Theses and Dissertations at Montana State University (MSU)
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/733
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Item Underwater acoustic propagation modeling and utilization for marine hydrokinetic devices(Montana State University - Bozeman, College of Engineering, 2024) Hafla, Erin Christine; Chairperson, Graduate Committee: Erick JohnsonOver the last two decades, there has been growing concern surrounding the increase in underwater anthropogenic sounds as expanding human populations interact with marine life and look for alternative energy production methods. That concern has led to a significant push worldwide to understand how propagated sound interacts with the surrounding marine environment. Marine hydrokinetic (MHK) devices are an alternative source of renewable energy available, which generate electricity from the motion of tidal and ocean currents, as well as ocean waves. Sounds produced by MHKs tend to overlap the frequency range common to both marine fauna communication and behavior. Preliminary measurements indicate that sound level values fall near the total sound decibel limitations presented by regulatory bodies. To date, the power optimization of MHK arrays has been prioritized over how its sound is produced, directed, and may impact the marine soundscape. There is a gap in knowledge regarding how marine fauna may respond to these sounds and what their physical and behavioral impact may be, and an absence in measured levels from insitu MHK deployments. A model for predicting the propagation of sound from an array of MHK sources in a real environment is essential for understanding potential impacts on a surrounding system. This work presents a fully three-dimensional solution to a set of coupled, linearized velocity-pressure equations in the time-domain as applied to underwater systems, and is an alternative sound propagation model to the Helmholtz and wave equation methods. The model is validated for a single source located within a series of increasingly complex two-dimensional and three-dimensional shallow water environments and compared against analytical solutions, examples from literature, and recorded sound pressure levels collected from Sequim Bay, WA. An uncertainty analysis for an array of MHK devices is presented to further understand how multiple turbine signals interact with one another in increasingly complex systems. This research presents a novel use of the velocity-pressure equations to analyze the variability associated with sound sources as sound propagates through a selected environment to inform the design and deployment of a MHK device or array of devices to minimize potential future impacts.Item Rheo-NMR of complex fluids under startup, steady state and large amplitude oscillatory shear(Montana State University - Bozeman, College of Engineering, 2021) Jayaratne, Jayesha S.; Chairperson, Graduate Committee: Joseph D. Seymour and Sarah L. Codd (co-chair); This is a manuscript style paper that includes co-authored chapters.Fluids are categorized as either simple or complex based on the intricacy of their structure and material response to deformation. Simple fluids composed of small molecules subject to deformation, readily flow with linear interaction dynamics with neighboring molecules. In contrast complex fluids like polymers, micelle solutions, colloidal gels and suspensions, composed of larger molecules or particulates alter the dynamics of individual constituents during deformation, requiring complicated constitutive models. Complex fluids are encountered daily, as they are found in consumer products such as food, pharmaceutical and personal care products. Knowing flow characteristics of these consumer products and their raw materials under industrially applicable deformations enables engineers to design efficient industrial processes and to formulate products to desired qualities. While classical rheology (the study of the flow and deformation of matter) techniques give good estimation of stress-strain bulk flow response, it fails to provide local flow information. Proton nuclear magnetic resonance (1H-NMR) has been used to measure spatially and temporally resolved velocities of fluids subject to mechanical deformation. This research field is known as 'Rheo-NMR' and is a novel flow measuring technique in that it is non-invasive and able to quantify three-dimensional velocity fields even of opaque fluids. Velocity responses of complex fluids like worm-like micelle solutions, yield stress fluids and shear thinning fluids were studied under varied mechanisms of deformation and were compared to the responses of simple Newtonian fluids. How local velocities of the fluids change over time when a steady shear is applied suddenly, how the velocity fields are affected on applying large oscillatory shear deformations and how using different shearing geometries impacts the local flow response were explored. Using Rheo-NMR techniques, experimental protocols to study spatio-temporal velocity fields of complex fluids were developed and data analysis methods for quantifying such measurements were established.Item Magnetic resonance imaging studies of forced and free convective heat transfer in packed beds and fluid columns(Montana State University - Bozeman, College of Engineering, 2021) Skuntz, Matthew Eric; Chairperson, Graduate Committee: Ryan Anderson; This is a manuscript style paper that includes co-authored chapters.Prediction of fluid flow and associated energy transport is an essential component in many engineering applications where analytical solutions are not possible. In these systems experimentation and numerical simulations are a necessary part of the design process. This work focuses on the experimental study of mass and energy transport in packed beds and pure fluids under forced and natural convection using nuclear magnetic resonance (NMR) imaging (MRI) techniques. It further evaluates the efficacy of commercial computational fluid dynamics (CFD) software to simulate these processes. The study of heat transfer via NMR has proven difficult historically, despite sensitivity of NMR parameters to temperature. Here, a novel experimental setup is pioneered, which enables the study of heat transfer in packed beds. The method employs fluorinated pore-filling fluid and hydrogen-rich core-shell packing particles. Hydrogen and fluorine are NMR-active chemicals that can be imaged with the same experimental equipment by adjusting the resonance frequency; providing means to image the two domains separately. Pore- fluid velocities and particle-wax melting are observed in the same packed bed, at sub-millimeter resolutions, presenting a more complete picture of the conditions in these hard-to-measure systems. In the presented studies, this methodology is demonstrated under forced convection and proven capable in identifying and correlating spatial variations in heat transfer to pore-fluid velocity. The technique is then employed to assess the accuracy of a CFD model in the commercial software package, STAR CCM+, using the melt to quantify energy absorbed by the bed. In natural convection studies of a pure fluid and packed bed in the Rayleigh-Bénard configuration, the axial circulation pattern is found to change with axial position in the long narrow cylinder, a result that is rarely discussed in literature. A CFD model is shown to match well with these experimental findings. In porous media convection with sub-, near- and super- critical fluid, the rapidly changing thermal diffusivity was captured by the rate the particles absorb energy. Finally, a correlation is developed allowing particle-wax T 2 relaxation time to be converted into temperature.Item Transient and steady state Rheo-NMR of shear banding wormlike micelles(Montana State University - Bozeman, College of Engineering, 2020) Al Kaby (Al Qayem), Rehab Noor; Chairperson, Graduate Committee: Sarah L. Codd and Jennifer Brown (co-chair); Jayesha S. Jayaratne, Timothy I. Brox, Sarah L. Codd, Joseph D. Seymour and Jennifer R. Brown were co-authors of the article, 'Rheo-NMR of transient and steady state shear banding under shear stratup' in the journal 'Journal of rheology' which is contained within this dissertation.; Sarah L. Codd, Joseph D. Seymour and Jennifer R. Brown were co-authors of the article, 'Characterization of velocity fluctuations and the transition from transient to steady state shear banding with and without pre-shear in a wormlike micelle solution under shear startup by Rheo-NMR' submitted to the journal 'Journal of applied rheology' which is contained within this dissertation.Over many years, the combination of nuclear magnetic resonance (NMR) techniques with rheometry, referred to as Rheo-NMR has been used to study materials under shear noninvasively. Rheo-NMR methods can provide valuable information on the rheological responses of materials or their behavior by temporally and spatially resolved mapping of the flow field. In this thesis, 1D velocity profiles across the fluid gap of a Couette shear cell are recorded using Rheo-NMR velocimetry to investigate the wormlike micelles (WLMs) surfactant system under transient and steady state flow conditions. The WLM system was a solution of 6 wt. % cetylpyridinium chloride (CPCl) and sodium salicylate (NaSal) in 0.5 M NaCl brine which is well-known for its ability to exhibit a mechanical response during flow known as shear banding. The shear banding phenomena is simply defined as the splitting of the flow into two macroscopic layers, a high and low shear band bearing different viscosities and local shear rates. Elastic instabilities are well known to develop in the unstable high shear band and manifest as fluctuations in the 1D measurements. Recently, it has been suggested that 1D velocimetry alone cannot reveal information about those observed fluctuations in terms of a sequence of elastic instabilities and 2D or 3D measurements are required. In this thesis, new Rheo-NMR equipment and quantitative analysis are used to characterize those fluctuations and show that 1D velocity measurements still have the potential to provide valuable information about 3D flows. Transient and steady state shear banding was observed for a range of shear rates across the stress plateau and the impact of several flow protocols were studied. The evolution of the high, low, and true shear rates, as well as interface position with time after shear startup was used to evaluate changes in the kinetics of shear band formation as a function of applied shear rate and flow protocol. Ultimately, these results will help in understanding the correlation between the macroscopic flow field and the microscopic structure and dynamics of WLMs and can also be a way to gain information about the presence and the dynamic of secondary flow without the need of a 3D measurement.Item Thermal energy storage with sensible heat in an air-alumina packed bed using axial flow, axial flow with layers and radial flow(Montana State University - Bozeman, College of Engineering, 2020) Al-Azawii, Mohammad Mahdie Saleh; Chairperson, Graduate Committee: Ryan Anderson; Carter Theade, Megan Danczyk, Erick Johnson and Ryan Anderson were co-authors of the article, 'Experimental study on cyclic behavior of thermal energy storage in an air-alumina packed bed' published in the journal 'Journal of energy storage' which is contained within this dissertation.; Carter Theade, Pablo Bueno and Ryan Anderson were co-authors of the article, 'Experimental study of layered thermal energy storage in an air-alumina packed bed using axial pipe injections' in the journal 'Applied energy' which is contained within this dissertation.; Duncan Jacobsen, Pablo Bueno and Ryan Anderson were co-authors of the article, 'Experimental study of thermal behavior during charging in thermal energy storage packed bed using radial pipe' in the journal 'Applied thermal engineering' which is contained within this dissertation.Thermal behavior in a packed bed thermal energy storage (TES) system is studied experimentally. TES systems are a promising solution to integrate renewable energy sources such as solar energy. The performance of such systems can be affected by different variables such as storage material size/type, pressure, temperature, heat transfer fluid (HTF), storage type (sensible/latent heat), and flow rate. Although these variables have been studied in literature, the resulting thermal dispersion and heat losses to the environment have been considered in few studies. This thesis studies the thermal behavior of an air-alumina TES packed bed focusing on dispersion and heat losses to quantify the thermal performance. Reducing their effects can improve the thermocline and thus thermal efficiency. The research efforts in this work quantify these effects and provide two new methods to reduce thermal dispersion and increase exergetic efficiency. Three configurations were considered in the present study. In the first configuration, a traditional packed bed is used focusing on performance for multiple partial cycles. This configuration quantified the thermal performance and served as a basis to compare the results from the other configurations. Dispersion effects were found to accumulate before a steady state was achieved during cycling. In the second and third configurations, novel pipe injection techniques were used to charge/discharge the bed. First, the normal bed is divided into layers via inserting pipes along the bed's axial length, focusing on a full charge-discharge cycle. Results show that exergy efficiency increases with flow rate and number of layers. The thermocline improved and dispersion losses decreased with number of layers. Second, a perforated pipe to facilitate radial flow was inserted at the center of the bed along the axial length to heat the bed. Radial charging shows higher charging efficiency compared to normal axial charging. Pipe injection is a novel method and a promising technique that improves the thermal performance of a lab scale storage bed, especially the layering method. Radial injection warrants more investigation to quantify its performance in thermal cycles.Item Intrusive uncertainty quantification method for simulations of gas-liquid multiphase flows(Montana State University - Bozeman, College of Engineering, 2020) Turnquist, Brian Robert; Chairperson, Graduate Committee: Mark Owkes; Mark Owkes was a co-author of the article, 'MULTIUQ: an intrusive uncertainty quantification tool for gas-liquid multiphase flows' in the journal 'Journal of computational physics' which is contained within this dissertation.; Mark Owkes was a co-author of the article, 'A fast, density decoupled pressure solver for an intrusive stochastic multiphase flow solver' submitted to the journal 'Journal of computational physics' which is contained within this dissertation.; Mark Owkes was a co-author of the article, 'MULTIUQ: a software package for uncertainty quantification of multiphase flows' submitted to the journal 'Computer physics communications' which is contained within this dissertation.; Mark Owkes was a co-author of the article, 'Exploration of basis functions for projecting a stochastic level set in a multiphase flow solver' submitted to the journal 'Atomization and sprays' which is contained within this dissertation.Simulations of fluid dynamics play an increasingly important role in the development of new technology. For example, engineers may need to simulate an atomizing jet to create a better direct injection system for improving fuel economy in a vehicle, or to more efficiently spray water for building fire mitigation systems. The increased use of computational fluid dynamics requires improvements in methodology to improve simulation efficiency and accuracy. We can extract a great deal from these models, including uncertainty information. Although simulation of gas-liquid multiphase flow scenarios are common, most are deterministic in nature. Model parameters, like fluid density or viscosity, are assumed to be known and fixed. But this is not usually the case, and a research gap exists for uncertainty analysis in these simulations. For efficient performance, an intrusive approach is used to create a multiphase solver capable of uncertainty analysis. Variables of interest, such as velocity and pressure, are converted into stochastic variables which are allowed to vary in an added uncertainty dimension. Variability is then added to fluid parameters or initial/boundary conditions and a simulation is run which produces stochastic results. To verify the solver, several cases are presented which compare the ability of the solver against analytic solutions. Once satisfied with the ability of the solver, we can answer questions about more complex scenarios. For instance, we may question how uncertainty about the surface tension force may affect the atomization of a jet and find that fluids with a lower surface tension coefficient breakup sooner (as expected). We could also consider scenarios that may not have such an obvious outcome, such as imposing uncertainty about the density ratio for an atomizing jet to determine the effect of running simulations at low vs high density ratios. multiUQ is capable of producing accurate results of real world situations. As a tool it can provide additional insight into understanding complicated multiphase flow systems.