Search NASA⌕ Search

SEARCH · Search NASA

Results for “flow efficiency”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,441 records · Page 80
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Utah FORGE 4-2492: Design and Implementation of Innovative Stimulation Treatments to Maximize Energy Recovery - Workshop Presentation

This is a presentation on the Design and Implementation of Innovative Stimulation Treatments to Maximize Energy Recovery Efficiency at the Utah FORGE Site project by The University of Texas at Austin, presented by Professor Mukul M. Sharma. The project's objectives were to place fractures uniformly in a horizontal well (improve cluster efficiency) to ensure uniform distribution of flow into all hydraulic fractures, maximize the area of the created fracture network, ensure connectivity of the fractures from the injector to the producer, and optimize fracture size. This presentation was featured in the Utah FORGE R&D Annual Workshop on September 7, 2023. The workshop provided a valuable opportunity to explore the progress made in each of the 17 Research and Development projects funded under Solicitation 2020-1 which aim to enhance our understanding of the crucial factors influencing the development of Enhanced Geothermal Systems (EGS) reservoirs and resources.

15 GEOTHERMAL ENERGY↗
NASA NTRS2001

The Development of the Multi-Center Traffic Management Advisor (MCTMA): Traffic Flow Management Research in a Multi-Facility Environment

The Traffic Management Advisor (TMA) is a decision-support tool for traffic managers and air traffic controllers that provides traffic flow visualization and other flow management tools. TMA creates an efficiently sequenced and safely spaced schedule for arrival traffic that meets but does not exceed specified airspace system constraints. TMA is being deployed at selected facilities throughout the National Airspace System in the US as part of the FAA's Free Flight Phase 1 program. TMA development and testing, and its current deployment, focuses on managing the arrival capacity for single major airports within single terminal areas and single en route centers. The next phase of development for this technology is the expansion of the TMA capability to complex facilities in which a terminal area or airport is fed by multiple en route centers, thus creating a multicenter TMA functionality. The focus of the multi-center TMA (McTMA) development is on the busy facilities in the Northeast comdor of the US. This paper describes the planning and development of McTMA and the challenges associated with adapting a successful traffic flow management tool for a very complex airspace.

Lee, Katharine K.↗
DOE OSTI2019

A Strongly Fluorescing Anaerobic Reporter and Protein-Tagging System for Clostridium Organisms Based on the Fluorescence-Activating and Absorption-Shifting Tag Protein (FAST)

Visualizing protein localization and characterizing gene expression activity in live Clostridium cells is limited for lack of a real-time, highly fluorescent, oxygen-independent reporter system. Enzymatic reporter systems have been used successfully for many years with Clostridium spp.; however, these assays do not allow for real-time analysis of gene expression activity with flow cytometry or for visualizing protein localization through fusion proteins. Commonly used fluorescent reporter proteins require oxygen for chromophore maturation and cannot be used for most strictly anaerobic Clostridium organisms. Here we show that the fluorescence-activating and absorption-shifting tag protein (FAST), when associated with the fluorogenic ligand 4-hydroxy-3-methylbenzylidene-rhodanine (HMBR; now commercially available) and other commercially available ligands, is highly fluorescent in Clostridium acetobutylicum under anaerobic conditions. Using flow cytometry and a fluorescence microplate reader, we demonstrated FAST as a reporter system by employing the promoters of the C. acetobutylicum thiolase (thl), acetoacetate decarboxylase (adc), and phosphotransbutyrylase (ptb) metabolic genes, as well as a mutant P thl and modified ribosome binding site (RBS) versions of P adc and P ptb . Flow cytometry-based sorting was efficient and fast in sorting FAST-expressing cells, and positively and negatively sorted cells could be effectively recultured. FAST was also used to tag and examine protein localization of the predicted cell division FtsZ partner protein, ZapA, to visualize the divisome localization in live C. acetobutylicum cells. Our findings suggest that FAST can be used to further investigate Clostridium divisomes and more broadly the localization and expression levels of other proteins in Clostridium organisms, thus enabling cell biology studies with these organisms.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2018

An enhanced AUSM + -up scheme for high-speed compressible two-phase flows on hybrid grids

Here in this work, an enhanced AUSM + -up scheme is presented for high-speed compressible two-phase flows using a six-equation two-fluid single-pressure model. Based on the observation that the AUSM + -up flux function does not take into account relative velocity between the two phases and thus is not stable and robust for computation of two-phase flows involving interaction of strong shock waves and material interfaces, the enhancement is in the form of a volume fraction coupling term and a modification of the velocity diffusion term, both proportional to the relative velocity between the two phases. These modifications in the flux function obviate the need to employ the exact Riemann solver, leading to a significantly less expensive yet robust flux scheme. Furthermore, the Tangent of Hyperbola for INterface Capturing (THINC) scheme is used in order to provide a sharp resolution for material interfaces. A number of benchmark test cases are presented to assess the performance and robustness of the enhanced AUSM + -up scheme for compressible two-phase flows on hybrid unstructured grids. Lastly, the numerical experiments demonstrate that the enhanced AUSM + -up scheme along with THINC scheme can efficiently compute high-speed two-fluid flows such as shock–bubble interactions, while accurately capturing material interfaces.

42 ENGINEERING↗
NASA NTRS1976

Development of a computer code for calculating the steady super/hypersonic inviscid flow around real configurations. Volume 1: Computational technique

A numerical procedure has been developed to compute the inviscid super/hypersonic flow field about complex vehicle geometries accurately and efficiently. A second order accurate finite difference scheme is used to integrate the three dimensional Euler equations in regions of continuous flow, while all shock waves are computed as discontinuities via the Rankine Hugoniot jump conditions. Conformal mappings are used to develop a computational grid. The effects of blunt nose entropy layers are computed in detail. Real gas effects for equilibrium air are included using curve fits of Mollier charts. Typical calculated results for shuttle orbiter, hypersonic transport, and supersonic aircraft configurations are included to demonstrate the usefulness of this tool.

Marconi, F.↗
DOE OSTI2021

An Improved Method for Extracting, Sorting, and AMS Dating of Pollen Concentrates From Lake Sediment

High-resolution chronologies are crucial for paleoenvironmental reconstructions, and are particularly challenging for lacustrine records of terrestrial paleoclimate. Accelerator Mass Spectrometry (AMS) radiocarbon measurement of terrestrial macrofossils is the most common technique for building age models for lake sediment cores, but relies on the presence of terrestrial macrofossils in sediments. In the absence of sufficient macrofossils, pollen concentrates represent a valuable source of dates for building high-resolution chronologies. However, pollen isolation and dating may present several challenges, as has been reported by different authors in previous work over the last few decades. Here we present an improved method for extracting, purifying and radiocarbon-dating pollen concentrates using flow cytometry to improve the extraction efficiency and the purity of the pollen concentrates. Overall, the nature of the sediments and the abundance of the pollen represent major considerations in obtaining enough pollen grains and, consequently, enough carbon to be dated. Further, the complete separation of pollen from other forms of organic matter is required to ensure the accuracy of the dates. We apply the method to surface samples and sediment cores recovered from two contrasting lake basins on the eastern side of the Sierra Nevada (California), and describe the variations that may be used to optimize pollen preparation from a variety of sediments.

58 GEOSCIENCES↗
DOE OSTI2022

Performance Modeling of a Thermoelectric Heat Pump Clothes Dryer with Very High Air Flow

Previous research has shown that a clothes dryer heated by thermoelectric (Peltier) heat pumps can be up to 85% more efficient than a conventional electric-resistance dryer. A previous thermoelectric prototype used a conventional dryer’s air flow of 120 ft3/min (0.06 m3/s) and provided about 1,300 W of thermoelectric heating capacity at a heating coefficient of performance (COP) of approximately 1.2. In this work, the performance of a clothes dryer with a very high air flow rate, up to 300 ft3/min (1.14 m3/s), and only 400 W of thermoelectric heating capacity was investigated using a thermohydraulic model. Key aspects of the model were validated experimentally. Results for dry time and efficiency are presented for various air flow and heating rates.

Boudreaux, Philip↗
DOE OSTI2019

A Leray regularized ensemble-proper orthogonal decomposition method for parameterized convection-dominated flows

Abstract Partial differential equations (PDEs) are often dependent on input quantities that are uncertain. To quantify this uncertainty PDEs must be solved over a large ensemble of parameters. Even for a single realization this can be a computationally intensive process. In the case of flows governed by the Navier–Stokes equations, an efficient method has been devised for computing an ensemble of solutions. To further reduce the computational cost of this method, an ensemble-proper orthogonal decomposition (POD) method was recently proposed. The main contribution of this work is the introduction of POD spatial filtering for ensemble-POD methods. The POD spatial filter makes possible the construction of the Leray ensemble-POD model, which is a regularized-reduced order model for the numerical simulation of convection-dominated flows of moderate Reynolds number. The Leray ensemble-POD model employs the POD spatial filter to smooth (regularize) the convection term in the Navier–Stokes equations, and diminishes the numerical inaccuracies produced by the ensemble-POD method in the numerical simulation of convection-dominated flows. Specifically, for the numerical simulation of a convection-dominated two-dimensional flow between two offset cylinders, we show that the Leray ensemble-POD method better reflects the dynamics of the benchmark results than the ensemble-POD scheme. The second contribution of this work is a new numerical discretization of the variable viscosity ensemble algorithm in which the average viscosity is replaced with the maximum viscosity. It is shown that this new numerical discretization is significantly more stable than those in current use. Furthermore, error estimates for the novel Leray ensemble-POD algorithm with this new numerical discretization are also proven.

Mathematics↗
DOE OSTI2019

Aerodynamic Improvement of a Compact Centrifugal Compressor

For the example of the JetCat P-200RX turbojet engine, optimization of the diffuser and straightening unit of a compact centrifugal compressor is considered, on the basis of a mathematical model of viscous turbulent air flow. The goal of optimization is to increase the isentropic (adiabatic) efficiency of the compressor.

42 ENGINEERING↗
DOE OSTI2016

Impact of alternative fuel rheology on spraying process of small pressure-swirl atomizer

A systematic investigation was made to analyse the atomizing performance of a small pressure-swirl atomizer with different crude-oil based fuels and water. The atomizer performance is characterized in terms of discharge coefficient, droplet Sauter mean diameter and nozzle efficiency. Phase-Doppler anemometry was used to measure droplets sizes and velocities and to determine the mean structure of the developed spray. A strong dependence of liquid viscosity on the mass flow rate through the atomizer as well as on the spray quality was found and discussed in comparison with relevant literature.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1974

The development of a solar powered residential heating and cooling system

A solar energy collector design is disclosed that would be efficient for both energy transfer and fluid flow, based upon extensive parametric analyses. Thermal design requirements are generated for the energy storage systems which utilizes sensible heat storage in water. Properly size system components (including the collector and storage) and a practical, efficient total system configuration are determined by means of computer simulation of system performance.

Oneill, M. J.↗
DOE OSTI2020

A GPU-based 2D shallow water quality model

In this paper, a 2D shallow water flow solver integrated with a water quality model is presented. The interaction between the main water quality constituents included is based on the Water Quality Analysis Simulation Program. Efficiency is achieved by computing with a combination of a Central Processing Unit (CPU) and a Graphics Processing Unit (GPU) device. This technique is intended to provide robust and accurate simulations with high computation speedups with respect to a single-core CPU in real events. The proposed numerical model is evaluated in cases that include the transport and reaction of water quality components over irregular bed topography and dry–wet fronts, verifying that the numerical solution in these situations conserves the required properties (C-property and positivity). The model can operate in any steady or unsteady form allowing an efficient assessment of the environmental impact of water flows. The field data from an unsteady river reach test case are used to show that the model is capable of predicting the measured temporal distribution of dissolved oxygen and water temperature, proving the robustness and computational efficiency of the model, even in the presence of noisy signals such as wind speed.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Blade Designs For Improved Multi-Phase Performance In sCO 2 Compressors; Part II - Optical Diagnostics In sCO 2 And Experimental Evaluation With Particle Image Velocimetry

This paper presents the second part of a study in which the leading-edge and suction surface of a compressor blade was modified to delay onset of phase change for sCO 2 compressors operating near the critical point. Using a first-of-its-kind apparatus for the measurement of sCO 2 flow fields, Particle Image Velocimetry (PIV) is used for local flow field measurements of two compressor blade geometries: the modified “biased-wedge,” and a conventional constant thickness blade. Utilizing the developed hardware, the feasibility of a simple, laser-based diagnostic for qualitatively measuring liquid phase regions, is also presented. The design of the optical diagnostics rig, a discussion of numerous challenges, and necessary considerations involved in performing optical-based measurements like PIV, in sCO 2 , are discussed. Velocity field measurements for the modified compressor profile show a much lower suction peak compared to a conventional blade. Furthermore, these results validate numerical results at the tested conditions, where the suction side profile of the biased wedge works to minimize the local pressure gradient.

14 SOLAR ENERGY↗
DOE OSTI2017

“Wine-Dark Sea” in an Organic Flow Battery: Storing Negative Charge in 2,1,3-Benzothiadiazole Radicals Leads to Improved Cyclability

Redox-active organic materials (ROMs) have shown great promise for redox flow battery applications but generally encounter limited cycling efficiency and stability at relevant redox material concentrations in nonaqueous systems. Here we report a new heterocyclic organic anolyte molecule, 2,1,3-benzothiadiazole, that has high solubility, a low redox potential, and fast electrochemical kinetics. Coupling it with a benchmark catholyte ROM, the nonaqueous organic flow battery demonstrated significant improvement in cyclable redox material concentrations and cell efficiencies compared to the state-of-the-art nonaqueous systems. Especially, this system produced exceeding cyclability with relatively stable efficiencies and capacities at high ROM concentrations (>0.5 M), which is ascribed to the highly delocalized charge densities in the radical anions of 2,1,3-benzothiadiazole, leading to good chemical stability. As a result, this material development represents significant progress toward promising next-generation energy storage.

25 ENERGY STORAGE↗
DOE OSTI2013

Industry Research and Recommendations for Small Buildings and Small Portfolios

Small buildings have been left behind in the energy efficiency marketplace because financial and technical resources have flowed to larger commercial buildings. DOE's Building Technologies Office works with the commercial building industry to accelerate the uptake of energy efficiency technologies and techniques in existing and new commercial buildings (DOE 2013). BTO recognizes the SBSP sector'spotential for significant energy savings and the need for investments in resources that are tailored to this sector's unique needs. The industry research and recommendations described in this report identify potential approaches and strategic priorities that BTO could explore over the next 3-5 years that will support the implementation of high-potential energy efficiency opportunities for thisimportant sector. DOE is uniquely positioned to provide national leadership, objective information, and innovative tools, technologies, and services to support cost-effective energy savings in the fragmented and complex SBSP sector. Properly deployed, the DOE effort could enhance and complement current energy efficiency approaches. Small portfolios are loosely and qualitatively defined asportfolios of buildings that include only a small number of small buildings. This distinction is important because the report targets portfolio owners and managers who generally do not have staff and other resources to track energy use and pursue energy efficiency solutions.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
NASA NTRS1998

Recent Advances in Visualizing 3D Flow with LIC

Line Integral Convolution (LIC), introduced by Cabral and Leedom in 1993, is an elegant and versatile technique for representing directional information via patterns of correlation in a texture. Although most commonly used to depict 2D flow, or flow over a surface in 3D, LIC methods can equivalently be used to portray 3D flow through a volume. However, the popularity of LIC as a device for illustrating 3D flow has historically been limited both by the computational expense of generating and rendering such a 3D texture and by the difficulties inherent in clearly and effectively conveying the directional information embodied in the volumetric output textures that are produced. In an earlier paper, we briefly discussed some of the factors that may underlie the perceptual difficulties that we can encounter with dense 3D displays and outlined several strategies for more effectively visualizing 3D flow with volume LIC. In this article, we review in more detail techniques for selectively emphasizing critical regions of interest in a flow and for facilitating the accurate perception of the 3D depth and orientation of overlapping streamlines, and we demonstrate new methods for efficiently incorporating an indication of orientation into a flow representation and for conveying additional information about related scalar quantities such as temperature or vorticity over a flow via subtle, continuous line width and color variations.

Interrante, Victoria↗
NASA NTRS2018

Low Reynolds Number Airfoil Evaluation for the Mars Helicopter Rotor

The present research is aimed at providing a performance model for the Mars Helicopter (MH), to understand the complexity of the flow, and future regions of improvement. The Martian atmosphere's low density and the MH's relatively small rotor result in very low chord-based Reynolds number flows, Rec = O(10(exp 3)-10(exp 4)). The low density and subcritical Reynolds number reduce the lifting force and lifting efficiency, respectively. The high drag coefficients in subcritical flow, especially for thicker sections, are attributed to laminar separation from the rear of the airfoil. The goal is to generate a performance model for the MH rotor for a free wake analysis, since the computational budget for a complete Navier-Stokes solution for a rotating body-fitted rotor is substantial. In this study, a RANS-based approach is used to generate the airfoil deck using OVERFLOW with stitched experimental data for very high angles of attack. The model is presented through airfoil data tables (C81 files) that are used by comprehensive rotor analysis codes such as CAMRADII, or the mid-fidelity CFD solver RotCFD. These codes have proven to provide accurate performance predictions for all rotor operations at only a fraction of the computational expense of three- dimensional body-fitted viscous grids.

Koning, Witold J. K.↗