Download or read book Wake Interaction Effects on the Transition Process on Turbine Blades written by R. W. Ainsworth and published by . This book was released on 1989 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The unsteady behavior of a 2-d gas turbine rotor blade boundary layer was observed using wide bandwidth surface heat transfer thin film gauges. The tests were conducted in a compression heated short duration wind tunnel cascade at realistic gas turbine aero/thermo-dynamic conditions. Wake passage effects were generated using a rotating set of upstream bars. The unsteadiness of the wake and shock interactions were observed through the effects on temporally and spatially accurate heat transfer measurements. Keywords: Gas turbine rotor blades; Thin film gauges; Wind tunnel tests; Two dimensional; Cascade structures; Gas turbine heat transfer; Boundary layer transition; Unsteady wake interactions; Great Britain. (EDC).
Download or read book Wake Interaction Effects on the Transition Process on Turbine Blades written by R. W. Ainsworth and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1990 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987-04 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wind Turbine Wake Interactions written by Daniel Curtis Saunders and published by . This book was released on 2017 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: Growing concerns about the environmental impact of fossil fuel energy and improvements in both the cost and performance of wind turbine technologies has spurred a sharp expansion in wind energy generation. However, both the increasing size of wind farms and the increased contribution of wind energy to the overall electricity generation market has created new challenges. As wind farms grow in size and power density, the aerodynamic wake interactions that occur between neighboring turbines become increasingly important in characterizing the unsteady turbine loads and power output of the farm. Turbine wake interactions also impact variability of farm power generation, acting either to increase variability or decrease variability depending on the wind farm control algorithm. In this dissertation, both the unsteady vortex wake loading and the effect of wake interaction on farm power variability are investigated in order to better understand the fundamental physics that govern these processes and to better control wind farm operations to mitigate negative effects of wake interaction. The first part of the dissertation examines the effect of wake interactions between neighboring turbines on the variability in power output of a wind farm, demonstrating that turbine wake interactions can have a beneficial effect on reducing wind farm variability if the farm is properly controlled. In order to balance multiple objectives, such as maximizing farm power generation while reducing power variability, a model predictive control (MPC) technique with a novel farm power variability minimization objective function is utilized. The controller operation is influenced by a number of different time scales, including the MPC time horizon, the delay time between turbines, and the fluctuation time scales inherent in the incident wind. In the current research, a non-linear MPC technique is developed and used to investigate the effect of three time scales on wind farm operation and on variability in farm power output. The goal of the proposed controller is to explore the behavior of an ‘ideal’ farm-level MPC controller with different wind, delay and horizon time scales and to examine the reduction of system power variability that is possible in such a controller by effective use of wake interactions. The second part of the dissertation addresses the unsteady vortex loading on a downstream turbine caused by the interaction of the turbine blades with coherent vortex structures found within the upstream turbine wake. Periodic, stochastic, and transient loads all have an impact on the lifetime of the wind turbine blades and drivetrain. Vortex cutting (or vortex chopping) is a type of stochastic load that is commonly observed when a propeller or blade passes through a vortex structure and the blade width is of the same order of magnitude as the vortex core diameter. A series of Navier-Stokes simulations of vortex cutting with and without axial flow are presented. The goal of this research is to better understand the challenging physics of vortex cutting by the blade rotor, as well as to develop a simple, physics-based, validated expression to characterize the unsteady force induced by vortex.
Download or read book Aeronautical Engineering A Cumulative Index to a Continuing Bibliography supplement 235 written by and published by . This book was released on 1989 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Elements of Transitional Boundary Layer Flowlements written by Robert Edward Mayle and published by Logos Verlag Berlin GmbH. This book was released on 2018 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: Second Enhanced Edition Suitable for advanced-level courses or an independent study in fluid mechanics, this text by an expert in the field provides the basic aspects of laminar-to-turbulent flow transition in boundary layers. Logically organized into three major parts, the book covers pre- and post-transitional flow, transitional flow, and several advanced topics in periodically disturbed transitional flow. Some of the subjects covered within the book include high-frequency unsteady laminar flow, turbulent flow, natural transition, bypass transition, turbulent spot theory, turbulent spot kinematics and production, correlations for the onset and rate of transition, global and conditional averaging, transitional flow models, wakeinduced transition, multimode transition, and separated-flow transition. Containing some 202 figures (all drawn by the author), 28 tables, 12 appendices, a supplement on tensors, and an extensive bibliography, the 415 page book provides a wealth of data and information about the subject.
Download or read book NASA SP written by and published by . This book was released on 1991 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeronautical Engineering written by and published by . This book was released on 1991 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).
Download or read book Wake Interaction Modeling Using a Parallelized Free Vortex Wake Model written by Kelsey Shaler and published by . This book was released on 2020 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbine-wake interactions pose significant challenges in the development of wind farms. These interactions can lead to an increase in wind energy cost through reduction in wind farm power efficiency as well as a reduction of functional turbine lifetime. The overall objective of this work is to extend and assess a moderatefidelity free vortex wake (FVW) model to capture turbine-wake interactions between multiple turbines. Specific focus areas include: (1) analyzing the effects of turbine-wake interaction; (2) benchmarking of the model against experimental wind farm measurements; and (3) comparing wake interaction effects between the FVW model and a dynamic wake meandering (DWM) model. Results show that FVW produces an increased dynamic response in wake-influenced turbines than FAST.Farm, which is an important factor in fatigue life of turbine blades. Parameter studies for various operating and layout conditions are performed. Analysis focuses on impact of wake interaction on wake structure, rotor power, and blade root bending moments. The parameter study shows expected power trends for all tested parameters. The effects of turbine-wake interactions are analyzed in terms of wake structure, rotor power, and structural response. The FVW model predicts increased unsteadiness in wake-influenced turbine rotor power and out-of-plane blade root bending moment. This could have implications for prediction of turbine life and suggests that the transient as well as average response of turbines should be considered to fully capture the effects of wake interaction. Comparisons between the FVW predictions and experimental measurements of relative rotor power are made over varying yaw angle and freestream velocity. Overall trends are predicted by the FVW approach, with less than 13% error on average when compared to wind farm measurements. These results indicate the FVW method is a useful tool for carrying out improved optimization of wind farms.
Download or read book Advanced technologies in flow dynamics and combustion in propulsion and power volume II written by Lei Luo and published by Frontiers Media SA. This book was released on 2023-02-09 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1989 with total page 1518 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Unsteady Wake Effects on Boundary Layer Transition and Heat Transfew Characteristics of Curved Plate and Turbine Blade written by Pitchaiah Chakka and published by . This book was released on 1998 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rotating Machinery written by J. H. Kim and published by CRC Press. This book was released on 1992-05-01 with total page 766 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work the first of two contains papers presented at an international conference on the technology of rotating machinery, which specifically address transport phenomena in terms of turbine cooling heat transfer, rotating surfaces, curved ducts and rotating channels, multiphase flow and more.
Download or read book Effects of Blade Boundary Layer Transition and Daytime Atmospheric Turbulence on Wind Turbine Performance Analyzed with Blade resolved Simulation and Field Data written by Tarak Nandi and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Relevant to utility scale wind turbine functioning and reliability, the present work focuses on enhancing our understanding of wind turbine responses from interactions between energy-dominant daytime atmospheric turbulence eddies and rotating blades of a GE 1.5 MW wind turbine using a unique data set from a GE field experiment and computer simulations at two levels of fidelity.Previous studies have shown that the stability state of the lower troposphere has a major impact on the coherent structure of the turbulence eddies, with corresponding differences in wind turbine loading response. In this study, time-resolved aerodynamic data measured locally at the leading edge and trailing edge of three outer blade sections on a GE 1.5 MW wind turbine blade and high-frequency SCADA generator power data from a daytime field campaign are combined with computer simulations that mimic the GE wind turbine within a numerically generated atmospheric boundary layer (ABL) flow field which is a close approximation of the atmospheric turbulence experienced by the wind turbine in the field campaign. By combining the experimental and numerical data sets, this study describes the time-response characteristics of the local loadings on the blade sections in response to nonsteady nonuniform energetic atmospheric turbulence eddies within a daytime ABL which have spatial scale commensurate with that of the turbine blade length. This study is the first of its kind where actuator line and blade boundary layer resolved CFD studies of a wind turbine field campaign are performed with the motivation to validate the numerical predictions with the experimental data set, and emphasis is given on understanding the influence of the laminar to turbulent transition process on the blade loadings.The experimental and actuator line method data sets identify three important response time scales quantified at the blade location: advective passage of energy dominant eddies (~ 25 - 50 s), blade rotation (1P, ~3 s) and sub-1P scale (
Download or read book Aeronautical Engineering A Cumulative Index to a Continuing Bibliography supplement 261 written by and published by . This book was released on 1991 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1990-03 with total page 1040 pages. Available in PDF, EPUB and Kindle. Book excerpt:
