The increased quality and quantity of sensors provide an ever-increasing capability to collect large quantities of high-quality data in the field. Research devoted to translating that data is progressing rapidly; however, translating field data into usable information can require high performance computing capabilities. While high performance computing (HPC) resources are available in centralized facilities, bandwidth, latency, security and other limitations inherent to edge location in field sensor applications may prevent HPC resources from being used in a timely fashion necessary for potential United States Army Corps of Engineers (USACE) field applications. To address these limitations, the design requirements for RECON are established and derived from a review of edge computing, in order to develop and evaluate a novel high-power, field-deployable HPC platform capable of operating in austere environments at the edge.

To push the thermal efficiency of turbomachinery, the turbine inlet temperature must be raised, eventually reaching and surpassing the blade material thermal limits. Internal geometry, such as pin fin arrays, has been the go-to solution for higher thermal environments to remove heat from blades and vanes to prevent material failure. The industry standard for turbomachinery in energy generation uses the steam Rankine or the Brayton cycle. Classically, these cycles have used air as the operating fluid environment. Over the past decade, novel solutions have begun changing how we design cycles, with one promising solution emerging: the supercritical carbon dioxide (sCO2) power cycle. Promising higher cycle efficiency with a smaller footprint has quickly become an attractive alternative for power generation. Although thorough research of pin fin arrays as turbulators in the trailing edge of turbine blade internal design has been a focus of research for the past several decades, in the sCO2 novel working environment, the need to re-visit the heat transfer characterization of internal cooling is necessary. This study was executed two-fold, first numerically and then experimentally. The first objective of this paper is to explore the heat transfer characteristics of sCO2 as the cooling environment in a staggered pin fin array, defined within the supercritical phase, using steady RANS conjugate heat transfer. An adapted correlation for the Nusselt number was derived, dependent on the Reynolds number, to provide a stronger correlation than existing air data-derived correlations in the literature. Taking this numerically derived correlation, the second objective of this paper is to design and run a matching experimental geometry fabricated for testing at target operating conditions of 400 Celsius and 200 bar. This data was then processed in tandem with the numerical and available derived data in the literature for direct comparison.

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<p>Solar thermosiphons integrated into the thermal envelop of buildings has been studied for their potential to take advantage of solar energy in heating buildings. The annual performance of the Solar Thermal Buffer Zone cannot currently be predicted with the correlations from previous research. Also, no work has been done on using the thermal buffer zone with a natural convection for energy savings in a building even though it has the potential to provide heating. The goal of this project was to design, analyze and determine the feasibility of a thermal buffer zone in a building. A thermal buffer zone can be defined as a fluid filled cavity which envelopes a building. This cavity provides a building with additional insulation but also allows for collection of solar energy and to be distributed throughout the structure in order to heat the interior. To show the physical aspect, the flow visualization in the project, computational fluid dynamic (CFD) software was used which was experimentally not possible. A physical prototype was then designed and constructed in order to test the effectiveness of the TBZ.</p> <p>This experiment included radiation as the heat source and the ability to vary geometric lengths. The performance parameters of mass flow rate were comparable between the numerical predictions and experimental results. However, due to uncertainties in the current experimental setup, full validation of the numerical model was not possible. These uncertainties would have to be addressed before the numerical model that was developed can be fully validated and used for generating correlations.</p> / Master of Applied Science (MASc)

<p>Among the six GEN-IV reactor concepts recommended by the Gen-IV International Forum, supercritical water-cooled reactors (SCWR) have gained significant interests due to its economic advantage, technology and experience continuity. In the last few years, extensive R&D activities have been launched covering the various aspects of SCWR development, especially in thermal-hydraulic analysis. In Canada, most R&D projects are led by AECL or NRCan.</p> <p>SCWR design and development require the modification of simulation codes used for design and safety demonstration of subcritical water-cooled reactors. This study modifies the subchannel code COBRA-TF, applicable to only subcritical water-cooled reactors, to a new version COBRA-TF-SC, applicable to both supercritical and subcritical water-cooled reactors. Supercritical water property data tables and supercritical water property formulations are implemented. Supercritical water heat transfer and pressure drop correlations are also added. The saturation curve in the subcritical model is extended by introducing a pseudo two-phase region at supercritical pressures to avoid any numerical instabilities consistent with other studies.</p> <p>Some simple fuel bundle experimental data on the flow and temperature distribution are used to evaluate the code. The fuel bundle experiment is simulated with both COBRA-TF-SC and AECL's ASSERT-PV-SC. The COBRA-TF-SC predicted results show good agreement with the experimental data and results obtained from ASSERT-PV-SC, demonstrating good feasibility and accuracy of this code. COBRA-TF-SC is then used to predict the detailed thermalhydraulics behaviour of the 62-element Canadian SCWR fuel bundle design. The advantage of COBRA-TF-SC is that it can accommodate transcritical flow conditions whereas the existing subchannel codes for SCWRs cannot.</p> / Master of Applied Science (MASc)

This paper determines the feasibility of adding a heater to an existing blowdown supersonic wind tunnel to unlock new high-enthalpy test applications, considering cost and power requirements at a variety of different states. This process includes both modeling the current range of test section properties in Cal Poly's blowdown wind tunnel and determining the new range of properties that a heat exchanger could induce. These results are verified with a computational fluid dynamics study. Additionally, sublimation and ablation properties of materials are explored to create appropriate models to study atmospheric re-entry once the heat exchanger is implemented. It is found that adding a heater to the supersonic wind tunnel would significantly increase the test section temperature. Additionally, enough heat could be added without damaging the facility to surpass the vapor pressure of camphor and naphthalene at test section conditions, allowing for the tunnel to be used for sublimation and ablation applications. Using the tunnel with the variable Mach nozzle currently installed would induce minimum heater power requirements of 75kW for a Mach 4 configuration and 200kW for the testing Mach 3.13 condition to reach this vapor pressure. However, this power requirement can be significantly reduced by installing a new nozzle that would induce flow at a Mach number of 6-8. Liquefaction is found to be avoided at every test and Mach condition, even without any heat added, while condensation cannot be avoided at any configuration, regardless of nozzle used or heat added. Therefore, we recommend that a dryer be installed to help remedy these issues.

This dissertation examines the assessment and mitigation of airborne noise from power generation equipment. The first half of the dissertation investigates the diagnosis and treatment of combustion oscillations in boilers. Sound is produced by the flame and is reflected downstream from the combustion chamber. The reflected sound waves perturb the mixture flow or equivalence ratio increasing the heat release pulsations and the accompanying sound produced by the flame. A feedback loop model for determining the likelihood of and diagnosing combustion oscillations was reviewed, enhanced, and then validated. The current work applies the feedback loop stability model to two boilers, which exhibited combustion oscillations. Additionally, a feedback loop model was developed for equivalence ratio fluctuations and validated. For the first boiler, the combustion oscillation problem is primarily related to the geometry of the burner and the intake system. For the second boiler, the model indicated that the combustion oscillations were due to equivalence ratio fluctuations. Principles for both measuring and simulating the acoustic impedance are summarized. An approach for including the effect of structural-acoustic coupling was developed. Additionally, a method for determining the impedance above the plane wave cut-off frequency, using the acoustic FEM, of the boiler was proposed. The second half of the dissertation examines the modeling of bar silencers. Bar silencers are used to mitigate the airborne noise from large power generation equipment (especially gas turbines). Due to the large dimensions of the full cross section, a small representative cell is isolated from the entire array for analysis purposes. To predict the acoustical performance of the isolated cell for different geometric configurations, a numerical method based on the direct mixed-body boundary element method (BEM) was used. An analytical solution for a simplified circular geometry was also derived to serve as a comparison tool for the BEM. Additionally, a parametric study focusing on the effects of flow resistivity, perforate porosity, length of bars, and cross-sectional area ratio was performed. A new approach was proposed to evaluate the transmission loss based on a reciprocal work identity. Moreover, extension of the transmission loss computation above the plane wave cut-off frequency was demonstrated.

The United States holds the world's largest estimated reserves of coal and is also a net exporter of it. Coal gasification provides a cleaner way to utilize coal than directly burning it. Gasification is an incomplete oxidation process that converts various carbon-based feedstocks into clean synthetic gas (syngas), which can be used to produce electricity and mechanical power with significantly reduced emissions. Syngas can also be used as feedstock for making chemicals and various materials. A Computational Fluid Dynamics (CFD) scheme has been used to simulate the gasification process for many years. However, many sub-models still need to be developed and improved. The objective of this study is to use the improved CFD modeling to understand the thermal-flow behavior and the gasification process and to provide guidance in the design of more efficient and cheaper gasifiers. Fundamental research has been conducted to improve the gasification sub-models associated with the volatile thermal cracking, water-gas-shift (WGS) reaction, radiation effect, low-rank-coal gasification, coal to synthetic-natural-gas (SNG), and ash deposition mechanisms. The improved volatile thermal cracking model includes H2S and COS contents. A new empirical WGS reaction model is developed by matching the result with experimental data. A new coal demoisturization model is developed for evaporating the inherent moisture inside the coal particles during low-rank-coal gasification. An ash deposition model has also been developed. Moreover, the effect of different radiation models on the simulated result has been investigated, and the appropriate models are recommended. Some improved model tests are performed to help modify an industrial entrained-flow gasifier. A two-stage oxygen feeding scheme and a unique water quench design are investigated. For the two-stage oxygen feeding design, both experimental data and CFD predictions verify that it is feasible to reduce the peak temperature and achieve a more uniform temperature distribution in the gasifier by controlling the injection scheme without changing the composition and production rate of the syngas. Furthermore, the CFD simulation can acceptably approximate the thermal-flow and reaction behaviors in the coal gasification process, which can then be used as a preliminary screening tool for improving existing gasifiers’ performance and designing new gasifiers.

The Kentucky Re-entry Universal Payload System (KRUPS) is an adaptable testbed for atmosphere entry science experiments, with an initial application to thermal protection systems (TPS). Because of the uniqueness of atmospheric entry conditions that ground testing is unable to replicate, scientists principally rely on numerical models for predicting entry conditions. The KRUPS spacecraft, developed at the University of Kentucky, provides an inexpensive means of obtaining validation data to verify and improve these models. To increase the technology readiness level (TRL) of the spacecraft, two sub-orbital missions were developed. The first mission, KUDOS, launched August 13th, 2017 on a Terrier-Improved Malamute rocket to an altitude of ~150 km. The second mission, KOREVET, launched on March 25th, 2018 on the same type of rocket to an altitude of ~170 km. The chief purpose of both missions was to validate the spacecraft design, ejection mechanism, on-board power, data transmission, and data collection. After both missions, the overall TRL improved from 4 to 5 by validating most subsystems in a relevant environment. Both of these missions were invaluable preparation for the project's ultimate goal of releasing multiple experimental testbeds from the ISS.

The Reciprocating Mechanism Driven Heat Loop (RMDHL) is a novel heat transfer device that utilizes reciprocating flow, either single-phase or two-phase flow, to enhance the thermal management in high tech inventions. The device attains a high heat transfer rate through a reciprocating flow of the working fluid inside the heat transfer device. Although the concept of the device has been tested and validated experimentally, analytical or numerical studies have not been undertaken to understand its working mechanism and provide guidance for the device design. The objectives of this study are to understand the underlying physical mechanisms of heat transfer in internal reciprocating flow, formulate corresponding heat transfer correlations, conduct an experimental study for the heat transfer coefficient, and numerically model the single-phase and two-phase operations of the RMDHL to predict its performance under different working conditions. The two-phase flow boiling model was developed from the Rensselaer Polytechnic Institute (RPI) model, and a virtual loop written in C programming language was used to eliminate the need for fluid structure interaction (FSI) modelling. The accuracy of several turbulence formulations, including the Standard, RNG, and Realizable k-ɛ Models, Standard and SST k-ω Models, Transition k - - ω Model, and Transition SST Model, have been tested in conjunction with a CFD solver to select the most suitable turbulence modelling techniques. The numerical results obtained from the single-phase and two-phase models are compared with relevant experimental data with good agreement. Three-dimensional numerical results indicate that the RMDHL can meaningfully reduce the peak temperature of an electronic device and result in significantly more uniform temperature across the device. In addition to the numerical study, experimental studies in conjunction with analytical studies are undertaken. Experimental data and related heat transfer coefficient as well as practically useful semi-empirical correlations have been produced, all of which provide archival information for the design of heat transfer devices involving a reciprocating flow. In particular, this research will lead to the development of more powerful RMDHLs, achieve a heat flux goal of 600 W/cm2, and significantly advance the thermal management at various levels. Considering the other advantages of coolant leakage free and the absence of cavitation problems, the RMDHL could also be employed for aerospace and battery cooling applications.