Download or read book Computational Investigation on the Application of Using Microjets as Active Aerodynamic Load Control for Wind Turbines written by Myra Louise Blaylock and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A fast, efficient way to control loads on industrial scale turbines is important for the growth of the wind industry. Active Aerodynamic Load Control (AALC) is one area which addresses this need. In particular, microjets, which are pneumatic jets located at the trailing edge of a wind turbine blade and blow perpendicular to the blade surface, are a possible AALC candidate. First, the Computational Fluid Dynamics (CFD) solver OVERFLOW is used to explore the effects of a microjet on lift, drag, and pitching moment. Then the interaction between an aerodynamic disturbance and an airfoil equipped with a microjet is modeled. The object of this dissertation is to investigate microtabs as viable AALC devices by presenting their aerodynamic properties and testing whether a proportional-integral (PI) controlled jets can alleviate loads caused by wind gusts. The use of CFD to simulate a microjet is validated by comparing the results to both previous experiments found in the literature as well as wind tunnel tests completed at UC Davis. The aerodynamic effectiveness of the jet is investigated as a function of various parameters such as Reynolds number, angle of attack, and the momentum coefficient of the jet. The effects of the microjet are found to be very similar to another AALC device, the microtab. An aerodynamic disturbance is simulated, and a control algorithm which is incorporated into the OVERFLOW code is used to activate the microjet, thus reducing the change of the blade load due to the gust. Finally, a more realistic model is made by adding both a linear and a torsional spring and damper to represent the blade movement. This two-degree of freedom system shows that during a gust the vertical blade movement is reduced when the microjets are activated. Microjets are found to work well to alleviate the changes in aerodynamic loads felt by the airfoil, and are therefore a good candidate for a practical AALC device. However, further investigation is needed in the areas of aeroacoustics, system energy requirements, and logistics of implementation.
Download or read book Investigation on Implementation of Microjets for Active Aerodynamic Load Control on the NREL 5 MW Reference Turbine Utilizing Active and Passive Methods written by Owen Francisco Hurley and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A computational investigation was performed analyzing the potential for reduction in wind turbine fatigue utilizing microjets for active aerodynamic load control. Increasing size of wind turbine rotors requires methods for reduction of critical fatigue and extreme loads. Active Aerodynamic Load Control provides local control of aerodynamic properties utilizing active flow control devices to alter loads along the wind turbine span to reduce total loading. These devices respond quickly allowing for on demand control of aerodynamic loading. Microjets have shown promising aerodynamic characteristics but require pneumatic input to operate which poses as a potentially difficult to overcome obstacle to implementation in wind turbine applications where Cost of Energy (COE) is critical. This thesis explores systems with both passive and active driven pneumatic systems comparing the energy input to the potential for fatigue reduction. Analysis of a wide range of potential configurations of microjets along the NREL Baseline Offshore 5-MW Reference Wind Turbine is conducted. A program developed to calculate flow potential at each configuration is integrated with WT-Perf, a BEM horizontal wind turbine performance simulation tool that is used to calculate the reduction in steady state flapwise root bending moment. Reduction in steady state flapwise root bending moment across the wind turbine's operating range is the primary metric for comparing the success of each microjet system configuration. Passive systems in which no externally driven pneumatic devices, such as blowers, are considered along with active systems which include external means of driving flow through the microjet. The findings in this thesis indicate that the optimum location for a microjet system on the NREL 5-MW begins approximately halfway down the span of the wind turbine blade extending a length of approximate one quarter of the total blade length. With a passive system, maximum reduction in flapwise root bending moment at rated wind speed was approximately 4.5% of the total flapwise moment which increases to 6% with the addition of a 5kPa blower.
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2007 with total page 960 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Investigation of the Aerodynamic Effects on Fluidic Thrust Vectoring written by Karen A. Deere and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental and Computational Investigations in Low Reynolds Number Aerodynamics with Applications to Micro Air Vehicles MAVs written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Investigation of Pneumatic Vortex Generator Jets for Boundary Layer Control written by Andrew R. Fenlon and published by . This book was released on 1999 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Performance Control of a PMSM Drive System in Application of a Novel Wind Turbine with Power Split written by Quian Liu and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wind Turbine Aerodynamics written by Wen Zhong Shen and published by MDPI. This book was released on 2019-10-04 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind turbine aerodynamics is one of the central subjects of wind turbine technology. To reduce the levelized cost of energy (LCOE), the size of a single wind turbine has been increased to 12 MW at present, with further increases expected in the near future. Big wind turbines and their associated wind farms have many advantages but also challenges. The typical effects are mainly related to the increase in Reynolds number and blade flexibility. This Special Issue is a collection of 21 important research works addressing the aerodynamic challenges appearing in such developments. The 21 research papers cover a wide range of problems related to wind turbine aerodynamics, which includes atmospheric turbulent flow modeling, wind turbine flow modeling, wind turbine design, wind turbine control, wind farm flow modeling in complex terrain, wind turbine noise modeling, vertical axis wind turbine, and offshore wind energy. Readers from all over the globe are expected to greatly benefit from this Special Issue collection regarding their own work and the goal of enabling the technological development of new environmentally friendly and cost-effective wind energy systems in order to reach the target of 100% energy use from renewable sources, worldwide, by 2050
Download or read book Computational Modeling of MEMS Microjets for Turbulent Boundary Layer Control written by and published by . This book was released on 2004 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: As a three year continuation of our earlier AFOSR work, we examine novel MEMS actuators for turbulent boundary layer control. The devices of interest are small and closely spaced and hence require detailed direct numerical simulation of the near surface flow to capture the physics. The devices we examine in most detail are arrays of discrete wall-normal jets to test a practical implementation of the opposition control schemes already shown to produce large drag reductions. We also performed some simple experiments examining pairs of small suction holes used to generate hairpin vortices. While the actuators are examined for their potential application for drag reduction, the emphasis of the work is more on studying the fundamental nature of the flows generated by such devices and how such small scale flows interact with the turbulent vortex structures in a wall-bounded flow. In this final report we emphasize results from simulations of arrays of 3-D slot-jet actuators triggered by practical wall-mounted sensors. Time averaged data show how the jet arrays affect the mean shear stress distribution over the controlled surface while instantaneous data show the interactions of the three-dimensional structures in detail.
Download or read book Aerodynamic Design of Transport Aircraft written by E. Obert and published by IOS Press. This book was released on 2009-04-16 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origin of Aerodynamic Design of Transport Aircraft stems from the time when the author was appointed part-time professor in the Aerospace Faculty of Delft University of Technology. At the time his main activities were those of leading the departments of Aerodynamics, Performance and Preliminary Design at Fokker Aircraft Company. The groundwork for this book started in 1987 as a series of lecture notes consisting mainly of pictorial material with a minimum of English explanatory text. After the demise of Fokker in 1996 one feared that interest in aeronautical engineering would strongly diminish. As a result of this, the course was discontinued and the relationship between the author and the faculty came to an end. Two years later the situation was reappraised, and the interest in aeronautical engineering remained, so the course was reinstated with a former Fokker colleague Ronald Slingerland as lecturer. The lecture notes from these courses form the foundation of this publication.
Download or read book Shock Wave Boundary Layer Interactions written by Holger Babinsky and published by Cambridge University Press. This book was released on 2011-09-12 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shock wave-boundary-layer interaction (SBLI) is a fundamental phenomenon in gas dynamics that is observed in many practical situations, ranging from transonic aircraft wings to hypersonic vehicles and engines. SBLIs have the potential to pose serious problems in a flowfield; hence they often prove to be a critical - or even design limiting - issue for many aerospace applications. This is the first book devoted solely to a comprehensive, state-of-the-art explanation of this phenomenon. It includes a description of the basic fluid mechanics of SBLIs plus contributions from leading international experts who share their insight into their physics and the impact they have in practical flow situations. This book is for practitioners and graduate students in aerodynamics who wish to familiarize themselves with all aspects of SBLI flows. It is a valuable resource for specialists because it compiles experimental, computational and theoretical knowledge in one place.
Download or read book Remote Sensing of Atmospheric Conditions for Wind Energy Applications written by Charlotte Bay Hasager and published by MDPI. This book was released on 2019-05-24 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Special Issue “Atmospheric Conditions for Wind Energy Applications” hosts papers on aspects of remote sensing for atmospheric conditions for wind energy applications. Wind lidar technology is presented from a theoretical view on the coherent focused Doppler lidar principles. Furthermore, wind lidar for applied use for wind turbine control, wind farm wake, and gust characterizations is presented, as well as methods to reduce uncertainty when using lidar in complex terrain. Wind lidar observations are used to validate numerical model results. Wind Doppler lidar mounted on aircraft used for observing winds in hurricane conditions and Doppler radar on the ground used for very short-term wind forecasting are presented. For the offshore environment, floating lidar data processing is presented as well as an experiment with wind-profiling lidar on a ferry for model validation. Assessments of wind resources in the coastal zone using wind-profiling lidar and global wind maps using satellite data are presented.
Download or read book Small Scale Energy Systems with Gas Turbines and Heat Pumps written by Satoru Okamoto and published by MDPI. This book was released on 2021-03-29 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: A heat pump system can produce an amount of heat energy that is greater than the amount of energy used to run the heat pump system. Thus, a heat pump system is considered to be a machine system that can use energies efficiently, as is the load leveling air-conditioning system utilizing unutilized energies at high levels. Adaptations of gas turbines for industrial, utility, and marine-propulsion applications have long been accepted as means for generating power with high efficiency and ease of maintenance. Cogeneration with gas turbine is frequently defined as the sequential production of useful thermal energy and shaft power from a single energy source. For applications that generate electricity, the power can either be used internally or supplied to the utility grid. This Special Issue intends to provide an overviews of the existing knowledge related with various aspects of “Small-Scale Energy Systems with Gas Turbines and Heat Pumps”, and contributions on, but not limited to the following subjects were encouraged: wake of stator vane to improve sealing effectiveness; gas turbine cycle with external combustion chamber for prosumer and distributed energy systems; computational simulation of gas turbine engine operating with different blends of biodiesel; experimental methodology and facility for the engine performance and emissions evaluation using jet and biodiesel blends; experimental analysis of an air heat pump for heating service; hybrid fuel cell-Brayton cycle for combined heat and power; design analysis of micro gas turbines in closed cycles. Seven papers were published in the Special Issue out of a total of 12 submitted.
Download or read book Technology and the Air Force written by Jacob Neufeld and published by DIANE Publishing. This book was released on 2009-06 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of a symposium co-sponsored by the Air Force Historical Foundation and the Air Force History and Museums Program. The symposium covered relevant Air Force technologies ranging from the turbo-jet revolution of the 1930s to the stealth revolution of the 1990s. Illustrations.
Download or read book Long term Research Challenges in Wind Energy A Research Agenda by the European Academy of Wind Energy written by Gijs van Kuik and published by Springer. This book was released on 2016-09-21 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the view of European wind energy experts on the long-term research challenges to be solved in order to develop wind energy beyond the applications of today and tomorrow. By this book, the European Academy of Wind Energy (eawe), representing universities and institutes with a significant wind energy programme in 14 countries, wants to: identify current technological and scientific barriers and to stimulate new creative ideas to overcome these barriers define priorities for future scientific research rethink our scientific view of wind energy stimulate the cooperation among researchers in fundamental and applied sciences towards wind energy research The eawe has discussed these long-term research with an explicit focus on a longer-term perspective, in contrast to research agendas addressing short- to medium-term research activities. In other words, this long-term research agenda is driven by problems and curiosity, addressing basic research and fundamental knowledge in 11 research areas, ranging from physics and design to environmental and societal aspects. Because of the very nature of this initiative, this document does not intend to be permanent or complete. It shows the vision of the experts of the European Academy of Wind Energy, but other views may be possible. The eawe sincerely hopes that it will spur an even more intensive discussion worldwide within the wind energy community.
Download or read book Design and Development of Aerospace Vehicles and Propulsion Systems written by S. Kishore Kumar and published by Springer Nature. This book was released on 2021-03-18 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents selected papers presented in the Symposium on Applied Aerodynamics and Design of Aerospace Vehicles (SAROD 2018), which was jointly organized by Aeronautical Development Agency (the nodal agency for the design and development of combat aircraft in India), Gas-Turbine Research Establishment (responsible for design and development of gas turbine engines for military applications), and CSIR-National Aerospace Laboratories (involved in major aerospace programs in the country such as SARAS program, LCA, Space Launch Vehicles, Missiles and UAVs). It brings together experiences of aerodynamicists in India as well as abroad in Aerospace Vehicle Design, Gas Turbine Engines, Missiles and related areas. It is a useful volume for researchers, professionals and students interested in diversified areas of aerospace engineering.
Download or read book Beyond Tube and Wing written by Bruce Larrimer and published by . This book was released on 2020-06-15 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
