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Inasmuch as power generation systems, in both avionic and stationary applications, are typically powered by liquid fuels, the process of liquid fuel/air mixture preparation plays a key role in combustion (i.e., fuel burning) of these systems. One of the most efficient liquid fuel/air mixture generation techniques in a combustion chamber is by injecting liquid fuel transversely into a gaseous crossflow (JICF). Amongst the various features of this type of flow-field, data describing the trajectory and breakup length of a transverse liquid jet is highly required for combustor design in order to prevent fuel impingement onto the combustor walls. More importantly, it is needed for predicting fuel distribution in a combustor, which directly affects droplets breakup, collision, evaporation, mixing rate with oxidants, and consequently the overall combustion efficiency of an engine. Due to the complexity associated with the theory behind a transverse liquid jet, a large body of investigations on its features is experimental; however, several experimental challenges such as the limitations in observing the dense spray region hinder the progress in understanding this topic. Moreover, the liquid jet’s trajectory and its breakup length vary significantly with changing liquid properties, test/operating conditions and nozzle/injector internal geometries, leading to huge discrepancies between published results/predictions. In this thesis, therefore, a phenomenological investigation, by integrating both theoretical and experimental approaches, has been carried out to gain a more comprehensive understanding of the complex process of a transverse liquid jet in a gaseous crossflow. A mathematical method was adopted to develop a model for predicting the penetration of a liquid jet in a subsonic gaseous crossflow over a wide range of liquid properties and test/operating conditions. In the near field zone, a force balance was applied to a control-volume, and forces acting upon the liquid

To investigate the effect of shroud on the performance of hydrokinetic turbines in inline and off-axis flows, a horizontal axis model turbine and two shrouds were designed and fabricated. Consistent power, torque, and thrust coefficients for the shrouded and unshrouded turbines were obtained for a complete range of performance curve in water tunnel experiments. A maximum power enhancement of 91% over the unshrouded turbine is obtained with the straight wall diffuser design. Power coefficients of the model turbine with the diffuser calculated based on the diffuser exit area, in agreement with the van Bussel momentum theory, is found comparable to the performance coefficients of the unshrouded turbine with the size of the diffuser exit diameter. In off-axis flows the output power of a hydrokinetic turbine is observed to decrease. The reduction is negligible up to 10° yaw angle but increases as the yaw angle increases beyond 10°. The model turbine with the convergent–divergent wall shroud design experiences negligible performance loss in yaw operations compared to the unshrouded turbine. Using the experimental results and in an analogy to the cosine rules of the linear momentum theory, similar cosine relations for the shrouded turbines are proposed for the first time. The optimum power of the model turbine with the shroud is experimentally observed to decrease with cosine of yaw angle. Based on this, the turbine with the shroud in a 45° yaw angle would generate 29% less power than in an inline flow. The unshrouded turbine, based on the cosine cubed rule of the momentum theory, would generate 65% less power in the same flow. This study addresses the fact why the reported augmentation factors for diffuser augmented wind turbines in the literature has a broad range from -36% to 760% which shows disagreements between researchers.

Distributed generation along with smart grid applications are poised to make important contributions to the clean-tech sector and remote communities. The dependence on one source for energy supply does not prove reliable enough when the renewable resource, such as wind or solar, is variable, creating a dependence on external fuel supply and a vulnerability to foreign control. Developing an energy strategy through intelligent energy system simulation and optimization can help communities make informed decisions about their energy investments. This dissertation reasons that distributed renewable energy systems without operative computational infrastructures face a fundamental economic challenge derived from their ad-hoc design and implementation. To address this, it proposes the method of Optimal Operational Awareness (OOA)—a feedback mechanism on the state of, and changes in, the properties of the implemented subsystems and their behaviour, to meet users objectives. Despite many applications of hybrid renewable energy systems, and reputable multi-objective evolutionary algorithms (MOEAs) for optimization, no one has applied MOEAs to dynamic system operation for optimized engagement of system components. This thesis describes an application of the NSGA-II algorithm to the multi-objective optimization of the operation of a stand-alone wind-PV-biomass-diesel system with batteries and CAES storage and a central controller. The simultaneous objectives are to minimize the levelized cost of energy (LCOE), and unmet load (UL) while maximizing the renewable energy ratio (RER). This work provides a case-study evaluation from data collected on-site at the island of Fernando de Noronha (FDN), Brazil. The results show that FDN could move from an annual average of 33% RER and LCOE range of $0.26 - $0.36 per kWh to an increased RER range of 60% - 100% and LCOE of $0.10 - $0.50 per kWh, while maintaining UL of 0%, by increasing its renewable energy generation and storage capacity ap

A review of the literature indicates that the understanding of the mixing phenomena in anaerobic digesters is limited and the ability to measure digester mixing characteristics is lacking. Moreover, rheological characteristics of the sludge are largely ignored. The need for a more thorough understanding of fundamental mixing relationships and the ability to measure these relationships in the anaerobic digester is recognized. To this end, investigations using experimental and numerical methods to visualize flow patterns and quantify mixing that impact biogas yields is reported. Results from this research identifies optimum mixing regimes for digesters depending on their sludge rheology, operational regimes, digester dimensions and mixing systems, and also produces an industrial guide to improve digester design. The results show that in order to accurately predict the optimum mixing regime for a particular anaerobic digester, it is necessary to determine to what extent biogas output is dependent upon, and can be influenced by flow patterns in an anaerobic digester. These flows are in turn determined by physical characteristics of the digester, the feed regime, the mixing system and the rheological properties of the sludge. Mixing regimes are tailored to produce flow patterns that could potentially increase biogas production and/or reduce mixing energy input of the digester. An all-inclusive anaerobic digester model is developed and validated using advanced experimental techniques that can be used to optimize the digestion process in terms of physical and biological parameters. In either case, the model provides an ongoing management of anaerobic digester process to improve overall energy yield from the digester and reduce its environmental impact.

The majority of vehicles over the near term will rely on petroleum, with electric vehicles poised to take over a significant market share of new light duty vehicles in the near future. The proposed Auxiliary Drive Device (ADD) instantly provides hybridization and electrification of an existing fossil fuel vehicle. The purpose is to contribute torque to increase fuel economy and to compensate for the load born by a towing vehicle to reduce the engine size. The ADD is simulated, built and tested for the first time in a towing vehicle configuration. A sensor integrated mechanism is used to measure the force of the trailer load onto the towing vehicle. A test bench platform verifies controls on a push plate in a force sensor feedback control loop configuration. In addition, a scaled prototype provides experimental data to verify mathematical models developed for the ADD. It is found that this new concept provides performance gains and fuel economy savings in a towing configuration.

There is a lack of available technology to make small-scale power from biomass cost effectively. The proposed Hybrid Brayton cycle is an indirectly heated Brayton cycle with evaporative cooling for combined heat and power generation. It converts a direct fired microturbine to an indirectly heated power system. The Hybrid Brayton cycle offers a flexible biomass power generation platform in the 30 to 250 kWe range, achieving competitive efficiencies and advantages compared to other systems of similar power level. This cycle is designed to be implemented in remote and off-grids communities, small industries and net-zero communities, where local biomass feedstock is sustainably available. This proposed platform keeps operator qualifications to a minimum. In an effort to validate this new power cycle, a 30 kWe experimental facility was developed and initial commission phases performed. This facility purpose is to validate numerical model predictions and is used for optimization. The facility is described and results of the commissioning tests are reported with various problems encountered, solutions implemented and recommendations proposed. The thermodynamic model of the Hybrid Brayton cycle is also implemented in the MatLAB environment, incorporating experimental findings and new properties for humidified air at high temperatures. The MatLAB model confirms that an indirect fired Brayton cycle with evaporative cooling could be a viable approach for small scale distributed power generation using biomass. Additional experimental data of humidified air at elevated temperatures would provide more certainty in property predictions. The MatLAB model provides a modeling tool to allow resolving the issues identified during the commissioning of the test facility and offers alternatives to optimize various design configurations, implementing the most up to date property correlations for humidified air at elevated temperatures.

A comprehensive framework is presented for the integration of electrified transportation and renewable energy through repurposing batteries of plug-in electric vehicles towards a sustainable energy future. The framework considers future market penetration scenarios of plug-in electric vehicles, availability of batteries at their vehicular end of life, and the storage capacity required to generate base-load wind power in the region of study. The objective is to develop a model that can be used as a policy tool to investigate how different scenarios and pertinent parameters can effectively meet the challenges of sustainability in the energy and transportation sectors when the ultimate goal is to simultaneously displace fossil fuels with new generation of low-cost intermittent renewable energy. A sample case study is performed for Canada to investigate and verify the performance of the model. The analysis shows that the proposed approach can further improve the energy sustainability performance of Canada in 2050 by 1.65–4.11%, depending on the confidence level and in addition to electrification of transportation. In the framework, a statistical algorithm is developed to calculate the capacity of an energy storage system required for delivering base-load electricity for a wind farm in the future electric grids. The algorithm contributes towards the goal of utilizing low- cost intermittent wind energy to base-load power generation in the future electric grids. The introduced algorithm presents three methods to perform the sizing calculations each representing a scenario associated with the stages of the wind energy industry. The results of the studied case are applied to estimate the cost of wind energy to produce rated power at different confidence levels, which show cost-effectiveness and less intermittency on the power systems allowing for larger penetrations of renewables. Advanced statistical methods are used to more accurately characterize the operational wind powe

The conversion of lignocellulosic wheat straw to bioethanol was found to bene5it from pre- treatment using superheated steam (SS). A 2-step pre-treatment method using pressurized hot water at 119 ̊C followed by SS at 220 ̊C yielded the best results, with the most pronounced effect on enzymatic sugar liberation occurring after 2 minutes of SS treatment. The net sugar conversion ef5iciencies were 46.4 and 53.5% for glucose and xylose, respectively. The glucose was recovered from the treated biomass, while the majority of the xylose was recovered from the supernatant of the hot water phase. With an energy demand of approximately 1998 kJ/kg of biomass, pre-treatment with SS consumes approximately 78% as much energy as steam explosion, and can produce ethanol at a comparable price, based on a preliminary economic assessment. Two technologies were examined for integration of solar energy into the SS process stream: evacuated tube solar collectors (ETSC) and parabolic trough solar collectors (PTSC). Utilization of ETSC was found not to be feasible for these applications due to low conversion ef5iciency (<12%) and progressive component failure at temperatures in excess of 175 ̊C. More promise was found with PTSC, which had higher conversion ef5iciencies of 36.4 and 55.8% at operating temperatures of 220 and 150 ̊C, respectively. Experimental results were based on numerical simulation, and indicate that on a large scale, a PTSC facility is capable of generating energy at a rate competitive with conventional energy sources (<$0.021/kWh), though the capital expenditures are substantial, if not prohibitive.

Experimental thermal-hydraulic study of a rectangular supercritical CO2 natural-circulation loop with a horizontal heated channel was conducted at different steady-state conditions. These included different system pressures and three different inlet temperatures, with different inlet and outlet valve openings. Approximately, 450 experimental steady-state data-points were collected. The data include measurements of pressure-drop along the heated channel, pressure-drop across inlet and outlet valves, applied heat on the heated channel, pressure, temperature and flow-rate. Steady-state curves of mass flow-rate versus power, outlet temperature versus power, and detailed information of frictional pressure drop and local head loss coefficients were produced. Comparison showed that for the available experimental set-up, computed frictional pressure-drops fell within 1-1.20 of the Blasius formula prediction. Moreover, flow oscillations were observed in several cases when outlet temperature of CO2 was higher than the pseudo-critical temperature on the negative slope part of the mass flow-rate versus power curve.

Anaerobic digestion is a process that simultaneously treats waste and produces renewable energy in the form of biogas. Applications include swine and cattle waste management, which is still dominated by aerobic digestion, a less environmental alternative. The low adoption rates of anaerobic digestion is partly caused by the lack of modelling basis for the technology. This is due to the complexity of the process, as it involves dozens of interrelated biochemical reactions driven by hundreds of species of micro-organisms, immersed in a three-phase, non-Newtonian fluid. As a consequence, no practical computer models exist, and therefore, unlike most other engineering fields, the design process for anaerobic digesters still relies heavily on traditional methods such as trial and error. The current state-of-the-art model is Anaerobic Digestion Model No. 1 (ADM1), published by the International Water Association in 2001. ADM1 is a bulk model, therefore it does not account for the effects of concentration gradients, stagnation regions, and particle settling. To address this, this thesis works toward the creation of the first three-dimensional spatially resolved anaerobic digestion model, called Anaerobic Digestion Model with Multi-Dimensional Architecture (ADM-MDA), by developing a framework. The framework, called Coupled Reaction-Advection Flow Transient Solver (CRAFTS), is a general reaction solver for single-phase, incompressible fluid flows. It is a novel partial differential and algebraic equation (PDAE) solver that also employs a novel programmable logic controller (PLC) emulator, allowing users to define their own control logic. All aspects of the framework are verified for proper function, but still need validation against experimental results. The biochemistry from ADM1 is input into CRAFTS, resulting in a manifestation of ADM-MDA; however the numerical stiffness of ADM1 is found to conflict with the second order accuracy of CRAFTS, and the resulting model can onl

Field and laboratory measurements characterize the performance of vertical axis hydrokinetic turbines operating in uniform and non-uniform inflow conditions for river applications. High sampling frequency velocity measurements, taken at 200 Hz upstream of a stopped and operating 25-kW H-type vertical axis hydrokinetic turbine in the Winnipeg River, show the existence of large eddies with an order of magnitude of the turbine’s diameter. Scaling laws allow modeling river conditions in the laboratory for more detailed investigations. A small-scale, 30 cm diameter, squirrel-cage vertical turbine designed, manufactured and equipped with a torque and position sensors is investigated for the detail behavior of the turbine subjected to different inflow conditions in a laboratory setting to study the effect of flow and fluid structures. The adjustable design of the laboratory turbine enables operations with different solidities, 0.33 and 0.67, and preset pitch angles, 0°, ±2.5°, ±5° and ±10°. Tests are first performed with uniform inflow condition to measure the sensitivity of the turbine to solidity, preset pitch angle, free-surface, and Reynolds number to obtain the optimum operating conditions. During the free-surface testing a novel dimensionless coefficient, clearance coefficient, is introduced that relates the change in turbine efficiency with change in the free-surface height. High-speed imaging at 500 fps of semi-submerged blades visualizes the vortex-shedding pattern behind the blades and air entrainment. High-speed imaging results of large eddy pattern behind the vertical turbine are consistent with theory and measurements. Subsequently, cylinders of different diameters create non-uniform inflow conditions in the water tunnel by placing them at different longitudinal and lateral locations upstream of the model turbine. Thus, the effects of non-uniform inflow generated under controlled settings shows the impact of eddies and wake on the turbine performance. High sam

Opportunities for enhancing the security and reliability of power supply as well as the utilization of renewable and efficient energy sources have generated major interest in Microgrids. A microgrid typically consists of interconnected loads, distributed generators (DG) and energy storages, and should be able to operate in parallel with the utility grid or as a power-island. The main focus of this thesis is on the transition between parallel and islanded operation of a microgrid. A literature review on existing microgrids was carried out. Based on the survey, a microgrid test system was implemented on PSCAD/EMTDC simulation program. The microgrid controls essential for the study and a load shedding scheme were designed and implemented. When the microgrid changes from parallel to islanded operation, its controls need to be changed. It was found that delays in microgrid control mode transition can impact the amount of load need to be shed to preserve the frequency stability and the power quality of the islanded microgrid. The importance of fast detection of islanding was therefore highlighted. The IEEE standard 1547.4-2011 recommends application of the existing DG synchronization criteria for microgrid synchronization. The adequacy of these criteria for synchronization of a microgrid with highly unbalanced loading was investigated. It was found that the required criteria can be met with the support of switched capacitors for voltage balancing, and a circuit breaker supervised by a synchro-check relay is sufficient to successfully reconnect an islanded microgrid back to the utility. In order to meet the requirement for fast detection of islanding of microgrids, new islanding detection technique was proposed. In the proposed scheme, Discrete Wavelet Transform was used to extract features from transient current and voltage signals, and then a Decision Tree classifier was employed to distinguish islanding events from other transients. Simulation based tests asserted that

This thesis introduces a power electronic interface for a kinetic hydropower generation platform that enables extraction of electric power from a free-flowing water source such as a river or a stream. The implemented system transfers power from a high-frequency permanent magnet synchronous generator (PMSG) to a 60-Hz load. Special configurations and control techniques were developed to cater for the long distance between the generator and the power interface; and also to address the wide range of the PMSG frequency and voltage variations. The proposed power-electronic interface was constructed and tested in the laboratory as well as in the field. The thesis also introduces two feasible methods for controlling a hydrokinetic plant to supply islanded loads or to deliver the maximum power available from the turbine-generator to the utility network. Application of multiple turbines in a kinetic farm was also investigated, and different approaches to controlling hydrokinetic turbines were developed.

Ice accretion on wind turbines is a major problem in cold climates that reduces power generation and fatigues turbine components. Effective anti-icing and de-icing strategies to manage ice accretion require reliable local assessment of icing conditions and a measure of ice accretion rate on structures. Such sensors could be located on meteorological towers near wind farms or the nacelle of wind turbines. A new concept for the estimation of atmospheric ice accretion based on the measurement of capacitance and resistance change between two charged cylinders as ice accretes on the cylinders is introduced in this study. Numerical simulation of the electric field between the charged cylinders is used to investigate the dependence of the sensitivity of capacitance to the distance between the cylindrical probes and location of ice deposits. The numerical results are validated experimentally using aluminum probes and a set of acrylic cylindrical sleeves that fit over the probes to simulate icing with accurate geometries. A charged cylindrical probes system constructed based on the numerical results is described and evaluated under controlled rime and glaze icing conditions in the University of Manitoba Icing Wind Tunnel. Test results indicate ice builds up on the cylindrical probes and the measured capacitance increases while the resistance decreases. The change in measured capacitance change correlates well with the increase in the ice mass. Rime and glaze ice are distinguishable based on the rate of change of resistance with ice accretion. The numerical and experimental results provide a proof of concept of the charged cylindrical probes ice accretion measurement concept.

This thesis examines how the non-Newtonian characteristics of liquid hog manure affect the flow conditions within a steady-flow anaerobic digester. There are three main parts to this thesis. In the first part of this thesis, the physical properties of liquid hog manure and their variation with temperature and solids concentration are experimentally determined. Naturally¬¬-settled manure sampled from an outdoor storage lagoon is studied, and density, viscosity, and particle size distribution are measured. Hog manure with total solids concentrations of less than 3.6% exhibits Newtonian behaviour; manure between 3.6% and 6.5% total solids is pseudoplastic, and fits the power law; manure with more than 6.5% total solids exhibits non-Newtonian and time-dependent characteristics. The second part of this thesis investigates the flow of Newtonian and non-Newtonian fluids—represented by tap water and xanthan gum solution, respectively—within four lab-scale reactor geometries, using residence time distribution (RTD) experiments. The effect of reactor geometry, flow rate, and fluid viscosity are evaluated. In the third part of this thesis, flow conditions within lab-scale and pilot-scale anaerobic digester reactors are simulated using three-dimensional modeling techniques. The RTDs of lab-scale reactors as predicted by the 3D numerical models compare well to the experimental results. The 3D models are also validated using data from particle image velocimetry (PIV) experiments. Finally, the viscous properties of liquid hog manure at 3% and 8% total solids are incorporated into the models, and the results are evaluated.

This thesis explored the opportunities to reduce energy demand and renewable energy feasibility at an off-grid science “community” called the Experimental Lakes Area (ELA) in Ontario. Being off-grid, ELA is completely dependent on diesel and propane fuel supply for all its electrical and heating needs, which makes ELA vulnerable to fluctuating fuel prices. As a result ELA emits a large amount of greenhouse gases (GHG) for its size. Energy efficiency and renewable energy technologies can reduce energy consumption and consequently energy cost, as well as GHG. Energy efficiency was very important to ELA due to the elevated fuel costs at this remote location. Minor upgrades to lighting, equipment and building envelope were able to reduce energy costs and reduce load. Efficient energy saving measures were recommended that save on operating and maintenance costs, namely, changing to LED lights, replacing old equipment like refrigerators and downsizing of ice makers. This resulted in a 4.8% load reduction and subsequently reduced the initial capital cost for biomass by $27,000, by $49,500 for wind power and by $136,500 for solar power. Many alternative energies show promise as potential energy sources to reduce the diesel and propane consumption at ELA including wind energy, solar heating and bio-mass. A biomass based CHP system using the existing diesel generators as back-up has the shortest pay back period of the technologies modeled. The biomass based CHP system has a pay back period of 4.1 years at $0.80 per liter of diesel, as diesel price approaches $ 2.00 per liter the pay back period reduces to 0.9 years, 50% the generation cost compared to present generation costs. Biomass has been successfully tried and tested in many off-grid communities particularly in a small-scale off-grid setting in North America and internationally. Also, the site specific solar and wind data show that ELA has potential to harvest renewable resources and produce heat and power at competitiv

One technique used to control the influx of renewable generation while maintaining competitive principles is a Request for Proposals (RFP). However, lack of transmission planning due to a disconnection between generation and transmission owners, difficulty in identifying viable projects, and high risk for proponents stand as obstacles to the goals of an RFP. This research proposes a procedure which minimizes the effect of these obstacles; meeting the purchaser requirements for low price and combining conventional planning concepts with feedback from competitive structures. The general features of the method include definition of generation limits and study area, expansion plan design, transmission cost evaluation, optimal selection of requested generation levels, and final selection of successful proponents. A case study using a real system in New Mexico demonstrates these concepts.

Atmospheric icing is a major design factor for guyed lattice masts and transmission lines in Canada and many others countries with cold climate. Tall and slender guyed lattice towers are particularly sensitive to ice accretion, wind or combination of both, as they are often located in remote areas, where meteorological data are limited. The variation of local topography and seasonal climate affects icing conditions and complicates standardization of icing accretion design guidelines. Icing design criteria was evaluated in this study through an extensive literature review of current design standards for latticed structures subjected to ice and wind load and/or a combination of both, field and laboratory work.

The total worldwide base of installed wind energy peak capacity reached 94 GW by the end of 2007, including 1846 MW in Canada. Wind turbine systems are being installed throughout Canada and often in mountains and cold weather regions, due to their high wind energy potential. Harsh cold weather climates, involving turbulence, gusts, icing and lightning strikes in these regions, affect wind turbine performance. Ice accretion and irregular shedding during turbine operation lead to load imbalances, often causing the turbine to shut off. They create excessive turbine vibration and may change the natural frequency of blades as well as promote higher fatigue loads and increase the bending moment of blades. Icing also affects the tower structure by increasing stresses, due to increased loads from ice accretion. This can lead to structural failures, especially when coupled to strong wind loads. Icing also affects the reliability of anemometers, thereby leading to inaccurate wind speed measurements and resulting in resource estimation errors. Icing issues can directly impact personnel safety, due to falling and projected ice. It is therefore important to expand research on wind turbines operating in cold climate areas. This study presents an experimental investigation including three important fundamental aspects: 1) heat transfer characteristics of the airfoil with and without liquid water content (LWC) at varying angles of attack; 2) energy losses of wind energy while a wind turbine is operating under icing conditions; and 3) aerodynamic characteristics of an airfoil during a simulated icing event. A turbine scale model with curved 3-D blades and a DC generator is tested in a large refrigerated wind tunnel, where ice formation is simulated by spraying water droplets. A NACA 63421 airfoil is used to study the characteristics of aerodynamics and convective heat transfer. The current, voltage, rotation of the DC generator and temperature distribution along the airfoil, which a

The research focus of this thesis is on modelling techniques for river kinetic turbines, to develop predictive numerical tools to further the design of this emerging hydro technology. The performance benefits of enclosing the turbine in a shroud are quantified numerically and an optimized shroud design is developed. The optimum performing model is then used to study river kinetic turbines, including different anchoring systems to enhance performance. Two different turbine numerical models are studied to simulate the rotor. Four different computational fluid dynamics (CFD) turbulence models are compared against a series of particle image velocimetry (PIV) experiments involving highly-separated diffuser-flow and nozzle-flow conditions. The risk of cavitation is briefly discussed as well as riverbed boundary layer losses. This study is part of an effort to develop this emerging technology for distributed power generation in provinces like Manitoba that have a river system well adapted for this technology.

A numerical analysis is performed for the three-dimensional, turbulent flow of air in a thyristor valve hall located at the Dorsey Converter Station, owned and operated by Manitoba Hydro. The goal of this analysis was to determine the configurations that result in increased air-side cooling effectiveness in the valve hall. The governing equations are solved using the Computational Fluid Dynamics (CFD) code CFX-5. This computer code uses a finite volume method of solution and is based on a finite element approach for representing the geometry. The effects of inlet and outlet opening geometry, inlet air mass flow rate, and inlet air angle on the thermal performance for the air-side cooling of the thyristor valve hall geometry are examined.

A numerical analysis is performed for the three-dimensional, turbulent flow of air in a thyristor valve hall located at the Dorsey Converter Station, owned and operated by Manitoba Hydro. The goal of this analysis was to determine the configurations that result in increased air-side cooling effectiveness in the valve hall. The governing equations are solved using the Computational Fluid Dynamics (CFD) code CFX-5. This computer code uses a finite volume method of solution and is based on a finite element approach for representing the geometry. The effects of inlet and outlet opening geometry, inlet air mass flow rate, and inlet air angle on the thermal performance for the air-side cooling of the thyristor valve hall geometry are examined.