Download or read book Reduction of Secondary Flow Losses in a Turbine for Use in Man portable Power Generation written by Andrew J. Yatsko and published by . This book was released on 2014 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the world has moved into a more energy-demanding environment, there has been the push for higher energy density in a smaller package. One of the potential solutions is through the application of a gas turbine engine; yet the challenge is extracting the energy efficiently through the small components. The focus of the research is on the turbine components and how secondary flow losses from generated airfoil shapes can be reduced to improve component performance. One of the secondary flow loss items to be addressed is the generation of the Horseshoe Vortex. The Horseshoe Vortex is an aerodynamic phenomenon that occurs in axial turbine cascades that degrades the aerodynamic performance. This research will show that through airfoil design optimization, the Horseshoe Vortex on small turbine nozzles can be reduced. The initial turbine design was generated using simple imcompressible flow calculations and then run through a Navier-Strokes SST solver. This solver allows for the interaction of the boundary layer with the airfoil geometry, therefore generating a new set of inlet velocity triangles. The geometry was then optimized to match the new inlet velocity triangle. The new optimized airfoil was run through the same boundary layer build up, and the same boundary conditions as the original incompressible design. The presented results will show that the Horseshoe Vortex has been mitigated and that the total pressure distribution at the exit of the turbine inlet nozzle cascade has improved by 7.6%.
Download or read book Secondary Flow Loss Reduction in Highly Loaded Turbines written by Sandor Becz and published by . This book was released on 2007 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Experimental Evaluation of Loss Production and Reduction in a Highly Loaded Low Pressure Turbine Cascade written by Philip Steven Bear and published by . This book was released on 2016 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improvements in turbine design methods have resulted in the development of blade profiles with both high lift and good Reynolds lapse characteristics. An increase in aerodynamic loading of blades in the low pressure turbine section of aircraft gas turbine engines has the potential to reduce engine weight or increase power extraction. Increased blade loading means larger pressure gradients and increased secondary losses near the endwall. Prior work has emphasized the importance of reducing these losses if highly loaded blades are to be utilized. The present study analyzes the secondary flow field of the front-loaded low-pressure turbine blade designated L2F with and without blade profile contouring at the junction of the blade and endwall. The current work explores the loss production mechanisms inside the low pressure turbine cascade. Stereoscopic particle image velocimetry data, total pressure loss data and oil flow visualization are used to describe the secondary flow field. The flow is analyzed in terms of total pressure loss, vorticity, Q-Criterion, Reynolds' stresses, turbulence intensity and turbulence production. The flow description is then expanded upon using an Implicit Large Eddy Simulation of the flow field. The RANS momentum equations contain terms with static pressure derivatives. With some manipulation these equations can be rearranged to form an equation for the change in total pressure along a streamline as a function of velocity only. After simplifying for the flow field in question the equation can be interpreted as the total pressure transport along a streamline. A comparison of the total pressure transport calculated from the velocity components and the total pressure loss is presented and discussed. Peak values of total pressure transport overlap peak values of total pressure loss through and downstream of the passage suggesting that total pressure transport is a useful tool for localizing and predicting loss origins and loss development using velocity data which can be obtained non-intrusively.
Download or read book Reduction in Secondary Flows and Losses in a Turbine Cascade by Upstream Boundary Layer Blowing written by Thomas Ernst Biesinger and published by . This book was released on 1993 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Secondary Flow Reduction Techniques in Linear Turbine Cascades written by Thomas Ernst Biesinger and published by . This book was released on 1993 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Invesitgation of Losses and Secondary Flow Turbine Cascades written by Wishaa Mohammed Hosny and published by . This book was released on 1971 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Secondary Flows and Losses Downstream of a Turbine Cascade written by Rajendra Y. Adhye and published by . This book was released on 1984 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Secondary Flows and Losses in a Turbine Cascade written by D. G. Gregory-Smith and published by . This book was released on 1983 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: In designing axial flow turbines, one needs relatively simple prediction techniques for the angle variations and losses produced by secondary flows. To improve the physical basis of such techniques, an investigation was made of the flow in a cascade of large scale rotor blades of some 110 deg of turning. The aspect around 0.2 of the span. The flow was traversed in great detailed on ten planes using cobra-type probes with a computerised data recording and analysis system. Results are presented graphically using contour and vector plots on various planes through the flow field. The horse-show vortex and passage vortex development are clearly seen, with the upstream boundary layer being shed downstream as a loss core. Another region of high loss is related to a counter vortex in the corner between the sunction surface and the end wall. Results were also pitch averaged, and compared with predictions of angle and loss distribution. Some traversing was carried out using hot wire anemometry. Regions of high turbulence intensity and shear stress were identified, associated with the regions of high loss. Some indication is given of the mechanisms of loss production within the cascade.
Download or read book Endwall Profiling for the Reduction of Secondary Flow in Turbines written by Grant Laidlaw Ingram and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Secondary Flows and Losses Downstream of a Turbine Cascade written by J. Moore and published by . This book was released on 1985 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analysis of Losses and Secondary Flow in Turbine Cascades written by W. Hosny and published by . This book was released on 1971 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: A general review of different cascade losses is presented with emphasis on the secondary flow. An analytical analysis utilizing the Squire and Winter secondary flow analysis along with the triangle model for end wall boundary layer proposed by Taylor is detailed in an attempt to show the behavior of streamlines near the end wall. (Author).
Download or read book Design and Implementation of Periodic Unsteadiness Generator for Turbine Secondary Flow Studies written by Nathan James Fletcher and published by . This book was released on 2019 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt: A primary source of periodic unsteadiness in low-pressure turbines is the wakes shed from upstream blade rows due to the relative motion between adjacent stators and rotors. These periodic perturbations can affect boundary layer transition, secondary flow, and loss generation. In particular, for high-lift front-loaded blades, the secondary flowfield is characterized by strong three-dimensional vortical structures. It is important to understand how these flow features respond to periodic disturbances. A novel approach was taken to generate periodic unsteadiness which captures some of the physics of turbomachinery wakes. Using stationary pneumatic devices, pulsed jets were used to generate disturbances characterized by velocity deficit, elevated turbulence, and spanwise vorticity. Prior to application in a turbine flow environment, the concept was explored in a small developmental wind tunnel using a single device. The disturbance flowfield for different input settings was measured using hot-film anemometry and Particle Image Velocimetry. Insight was also garnered on how to improve later design iterations. With an array of devices installed upstream of a linear cascade of high-lift front-loaded turbine blades, settings were found which produced similar disturbances at varying frequencies that periodically impinged upon the leading-edge region. These settings were used to conduct an in-passage secondary flow study using high-speed Stereoscopic Particle Image Velocimetry. Results demonstrated the application of the periodic unsteadiness generator but found minor changes to the passage vortex. The vortex rotational strength decreased, and migration increased with increased perturbation frequency. Fourier analyses found the PV to be responsive at the actuation frequency with phase-locked ensemble-averaged data revealing that the disturbance periodically caused the PV to lose rotational strength. However, at the tested discrete frequencies, the vortex did not become locked-in and was defined by an erratic time-character similar to without the disturbances.
Download or read book End wall Skin Friction and Secondary Flow Losses Downstrean of a Turbine Blade Cascade written by Abdelkader Boumedmed 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 Impact of Unsteady Secondary Air Flow Interaction with Main Flow on Loss Generation in Axial Turbines written by David Madison Clifton and published by . This book was released on 2014 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Secondary air, often called purge air, is injected through the endwall gap between stationary vanes and rotating rotors in axial turbines to prevent ingestion of the hot working gas into the endwall cavities. Three-dimensional flow computations, unsteady as well as steady, have been carried out to assess the role of vane-rotor stage induced flow unsteadiness on loss generation from purge flow interacting with main flow. Computational models of varying physical and geometry complexity that range from simple bladeless annulus configurations to vane-rotor stage configurations were used for identifying the specific flow features responsible for loss generation; these were also complemented by control volume analyses of simple two streams flow model. Computed results showed that the vane induced circumferentially non-uniform static pressure field, and to a much lesser extent rotor blade induced bow waves, significantly increases loss generation upon introduction of injected flow with and without swirl; any flow approximations that renders the pressure field imposed on the purge flow as circumferentially uniform would underestimate the loss due to purge flow-main flow interaction. Flow unsteadiness induced by vane-rotor interaction has marginal, if any, impact on loss generation from introducing purge flow into the main flow path. Judicious flow path modification such as endwall contouring that reduces or eliminates vane-induced static pressure circumferential non-uniformity imposed upon the purge flow has been shown to significantly reduce the purge flow driven loss. Computed results also show that loss generation increases linearly with injected mass flow rate ( 7.5% more loss per 1% purge flow) and decreases quadratically with purge flow swirl until it matches the main flow circumferential velocity ( 85% reduction in purge flow induced based loss at that point). Purge flow induced loss has a weak dependence on the width of the purge duct and angle of injection.
Download or read book Secondary Flow Total Pressure Loss and the Effect of Circumferential Distortions in Axial Turbine Cascades written by Earl William Renaud and published by . This book was released on 1991 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Wind Energy Explained written by James F. Manwell and published by John Wiley & Sons. This book was released on 2010-09-14 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wind energy’s bestselling textbook- fully revised. This must-have second edition includes up-to-date data, diagrams, illustrations and thorough new material on: the fundamentals of wind turbine aerodynamics; wind turbine testing and modelling; wind turbine design standards; offshore wind energy; special purpose applications, such as energy storage and fuel production. Fifty additional homework problems and a new appendix on data processing make this comprehensive edition perfect for engineering students. This book offers a complete examination of one of the most promising sources of renewable energy and is a great introduction to this cross-disciplinary field for practising engineers. “provides a wealth of information and is an excellent reference book for people interested in the subject of wind energy.” (IEEE Power & Energy Magazine, November/December 2003) “deserves a place in the library of every university and college where renewable energy is taught.” (The International Journal of Electrical Engineering Education, Vol.41, No.2 April 2004) “a very comprehensive and well-organized treatment of the current status of wind power.” (Choice, Vol. 40, No. 4, December 2002)
Download or read book Axial and Radial Turbines written by Hany Moustapha and published by Concepts Eti. This book was released on 2003 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanical Engineering Design and Analysis of Axlal and Radial Turbines.
