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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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At least 19 records

Markets and Economics for Thermal Power Extraction from Nuclear Power Plants Aiding the Decarbonization of Industrial Processes

This report analyzes the domestic industrial heat markets which may be plausible for using heat extracted from existing LWRs, contributing to the decarbonization of industry. It conceptualizes ideas for a future energy park centered around an LWR with various participating synergistic industries with extensive heat and material integrations with the LWR. It also presents comparison calculations for energy storage options and the levelized cost of heat from an LWR versus the levelized cost of heat from a conventional natural gas boiler and shows under what circumstances heat from LWRs is competitive with and beats natural gas.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Investigations into Balancing Peak-to-Average Power Ratio and Mean Power Extraction for a Two-Body Point-Absorber Wave Energy Converter

The power harnessed by wave energy converters (WECs) in oceans is highly variable and, therefore, has a high peak-to-average power (PTAP) ratio. To minimize the cost of a WEC power take off (PTO) system, it is desirable to reduce the PTAP ratio while maximizing the mean power extracted by WECs. The important issue of how PTAP ratio reduction measures (such as adding an inertia element) can affect the mean power extracted in a reference model has not been thoroughly addressed in the literature. To investigate this correlation, this study focuses on the integration of the U.S. Department of Energy’s Reference Model 3, a two-body point absorber, with a slider-crank WEC for linear-to-rotational conversion. In the first phase of this study, a full-scale numerical model was developed that predicts how PTO system parameters, along with an advanced control algorithm, can potentially affect the proposed WEC’s PTAP ratio as well as the mean power extracted. In the second phase, an appropriate scaled-down model was developed, and extracted power results were successfully validated against the full-scale model. Finally, numerical and hardware-in-the-loop (HIL) simulations based on the scaled-down model were designed and conducted to optimize or make trade-offs between the operational performance and PTAP ratio. The initial results with numerical and HIL simulations reveal that gear ratio, crank radius, and generator parameters substantially impact the PTAP ratio and mean power extracted.

16 TIDAL AND WAVE POWER↗

Utilizing Electrical Power Extraction for Stability Bleed Reduction within Gas Turbine Engines

This paper studies the role of power extraction in gas turbine stability and how an engine may be designed to utilize this extraction to replace engine stability bleed requirements with electrical system requirements. The considered engine architecture contains two engine spools and a power turbine spool. In the baseline, low-pressure compressor stall margin is maintained by bleed air from the back of the low-pressure compressor, which is then dumped to the bypass. Power extraction from the high-pressure and low-pressure shafts are then utilized as a replacement for this bleed. This study considers component performance, sizing, efficiency, and operability, but does not consider weight or cost. Analysis within this paper is general and the concepts could be applied to other dual spool engine types, including a turbofan. Results show it is possible to completely remove the stability bleed between the low pressure and high-pressure compressor by utilizing a 35% power extraction from the high-pressure shaft or a 1.5% power extraction from the low-pressure turbine.

Gas Turbine↗

Utilizing Electrical Power Extraction for Stability Bleed Reduction within Gas Turbine Engines

This paper studies the role of power extraction in gas turbine stability and how an engine may be designed to utilize this extraction to replace engine stability bleed requirements with electrical system requirements. The considered engine architecture contains two engine spools and a power turbine spool. In the baseline, low-pressure compressor stall margin is maintained by bleed air from the back of the low-pressure compressor, which is then dumped to the bypass. Power extraction from the high-pressure and low-pressure shafts are then utilized as a replacement for this bleed. This study considers component performance, sizing, efficiency, and operability, but does not consider weight or cost. Analysis within this paper is general and the concepts could be applied to other dual spool engine types, including a turbofan. Results show it is possible to completely remove the stability bleed between the low pressure and high-pressure compressor by utilizing a 35% power extraction from the high-pressure shaft or a 1.5% power extraction from the low-pressure turbine.

Gas Turbine↗

Turbofan Engine Power Extraction Demonstration Final Report

As GE Aerospace advances toward a revolutionary step change in propulsion efficiency, the integration and demonstration of new engine architectures and technology systems are essential. The NASA Turbofan Engine Power Extraction Demonstration (PEx), conducted through the Hybrid Thermally Efficient Core (HyTEC) project, aims to develop and demonstrate megawatt-class hybrid electric capability on a modern commercial turbofan engine. The hybrid electric system is critical to meeting the needs of the U.S. aviation industry for next-generational propulsion systems with greater efficiency, durability, and range. This supports energy independence and helps ensure the security and resilience of one of America's largest export industries. The PEx project specifically targets three key objectives: mechanically integrating hybrid electric capability into a commercial turbofan engine, integrating electric machine control with turbofan control for advanced power management, and de-risking performance modeling of future hybrid electric architectures. To mature these technologies to Technology Readiness Level (TRL) 6, a series of electric power system component tests and a baseline engine performance test campaign were conducted. These efforts culminated in an integrated hybrid electric turbofan test campaign demonstrating power extraction, power insertion, and power transfer between spools. Tests of the electric power system were completed at GE Aerospace’s Electrical Power Integrated Systems Center in Dayton, Ohio and engine tests were completed at Peebles Test Operation in Peebles, Ohio. Hybrid electric trade studies extended the demonstrated capability to altitude using the validated cycle model from the PEx test campaigns, allowing for comments on expanded mission benefits not demonstrated in the ground campaign. The knowledge gained from PEx also supports GE Aerospace’s Compact Core Demonstrator as part of HyTEC Phase 2 and ultimately informs the implementation of hybrid electric systems in the next generation of GE Aerospace commercial engine products. This report provides a summary of the program background, test campaigns, trade studies, and insights into the technical maturation required to support future commercial products.

Hybrid Electric↗

A Study of Large Scale Power Extraction and Insertion on Turbofan Performance and Stability

This describes the effects of turbofan power extraction and insertion (augmentation) on engine performance and stability. The purpose of this paper is to present how power augmentation affects a dual spool gas turbine engine cycle where the engine will also be required to provide thrust. The goals for the paper are to describe effective limits of power augmentation and offer strategies, utilizing spool choice and variable geometries, to maximize augmentation effect. While Analysis is general, two potential uses are explored: Power extraction for electrified aircraft propulsion and power insertion for thrust assist. Results of the paper show it is possible to extract over 20% (at 85% max thrust) and gain roughly 12% of maximum thrust through power insertion.

Gas Turbine engines↗

A Study of Large-Scale Power Extraction and Insertion on Turbofan Performance and Stability

This paper describes the effects of turbofan power extraction and insertion (augmentation) on engine performance and stability. The purpose of this paper is to present how power augmentation affects a dual spool gas turbine engine cycle where the engine will also be required to provide thrust. The goals for the paper are to describe effective limits of power augmentation and offer strategies, utilizing spool choice and variable geometries, to maximize augmentation effect. While Analysis is general, two potential uses are explored: Power extraction for electrified aircraft propulsion and power insertion for thrust assist. Results of the paper show it is possible to extract over 20% (at 85% max thrust) and gain roughly 12% of maximum thrust through power insertion.

Gas Turbine engines↗

A Study of Large Scale Power Extraction and Insertion on Turbofan Performance and Stability

This paper describes the effects of turbofan power extraction and insertion (augmentation) on engine performance and stability. The purpose of this paper is to present how power augmentation affects a dual spool gas turbine engine cycle where the engine will also be required to provide thrust. The goals for the paper are to describe effective limits of power augmentation and offer strategies, utilizing spool choice and variable geometries, to maximize augmentation effect. While Analysis is general two potential uses are explored: Power extraction for electrified aircraft propulsion purposes. And, Power insertion for thrust assist. Results of the paper show it is possible to extract over 20% (at 85% max thrust) and gain roughly 12% of maximum thrust through power insertion.

Gas Turbine Engines↗

Pulse Detonation Engine for Advanced Oxy-Combustion of Coal-Based Fuel for Direct Power Extraction Applications

Pressure gain combustion and magnetohydrodynamic (MHD) systems have the potential to provide a step increase in the efficiency of combined-cycle power plants. Specific advantages include a net pressure increase to the system instead of a pressure drop, the high temperature of the detonation waves can increase the efficiency of power extraction compared to other processes, significant thermal energy can be released in a compact region, and the high velocities of the flow increase extraction of electrical power. In summary, a pressure gain combustor coupled with a MHD has the potential to be transformative. Despite the potential advantages, relatively little research has been conducted considering coupled pressure gain combustion systems with MHD systems. With this background and motivation, the overall goal of this effort was to advance the knowledge, technology, and computational tools associated with coupled detonation and MHD systems. A joint experimental and computational approach was used while seeking to accomplish the goals of this work. Specifically, two pulse detonation engines were developed and used for the experiments to produce detonations. Detonation speeds were measured for a variety of flow and fuel conditions (e.g., methane, propane, with coal particles). Preliminary electrical conductivity measurements were collected. An extensive amount of research was performed to identify sensitivities of detonation behaviors to the presence of combustion products. Computationally, a twofold approach was used in this work. First, a solver was developed for solving the governing equations for a reactive flow with coupled detonation and ionization chemistry. The solver was applied to study the impacts of seed material ionization on detonation. Second, a conservation element-solution element (CE-SE) based numerical solver for detonation studies with a reduced reaction mechanism for oxy-methane combustion was developed and verified on standard test cases. Key findings and contributions from this work are as follows. A system was developed for injecting powderized coal, or other seeding material, into a pulse-detonation system. The influence of a combustion product (i.e., CO 2 ) on detonation behavior was identified. Knowledge gained from this work is applicable to devices such as rotating detonation engines, where combustion products mix with fresh reactants. A system for measuring the electrical conductivity of the exhaust from a pulse-detonation engine was developed. The open-source solver, Clawpack, was extended to solve the reactive Euler equations for simulating detonations. A coupled combustion and ionization chemistry was developed in a single chemical kinetic model for methane oxidation. This model can be used to solve coupled MHD and detonation simulations. It was found that parasitic interactions from ionization chemistry with the magnetic field can reduce the detonation velocity by up to 8%, with a potential impact on power extraction of 15%. It is recommended that interactions between the detonation front and MHD field be considered. Higher gas temperatures and velocities were achieved owing to oxy-fuel detonations. Use of radical dissociation reactions in the reduced reaction mechanism, was found to be critical in predicting detonation temperature and velocity accurately.

01 COAL, LIGNITE, AND PEAT↗

Scoping Study for Direct Power Extraction (DPE) Systems (Final Report)

NETL led a detailed scoping study of various direct power extraction systems and concepts for utility power generation. The study consisted of qualitative analysis along with quantitative techno-economic analysis of selected systems which use magnetohydrodynamic (MHD) power generators.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Design of a System Interface for Flexible Thermal Power Extraction from Two Advanced Reactors

This report presents the design of system interfaces enabling flexible thermal power extraction from two advanced nuclear reactor concepts: a sodium-cooled fast reactor (SFR) operating on a Rankine cycle, and a gas-cooled reactor (GCR) utilizing a Brayton cycle. The study addresses the dual challenge of ensuring reliable base-load electricity generation while meeting the variable high-temperature steam demands of industrial processes (IPs).

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

Novel High Temperature Carbide and Boride Ceramics for Direct Power Extraction Electrode Applications. Final report

The current project aims to develop new carbide and boride ceramic materials that incorporate different metal elements (e.g., (Hf 1-x Zr x )B 2 , also called ceramic solid solutions) and understand the fundamental composition-processing-structure-property relationships for such materials. Specifically, nano powders and related nano-composites for selected mixed metal carbide and boride materials are synthesized from nano-scale mixed precursors obtained from solution-based processing via heat treatment in inert atmosphere. The obtained fine powders were then consolidated into dense ceramics via a novel flash sintering process. The mechanical properties and thermal oxidation resistance for the obtained materials were evaluated for these materials. It was found that different synthesis routes produced powders with somewhat different characteristics in terms of composition and microstructure, which then led to different properties for the final ceramics. The synthesis and processing methods demonstrated in this study might be adopted for developing other similar high temperature ceramics, while the mixed metal or solid solution ceramic materials obtained from this study might be used as hot electrodes for direction power extraction and other energy-related applications.

20 FOSSIL-FUELED POWER PLANTS↗

Potassium carbonate decomposition modeling within rotating detonation engines for direct power extraction applications

We report that recently, there has been a significant interest in detonation-based combustion systems, such as rotating detonation engines (RDE), due to potential performance advantages in propulsion and energy applications. This includes improvements in thermodynamic efficiency, inherently high gas velocities, and the possibility of achieving an increase in total pressure (i.e. pressure gain) through the combustion process. Due to approximating a constant volume combustion process, these devices also tend to exhibit extremely high local gas temperatures relative to a comparable constant pressure combustor. These advantages overlap well with desirable performance characteristics of direct power extraction (DPE) technologies, such as a magnetohydrodynamic (MHD) generator. Typically, in DPE systems hot combustion products are seeded with an easily ionizable material such as potassium carbonate (K 2 CO 3 ) in order to boost the electrical conductivity. However, due to the short gas residence times within an RDE, it was unclear whether forming an electrically conductive combustion plasma would be feasible for integration with a downstream MHD generator. A model is presented which describes the heating, decomposition, and ionization of solid K 2 CO 3 particles and aqueous solutions of K 2 CO 3 in water, for a given initial particle diameter. This model was combined with available computational fluid dynamics (CFD) data for an oxygen-methane RDE in a one-way coupled Eulerian-Lagrangian framework to predict particle trajectories and the corresponding heating, decomposition, and ionization histories. Electrical conductivities were computed using a previously developed model, and a method was proposed to determine an equivalent average electrical conductivity. Results show that particle sizes below ~30 µm are able to fully decompose before reaching the exit of the RDE. While the one-way coupled nature of the simulations precluded rigorous evaluation of the effects of seed material on detonability, a substantial temperature reduction is expected at the detonation wave front due to heating and decomposition. A preliminary comparison is presented between the RDE and an equivalent constant pressure adiabatic combustor, showing a potential performance advantage for the RDE.

42 ENGINEERING↗

Magnetogasdynamic Power Extraction and Flow Conditioning for a Gas Turbine

An extension of the Russian AJAX concept to a turbojet is being explored. This magnetohydrodynamic (MHD) energy bypass engine cycle incorporating conventional gas turbine technology has MHD flow conditioning at the inlet to electromagnetically extract part of the inlet air kinetic energy. The electrical power generated can be used for various on-board vehicle requirements including plasma flow control around the vehicle or it may be used for augmenting the expanding flow in the high speed nozzle by MHD forces to generate more thrust. In order to achieve this interaction, the air needs to be ionized by an external means even up to fairly high flight speeds, and the leading candidates may be classified as electrical discharge devices. The present kinetic modeling calculations suggest that the use of electron beams with characteristics close to the commercially available e-beam systems (electron energy approx. 60 keV, beam current approx. 0.2 mA/sq cm) to sustain ionization in intermediate pressure, low-temperature (P = 0.1 atm, T = 300 K) supersonic air flows allows considerable reduction of the flow kinetic energy (up to 10 to 20 percent in M = 3 flows). The calculations also suggest that this can be achieved at a reasonable electron beam efficiency (eta approx. 5), even if the e-beam window losses are taken into account. At these conditions, the exit NO and O atom concentrations due to e-beam initiated chemical reactions do not exceed 30 ppm. Increasing the beam current up to approx. 2 mA/sq cm, which corresponds to a maximum electrical conductivity of sigma(sub max) approx. 0.8 mho/m at the loading parameter of K = 0.5, would result in a much greater reduction of the flow kinetic energy (up to 30 to 40 percent). The MHD channel efficiency at these conditions would be greatly reduced (to eta approx. 1) due to increased electron recombination losses in the channel. At these conditions, partial energy conversion from kinetic energy to heat would result in a significant total pressure loss (P(sub 0)/P(sub 0i) approx. 0.3). The total pressure loss can be reduced operating at the loading parameter closer to unity, at the expense of the reduced electrical power output. Raising the beam current would also result in the increase of the exit O atom concentrations (up to 600 ppm) and NO (up to 150 ppm).

Adamovich, Igor V.↗

Maximizing Wave Energy Converter Power Extraction by Utilizing a Variable Negative Stiffness Magnetic Spring

Complex conjugate impedance matching is a key concept for wave energy converter design. Matching the impedance of the power take-off (PTO) system to the complex conjugate of the wave energy converter's (WEC) impedance ensures efficient transfer of energy from the WEC body motion to electrical power. In low frequency waves, impedance matching often requires a negative PTO stiffness. In this paper, an adjustable stiffness magnetic torsion spring will be presented and modeled to understand its potential to improve WEC performance. The spring has the ability to provide a negative stiffness, allowing the PTO impedance to more closely match the complex conjugate of the WEC impedance at low frequencies. The spring also supports an adjustable stiffness value, meaning it can be tuned according to the incoming wave conditions. The spring's tunability may put less stress on the rest of the PTO system in wave conditions outside its normal operation zone without sacrificing electrical power output. The adjustable magnetic spring's effects are modeled and explored in this paper by examining the resultant average annual electrical power and capacity factor. The study suggests that the tunable magnetic spring has the potential to significantly improve capacity factor while maintaining a high average electrical power.

16 TIDAL AND WAVE POWER↗

Performance of J33 turbojet engine with shaft-power extraction III : turbine performance

The performance of the turbine component of a J33 turbojet engine was determined over a range of turbine speeds from 8000 to 11,500 rpm.Turbine-inlet temperature was varied from the minimum required to drive the compressor to a maximum of approximately 2000 degrees R at each of several intermediate turbine speeds. Data are presented that show the horsepower developed by the turbine per pound of gas flow. The relation between turbine-inlet stagnation pressure, turbine-outlet stagnation pressure, and turbine-outlet static pressure was established. The turbine-weight-flow parameter varied from 39.2 to 43.6. The maximum turbine efficiency measured was 0.86 at a pressure ratio of 3.5 and a ratio of blade speed to theoretical nozzle velocity of 0.39. A generalized performance map of the turbine-horsepower parameter plotted against the turbine-speed parameter indicated that the best turbine efficiency is obtained when the turbine power is 10 percent greater than the compressor horsepower. The variation of efficiency with the ratio of blade speed to nozzle velocity indicated that the turbine operates at a speed above that for maximum efficiency when the engine is operated normally with the 19-inch-diameter jet nozzle.

Huppert, M C↗