Coupled Euler-Lagrange simulations of metal fragmentation in pipe bomb configurations.
Abstract not provided.
Gullerud, Arne S.↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Effects of the legacy pipe ends on the behaviour of pipe-in-pipe repair systems under internal pressure
Not Available
42 ENGINEERING↗
Characterization and Remediation of the Hanford 618-10 Burial Ground Steel-pipe Vertical Pipe Units - 18238
The 618-10 Burial Ground is approximately 485 feet by 470 feet and consisted of 12 trenches and 94 VPUs. It is located approximately 5 miles north of Richland, Washington in the 600 Area of the Hanford Site. The 618-10 Burial Ground received low- to high-activity waste (e.g., fission products and some plutonium-contaminated waste). Most of the waste originated at the 300 Area laboratory facilities. Lower activity radioactive material and shielded drums were disposed in trenches, while laboratory wastes with higher levels of radiation were disposed in Vertical Pipe Units (VPUs). The 618-10 Burial Ground contained approximately 94 VPUs (uncertain mix of first and second generation). There are different variants of VPUs. The first generation of VPUs was simply corrugated culverts or standard pipes, 14-in diameter and 10- to 15-ft long, buried vertically. The second generation of VPUs was 22-in diameter, 15-ft long waste receptacles constructed by welding five 55-gallon bottomless drums together end-to-end and burying them vertically, separated by approximately 10 feet on center in rows approximately 25 feet apart. A subset of the first generation VPUs consisted of the steel pipe VPUs represented by carbon-steel pipes, 10 to 24 in. in diameter with various wall thicknesses. This paper will present the remediation of the steel-pipe VPUs, which were the last of the VPUs remediated in this project. The remediation process developed for steel pipe VPUs included exposing a section of the VPU within an excavated trench, placing a mix box around the VPU, filling the mix box with grout, shearing the VPU and contents, and then removing the grout waste mixture into a waste box for disposal at the Hanford Environmental Restoration Disposal Facility (ERDF). Prior the start of remedial activities extensive mock-ups were performed on surrogate steel-pipe VPUs to ensure the effectiveness of the process before introducing the hazards of radioactive VPU waste. The critical steps in the process of size reducing steel-pipe VPUs and mixing the contents with grout was successfully demonstrated. This process was completed for each steel-pipe VPU in successive lifts until the entire set of steel-pipe VPUs were mixed in grout and removed from the excavation. The remediation of the steel-pipe VPUs proved be successful in that all the VPUs were removed and transported to ERDF without a release to the local environment. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
A CONDUCTION-BASED HEAT PIPE MODEL FOR ANALYZING THE ENTIRE PROCESS OF LIQUID-METAL HEAT PIPE STARTUP
The Heat Pipe-cooled Microreactor (HPM) is one of the micro nuclear reactor designs under active study at the U.S. Idaho National Laboratory. Among the major concerns of HPM research is to understand the startup behavior of the heat pipe-cooled system associated with the startup of the liquid-metal heat pipes initialing from frozen state. The startup of liquid-metal heat pipes typically involves a number of nonlinear mass and heat transport processes including the phase change from solid to liquid and vapor. Hence, it is still a huge challenge to simulate the liquid-metal heat pipe startup using conventional CFD methods and software. The major difficulties of numerical CFD modeling come from the phase-change process, multiphase interaction, microporous wick flow, and compressible gas dynamics that occur during startup of the liquid-metal heat pipes. This paper proposes a simplified conduction-based method to provide practical insights into the entire startup process of the liquid-metal heat pipes while mitigating the challenges of addressing all the complex physics. We discuss the theoretical basis and modeling assumptions to analyze the liquid-metal heat pipe startup from frozen state based solely on heat-conduction equations. Then, the proposed model is implemented into the commercial CFD software to verify the model performance. The model prediction results are discussed via the comparison with the experimental data obtained from sodium heat-pipe startup experiments.
42 ENGINEERING↗
Thermal Performance of High Temperature Titanium -- Water Heat Pipes by Multiple Heat Pipe Manufacturers
Titanium - water heat pipes are being investigated for use in heat rejection systems for lunar and Mars fission surface power systems. Heat pipes provide an efficient and reliable means to transfer heat to a radiator heat rejection system. NASA Glenn Research Center requisitioned nine titanium water heat pipes from three vendors. Each vendor supplied three heat pipes 1.25 cm diameter by 1.1 meter long with each vendor selecting a different wick design. Each of the three heat pipes is slightly different in construction. Additional specifications for the heat pipes included 500 K nominal operating temperature, light weight, and freeze tolerance. The heat pipes were performance tested gravity-aided, in the horizontal position and at elevations against gravity at 450 K and 500 K. Performance of the three heat pipes is compared. The heat pipe data will be used to verify models of heat pipe radiators that will be used in future space exploration missions.
Sanzi, James L.↗
Thermal Performance of High Temperature Titanium-Water Heat Pipes by Multiple Heat Pipe Manufacturers
Titanium-water heat pipes are being investigated for use in heat rejection systems for lunar and Mars fission surface power systems. Heat pipes provide an efficient and reliable means to transfer heat to a radiator heat rejection system. NASA Glenn Research Center requisitioned nine titanium water heat pipes from three vendors. Each vendor supplied three heat pipes 1.25 cm diameter by 1.1 meter long with each vendor selecting a different wick design. Each of the three heat pipes is slightly different in construction. Additional specifications for the heat pipes included 500 K nominal operating temperature, light weight, and freeze tolerance. The heat pipes were performance tested gravity-aided, in the horizontal position and at elevations against gravity at 450 and 500 K. Performance of the three heat pipes is compared. The heat pipe data will be used to verify models of heat pipe radiators that will be used in future space exploration missions.
Sanzi, James L.↗
Fabrication and testing of tungsten heat pipes for heat pipe cooled reactors.
The choice of chemically vapor deposited (CVD) tungsten as material for the heat pipes is based on studies reported by Busse et al. (1970). Aspects of pipe construction are discussed together with wick construction, and heat pipe operation. An auxiliary heater was used to overcome problems during the start of operation in the case of a thermally loaded pipe. Two heat pipes were operated at temperatures up to 1850 K. Annular and channeled wicks were investigated. The design of a cross flow heat exchanger is presented together with the design of a reactor heat pipe life test station.
Bacigalupi, R. J.↗
Vapor-modulated heat pipe report. Flight data analysis and further development of variable-conductance heat pipes
The design and testing of a heat pipe for spacecraft application is presented. The application in mind calls for heat loads up to 20 watts, a set-point temperature of 294K, and a sink that varies from -220K to nearly as high as the set-point. The overall heat pipe length is 137 cm. Two basically different mechanisms of achieving variable conductance in the pipe by vapor-flow throttling were studied. In one, the thermal resistance between the heat source and sink is due to a saturation-temperature drop corresponding to the vapor-pressure drop developed across the valve. In the other, the pressure difference across the valve induces capillary groove and wick dry out in an evaporation region, and thus results in an increased thermal resistance. This mechanism was selected for fabrication and testing. The pipe is a stainless-steel/methanol two-heat-pipe system. Results are presented and discussed. Engineering drawings and specifications of the pipe are shown.
Eninger, J. E.↗
Novel Radiometry for In-Pipe Robotic Inspection of Holdup Deposits in Gaseous Diffusion Piping - 19503
This paper details the first complete, DOE approved, deployed and operational radiometry for robotic nondestructive assay (NDA) of holdup deposits in gaseous diffusion piping. Some features, like peak-finding, Compton correction, detector efficiency, and material properties are characteristic of typical manual methods. Most features are specific to in-pipe robotic deployment. These include in-motion radiometry, self-determined location, geometric modeling of thick deposits, bounding of self-attenuation thickness and auto-checking of replicate measurements. Significant are the means for determining all the properties, equations, and constants for automatically computing and displaying all the quantities, uncertainties and information needed for NDA reporting, analysis, and review. Earlier work by this team demonstrated rudimentary but convincing robotic in-pipe NDA of holdup deposits in pipes. Cold testing with high-enrichment mat sources and hot tests with low U-235 loadings together succeeded to exhibit convincing proof-of-principle. This research-grade radiometry implementation lacked accurate odometry, efficiency calibration, high-fidelity detector modeling, attenuation modeling, forward geometric modeling, auto-segmenting, uncertainty modeling, replicate checking, deconvolution and much more. This work explains the technical basis behind robotic in-pipe NDA. It includes discussion of a new method for modeling of self-attenuation using in-pipe deposit geometry information, detail of the method's total measurement uncertainty, and explanation of calibration methods and results. Beyond development of automation-specific radiometric elements, the paper highlights analyses, testing, and technical bases specific to and supportive of the methodology. Examples include collimation characterization, detector efficiency determination, auto-calibration methodology, and odometric replicate-checking. Results of this methodology are formalized in a DOE EM Technical Basis Document, implemented in software, formally verified in review and acceptance testing and proceduralized as a means for D and D NDA at the Portsmouth enrichment facility. Measurement of U-235 quantity is a well-known cost and schedule driver in D and D of every defunct gaseous diffusion enrichment facility in the world. The radiometry methodologies and results detailed in this paper were the high hurdles. Having established the technical basis for this automated NDA, the opportunity is to apply this to many sizes and robot forms for addressing holdup deposit NDA throughout the D and D community. (authors)
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
Studies of the influence of heat pipe model and coupling strategy in heat pipe microreactor simulations using Sockeye
This work demonstrates various modeling approaches for thermally coupling heat pipes to a graphite monolithic block in a microreactor context, accounting for the presence of a gap. We show that heat pipe model selection has a significant impact on the transient behavior of a three-dimensional coupled microreactor assembly problem by comparing results obtained using different heat pipe models from the heat pipe code Sockeye. Additionally, we show that the choice of coupling strategy has significant consequences for both accuracy and performance. Furthermore, we found that our heat flux transfer strategy exhibited greater accuracy than our temperature transfer strategy, even when comparing a loose coupling of the heat flux transfer strategy to a tight coupling of the temperature transfer strategy. Although this research uses only theoretical test problems, it provides important insights in modeling thermal fluids phenomena in heat pipe microreactors.
Direwolf↗
Design guidelines for avoiding thermo-acoustic oscillations in helium piping systems
Thermo-acoustic oscillations are a commonly observed phenomenon in helium cryogenic systems, especially in tubes connecting hot and cold areas. The open ends of these tubes are connected to the lower temperature (typically at 4.2 K), and the closed ends of these tubes are connected to the high temperature (300K). Cryogenic instrumentation installations provide ideal conditions for these oscillations to occur due to the steep temperature gradient along the tubing. These oscillations create errors in measurements as well as an undesirable heat load to the system. The work presented here develops engineering guidelines to design oscillation-free helium piping. This work also studies the effect of different piping inserts and shows how the proper geometrical combinations have to be chosen to avoid thermo-oscillations. The effect of an 80 K intercept is also studied and shows that thermo-oscillations can be dampened by placing the intercept at an appropriate location.
43 PARTICLE ACCELERATORS↗
Pipe-in-Pipe by Rapid, Continuous, Smart Alloy Coating
Our team has developed a comprehensive solution for performing in-situ structural repairs on metal piping and pipelines. This is based on a multifaceted and integrated (experimental and computational) approach, that uses a slurry-based coating and our patented high temperature sintering process, to build new metal in a pipe-in-pipe configuration. This can be utilized in either a complete pipe-in-pipe embodiment, or for patch repairs.
42 ENGINEERING↗
Reusable high-temperature heat pipes and heat pipe panels
A reusable, durable heat pipe which is capable of operating at temperatures up to about 3000 F in an oxidizing environment and at temperatures above 3000 F in an inert or vacuum environment is produced by embedding a refractory metal pipe within a carbon-carbon composite structure. A reusable, durable heat pipe panel is made from an array of refractory-metal pipes spaced from each other. The reusable, durable, heat-pipe is employed to fabricate a hypersonic vehicle leading edge and nose cap.
Camarda, Charles J.↗
Thermal Management System for an Electric Machine with Additively Manufactured Hollow Conductors with Integrated Heat Pipes: Preprint
This paper discusses steps taken to size a thermal management system for an aircraft propulsion electric machine containing additively manufactured coils integrated with heat pipes aimed at boosting its specific power. Experimental setups are used to size and characterize heat pipes for the application and 3D thermal FEA is used to determine optimum heat transfer coefficient of convective boundaries. Geometric details of fin-based surface area enhancement required to reach target combined overall heat transfer coefficient (U) and surface area (A) performance (UA) in W/K, is worked out for relevant boundaries and the resulting UA is verified in 3D thermal FEA. Thermal management system's UA (by extension specific power) sensitivity to coolant temperature is explored and temperature distribution plots of optimized machine components are presented and discussed.
additive manufacturing↗
Composite heat pipe development status: Development of lightweight prototype carbon-carbon heat pipe with integral fins and metal foil liner
This report discusses development and proof-of-concept testing of a new lightweight carbon-carbon (C-C) space radiator heat pipe, carried out under the NASA Civil Space Technology Initiative (CSTI) High Capacity Power Program. The prototype heat pipe, equipped with a niobium-zirconium foil liner, was filled with potassium working fluid and tested for 11 hours, including startup from ambient temperature with the working fluid initially in the frozen state to near 700 K condenser temperature. Steady-state heat pipe input power during testing was facility limited to about 300 watts. Post test inspection showed the heat pipe to be in excellent condition after eight thermal cycles from ambient to steady-state operating temperature. Utilization of other liner materials and working fluids would greatly extend the spectrum of service temperatures for this technology, with potential applications ranging from small spacecraft heat rejection to aircraft and terrestrial uses.
Juhasz, Albert J.↗
A broadly-applicable unified closure relation for Taylor bubble rise velocity in pipes with stagnant liquid
Taylor bubble velocity in slug flow is a closure relation which significantly affects the prediction of liquid holdup (or void fraction) and pressure gradient in mechanistic models of slug flow for oil and gas pipe applications. In this work, we use a validated Computational Fluid Dynamics (CFD) approach to simulate the motion of Taylor bubbles in pipes; the interface is tracked with a Level-Set method implemented in a commercial code. A large numerical database is generated covering the most ample range of fluid properties and pipe inclination angles explored to date (Eo ∊ [10, 700],Mo ∊ [1 x 10 -6 , 5 x 10 3 , and θ ∊ [0°, 90°]). A unified Taylor bubble rise velocity correlation is extracted from that database. The new correlation predicts the numerical database with 8.6% absolute average relative error and a coefficient of determination R 2 = 0.97 and other available experimental data with 13.0% absolute average relative error and R 2 = 0.84 outperforming existing correlations and models.
Mechanics↗
Classification of Methane Emissions from Industrial Meters, Vintage vs Modern Plastic Pipe, and Plastic-lined Steel and Cast-Iron Pipe (Final Report)
The project focus was to improve the characterization of methane (CH 4 ) emissions currently detailed in the U.S. Environmental Protection Agency (EPA) Greenhouse Gas Inventory (GHGI) for categories of assets within the Natural Gas (NG) distribution system to isolate what is driving inflation or deflation behind current, nationwide, aggregated Emission Factors (EFs). These specific categories included industrial/commercial NG customer meters, modern and vintage plastic pipe, along with plastic-lined steel and cast-iron pipe. CH 4 emission rate data was gathered during 25 sampling campaigns at industrial/commercial meter sites, vintage and modern plastic pipe sites, as well as plastic-lined steel and cast-iron sites located within NG distribution networks.
03 NATURAL GAS↗