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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Data supporting the article titled "Heterogeneous Multiphase Flow Properties of Volcanic Rocks and Implications for Noble Gas Transport from Underground Nuclear Explosions"

The submission is a Reproducible Research (RR) data archive that contains the supporting multiphase fluid flow and curve fitting results of the Vadose Zone Journal article titled: "Heterogeneous Multiphase Flow Properties of Volcanic Rocks and Implications for Noble Gas Transport from Underground Nuclear Explosions." The article's DOI number is the following: https://doi.org/10.1002/vzj2.20123. Please see the "Methods and Materials" section of the journal article and the ReadMe.txt in the RR_ARCHIVE folder for further details. 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. SAND Number: SAND2021-3407 O.

mercury injection capillary pressure↗
NASA NTRS2002

Gas/Liquid Separator Being Developed for Microgravity

The examination and research of how liquids and gases behave in very low gravity will improve our understanding of the behavior of fluids on Earth. The knowledge of multiphase fluid behavior is applicable to many industries on Earth, including the pharmaceutical, biotechnology, chemical, and nuclear industries, just to name a few. In addition, this valuable knowledge applies very well to the engineering and design of microgravity materials processing and of life-support systems for extended space flight. Professors Ashok Sangani of Syracuse University and Donald Koch of Cornell University are principal investigators in the Microgravity Fluid Physics Program, which is managed and sponsored by the NASA Glenn Research Center. Their flight experiment entitled "Microgravity Observations of Bubble Interactions" (MOBI) is planned for operation in the Fluids and Combustion Facility aboard the International Space Station.

Hoffmann, Monica I.↗
NASA NTRS2003

Results of the Workshop on Two-Phase Flow, Fluid Stability and Dynamics: Issues in Power, Propulsion, and Advanced Life Support Systems

The Two-phase Flow, Fluid Stability and Dynamics Workshop was held on May 15, 2003 in Cleveland, Ohio to define a coherent scientific research plan and roadmap that addresses the multiphase fluid problems associated with NASA s technology development program. The workshop participants, from academia, industry and government, prioritized various multiphase issues and generated a research plan and roadmap to resolve them. This report presents a prioritization of the various multiphase flow and fluid stability phenomena related primarily to power, propulsion, fluid and thermal management and advanced life support; and a plan to address these issues in a logical and timely fashion using analysis, ground-based and space-flight experiments.

McQuillen, John↗
DOE OSTI2017

On the physics-based processes behind production-induced seismicity in natural gas fields

Induced seismicity due to natural gas production is observed at different sites worldwide. Common understanding states that the pressure drop caused by gas production leads to compaction, which affects the stress field in the reservoir and the surrounding rock formations and hence reactivates preexisting faults and induces earthquakes. We show that the multiphase fluid flow involved in natural gas extraction activities should be included. We use a fully coupled fluid flow and geomechanics simulator, which accounts for stress-dependent permeability and linear poroelasticity, to better determine the conditions leading to fault reactivation. In our model setup, gas is produced from a porous reservoir, divided into two compartments that are offset by a normal fault. Results show that fluid flow plays a major role in pore pressure and stress evolution within the fault. Fault strength is significantly reduced due to fluid flow into the fault zone from the neighboring reservoir compartment and other formations. We also analyze scenarios for minimizing seismicity after a period of production, such as (i) well shut-in and (ii) gas reinjection. In the case of well shut-in, a highly stressed fault zone can still be reactivated several decades after production has ceased, although on average the shut-in results in a reduction in seismicity. In the case of gas reinjection, fault reactivation can be avoided if gas is injected directly into the compartment under depletion. However, gas reinjection into a neighboring compartment does not stop the fault from being reactivated.

03 NATURAL GAS↗
DOE OSTI2017

Eulerian Two-Fluid RANS-based CFD Simulations of a Helical Coil Steam Generator Boiling Tube

As part of a larger effort to demonstrate a simulation-based capability for the evaluation and optimization of helical coil steam generators, the performance of a helical coil steam generator tube is being considered using a Eulerian two-fluid multiphase flow capability implemented within the commercial computational fluid dynamics (CFD) code STAR-CCM+. The objective of these evaluations is to characterize boiling and the resultant two-phase flow structures within the helical coil heat exchanger tube so that structural analyses can more accurately account for vibration sources and damping. These studies have shown that CFD predictions using the two-fluid model are consistent with published measurements of pressure drop and heat transfer characteristics. The sensitivity of model predictions to both flow conditions and modeling parameters associated with bubble dynamics closure models has been investigated.

Pointer, Dave↗
DOE OSTI2018

Fluid Flow, Dissolution, and Mixing Phenomena in Argon-Stirred Steel Ladles

In the current study, the multiphase fluid flow in argon-stirred steel ladles is simulated using an Eulerian–Lagrangian two-phase approach. The momentum source and the turbulent kinetic energy source due to the motion of the bubble are considered for the liquid phase. Argon bubbles are treated as discrete phase particles, and the interfacial forces between the bubbles and the liquid phase; the dependence of the gas density and the bubble diameter on the temperature and the static pressure; and the bubble size distribution are considered. When the fluid flow reaches the quasi-steady state, the ferroalloy melting and mixing phenomena is also modeled. The melting time and the trajectory length of each ferroalloy particle are recorded using a user-defined function (UDF). Local mixing time is predicted in the entire computational domain by checking the mixing criteria in every cell. The effects of gas flow rate, porous plug location, and separation angle of two porous plugs on the fluid flow and the mixing phenomena are investigated. The results show that the flow intensity increases, and the mixing time decreases with the increasing gas flow rate. The optimal porous plug’s radial position with one porous plug is 0.50R for its best mixing condition. When two porous plugs are adopted, the separation angle of 90 deg is recommended to improve the flow field and mixing phenomena.

42 ENGINEERING↗
DOE OSTI2014

Integrated Lift- and Wall-Force Closures in Computational Fluid Dynamics (CMFD)

In this report, we provide the necessary background to put this work in context and for a more detailed background, the reader is referred to CASL 2013 report. Central constraints on the design of LWRs are thermal-structural limits, e.g., maximum fuel pin temperature and maximum allowable working pressure in a pressure vessel. In both of these cases, the knowledge of the spatially and temporally varying two-phase flow is required to make accurate predictions as the distribution of both the phases have an impact on heat extraction as well as neutron moderation. Engineered two-phase flow systems have complex geometry and often high Reynolds numbers which increase the computational cost of an analysis, and generally make direct numerical simulations of the flow field impossible even on the fastest computers today. Consequently, a number of models which seek to reduce this computational cost have been created over the years. One of these called the two-fluid model has become the standard in three dimensional CFD (Computational Fluid Dynamics) codes and is and is also referred to as CMFD (Computational Multiphase Fluid Dynamics). The two-fluid model splits each conserved quantity into two fields, one for each phase that is treated as interspersed continua. Splitting one field into two requires additional interfacial closure relationships. In the two-fluid model, the momentum flux between the phases is governed by a number of these closure relationships. Generally, the net force on the dispersed phase is decomposed into inertial, added mass, buoyancy, drag, lift, and wall forces. In addition, there is a time-dependent Basset force, as well as turbulent dispersion effects.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

Coupled Hydromechanical Modeling of Induced Seismicity From CO 2 Injection in the Illinois Basin

Injection of CO 2 for geologic carbon sequestration into deep sedimentary formations involves fluid pressure increases that engage hydromechanical processes that can cause seismicity by activation of existing faults. In this work, we use a coupled multiphase fluid flow and geomechanical simulator to model spatiotemporal fluid pressure and stress changes in order to study the poroelastic effect of CO 2 injection on faults in crystalline basement rock below the injection zone. The seismicity rate along features interpreted to be basement faults is modeled using Dieterich's rate-and-state earthquake nucleation model. The methodology is applied to microseismicity detected during CO 2 injection into the Mount Simon formation during the Illinois Basin—Decatur Project. The modeling accurately captures an observed reduction in seismicity rate when the injection in the second well was into a slightly shallower zone above the base of the Mount Simon formation. Moreover, the modeling shows that it is important to consider poroelastic stress changes, in addition to fluid pressure changes for accurately modeling of the observed seismicity rate.

58 GEOSCIENCES↗
NASA NTRS1994

An application of miniscale experiments on Earth to refine microgravity analysis of adiabatic multiphase flow in space

Adiabatic two-phase flow is of interest to the design of multiphase fluid and thermal management systems for spacecraft. This paper presents original data and unifies existing data for capillary tubes as a step toward assessing existing multiphase flow analysis and engineering software. Comparisons of theory with these data once again confirm the broad accuracy of the theory. Due to the simplicity and low cost of the capillary tube experiments, which were performed on earth, we were able to closely examine for the first time a flow situation that had not previously been examined appreciably by aircraft tests. This is the situation of a slug flow at high quality, near transition to annular flow. Our comparison of software calculations with these data revealed overprediction of pipeline pressure drop by up to a factor of three. In turn, this finding motivated a reexamination of the existing theory, and then development of a new analytical and is in far better agreement with the data. This sequence of discovery illustrates the role of inexpensive miniscale modeling on earth to anticipate microgravity behavior in space and to complete and help define needs for aircraft tests.

Rothe, Paul H.↗
DOE OSTI2023

Implementation of a High-Fidelity Interface Resolving Method in Nek5000

The development and utilization of computational fluid dynamics (CFD) models for large, high-temperature electric melters in the Waste Treatment and Immobilization Plant (WTP) in eastern Washington State have proven to be valuable for various purposes. These models allow for a better understanding of the physio-chemical processes occurring within the melter vessels and can contribute to improving operational efficiency, throughput, and addressing operational issues related to vitrification. The CFD models employed for these melter vessels incorporate multiphase fluid flow and heat transfer simulations in different regions, including the plenum, cold cap, and molten glass regions. As the tank waste and glass formers are introduced into the melter, a reacting batch layer known as the cold cap forms on top of the molten glass. To enhance the melt rate, forced convection bubblers located at the bottom of the melters generate convection currents that help homogenize the molten glass and provide heat to the cold cap. As the bubbles rise through the highly viscous glass, they adopt a spherical-cap shape [1]. Meanwhile, the conversion of the batch to glass generates significant amounts of gases (such as water vapor, carbon dioxide, sulfur dioxide, and NOx) due to thermal decomposition [2]. These gases become trapped between the cold cap and molten glass, forming a foam layer [3]. For modeling multiphase flow in CFD and heat transfer simulations of waste glass melters at different scales, efforts are underway to augment the capabilities of the Nek5000 [4] and NekRS [5] open-source codes [6]. Nek5000/NekRS is a scalable and efficient spectral element code that has been successfully applied to a wide range of fluid dynamics problems. By leveraging the Nek5000/NekRS software, it becomes possible to model the melter systems more affordably and with lower computational requirements compared to currently utilized commercial CFD software. The specific objectives of this ongoing effort include: 1. Implementation of a level set method in Nek5000/NekRS: The level set method is a numerical technique commonly employed in CFD simulations to track and represent the interface between different phases or materials accurately. By incorporating this method into Nek5000/NekRS, the ability to simulate multiphase flows in waste glass melters at a high level of fidelity can be achieved. 2. Demonstration of capability for air bubbling through molten glass: As part of the development process, a specific case of air bubbling through molten glass will be simulated using the augmented Nek5000/NekRS code. This demonstration aims to showcase the ability of the software to accurately capture and analyze the complex phenomena involved in the multiphase flow within waste glass melters. By achieving these objectives, the improved Nek5000/NekRS code will offer a powerful computational tool for simulating and analyzing waste glass melter systems, enabling better understanding, optimization, and troubleshooting of these vitrification processes. The ability to accurately model and simulate multiphase flows has broad relevance across many industries and scientific domains, and the improved functionality can contribute to advancements in various fields beyond waste glass melter simulations.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Diffusion-to-Imbibition Transition in Water Sorption in Nanoporous Media: Theoretical Studies

The ability to predict multiphase fluid transport in nanoporous rocks such as shales is critical for many geoscience applications, for example unconventional hydrocarbon production, geologic carbon sequestration, and nuclear waste disposal. When the pore sizes approach nanoscales, the impact of the molecular interaction forces between fluids and solids becomes increasingly important. These forces can alter macroscopic fluid phase behavior and control transport. Recent experimental studies have shown that capillary condensation and subsequent imbibition of liquid water can occur in hydrophilic nanoporous media even if the vapor phase is at a critical relative humidity (rhcrit) well below vapor saturation. This study presents a theoretical investigation of the processes controlling adsorption, capillary condensation and imbibition in nanoporous media, using the square-gradient classical density functional theory. The proposed theoretical model explicitly includes the relevant interaction forces among fluids and solids in macroscopic porous media. Application of the model to a relative-humidity-controlled water adsorption experiment is presented to demonstrate the impact of water-pore wall attractive forces on multiphase water behavior in a hydrophilic silicon nanoporous medium. Here, the model represents well the measured time-dependent evolution of the water imbibition front inside the nanoporous medium and also explains the diffusion-like water transport regimes observed at rh < rh crit and the imbibition-like flow regimes observed at rh > rh crit . The study furthermore gives an insight on hysteresis phenomenon in adsorption and desorption isotherms.

58 GEOSCIENCES↗
NASA NTRSDate not supplied

CFD Simulation of Ignition Overpressure and Plume-Water Interaction in the SLS Scale Model Acoustics Test

The solid rocket boosters (SRBs) on the Space Launch System (SLS) generate powerful ignition overpressure (IOP) waves that can potentially damage the vehicle and surrounding ground structures. Based on historical Shuttle experience, the IOP will be mitigated by utilizing an IOP/Sound Suppression (SS) water system which sprays water in and around the SRB and RS-25 engine plumes. However, the complex multiphase physics of the resulting plume-water interaction can lead to undesirable effects, such as high velocity water spray onto the engine nozzles and SRB nozzle side loads. Prior to launch, insight into this environment can be achieved through scale model testing and predictive computational fluid dynamics (CFD) modeling. The Scale Model Acoustic Test (SMAT) was conducted at Marshall Space Flight Center to provide the data necessary to develop the SLS liftoff acoustic environments by using a 5% scale SLS vehicle, fully integrated with a scaled IOP/SS water system, mobile launcher (ML), and tower. NASA engineers have put forth significant effort in validating the Loci/CHEM-Real Fluids multiphase CFD solver on a wet hold down test from the SMAT series. In this paper, the IOP acoustics and plume-water interactions predicted by the CFD model are compared and validated against the experiment, enabling relatively inexpensive, rapid turnaround for multiphase launch environment analyses to support future flights and design evolutions of SLS and other launch vehicles.

Computational Fluid Dynamics↗
DOE OSTI2025

Modeling supercritical CO2 injection induced rupture of a minor fault embedded in a poroelastic layered reservoir-caprock system

CO2 injection for geologic carbon sequestration involves hydromechanical processes that lead to changes in fluid pressure and stresses that can activate existing faults. This paper presents a new method and workflow of modeling fault activation considering more complex three-dimensional geometry of natural faults using the TOUGH-FLAC multiphase fluid flow and geomechanical simulator. In this method and workflow, FLAC3D mechanical interfaces and TOUGH3 finite volume elements are discretized using computer aided design and gridding software along with a tailored mesh translation routine. The method and workflow are demonstrated with a model of a curved minor fault embedded in a poro-elastic layered reservoir-caprock system. The model is used for a comprehensive sensitivity analysis of fault responses to fault length, injection mass rate, injection schedule, well-fault distance, and well locations versus fault location. Four metrics (CO2 plume, shear state of fault, pressure and stress path at fault monitoring points) are selected to assess CO2 migration, pressure change, and the reactivation of faults. The results reveal that CO2 can bypass around the tip of the minor impermeable fault, building up pressure and poro-elastic stress on both sides that tends to impede fault rupture. Our study shows the benefit of carefully designing the injection to achieve the targeted final storage volume, starting at a relatively low rate for considerable time, and then ramping up the injection rate to the full rate of injection. The initial low injection has two distinct benefits: (1) it allows for the formation of an extensive CO2 plume with a much higher mobility through a low viscosity that will result in a lower pressure for a given injection rate, and (2) it allows for gradual build-up of horizontal poro-elastic stress within the reservoir that will tend to impede activation of steeply dipping faults. The injection scenario starting at a low injection rate, denoted here as conservative injection, can significantly reduce the risk of fault activation as high fluid mobility and reservoir strengthening poro-elastic stress has been established long before reaching the peak injection rates. Moreover, simultaneous injection in two injection wells on both sides of fault can provide further reservoir strengthening through poro-elastic stress buildup acting on a fault under normal faulting stress regime. The findings presented in the paper can provide practical and effective guidance on long-term, safe, and reliable geological CO2 storage.

Cao, Meng↗
DOE OSTI2016

Dynamic simulation of CO 2 -injection-induced fault rupture with slip-rate dependent friction coefficient

It is known that poro-elastic stress and effective stress reduction associated with deep underground fluid injection can potentially trigger shear rupture along pre-existing faults. We modeled an idealized CO 2 injection scenario, to assess the effects on faults in the first phase of a generic CO 2 aquifer storage operation. We used coupled multiphase fluid flow and geomechanical numerical modeling to evaluate the stress and pressure perturbations induced by fluid injection and the response of a nearby normal fault. Slip-rate dependent friction and inertial effects have been taken into account during rupture. Contact elements have been used to take into account the frictional behavior of the rupture plane. We investigated different scenarios of injection rate to induce rupture on the fault, employing various fault rheologies. Published laboratory data on CO 2 -saturated intact and crushed rock samples, representative of a potential target aquifer, sealing formation and fault gouge, have been used to define a scenario where different fault rheologies apply at different depths. Nucleation of fault rupture takes place at the bottom of the reservoir, in agreement with analytical poro-elastic stress calculations, depending on injection-induced reservoir inflation and the tectonic stress scenario. For the stress state considered here, the first triggered rupture always produces the largest rupture length and slip magnitude, both of which correlate with the fault rheology. Velocity weakening produces larger ruptures and generates larger magnitude seismic events. Heterogeneous faults have been considered including velocity-weakening or velocity strengthening sections inside and below the aquifer, with the upper sections being velocity-neutral. Nucleation of rupture in a velocity-strengthening section results in a limited rupture extension, both in terms of maximum slip and rupture length. For a heterogeneous fault with nucleation in a velocity-weakening section, the rupture may propagate into the overlying velocity-neutral section, if the extent of velocity-weakening and associated friction drop are large enough.

58 GEOSCIENCES↗
NASA NTRS2002

The NASA Microgravity Fluid Physics Program: Knowledge for Use on Earth and Future Space Missions

Building on over four decades of research and technology development related to the behavior of fluids in low gravity environments, the current NASA Microgravity Fluid Physics Program continues the quest for knowledge to further understand and design better fluids systems for use on earth and in space. The purpose of the Fluid Physics Program is to support the goals of NASA's Biological and Physical Research Enterprise which seeks to exploit the space environment to conduct research and to develop commercial opportunities, while building the vital knowledge base needed to enable efficient and effective systems for protecting and sustaining humans during extended space flights. There are currently five major research areas in the Microgravity Fluid Physics Program: complex fluids, multiphase flows and phase change, interfacial phenomena, biofluid mechanics, and dynamics and instabilities. Numerous investigations into these areas are being conducted in both ground-based laboratories and facilities and in the flight experiments program. Most of the future NASA-sponsored fluid physics and transport phenomena studies will be carried out on the International Space Station in the Fluids Integrated Rack, in the Microgravity Science Glovebox, in EXPRESS racks, and in other facilities provided by international partners. This paper will present an overview of the near- and long-term visions for NASA's Microgravity Fluid Physics Research Program and brief descriptions of hardware systems planned to achieve this research.

Kohl, Fred J.↗
DOE OSTI2017

Advanced Analysis of Hydraulic Fracture Propagation and Efficiency Using Natural Gas as an Alternative to Water

Over the past years, new technologies have been presented as an alternative to minimize or eliminate the use of water in hydraulic fracturing for unconventional reservoirs, improve resource recovery, cost management and reduce environmental impact. As part of these technologies, energized fluids have been developed to mitigate the environmental impact caused by the application of large volumes of water during hydraulic fracturing. When a fracture is energized, the amount of water pumped during the fracturing process is reduced or eliminated by adding a gas component to the fracturing fluid. The less water that is pumped, the less damage it will create. A new technology called “Energized Natural Gas (ENG)” has recently been proposed for effective hydraulic fracturing in unconventional reservoirs. The ENG process shows that it may be a viable solution for the oil and gas industry. Due to the complexity of multiphase fluid behavior and fracture mechanics, further research and documentation is required to effectively apply gas and gas-water mixtures as a treatment fluid. The objective of this research is to further develop and demonstrate the use of natural gas as an optimum fracturing fluid for tight shale gas formations. GeoMechanics Technologies proposes to complete advanced analyses of hydraulic fracture propagation efficiency using natural gas as an alternative to water. A comprehensive review on the transport properties of gas and water mixtures was performed to investigate the rheology differences of conventionally-used fresh water and the natural gas mixture. This research helped to determine how rheology affects hydraulic fracturing. Then we developed a coupled 3D geomechanical model and fluid flow model to simulate hydraulic fracturing using various mixtures of natural gas and water to determine an effective combination. Gas production was also simulated to further test the effectiveness of the induced fracture. Finally, the technical and economic feasibility of this novel technology was considered and documented.

02 PETROLEUM↗
DOE OSTI2022

Modeling gas breakthrough and flow phenomena through engineered barrier systems using a discrete fracture approach

Compacted clays are being considered to build engineered barrier systems (EBS) intended for the safe isolation of high-level nuclear waste (HLW) and spent nuclear fuel (SNF). The corrosion of the metallic canister containing the HLW/SNF will lead to the generation and buildup of the gas pressure in the more internal part of the clay buffer. This phenomenon would eventually trigger the formation and propagation of fractures in the clay barrier, jeopardizing its safety functions. Here, in this work, we propose to use the fragmentation technique (MFT) to model evolving fractures in clays triggered by gas pressurization. The MFT has been successfully used to model the formation of fractures in concrete, drying cracks in soil, hydraulic and thermo-fractures in rocks. In this work, we extend the MFT to deal with multiphase fluid flow in deformable porous media, and we upgraded a fully coupled computer finite element code using the extended technique. The proposed approach is first verified against analytical solutions and is then applied to model gas breakthrough experiments in clays. A very satisfactory performance of the method is observed in all the analyses, showing the potential of the MFT to tackle multiphase flow problems in deformable porous media with evolving discontinuities.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2017

Application of gas-liquid fluid dynamics techniques to the modeling of sprays

The purpose of this paper is to provide an overview of modern computational techniques for gas-liquid systems as they are found in liquid fuel atomization applications. Fuel atomization – the generation of ligaments and droplets from the bulk of liquid injection – offers several modeling challenges: a localized surface tension force, depending on the accurate evaluation of interface curvature; drastic topology changes, which complicate interface advection and introduce local length scales; and separation of phases that have substantially different physical properties. The techniques presented in this review specifically target the gas-liquid interface and couple its evolution in time with the equations of multiphase fluid dynamics. Recent algorithmic advances in this area are discussed first, including new methods that improve conservation properties and deal with very large density ratios and compressibility effects. This part is followed by a discussion on the issue of convergence in simulations with topology changes (i.e., surface pinch-off) and on the viewpoint offered by atomistic and statistical modeling. State-of the-art simulations for various types of fuel injectors are presented next, with particular attention to numerical convergence and to the inclusion of realistic inlet boundary conditions. The review is concluded by the discussion of some of the challenges that still remains in this field.

42 ENGINEERING↗