196 research outputs found
Improvement of Quality in Publication of Experimental Thermophysical Property Data: Challenges, Assessment Tools, Global Implementation, and Online Support
Article on the improvement of quality in the publication of experimental thermophysical property data
Aerocapture Systems Analysis for a Titan Mission
Performance projections for aerocapture show a vehicle mass savings of between 40 and 80%, dependent on destination, for an aerocapture vehicle compared to an all-propulsive chemical vehicle. In addition aerocapture is applicable to multiple planetary exploration destinations of interest to NASA. The 2001 NASA In-Space Propulsion Program (ISP) technology prioritization effort identified aerocapture as one of the top three propulsion technologies for solar system exploration missions. An additional finding was that aerocapture needed a better system definition and that supporting technology gaps needed to be identified. Consequently, the ISP program sponsored an aerocapture systems analysis effort that was completed in 2002. The focus of the effort was on aerocapture at Titan with a rigid aeroshell system. Titan was selected as the initial destination for the study due to potential interest in a follow-on mission to Cassini/Huygens. Aerocapture is feasible, and the performance is adequate, for the Titan mission and it can deliver 2.4 times more mass to Titan than an all-propulsive system for the same launch vehicle
Summaries of FY 1997 Research in the Chemical Sciences
The objective of this program is to expand, through support of basic research, knowledge of various areas of chemistry, physics and chemical engineering with a goal of contributing to new or improved processes for developing and using domestic energy resources in an efficient and environmentally sound manner. Each team of the Division of Chemical Sciences, Fundamental Interactions and Molecular Processes, is divided into programs that cover the various disciplines. Disciplinary areas where research is supported include atomic, molecular, and optical physics; physical, inorganic, and organic chemistry; chemical energy, chemical physics; photochemistry; radiation chemistry; analytical chemistry; separations science; heavy element chemistry; chemical engineering sciences; and advanced battery research. However, traditional disciplinary boundaries should not be considered barriers, and multi-disciplinary efforts are encouraged. In addition, the program supports several major scientific user facilities. The following summaries describe the programs
Ultra-high temperature concentrated solar thermal energy
Given the extremely high surface temperature of the Sun (~5778 K), solar radiation has the theoretical potential, in accordance with the second law of thermodynamics, to heat a receiver on Earth up to ultra-high temperatures (specified in this thesis as >1300 K). However, there is a gap between theory and practice, as contemporary solar thermal energy systems are still limited to temperatures below 900 K due to material and mechanical limitations. Running solar thermal energy at ultra-high temperatures promises greater energy conversion efficiencies for power plants by upgrading their basic cycles to include more advanced power cycles. Furthermore, the provision of solar thermal energy at ultra-high temperatures can unlock a wide range of energy-intensive industrial applications, including hydrogen and cement production, which can contribute to decarbonising sectors which are difficult to electrify.
This thesis proposes a novel concept of an ultra-high temperature solar cavity receiver based on an optically exposed liquid metal heat transfer fluid, which flows down a corrugated back plate. The concept is investigated using a quasi-steady-state analytical energy model, in addition to a radiation-coupled Computational Fluid Dynamics (CFD) solution. The developed analysis methods are tailored to the proposed class of receivers, nonetheless, they can be generalised for broad solar receiver analysis or for analysing similar problems involving volumetric radiation absorption in other thermal applications. The concept is shown implementable at its absorptive cavity configuration with an overall (optical and thermal) receiver efficiency exceeding 70%. The proposed concept is a step towards narrowing the technological mismatch, in terms of temperature and scale, between state-of-the-art thermal energy storage and concentrated solar thermal at ultra-high temperatures.
A characterisation of prospective ultra-high temperature receivers is presented, which involved a review of state-of-the-art solar thermal technologies with the purpose of identifying the existing challenges to operating at ultra-high temperatures. Based on this characterisation, the proposed receiver is designed to address the literature concerns. The proposed receiver concept involved novel engineering features, including the use of refractory containment materials and a transparent ceramic window to seal the aperture. Therefore, the conceptual investigation attempted to address possible concerns that might be introduced by the new features. Finally, the proposed receiver is demonstrated in a concentrated solar power plant application to emphasise, using quantitative terms, the benefits of operating the receiver at ultra-high temperatures for large-scale applications
NASA SBIR abstracts of 1991 phase 1 projects
The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included
NASA thesaurus. Volume 1: Hierarchical Listing
There are over 17,000 postable terms and nearly 4,000 nonpostable terms approved for use in the NASA scientific and technical information system in the Hierarchical Listing of the NASA Thesaurus. The generic structure is presented for many terms. The broader term and narrower term relationships are shown in an indented fashion that illustrates the generic structure better than the more widely used BT and NT listings. Related terms are generously applied, thus enhancing the usefulness of the Hierarchical Listing. Greater access to the Hierarchical Listing may be achieved with the collateral use of Volume 2 - Access Vocabulary and Volume 3 - Definitions
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Rational Fuel Design for Low Temperature Internal Combustion Engines
This work introduces a new methodology to design transportation fuels offering improved efficiency and reduced emissions, aimed to complement both traditional and emerging engine technologies. Many of these emerging technologies are centered around exploiting low temperature combustion (LTC) strategies that offer improved efficiency and reduced emissions. However, a standardized fuel does not exist to effectively operate in a LTC mode. Through engine simulations, supervised machine learning, and multivariate optimization, this work provides a tool to create fuels tailored to a specific LTC engine application. Engine simulations in this work characterize the LTC performance for hundreds of fuel samples, quantified by a fuel performance metric called the LTC index. Supervised machine learning provides correlations between measured fuel infrared absorbance spectra to various fuel performance metrics: the LTC index, Research Octane Number (RON) and Motor Octane Number (MON). The predictive models of these metrics circumvent the need for costly and time consuming engine experiments to explore the performance of uncharacterized fuels.
The success of this work is heavily reliant on the ability of the models to make accurate predictions of the fuel performance metrics, viz. the LTC index, which is assessed through two efforts. The first effort is generating a robust validation data set to benchmark model predictive performance. Here, multivariate optimization is also used to create surrogates for the FACE gasolines. These surrogates are paired with engine simulations to determine the true LTC index and compare to predicted values. LTC indices of most FACE gasolines are found to be accurately predicted within 3 units, and at worst within 6. The second effort toward predictive model validation is a novel experimental campaign, measuring first and second-stage fuel-spray ignition delays in a constant volume combustion chamber (CVCC). The novelty comes by using ultra-short injections to enhance mixing prior to ignition phenomena, quantified by a state-of-the-art optical diagnostic---developed in this work---that images spatiotemporal fuel-spray concentrations. The mixture data are compared to a spray-ignition model with simplified fluid mechanics, found to capture spray mixing exceedingly well. The validated spray physical model is paired with a comprehensive chemical mechanism to predict and compare to experimentally-obtained spray-ignition onsets, thereby establishing a novel way to assess the accuracy of chemical mechanisms and surrogate fuels.
The validated LTC index predictive model is finally paired with multivariate optimization techniques to design a fuel tailored to a dual mode engine. In theory, this engine would operate in LTC mode where possible for efficiency improvements, and switch to traditional spark-ignition where needed. The tools developed in this work simultaneously point fuel and vehicle technology in a unique direction for designing high efficiency, next-generation combustion systems
New Perspectives on Geothermal Energy Exploration and Evaluation of Geothermal Potential
This book describes interesting case studies of the exploration, characterization, and use of geothermal resources in Spain, Sweden, Italy, Croatia, China, Djibouti, and Canada. A new open-source software, with an easy-to-use graphical user interface, is applied to assess the deep geothermal potential of the Reus-Valls sedimentary basin in Spain. Then, a high-temperature borehole thermal energy storage facility at Linköping, Sweden, is described to shift excess heat generated from a waste incineration plant during the summer to the winter season. Next, a plastic plate heat exchanger was geometrically and thermodynamically modeled, optimized, and applied to a direct geothermal heating system for a building in Southern Italy. In the last European study, in Croatia, an unconventional hydrocarbon gas reservoir is analyzed (geothermal gradient of 49°C/km), in the geothermal field Velika Ciglena. Going down to Africa, the assessment of the geothermal resources in the Asal Rift (Djibouti) through multiphase flow and heat transfer simulations is presented. Moving to Asia, in the Chinese province of Guangdong, magnetotelluric profiles are used to interpret the crust and upper mantle structure and its geothermal implications. Then, in the remote Canadian Northern regions, uncertainty and risk evaluation of deep geothermal energy resources (> 4 km) for heat production and electricity generation are described. Finally, a literature review provides a comparison of geothermal projects in unconventional reservoirs in United Kingdom (Cornubian Batholith), Canada (Williston Sedimentary Basin), and Italy (Campi Flegrei Caldera)
Sustainable energy for a resilient future: proceedings of the 14th International Conference on Sustainable Energy Technologies
Volume I, 898 pages, ISBN 9780853583134
Energy Technologies & Renewables
Session 1: Biofuels & Biomass
Session 5: Building Energy Systems
Session 9: Low-carbon/ Low-energy Technologies
Session 13: Biomass Systems
Session 16: Solar Energy
Session 17: Biomass & Biofuels
Session 20: Solar Energy
Session 21: Solar Energy
Session 22: Solar Energy
Session 25: Building Energy Technologies
Session 26: Solar Energy
Session 29: Low-carbon/ Low-energy Technologies
Session 32: Heat Pumps
Session 33: Low-carbon/ Low-energy Technologies
Session 36: Low-carbon/ Low-energy Technologies
Poster Session A
Poster Session B
Poster Session C
Poster Session E
Volume II, 644 pages, ISBN 9780853583141
Energy Storage & Conversion
Session 2: Heating and Cooling Systems
Session 6: Heating and Cooling Systems
Session 10: Ventilation and Air Conditioning
Session 14: Smart and Responsive Buildings
Session 18: Phase Change Materials
Session 23: Smart and Responsive Buildings
Session 30: Heating and Cooling System
Session 34: Carbon Sequestration
Poster Session A
Poster Session C
Poster Session D
Policies & Management
Session 4: Environmental Issues and the Public
Session 8: Energy and Environment Security
Session 12: Energy and Environment Policies
Poster Session A
Poster Session D
Volume III, 642 pages, ISBN 9780853583158
Sustainable Cities & Environment
Session 3: Sustainable and Resilient Cities
Session 7: Energy Demand and Use Optimization
Session 11: Energy Efficiency in Buildings
Session 15: Green and Sustainable Buildings
Session 19: Green Buildings and Materials
Session 24: Energy Efficiency in Buildings
Session 27: Energy Efficiency in Buildings
Session 28: Energy Efficiency in Buildings
Session 31: Energy Efficiency in Buildings
Session 35: Energy Efficiency in Buildings
Poster Session A
Poster Session D
Poster Session
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