSAT Journals
Abstract The effect of radial-axial impeller combination in dual configuration was tested for gas liquid mass transfer coefficient (KLa) and compared with that of dual axial impeller (30º Pitched blade) combination. The trials were conducted at gas rates of 2litre/min to 10litre/min and agitation rates of 180rpm to 360rpm.Good mass transfer coefficient was obtained by replacing the lower axial impeller with a radial impeller. Rushton Turbine and Curved blade (half pipe) impeller were used in replacing the lower axial impeller. Amongst the two radial impellers, curved blade resulted in higher KLa than Rushton Turbine at highest gassing rate tested. About 15-35% and 20-48% increase in KLa was observed by replacing lower pitched blade impeller with Rushton and Curved blade impeller each. The results from the present study shows the capability of replacing lower axial impeller with Radial impeller and retrofitting existing lower Rushton Turbine with Curved blade impeller. Keywords: Mass transfer coefficient, Rushton, Axial, agitated vessel.
The Plume Rise Model Enhancements (PRIME) formulation in AERMOD has been updated based new equations developed from wind tunnel measurements taken downwind of various solid and streamlined structures. These new equations, along with other building downwash improvements have been included as alpha options in the upcoming new version of AERMOD. The PRIME2 options include: • PRIME2UTurb which enables enhanced calculations of turbulence and wind speed • PRIME2Ueff which defines the height used to compute effective parameters Ueff, Sweff, Sveff and Tgeff at plume height and at 30 m • Streamline defines the set of constants for modeling all structures as streamlined. If omitted, rectangular building constants are used. The ORD Options include: • PRIMEUeff which controls the heights for which the wind speed is calculated for the main plume concentrations. • Average between plume height and receptor height recommended in ORD version • Default is current method in AERMOD, stack height wind speed. • PRIMETurb which adjusts the vertical turbulence intensity, wiz0 from 0.6 to 0.7. • PRIMECav modifies the cavity calculations These improvements aim to address important theoretical issues that significantly affect the accuracy of predicted concentrations subject to downwash effects. This research effort was funded in part by the American Petroleum Institute, the Electric Power Research Institute, the Corn Refiners Association and the American Forest & Paper Association. As part of it, the PRIME2 subcommittee under the A&WMA APM committee was formed to: (1) establish a mechanism to review, approve and implement new science into the model for this and future improvements; and (2) provide a technical review forum to improve the PRIME building downwash algorithms. Collaboration and cooperation from the EPA Office of Research and Development (ORD) has been on-going during the research project resulting in new alpha options aimed at solving known issues with the treatment of building downwash effects in AERMOD. The intent is that these experimental options will be tested by the user community to create enough justification to make these beta (approved on a case-by-case basis) and eventually default options in AERMOD. A preliminary evaluation for the following four cases will be presented: • Arconic- Davenport, IA (formerly Alcoa) • Mirant Potomac River Generating Station- Alexandria, VA • Basic American Foods- Blackfoot, ID • Oakley Generating Station- Oakley, CA The evaluation includes comparing 1-hr, 24-hr and annual averages along with Q-Q plots and isopleths. A discussion related to the results obtained will also be presented.
Solution to AERMOD/PRIME PM10 Overpredictions for Extremely Short, Long and W...Sergio A. Guerra
The current formulation in AERMOD/PRIME is prone to downwash overestimations as documented by Petersen et al. Some of these overpredictions can be minimized by conducting a wind tunnel study to refine the building inputs used in AERMOD/PRIME for critical stacks and wind directions. Most of the wind tunnel studies conducted to date involve taller building structures of at least 20 meters in height. However, a recent wind tunnel study was conducted for the Basic American Foods, Blackfoot, Idaho facility, which has extremely short buildings (7 to 12 meters in height) with very long and wide footprints and many exhaust stacks which are less than 25 meters above ground
The wind tunnel study confirmed that AERMOD was vastly overstating downwash effects for certain critical wind directions. In some cases, AERMOD-predicted concentrations were almost four times higher without the wind tunnel refinements. This study indicates that the previously identified tendency of AERMOD to overpredict downwash using the traditional BPIP-derived building inputs also applies to sites with shorter buildings. Because shorter buildings with shorter stacks are common in many sources subject to the minor New Source Review program (such as most food and beverage and manufacturing facilities), AERMOD’s overpredictions may be causing significantly higher predicted concentrations for many industrial sources.
This paper describes the wind tunnel study performed for this site, presents the benefits obtained from these building input refinements, and reviews comments received on the project from regulatory agencies.
02 highlights from integrated waste management system analyses, storage and t...leann_mays
This document discusses several ongoing projects related to integrated waste management:
1) ORNL is developing the UNF-ST&DARDS tool to integrate data and analysis capabilities for spent nuclear fuel characterization, storage, transportation, and disposal.
2) Recent studies show that an interim spent fuel storage facility could reduce total system costs over the long term but would require a large near-term investment.
3) ORNL is working on a design and topical safety analysis report for a generic interim storage facility to support licensing. This includes developing canister acceptance criteria and an aging management program.
This document discusses a viability study on converting seawater to fuel for unmanned vessels. It begins by researching the electrochemical acidification cell and Fischer-Tropsch processes that are used to extract carbon dioxide from seawater and convert it into hydrocarbon fuel. Calculations are performed to determine that producing 1 gallon of fuel per day requires 0.45213513 moles of hydrogen and 0.14627901 moles of carbon dioxide. Various renewable energy sources are considered for powering the fuel production process, including buoy technology and solar thermal. A concept-level design of the refueling platform is presented, including an interface diagram showing the processes involved. Calculations are also included to determine the optimal placement of the
To study Magnus Effect on Flettner RotorIRJET Journal
This document discusses using computational fluid dynamics (CFD) software to simulate the Magnus effect on Flettner rotors. It first provides background on Flettner rotors and the Magnus effect. It then describes the methodology, which includes analyzing experimental data on rotating cylinders, establishing relationships between parameters, setting boundary conditions in CFD, running simulations, and validating the results. The simulations model the fluid flow around stationary and rotating cylinders and calculate lift and drag coefficients. The CFD analysis is found to capture the Magnus effect and related fluid phenomena on the rotating cylinders.
This document provides guidance on secondary validation and processing of hydro-meteorological and surface water quantity and quality data for a hydrological information system in India. It describes various procedures for validating rainfall, climatic, water level, discharge, and sediment data through time series analysis, comparison between stations, and relationship curves. It also provides methods for correcting errors and completing missing data through interpolation, rating curves, and areal estimation techniques. The overall goal is to develop a sustainable hydrological information system with standardized, computerized data to support water resources planning and management.
This document provides guidance on correcting and completing rainfall data. It discusses using autographic rain gauge (ARG) and standard rain gauge (SRG) data to correct errors when one instrument fails. When the SRG fails but ARG data is available, the SRG data can be replaced with totals from the ARG record. When the ARG fails, hourly distributions from neighboring stations can be used to estimate missing hourly values based on the daily total from the station's SRG. The document also discusses correcting errors like wrong dates and apportioning partial daily accumulations. It describes using double mass analysis to adjust for systematic shifts and spatial interpolation methods to estimate missing values using data from surrounding stations. Examples are provided to demonstrate the techniques.
IRJET-A Review on Advances in the Design and Analysis of Draft Tube for React...IRJET Journal
This document reviews research on the design and analysis of draft tubes for reaction turbines. It discusses how computational fluid dynamics (CFD) has been used by researchers to optimize draft tube design and predict turbine performance. The document outlines several studies that have used CFD to simulate draft tube flow and analyze the effects of design parameters like length and angle on performance. It concludes that CFD is an effective tool for draft tube analysis that can save resources and time compared to physical testing during the design phase.
11 spent fuel matrix degradation and canister corrosion quantifying the effec...leann_mays
The document discusses the fuel matrix degradation model (FMDM) which quantifies the effect of hydrogen on spent nuclear fuel corrosion and canister corrosion. It summarizes work in 2017 to integrate the FMDM with the general disposal system analysis source term model and validate the hydrogen effect. It also outlines priorities for 2018, including further integration with geochemical process models, developing experimental methods to study fuel corrosion under various hydrogen concentrations, and optimizing the FMDM model.
Chato liquid acquisition strategies for exploration missions current status 2010David Chato
NASA is developing propulsion systems for future exploration missions to the Moon that will use cryogenic propellants like liquid oxygen and methane. These propulsion systems require delivering the propellants in a vapor-free manner from storage tanks to engines. NASA has started testing liquid acquisition devices (LADs) that use fine mesh screens to manage cryogenic propellants. Recent tests measured the bubble point pressures of screens with liquid methane and investigated heat retention. Upcoming work will continue testing LADs with other cryogens like liquid hydrogen and studying effects of microgravity conditions.
A renewed interest and scrutiny of downwash shortcomings has fueled a parallel, yet complementary effort, led by industry and EPA. Industrial groups funded the update to the Plume Rise Model Enhancements (PRIME) formulation in AERMOD based on new equations derived from wind tunnel measurements. Concurrently, EPA’s Office of Research and Development (ORD) conducted research that led to new enhancements to the downwash formulation.2 The new PRIME equations (PRIME2), along with EPA-ORD’s building downwash improvements, have been included as alpha options in an upcoming new EPA version of AERMOD.
As part of the renewed interest in building downwash, the PRIME2 subcommittee under the A&WMA APM committee was formed to: (1) establish a mechanism to review, approve and implement new science into the model for this and future improvements; and (2) provide a technical review forum to improve the PRIME building downwash algorithms. Collaboration and cooperation from EPA’s ORD and OAQPS have been on-going during this research project. These efforts included a downwash summit at EPA’s RTP facilities on February 16, 2018 where representatives of the PRIME2 committee and research funders met with EPA’s ORD and OAQPS staff to discuss the newly developed building downwash improvements. During that meeting it was decided that these enhancements would be included as new alpha options in AERMOD. The intent is that these experimental options will be tested by the user community to create enough justification to transition them to a beta status (approved on a case-by-case basis) and eventually to default options in AERMOD. An evaluation of some of these new downwash options is presented.
01 thermal profiles gap hanson pnnl sa-126282leann_mays
This document summarizes research on spent nuclear fuel cladding temperatures during dry cask storage. It finds that typical thermal models used in licensing are conservative and may overestimate cladding temperatures. Actual temperature measurements and decay heat profiles show temperatures are lower than predicted, suggesting fuel can be transferred to dry storage sooner. Validation against measurement data and ongoing testing aims to close knowledge gaps and support regulatory decisions.
Stephen Barthelson has over 30 years of experience in aerothermal/CFD engineering. He holds a PhD in mechanical engineering and has worked for companies such as NASA, GE Aircraft Engines, Hunter Fan, and Capstone Turbine conducting CFD analysis and simulations. His areas of expertise include thermal modeling, combustion modeling, turbomachinery analysis, and providing 3D CFD flow analysis of engine and fan components. Currently he is seeking a position as an aerothermal/CFD engineer where he can improve products and enhance profitability with his skills and experience.
PRIME2: Consequence Analysis and Model EvaluationSergio A. Guerra
This presentation will cover a preliminary consequence analysis and field evaluation related to the updates to the Plume Rise Model Enhancements updates (PRIME2). Additional research needs uncovered through this research project will also be discussed.
NOVEL DATA ANALYSIS TECHNIQUE USED TO EVALUATE NOX AND CO2 CONTINUOUS EMISSIO...Sergio A. Guerra
The current study presents a new data analysis technique developed while evaluating continuous emission data collected from a trash compactor. The evaluation involved tailpipe sampling with a portable emission monitoring system (PEMS) from a diesel fueled 525-horsepower trash
compactor. The sampling campaign took place by running the compactor with regular no. 2 diesel, B20 and ULSD fuels. The purpose was to determine the possible emission reductions in nitrous oxides (NOx) and carbon dioxide (CO2) from the use of B20 and ULSD in an off-road
vehicle. The results from the NOx analysis are discussed.
The initial data analysis identified two important issues. The first concern related to a bias in the calculated F values due to the very large number of samples (N). The large N influenced the probability values and indicated a false statistical significance for all factors tested. Additionally,
the data observations were found to be highly autocorrelated. Thus, a time interval data reduction
technique was used to address these two statistical limitations to the robustness of the statistical
analyses. The result in each case was a subset of quasi-independent observations sampled at an interval of 800 seconds. The autocorrelation and false statistical significance issues were promptly resolved by using this technique. Since the issues of false statistical significance and autocorrelation are inherent in continuous data, the positive results obtained from the use of this technique can be far-reaching. This technique allowed for a valid use of the general linear model (GLM) with engine speed as the covariate factor to test day, fuel type and compactor factors. This technique is most relevant given the advancements in data collection capabilities that
require data handling techniques to satisfy the statistical assumptions necessary for valid analyses to ensue.
Evaluation of the Theoretical Problems with Building Downwash Using A New Met...Sergio A. Guerra
While the current EBD method is the best available option to determine correct building dimensions in the model, a different method was suggested by EPA in the 2011 Memo: Model Clearinghouse Review of EBD for AERMOD. Attachment B to the 2011 Memo includes an assessment of the Alcoa Davenport Works EBD Study. In this evaluation EPA compared wind tunnel observations with AERMOD derived concentrations. However, this evaluation has important shortcomings. First, to carry out this comparison between wind tunnel and AERMOD concentrations, it is necessary to collect velocity profiles that include longitudinal and vertical turbulent intensity measurements upwind of the stack. These data were not available for the EPA evaluation of the Alcoa Davenport Works EBD Study. Second, the wind tunnel model operating conditions were converted to full scale conditions by using exact similarity. However, exact similarity is not used to specify model operating conditions since only momentum ratios are matched but not buoyancy ones. Whereas EPA did not provide important details on how this study was performed, this paper outlines how to properly carry out this new method where AERMOD is used to determine equivalent building dimensions. The viability of this new method was also evaluated and discussed.
This document provides an overview of sealing in turbomachinery. It discusses how seals are used to control clearances between rotating and stationary components in gas and steam turbines. Maintaining precise clearances is important for efficiency, stability, and component life. The document outlines different types of seals, including static seals, dynamic seals, and advanced seal designs. It also addresses sealing environments, benefits of sealing for performance and fuel savings, and life and limitation issues for seals.
This document summarizes testing of a 1,500 lbf thrust liquid oxygen/liquid methane rocket engine. The engine was developed through a collaboration between Armadillo Aerospace and NASA and tested at both sea level and simulated altitude conditions. Key findings included:
1) The engine was successfully ignited using both a gas torch and pyrotechnic igniter at sea level and vacuum.
2) Performance data was obtained for the engine using a dual-bell nozzle configuration at altitudes from 90,000 to 50,000 feet.
3) Armadillo Aerospace conducted the first tests of a self-pressurizing liquid oxygen/liquid methane propulsion system, eliminating the need for helium pressurization
This is my first crack at writing a technical report for an assignment in a mechanical engineering course at the University of Alberta. How was the clarity? Any feedback on how I can improve?
The document summarizes a student project analyzing the cycle and performing trade studies of the RS-25 Space Shuttle Main Engine powerhead using high-fidelity modeling tools. The student developed a model of the SSME using the ROCETS tool and benchmarked it against published performance data, showing matches within 2.5%. Trade studies examined the effects of increased chamber pressure, reduced oxidizer-to-fuel ratio, and reduced pump diameter on performance. The analysis identified potential design changes that could increase performance for the SSME variant used on the upcoming Space Launch System, such as increasing chamber pressure or reducing oxidizer-to-fuel ratio, while maintaining affordability.
The Plume Rise Model Enhancements (PRIME) formulation in AERMOD has been updated based new equations developed from wind tunnel measurements taken downwind of various solid and streamlined structures. These new equations, along with other building downwash improvements have been included as alpha options in the upcoming new version of AERMOD. The PRIME2 options include: • PRIME2UTurb which enables enhanced calculations of turbulence and wind speed • PRIME2Ueff which defines the height used to compute effective parameters Ueff, Sweff, Sveff and Tgeff at plume height and at 30 m • Streamline defines the set of constants for modeling all structures as streamlined. If omitted, rectangular building constants are used. The ORD Options include: • PRIMEUeff which controls the heights for which the wind speed is calculated for the main plume concentrations. • Average between plume height and receptor height recommended in ORD version • Default is current method in AERMOD, stack height wind speed. • PRIMETurb which adjusts the vertical turbulence intensity, wiz0 from 0.6 to 0.7. • PRIMECav modifies the cavity calculations These improvements aim to address important theoretical issues that significantly affect the accuracy of predicted concentrations subject to downwash effects. This research effort was funded in part by the American Petroleum Institute, the Electric Power Research Institute, the Corn Refiners Association and the American Forest & Paper Association. As part of it, the PRIME2 subcommittee under the A&WMA APM committee was formed to: (1) establish a mechanism to review, approve and implement new science into the model for this and future improvements; and (2) provide a technical review forum to improve the PRIME building downwash algorithms. Collaboration and cooperation from the EPA Office of Research and Development (ORD) has been on-going during the research project resulting in new alpha options aimed at solving known issues with the treatment of building downwash effects in AERMOD. The intent is that these experimental options will be tested by the user community to create enough justification to make these beta (approved on a case-by-case basis) and eventually default options in AERMOD. A preliminary evaluation for the following four cases will be presented: • Arconic- Davenport, IA (formerly Alcoa) • Mirant Potomac River Generating Station- Alexandria, VA • Basic American Foods- Blackfoot, ID • Oakley Generating Station- Oakley, CA The evaluation includes comparing 1-hr, 24-hr and annual averages along with Q-Q plots and isopleths. A discussion related to the results obtained will also be presented.
Solution to AERMOD/PRIME PM10 Overpredictions for Extremely Short, Long and W...Sergio A. Guerra
The current formulation in AERMOD/PRIME is prone to downwash overestimations as documented by Petersen et al. Some of these overpredictions can be minimized by conducting a wind tunnel study to refine the building inputs used in AERMOD/PRIME for critical stacks and wind directions. Most of the wind tunnel studies conducted to date involve taller building structures of at least 20 meters in height. However, a recent wind tunnel study was conducted for the Basic American Foods, Blackfoot, Idaho facility, which has extremely short buildings (7 to 12 meters in height) with very long and wide footprints and many exhaust stacks which are less than 25 meters above ground
The wind tunnel study confirmed that AERMOD was vastly overstating downwash effects for certain critical wind directions. In some cases, AERMOD-predicted concentrations were almost four times higher without the wind tunnel refinements. This study indicates that the previously identified tendency of AERMOD to overpredict downwash using the traditional BPIP-derived building inputs also applies to sites with shorter buildings. Because shorter buildings with shorter stacks are common in many sources subject to the minor New Source Review program (such as most food and beverage and manufacturing facilities), AERMOD’s overpredictions may be causing significantly higher predicted concentrations for many industrial sources.
This paper describes the wind tunnel study performed for this site, presents the benefits obtained from these building input refinements, and reviews comments received on the project from regulatory agencies.
02 highlights from integrated waste management system analyses, storage and t...leann_mays
This document discusses several ongoing projects related to integrated waste management:
1) ORNL is developing the UNF-ST&DARDS tool to integrate data and analysis capabilities for spent nuclear fuel characterization, storage, transportation, and disposal.
2) Recent studies show that an interim spent fuel storage facility could reduce total system costs over the long term but would require a large near-term investment.
3) ORNL is working on a design and topical safety analysis report for a generic interim storage facility to support licensing. This includes developing canister acceptance criteria and an aging management program.
This document discusses a viability study on converting seawater to fuel for unmanned vessels. It begins by researching the electrochemical acidification cell and Fischer-Tropsch processes that are used to extract carbon dioxide from seawater and convert it into hydrocarbon fuel. Calculations are performed to determine that producing 1 gallon of fuel per day requires 0.45213513 moles of hydrogen and 0.14627901 moles of carbon dioxide. Various renewable energy sources are considered for powering the fuel production process, including buoy technology and solar thermal. A concept-level design of the refueling platform is presented, including an interface diagram showing the processes involved. Calculations are also included to determine the optimal placement of the
To study Magnus Effect on Flettner RotorIRJET Journal
This document discusses using computational fluid dynamics (CFD) software to simulate the Magnus effect on Flettner rotors. It first provides background on Flettner rotors and the Magnus effect. It then describes the methodology, which includes analyzing experimental data on rotating cylinders, establishing relationships between parameters, setting boundary conditions in CFD, running simulations, and validating the results. The simulations model the fluid flow around stationary and rotating cylinders and calculate lift and drag coefficients. The CFD analysis is found to capture the Magnus effect and related fluid phenomena on the rotating cylinders.
This document provides guidance on secondary validation and processing of hydro-meteorological and surface water quantity and quality data for a hydrological information system in India. It describes various procedures for validating rainfall, climatic, water level, discharge, and sediment data through time series analysis, comparison between stations, and relationship curves. It also provides methods for correcting errors and completing missing data through interpolation, rating curves, and areal estimation techniques. The overall goal is to develop a sustainable hydrological information system with standardized, computerized data to support water resources planning and management.
This document provides guidance on correcting and completing rainfall data. It discusses using autographic rain gauge (ARG) and standard rain gauge (SRG) data to correct errors when one instrument fails. When the SRG fails but ARG data is available, the SRG data can be replaced with totals from the ARG record. When the ARG fails, hourly distributions from neighboring stations can be used to estimate missing hourly values based on the daily total from the station's SRG. The document also discusses correcting errors like wrong dates and apportioning partial daily accumulations. It describes using double mass analysis to adjust for systematic shifts and spatial interpolation methods to estimate missing values using data from surrounding stations. Examples are provided to demonstrate the techniques.
IRJET-A Review on Advances in the Design and Analysis of Draft Tube for React...IRJET Journal
This document reviews research on the design and analysis of draft tubes for reaction turbines. It discusses how computational fluid dynamics (CFD) has been used by researchers to optimize draft tube design and predict turbine performance. The document outlines several studies that have used CFD to simulate draft tube flow and analyze the effects of design parameters like length and angle on performance. It concludes that CFD is an effective tool for draft tube analysis that can save resources and time compared to physical testing during the design phase.
11 spent fuel matrix degradation and canister corrosion quantifying the effec...leann_mays
The document discusses the fuel matrix degradation model (FMDM) which quantifies the effect of hydrogen on spent nuclear fuel corrosion and canister corrosion. It summarizes work in 2017 to integrate the FMDM with the general disposal system analysis source term model and validate the hydrogen effect. It also outlines priorities for 2018, including further integration with geochemical process models, developing experimental methods to study fuel corrosion under various hydrogen concentrations, and optimizing the FMDM model.
Chato liquid acquisition strategies for exploration missions current status 2010David Chato
NASA is developing propulsion systems for future exploration missions to the Moon that will use cryogenic propellants like liquid oxygen and methane. These propulsion systems require delivering the propellants in a vapor-free manner from storage tanks to engines. NASA has started testing liquid acquisition devices (LADs) that use fine mesh screens to manage cryogenic propellants. Recent tests measured the bubble point pressures of screens with liquid methane and investigated heat retention. Upcoming work will continue testing LADs with other cryogens like liquid hydrogen and studying effects of microgravity conditions.
A renewed interest and scrutiny of downwash shortcomings has fueled a parallel, yet complementary effort, led by industry and EPA. Industrial groups funded the update to the Plume Rise Model Enhancements (PRIME) formulation in AERMOD based on new equations derived from wind tunnel measurements. Concurrently, EPA’s Office of Research and Development (ORD) conducted research that led to new enhancements to the downwash formulation.2 The new PRIME equations (PRIME2), along with EPA-ORD’s building downwash improvements, have been included as alpha options in an upcoming new EPA version of AERMOD.
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01 thermal profiles gap hanson pnnl sa-126282leann_mays
This document summarizes research on spent nuclear fuel cladding temperatures during dry cask storage. It finds that typical thermal models used in licensing are conservative and may overestimate cladding temperatures. Actual temperature measurements and decay heat profiles show temperatures are lower than predicted, suggesting fuel can be transferred to dry storage sooner. Validation against measurement data and ongoing testing aims to close knowledge gaps and support regulatory decisions.
Stephen Barthelson has over 30 years of experience in aerothermal/CFD engineering. He holds a PhD in mechanical engineering and has worked for companies such as NASA, GE Aircraft Engines, Hunter Fan, and Capstone Turbine conducting CFD analysis and simulations. His areas of expertise include thermal modeling, combustion modeling, turbomachinery analysis, and providing 3D CFD flow analysis of engine and fan components. Currently he is seeking a position as an aerothermal/CFD engineer where he can improve products and enhance profitability with his skills and experience.
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Evaluation of the Theoretical Problems with Building Downwash Using A New Met...Sergio A. Guerra
While the current EBD method is the best available option to determine correct building dimensions in the model, a different method was suggested by EPA in the 2011 Memo: Model Clearinghouse Review of EBD for AERMOD. Attachment B to the 2011 Memo includes an assessment of the Alcoa Davenport Works EBD Study. In this evaluation EPA compared wind tunnel observations with AERMOD derived concentrations. However, this evaluation has important shortcomings. First, to carry out this comparison between wind tunnel and AERMOD concentrations, it is necessary to collect velocity profiles that include longitudinal and vertical turbulent intensity measurements upwind of the stack. These data were not available for the EPA evaluation of the Alcoa Davenport Works EBD Study. Second, the wind tunnel model operating conditions were converted to full scale conditions by using exact similarity. However, exact similarity is not used to specify model operating conditions since only momentum ratios are matched but not buoyancy ones. Whereas EPA did not provide important details on how this study was performed, this paper outlines how to properly carry out this new method where AERMOD is used to determine equivalent building dimensions. The viability of this new method was also evaluated and discussed.
This document provides an overview of sealing in turbomachinery. It discusses how seals are used to control clearances between rotating and stationary components in gas and steam turbines. Maintaining precise clearances is important for efficiency, stability, and component life. The document outlines different types of seals, including static seals, dynamic seals, and advanced seal designs. It also addresses sealing environments, benefits of sealing for performance and fuel savings, and life and limitation issues for seals.
This document summarizes testing of a 1,500 lbf thrust liquid oxygen/liquid methane rocket engine. The engine was developed through a collaboration between Armadillo Aerospace and NASA and tested at both sea level and simulated altitude conditions. Key findings included:
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This is my first crack at writing a technical report for an assignment in a mechanical engineering course at the University of Alberta. How was the clarity? Any feedback on how I can improve?
The document summarizes a student project analyzing the cycle and performing trade studies of the RS-25 Space Shuttle Main Engine powerhead using high-fidelity modeling tools. The student developed a model of the SSME using the ROCETS tool and benchmarked it against published performance data, showing matches within 2.5%. Trade studies examined the effects of increased chamber pressure, reduced oxidizer-to-fuel ratio, and reduced pump diameter on performance. The analysis identified potential design changes that could increase performance for the SSME variant used on the upcoming Space Launch System, such as increasing chamber pressure or reducing oxidizer-to-fuel ratio, while maintaining affordability.
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This report compares the modal analysis results from a NASTRAN finite element model of a UH-60A Black Hawk helicopter to experimental ground vibration test results. The finite element model was updated to include additional secondary structural components beyond the original primary structure-only model. The inclusion of secondary components like doors and transmission bridges significantly improved the correlation between the analytical model and test data, particularly at lower frequencies. This comparison seeks to validate modeling techniques for the helicopter within the context of the NASA/ARMY Modern Technology Rotor Airloads Program.
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1. NASA/TM—2014-218396
Test Facility Simulation Results for Aerospace
Loss-of-Lubrication of Spur Gears
Robert F. Handschuh and Lucas J. Gargano
Glenn Research Center, Cleveland, Ohio
October 2014
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3. NASA/TM—2014-218396
Test Facility Simulation Results for Aerospace
Loss-of-Lubrication of Spur Gears
Robert F. Handschuh and Lucas J. Gargano
Glenn Research Center, Cleveland, Ohio
National Aeronautics and
Space Administration
Glenn Research Center
Cleveland, Ohio 44135
October 2014
4. Level of Review: This material has been technically reviewed by technical management.
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Hanover, MD 21076–1320
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Available electronically at http://www.sti.nasa.gov
5. Test Facility Simulation Results for Aerospace
Loss-of-Lubrication of Spur Gears
Robert F. Handschuh and Lucas J. Gargano*
National Aeronautics and Space Administration
Glenn Research Center
Cleveland, Ohio 44135
Abstract
Prior to receiving airworthiness certification, extensive testing is required during the development of
rotary wing aircraft drive systems. Many of these tests are conducted to demonstrate the drive system’s
ability to operate at extreme conditions, beyond that called for in the normal to maximum power
operating range. One of the most extreme tests is referred to as the loss-of-lubrication or run dry test.
During this test, the drive system is expected to last at least 30 min without failure while the primary
lubrication system is disabled for predetermined, scripted flight conditions. Failure of this test can lead to
a partial redesign of the drive system or the addition of an emergency lubrication system. Either of these
solutions can greatly increase the aircraft drive system cost and weight and extend the schedule for
obtaining airworthiness certification.
Recent work at NASA Glenn Research Center focused on performing tests, in a relevant aerospace
environment, to simulate the behavior of spur gears under loss-of-lubrication conditions. Tests were
conducted using a test facility that was used in the past for spur gear contact fatigue testing. A loss-of-lubrication
test is initiated by shutting off the single into mesh lubricating jet. The test proceeds until the
gears fail and can no longer deliver the applied torque. The observed failures are typically plastically
deformed gear teeth, due to the high tooth temperatures, that are no longer in mesh. The effect of several
different variables to gear tooth condition during loss-of-lubrication have been tested such as gear pitch,
materials, shrouding, lubrication condition, and emergency supplied mist lubrication in earlier testing at
NASA.
Recent testing has focused on newer aerospace gear steels and imbedding thermocouples in the
shrouding to measure the air—oil temperatures flung off the gear teeth. Along with the instrumented
shrouding, an instrumented spur gear was also tested. The instrumented spur gear had five thermocouples
installed at different locations on the gear tooth and web. The data from these two types of measurements
provided important information as to the thermal environment during the loss-of-lubrication event. This
data is necessary to validate on-going modeling efforts.
Background and Introduction
The drive system used in rotorcraft applications is required to pass a 30-min loss-of-lubrication test
prior to aircraft certification. This means that the drive system must continue to operate for 30 min with
the primary lubrication system inoperative (Ref. 1). To achieve this capability, gears are extremely
susceptible to failure due to a starved lubrication condition. High load, high pitch line velocity, or the
combination of both can cause the gears, due to the meshing process, to heat to the point of failing.
Failure mechanisms of gear contacts can be summarized by Figure 1 (Ref. 2). In Figure 1, two of the
mechanisms are of most importance for loss-of-lubrication. The first is the wear region where extreme
loading at slower sliding speeds under starved lubrication conditions generates sufficient heat to expedite
wear. The other region is the scoring region where high relative sliding of the teeth influences the heat
being generated. In either case, the friction coefficient increases due to the loss of the full
elastohydrodynamic fluid film, thus increasing the heat generation rate.
*NASA Glenn Research Center, LERCIP intern.
NASA/TM—2014-218396 1
6. Figure 1.—Effects of speed and load on gear wear mechanisms.
Recent studies (Refs. 3 to 5) made initial attempts at evaluating the loss-of-lubrication behavior of
tested components typically used at NASA Glenn for contact fatigue studies. In prior and current NASA
testing, all tests were run in a dry sump manor, where all lubrication is jet fed and gravity drained. This
type of lubrication system results in efficient operation of the drive system and is the lubrication mode
typical in all rotorcraft main transmissions.
In these prior tests, many aspects were considered including run-dry conditions, vapor-mist
lubrication, grease lubrication, test gearbox drainage, and shrouding. These test results indicated that
testing in a relevant environment was essential for the generation of useful test results. Therefore, the
current test arrangement evolved to represent an aerospace environment. Gear shrouding was used in all
tests conducted in this paper.
The test results described in this paper document the on-going research assessment of aerospace
quality components subjected to loss-of-lubrication conditions. Static instrumentation located in the gear
shrouding was used on all tests. Also, one test gear was instrumented with thermocouples to provide
temperature data on the gear. This gear was subjected to normal and loss-of-lubrication conditions.
Results from these tests are described in this report.
Test Facility
The test facility used for conducting all loss-of-lubrication simulation tests is the NASA Glenn
Contact Fatigue Test Facility (Refs. 6 to 8). The facility is shown in the sketch illustrated in Figure 2. The
facility is a torque regenerative test rig that locks torque in the loop via a rotating torque applier. The test
gears have a 1:1 ratio. Facility speed and torque can be varied as needed during a test. The basic gear
design information of the tested gears is listed in Table 1.
As previously mentioned, the facility went through an evolutionary period (Ref. 5) where shrouding,
visual access, gearbox lubricant removal, and instrumentation were added to the test section. A
photograph of the current test gearbox arrangement is shown in Figure 3.
NASA/TM—2014-218396 2
7. Figure 2.—Cross-sectional sketch of the test gearbox
used for loss of lubrication testing.
TABLE 1.—BASIC GEAR DESIGN INFORMATION
Shrouds
NASA/TM—2014-218396 3
28 tooth gear
Module, mm [diametral pitch (1/in.)] 3.175 (8)
Pressure angle (deg.) 20
Pitch diameter, mm (in.) 88.9 (3.5)
Addendum, mm (in.) 3.175 (0.125)
Whole depth, mm (in.) 7.14 (0.281)
Chordal tooth thickness, mm (in.) 4.85(0.191)
Face width, mm (in.) 6.35 (0.25)
Figure 3.—Current test gearbox arrangement utilizing shrouds (bottom exit shown).
8. Figure 4.—Example of test gear arrangement with outer gearbox cover removed, top exit shrouds shown.
Static shroud thermocouples were utilized during all tests. High temperature glass was also utilized as
the outside shroud to encase the gears. Ballistic plastic and another layer of high temperature glass
provided visual (and video) access to the gears during operation. Lubricant for normal operation was fed
at the into-mesh location through part of the shroud (Fig. 4). The normal operational flow rate was
approximately 0.42 l/min (0.11 gpm) at 207 kPa (30 psig) jet pressure with the lubricant inlet temperature
of ~110 C (230 F). Instrumentation and normal lubricant jet locations are shown in Figure 4. A turbine
engine—drive system lubricant, MIL-L-85734, was used during the testing to be described in this report.
Testing Methodology
Prior to loss-of-lubrication testing discussed in this paper, the gears were broken-in to allow normal
run-in wear to occur. The gears were operated for at least 1 hr at ~50 percent of maximum torque and at
full facility speed (10000 rpm). After this period, the load was then increased to the maximum load and
run for at least several more hours prior to conducting a loss-of-lubrication test. Most tests were run until
the teeth failed to continue to carry torque (plastically deformed) or stopped just prior to this condition.
During all tests, the static instrumentation and live video were carefully monitored. Data from all
sensors were collected at 1 Hz and stored for post-processing.
Testing and Discussion of Results
The test results to be described in this report were from the same lot of gears manufactured to the
basic gear design information as shown in Table 1. The gear material was an aerospace gear steel (Ref. 9),
that was carburized and final ground. The surface roughness was 0.41 micro-meters (16 micro-inch) or
better. The gears have some tip relief starting at the highest point of single tooth contact and a small
amount of crowning across the face width that is symmetric.
NASA/TM—2014-218396 4
9. Five test results will be described in this report. The tests in the loss-of-lubrication condition were
conducted at one of two load levels as documented in Table 2. The gear basic design information along
with the load level produced maximum level of bending and contact stress found via the analysis
technique of Reference 10.
An example of each of the two load levels will now be described. At the lower level of the two loads,
two tests were conducted with the loss-of-lubrication time of 40.8 and 43.1 min in length. The data from
the static thermocouples imbedded in the shrouds along with other facility temperatures is shown in
Figure 5.
The gears in the post-test condition are shown in Figure 6. Note that the test was conducted until the
gear tooth meshing heat generation and resultant temperature was high enough to plastically deform the
gear teeth. This type of post-test condition occurred whenever the test was permitted to continue until
total loss of torque delivery was achieved. A typical loss of lubrication failure at this condition is shown
in Figure 7.
Two other tests were conducted at an elevated level of load (~83.6 N*m (740 in*lb)). These two tests,
in the loss-of-lubrication mode, produced failures in 7.9 and 9.2 min. The test temperature data from the
7.9 min loss-of-lubrication test is shown in Figure 8. As can be seen from this data, the temperature did
not reach an increased steady-state condition prior to increasing to failure as it did in the test shown in
Figure 5. After the primary lubrication system was disconnected the temperature just continued to rise.
The post-test condition of the test gears is shown in Figure 9 with the gearbox cover removed.
TABLE 2.—TEST CONDITION STRESS ANALYSIS RESULTS (REF. 10)
Torque Maximum contact stress Maximum bending stress
N*m (in*lb) GPa (ksi) GPa (ksi)
59.3 (525) 1.67 (242) 0.214 (30.9)
83.6 (740) 1.88 (272) 0.296 (43)
Figure 5.—LOL data for 1.72 kPa (250 psi) load pressure ~59.3 N*m (540 in*lb)
torque tested at 10000 rpm.
NASA/TM—2014-218396 5
10. Figure 6.—Post-test condition of the gears (gearbox
cover and outer high temperature glass removed).
Figure 7.—Example of loss-of-lubrication test during final seconds of operation.
NASA/TM—2014-218396 6
11. Figure 8.—Loss-of-lubrication data from higher load test 83.6 N*m (740 in*lb).
Figure 9.—Post-test photograph of increased load test gears with
outer shroud high temperature glass fractured.
NASA/TM—2014-218396 7
12. Instrumented Gear Test
The most desired test for loss-of-lubrication behavior is to have on-component information. While it
would be of great benefit to have instrumentation at the gear-meshing surface, this has been shown to be
very difficult to accomplish. Even with full elastohydrodynamic film the lubricant viscosity of turbine
engine lubricants, as used in rotorcraft drive systems, is insufficient to develop films thick enough to keep
the on-surface instrumentation from wearing away. Therefore, thermocouples were installed at locations
in areas of the gear where contact does not occur were used.
The gear used in these tests is shown in Figure 10. It was the gear installed in the left side of the
gearbox. The left side gear acts as the driving gear of the test section of the facility. A total of five
thermocouples were attached to the gear at the tooth tip mid-face width, root mid-face width, and on the
side of the gear at the pitch radius, root radius and mid-web locations. As shown in Figure 10, the
thermocouple wires were covered by a thin metal foil that was spot welded to the side of the gear to
protect the instrumentation during operation. The rest of the required hardware is shown in Figure 11
prior to installation in the test rig. The assembly in the test rig is shown in Figure 12.
Figure 10.—Instrumented LOL test specimen before testing.
NASA/TM—2014-218396 8
13. Figure 11.—Loss-of-lubrication test specimen and related components.
Figure 12.—Test set up for instrumented test gear.
NASA/TM—2014-218396 9
14. The initial data for warm-up and operation of the facility in the normal to loss-of-lubrication mode is
shown in Figure 13. During this same test the lubricant was shut off and the test run until failure. The data
from loss-of-lubrication initiation to failure for the shroud (static) and other facility thermocouples is
shown in Figure 14.
The data in Figures 13 and 14 indicate that the bulk temperatures of the gear were exceeding the
temperature that was found from the static shroud thermocouples. In the normal lubrication condition this
value was 20 to 40 F depending on the location. In the loss-of-lubrication mode, this amount was as high
as 500 F higher on the gear than that of the static shroud thermocouples. In Figure 13, the data beyond
8200 sec is believed to be invalid due to post-test inspection of the thermocouple wiring that was melted
together at the common locations through the shaft. The thermocouple wiring coating was exposed to
bulk temperatures in the gear beyond the melting point of the wire coating.
Figure 13.—On-gear and out-of-mesh thermocouple data from star-up to
instrumentation failure during loss-of-lubrication.
Figure 14.—Data from shroud and facility (static) thermocouples.
NASA/TM—2014-218396 10
15. The post-test condition of the gears used in this test is shown in Figure 15. What can be noted is that a
bending failure occurred before the loss-of-lubrication test, as the failed tooth has no evidence of running
in this post-test condition. A hypothesis is that the failed tooth was initiated by a spot weld in the root-fillet
region from the thin metal protection strap that was used to cover the thermocouple wiring.
In Figure 16, the tooth that failed in bending shows no apparent damage due to loss-of-lubrication
since it occurred before this lubrication condition was initiated. Upon closer examination, the thin metal
strapping used to overcoat the wiring and spot-welded to the tooth, was found to be the initiation site of
the bending failure. Future test hardware for this purpose will not have this as a hold-down feature for the
tooth root-fillet area.
Figure 15.—Post-test condition after loss-of-lubrication test was completed.
Gearbox housing, slip ring and outer high temperature glass removed.
Figure 16.—Instrumented spur gear post-loss-of-lubrication test condition.
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16. Conclusions
A series of five loss-of-lubrication tests were conducted in an aerospace simulated environment using
consistent sets of test hardware. The following is a summary of the test results:
1. Applied torque can have a drastic effect on loss-of-lubrication time. An increase of torque by
40 percent, 59.3 to 83.6 N*m (525 to 740 in.-lbs) resulted in a decrease in loss-of-lubrication
operation time by 75 percent (42 to 8 min).
2. Operation in loss-of-lubrication mode at lower torque produced an elevated steady state temperature
condition. The higher torque level did not have this operating time at an elevated steady state
temperature condition. During the higher torque tests, the temperature continued to increase until
failure of the teeth.
3. On-component thermocouple data revealed that the gear under normal conditions have bulk
temperatures that are 20 to 40 F higher than the fling-off temperatures measured by the static shroud
thermocouples.
4. On-component thermocouple data indicated that during loss-of-lubrication, conditions bulk
temperatures on the gear are from 150 to 500 F higher at certain times during this test mode when
compared to the static shroud temperatures.
References
1. ADS-50-PRF, Aeronautical Design Standard, Rotorcraft Propulsion Performance and Qualification
Requirements and Guidelines, U. S. Army Aviation Troop Command, April, 1996.
2. Handschuh, R.: Thermal Behavior of Spiral Bevel Gears, NASA–TM-106518, ARL-TR-403,
January 1995.
3. Morales, W. and Handschuh, R.: A Preliminary Study on the Vapor/Mist Phase Lubrication of a
Spur Gearbox NASA TM-1999-208833, February 1999.
4. Morales, W., Handschuh, R., and Krantz, T.: Feasibility Study of Vapor-Mist Phase Reaction
Lubrication Using a Thioether Liquid, NASA/TM—2007-215035, December 2007.
5. Handschuh, R., Polly, J., and Morales, W.: Gear Mesh Loss-of-Lubrication Experiments and
Analytical Simulation, NASA/TM—2011-217106, November 2011.
6. Oswald, F.: Mechanical Components Branch Test Facilities and Capabilities, NASA/TM—2004-
212722, January 2004.
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Viscosity and Additives on Gear Wear, NASA/TM—2005-213956, ARL-TR-3126, October 2005.
8. Krantz, T.: The Influence of Roughness on Gear Surface Fatigue, NASA/TM—2005-213958,
October, 2005.
9. Pyrowear Alloy 53, Carpenter Technology Corporation, AMS 6308B.
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OH, February 2005.
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