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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 37 records · Page 2

Tank 49H Solids Disturbance Analysis

Tank 49H will serve as the feed tank for the Salt Waste Processing Facility (SWPF). Transfers into Tank 49H may disturb solids that have settled to the bottom of the tank, resulting in feed that may exceed the insoluble solids content limit of 1200 mg/L from the SWPF Waste Acceptance Criteria (WAC). During a transfer into Tank 49H, material that free falls from the Tank 49H B4 downcomer and passes through the supernate could potentially disturb the solids on the bottom of the tank and scour or suspend solids from a settled solids layer or turbid region. The scope of this task is to perform fluid flow analysis to determine the impact of a “plunging jet” through the B4 downcomer on solids in Tank 49H and to determine a minimum liquid level to be maintained in Tank 49H prior to transfers that will minimize disturbing the solids and exceeding the SWPF WAC limits for insoluble solids carryover to SWPF.

54 ENVIRONMENTAL SCIENCES↗

Opportunities to Update the Model of Tank Closure Grout Aging (SRNL-STI-2012-00404) Based on Experimental Results by the Savannah River Ecology Laboratory

The purpose of this report was to review the results of experiments on evolution of tank grout pore fluids performed by the Savannah River Ecology Laboratory (SREL) and reported in Seaman et al. (2020) and highlight opportunities for updating the model of tank grout degradation presented in Denham and Millings (2012). The SREL experimental results validate some assumptions used in the 2012 grout degradation model and provide information useful for updating the model. All experiments on tank grout degradation have limitations because of reaction rates and the enormous disparity between duration of the experiments and the duration of the degradation of the real tank grout system. Given these limitations, the experimental results form the basis for several recommendations for updating the grout degradation model described in this report.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Heat pipe stability. 1: A preliminary investigation into thermally assisted cavitation

The notion is introduced of thermally assisted cavitation by localized fluctuations in capillary forces. Because cavitation in liquids can be closely approximated by an isothermal process, only momentum and mass balances are used to introduce the notion for liquids under mechanical tension. Brief attention is given to developing a stability theory in terms of the stiffness and compliance coefficients for a working fluid. Interestingly, the particular thermodynamic approach taken can be used to suggest experiments relating working fluid performance to meniscus behavior. A correction to the liquid flow equation is suggested.

Source record↗

Liquid solar collector

Report documents evaluation test on commercial flat-plate solar collector that uses water as working fluid. Performance was measured before and after 34-day exposure to natural environment. Tables in metric and English units present data on air and water temperatures, waterflow, insolation, efficiency, and windspeed and direction.

Source record↗

The properties of perfluoropolyethers used for space applications

The perfluoropolyether (PFPE) class of liquid lubricants has been used for space applications for over two decades. At first, these fluids performed satisfactorily as early spacecraft placed few demands on their performance. However, as other spacecraft components have become more reliable and lifetimes have been extended, PFPE lubricant deficiencies have been exposed. Therefore, the objective of this paper is to review the PFPE properties that are important for successful long term operation in space.

Jones, William R., Jr.↗

The Nozzle Acoustic Test Rig: an Acoustic and Aerodynamic Free-jet Facility

The nozzle acoustic test rig (NATR) was built at NASA Lewis Research Center to support the High Speed Research Program. The facility is capable of measuring the acoustic and aerodynamic performance of aircraft engine nozzle concepts. Trade-off studies are conducted to compare performance and noise during simulated low-speed flight and takeoff. Located inside an acoustically treated dome with a 62-ft radius, the NATR is a free-jet that has a 53-in. diameter and is driven by an air ejector. This ejector is operated with 125 lb/s of compressed air, at 125 psig, to achieve 375 lb/s at Mach 0.3. Acoustic and aerodynamic data are collected from test nozzles mounted in the free-jet flow. The dome serves to protect the surrounding community from high noise levels generated by the nozzles, and to provide an anechoic environment for acoustic measurements. Information presented in this report summarizes free-jet performance, fluid support systems, and data acquisition capabilities of the NATR.

Castner, Raymond S.↗

Properties of Perfluoropolyethers for Space Applications

The perfluoropolyether (PFPE) class of liquid lubricants has been used for space applications for over two decades. At first, these fluids performed satisfactorily as early spacecraft placed few demands on their performance. However, as other spacecraft components have become more reliable and lifetimes have been extended, PFPE lubricant deficiencies have been exposed. Therefore, the objective of this paper is to review the PFPE properties that are important for successful long term operation in space.

Jones, William R., Jr.↗

Properties of Perfluoropolyethers for Space Applications

The perfluoropolyether (PEPE) class of liquid lubricants has been used for space applications for over two decades. At first, these fluids performed satisfactorily, as early spacecraft placed few demands on their performance. However, as other spacecraft components have become more reliable and lifetimes have been extended, PEPE lubricant deficiencies have been exposed. Therefore, the objective of this paper is to review the PEPE properties that are important for successful long term operation in space.

Jones, William R., Jr.↗

Space Shuttle solid rocket motor slag expulsion mechanisms

A 13 psi pressure perturbation occurred at approximately 68 seconds on the right Redesigned Solid Rocket Motor (RSRM) during the STS-54 space shuttle mission. While pressure perturbations are a normal characteristic of RSRM operation, the magnitude of the STS-54 perturbation and the resulting thrust imbalance between the left and right motors was outside of flight experience. A joint Marshall Space Flight Center (MSFC) and Thiokol Corporation (RSRM manufacturer) team soon narrowed the probable cause to a temporary nozzle restriction due to slag expulsion. In support of the team, Rockwell Aerospace performed fluid finite element simulations and vehicle flight dynamic correlations to investigate possible slag expulsion mechanisms responsible for pressure perturbations. Results of the simulations and analyses provided evidence that the combination of flight induced accelerations acting on accumulated slag and nozzle vectoring were the most probable cause of RSRM slag expulsion.

Hopson, Charles B.↗

Tensoral Present and Future

The coding of high-performance fluids simulations requires significant knowledge of both numerical and computational details. The magnitude and complexity of low-level details is often enough to discourage many users of turbulence data wishing to study more important, higher-level fluid dynamical questions. These same complexities are often a practical barrier to simulation experts who develop, verify and maintain the codes which generate this data. Future fluids codes, with high resolution and complex geometries, are likely to involve far more coding complexity. The research--the design and implementation of the Tensoral computer language--aims to greatly ease the coding of today's simulation and post-processing codes and at the same time provide a general computational tool for future simulations.

Dresselhaus, Eliot↗

Replacement of Hydrochlorofluorocarbon (HCFC) -225 Solvent for Cleaning and Verification Sampling of NASA Propulsion Oxygen Systems Hardware, Ground Support Equipment, and Associated Test Systems

Since the 1990's, NASA's rocket propulsion test facilities at Marshall Space Flight Center (MSFC) and Stennis Space Center (SSC) have used hydrochlorofluorocarbon-225 (HCFC-225), a Class II ozone-depleting substance, to safety clean and verify the cleanliness of large scale propulsion oxygen systems and associated test facilities. In 2012 through 2014, test laboratories at MSFC, SSC, and Johnson Space Center-White Sands Test Facility collaborated to seek out, test, and qualify an environmentally preferred replacement for HCFC-225. Candidate solvents were selected, a test plan was developed, and the products were tested for materials compatibility, oxygen compatibility, cleaning effectiveness, and suitability for use in cleanliness verification and field cleaning operations. Honewell Soltice (TradeMark) Performance Fluid (trans-1-chloro-3,3, 3-trifluoropropene) was selected to replace HCFC-225 at NASA's MSFC and SSC rocket propulsion test facilities.

Burns, H. D.↗

Effect of Initial Water Saturation on The Performance of Fracturing Fluids With and Without Polyallylamine under Simulated EGS Conditions

Objectives/Scope: StimuFrac (US Patents 9,873,828 B2 and 9,447,315 B2), a CO2-reactive polymer aqueous solution [polyallylamine (PAA) 1wt% in water] combined with CO2, can be used as a less water-intensive fracturing fluid for enhanced geothermal systems (EGS). Our previous results show that in hot dry rock (HDR), PAA/CO2 fracturing fluids outperformed other fluids such as water, CO2, and CO2/water in generating large fractures with less fluid consumed. The objective of this work is to study the effect of initial water saturation of rock on the performance of StimuFrac fluid in ½ foot cubic rock samples and under representative EGS pressure/temperature conditions using cyclic and constant flow rate injection strategies. The fracturing results are compared with results using different fracturing fluids in terms of controlling fracture propagation rates, fracture hydraulic conductivity, breakdown pressures and volumes of fluids required. Methods/Procedures/Process: In all tests, water was initially injected into the rock to increase the water saturation before the fracturing processes to simulate actual geothermal reservoir conditions. For the cyclic injection, one complete cycle consisted of (1) a PAA slug (or water slug) injection followed by (2) CO2 injection to initiate the fracture. In the second step of the first cycle, the pressure of CO2 is increased until a maximum pressure is reached (fracture is initiated at this moment), and then the injection of CO2 is allowed for another 30 seconds to propagate the fracture. Then, the two-step cycle of PAA followed by CO2 injection (up to 2-4 mL/min) was continued. For the constant flow rate injection strategies, the initial water saturation was increased by injecting water at 1000 psi and 200°C for three days. After that, an initial slug of water, CO2, or PAA was injected and then fracturing was initiated and propagated by injecting CO2 at a constant flow rate. Applications/Significance/Novelty: The results of this study suggest that water saturation, especially near the wellbore region, will significantly affect the fracturing fluid transmission into the rock porous media by changing the relative permeability of CO2 or water, thus affecting the fracture initiation and propagation. In this study, fracturing with cyclic injection or constant flow rate injection methods were performed using three different kinds of fluids systems. These fluids are water, CO2, or CO2 with PAA. Splitting the rock samples in half after fracturing reveals that the fracture propagation is significantly limited under these high water saturated conditions compared to dry initial conditions: The fractures propagate less than 1/3 length of the distance from the wellbore to rock surface, and in some cases no fracture is generated. This may be caused by the fact that leak-off is dominating the fracturing process and the injected fluid flow rate is not high enough to overcome the leak-off even under high flow rate injection conditions. Additionally, CO2 could be leaking off into the wellbore annulus and this may be making it more difficult to generate pressure gradients away from the near-wellbore region.

Jian, Guoqing↗

Computational model for predicting the performance of fluid-powered longiudinal piston modules and motors.

A Matlab-based computational model line code has been developed for predicting the performance of fluid-powered longitudinal piston modules and motors. A system of equations has been developed based upon applying the conservation of mass to a control volume defined by a reciprocating piston. The method results in a differential equation that predicts the pressure gradient in the control volume as a function of rotor rotation angle. The model uses an integration scheme to predict the pressure state in the control volume. The orifice equation is used to predict the flowrate in and out of the control volume. From the resulting solution the torque and speed characteristics of the motor configuration can be predicted, optimized, or tailored for a specific requirement.SAND2019-13983 M Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

Taylor, Michael↗

Estimation of the Thermal-Fluids and Thermal-Structural Performance of Helium-Cooled Modular Finger-Type Divertors

Over the past decade, our group has investigated the thermal-fluid performance of the helium-cooled modular divertor with multiple jets (HEMJ) and a simplified “flat” design of the HEMJ for long-pulse magnetic fusion energy (MFE) reactors. Experimental studies were performed in a helium (He) loop at the prototypical pressure of 10 MPa, nearly prototypical He temperatures and incident heat fluxes using test sections made from stainless steel and tungsten alloys. Correlations for average Nusselt numbers and pressure loss coefficients were developed from the data and are used to validate computational fluid dynamics (CFD) models. Here, this work presents updated thermal-fluids performance curves based on these correlations that estimate the maximum heat flux that can be accommodated by the plasma-facing surface and coolant pumping power requirements at prototypical operating conditions. Thermal-structural performance curves developed from ITER structural design criteria are introduced, which include protection against ductile and non-ductile failure, ratcheting fatigue, and creep fatigue. The performance design curves for these finger-type divertors demonstrate that the “flat” design, with a significantly less complicated geometry than the HEMJ, has thermal-fluid and thermal-structural performance comparable to the original HEMJ concept, and may be superior in terms of non-ductile failure criteria.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

Fluid dynamic and thermal performance of a slotted cylinder at low Reynolds number

The fluid dynamic and thermal performance of a circular cylinder with a slot parallel to the flow is numerically investigated. The study utilized the semi-implicit finite volume multi-material algorithm MPM-ICE, a component of the Uintah framework. The normalized slot width s/D ranges from 0.1 - 0.3, introducing an additional heat transfer surface area between ~ 10 and ~ 50%, and a mass reduction between ~ 13 and ~ 38% in the cylinder. We assumed two-dimensional incompressible flow and simulated a Reynolds number Re D between 100 and 1000. The slotted cylinders are found to have a total drag force reduction up to ~ 45%, compared to a solid cylinder despite the additional viscous drag force in the slot. Convection heat transfer is enhanced up to ~ 70%. Further, the slotted cylinder performance index, defined as the ratio of the heat rate to the drag force, increases up to maximum of ~ 3, indicating better overall thermal fluid performance. An entropy analysis showed the best performance index occurs at the highest Re D . Correlations for drag coefficient and Nusselt number are proposed along with an entropy optimization method.

42 ENGINEERING↗

TO252: Parabolic Flight Demonstration of Fluid Dispensing Tube Performance Limits for Drop Delivery

Ring Shear Drop (RSD) ISS flight hardware failed to pin sample fluid drops between two rings, likely due to dynamic instability inherent to the dispensing tube (D-Tube) design. The first parabolic flight tested 5 D-tube tip designs with two bounding surface tension fluids, enabling an engineering design decision. D-tube Tip Cage Design was selected based on the November 2020 parabolic flight test data. Flight Operations Program (FOP) approved a reflight proposal to include 2 parabolic flight days during the April/May 2021 campaign with following objectives: • Validate ISS hardware flight design with actual flight fluids (test as you fly), demonstrating the ability to deliver 1” fluid drops in near-microgravity conditions. • Demonstrate pinning of 1” flight fluid drops: a secondary pinning ring is planned to be installed in the parabolic flight hardware to meet this objective. Fluid flow rates will also be varied as needed and as possible. • Provide data to validate computational models used to guide ISS operational deployment decisions and demonstrate the viability of the redesigned hardware to accommodate a range of future flight investigations. This presentation introduces highlights and lessons learned during this recent flight campaign for discussion in the Flight Opportunities Program Panel, “Leveraging Suborbital Flight Tests to Advance Science and Technology."

Sridhar Gorti↗

Dielectric Fluids for the Direct Forced Convection Cooling of Power Electronics

The future of electrification of vehicles and other systems will require the creation of high-power density power electronics with low junction-to-fluid thermal resistance cooling solutions. One way to create this solution is to move high-heat-flux liquid cooling (single- or two-phase) as close to the power electronics components as possible. One novel approach involves submersion in dielectric fluids as the cooling solution. We first provide the range of fluid properties and develop a figure of merit (FOM) to aid in dielectric fluid selection. Next, we perform computational fluid dynamics/heat transfer (CFD/HT) modeling using single-phase cooling (submerged jet impingement on an enhanced surface) to validate the dielectric fluid FOM. Results of the study show that the developed FOM is a good representation of the performance of the fluids when compared to the results of the CFD/HT analysis. Both FOM and the CFD/HT analysis show that based on pure thermohydraulic considerations, several commercially available fluids present higher performance, on the order of 5% of water. Finally, the FOM can be used to quickly assess the thermohydraulic performance of a dielectric fluid, as well as the secondary application-specific properties such as boiling point, saturation pressure, flash point, and global warming potential, thereby allowing for fluid candidates to be readily compared.

computational fluid dynamics↗