Download or read book A computational study for the utilization of jet pulsations in gas turbine film cooling and flow control written by Olga Valeryevna Kartuzova and published by . This book was released on 2012 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A computational study for the utilization of jet pulsations in gas turbine film cooling and flow control written by Olga Valeryevna Kartuzova and published by . This book was released on 2012 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computational Film Cooling Methods for Gas Turbine Airfoils written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A previously documented CFD methodology is further generalized and applied to realistic turbine airfoil film cooling test cases. First, a series of fundamental test cases are examined in order to document the ability of the robust and practical CFD methodology to deal with the effects of the individually isolated key physics mechanisms on film cooling. These include: (1) favorable and adverse pressure gradients; (2) convex curvature; (3) horseshoe vortex; (4) profile losses with and without coolant jets; (5) laminar-to-turbulent boundary layer transition; and (6) discontinuities. Second, in addition to the fundamental flow test cases, two turbine airfoil cascade, one low subsonic and another transonic, configurations were modeled. The subsonic cascade case was designed to study the aerodynamics losses with and without film cooling jets, as well as, the adiabatic effectiveness for a range of parameters. The transonic turbine cascade represents a truly modern design at realistic engine conditions. A total of 18 test configurations, corresponding to compound-round, axial-shaped, and compound-shaped film holes, are simulated in order to document in detail the current state of the readily available robust and practical CFD technology for use by the gas turbine design community.
Download or read book Experimental and Computational Studies of Film Cooling with Compound Angle Injection written by and published by . This book was released on 1995 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: The thermal efficiency of gas turbine systems depends largely on the turbine inlet temperature. Recent decades have seen a steady rise in the inlet temperature and a resulting reduction in fuel consumption. At the same time, it has been necessary to employ intensive cooling of the hot components. Among various cooling methods, film cooling has become a standard method for cooling of the turbine airfoils and combustion chamber walls. The University of Minnesota program is a combined experimental and computational study of various film-cooling configurations. Whereas a large number of parameters influence film cooling processes, this research focuses on compound angle injection through a single row and through two rows of holes. Later work will investigate the values of contoured hole designs. An appreciation of the advantages of compound angle injection has risen recently with the demand for more effective cooling and with improved understanding of the flow; this project should continue to further this understanding. Approaches being applied include: (1) a new measurement system that extends the mass/heat transfer analogy to obtain both local film cooling and local mass (heat) transfer results in a single system, (2) direct measurement of three-dimensional turbulent transport in a highly-disturbed flow, (3) the use of compound angle and shaped holes to optimize film cooling performance, and (4) an exploration of anisotropy corrections to turbulence modeling of film cooling jets.
Download or read book Analysis and Comparison of Wall Cooling Schemes for Advanced Gas Turbine Applications written by Raymond Strong Colladay and published by . This book was released on 1972 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The relative performance of (1) counterflow film cooling, (2) parallel-flow film cooling, (3) convection cooling, (4) adiabatic film cooling, (5) transpiration cooling, and (6) full-coverage film cooling was investigated for heat loading conditions expected in future gas turbine engines. Assumed in the analysis were hot-gas conditions of 2200 K (3500 F) recovery temperature, 5 to 40 atmospheres total pressure, and 0.6 gas Mach number and a cooling air supply temperature of 811 K (1000 F). The first three cooling methods involve film cooling from slots. Counterflow and parallel flow describe the direction of convection cooling air along the inside surface of the wall relative to the main gas flow direction. The importance of utilizing the heat sink available in the coolant for convection cooling prior to film injection is illustrated.
Download or read book Film Cooling in a Pulsating Wall Jet written by and published by . This book was released on 2000 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent wall jets have many important engineering applications. Much effort has been spent to investigate the plane turbulent wall jet without external stream (Launder and Rodi 1981,1983, Katz et al 1992, Wygnanski et al 1992) and with a relatively slow external stream (Zhou and Wygnanski 1993, Zhou et al 1996). However, many engineering applications seem to be described better by a wall jet embedded in a uniform stream of comparable velocity (the weak wall jet), for example, the cooling turbine blades and the flows over a wing equipped with a slotted flap (Fig. 1) represents such flows. The recently developed technique for separation control by periodic blowing/suction on the flap also belongs to category (Fig. 2). Thus, it is important to provide a better understanding of the development of these flows. For example: the possibility of flow similarity, normalization of the mean velocity fields, scaling laws for the governing parameters, as well as the various responses to external excitations. This report represents but a single facet of the general effort endeavoring to use the wall jet for boundary layer control, film cooling and the exertion of force on a body through the use of what is commonly known as the Coanda Effect.
Download or read book Prediction of Film Cooling on Gas Turbine Airfoils written by and published by . This book was released on 1994 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Active Control of Transverse Jets for Film Cooling Applications A Limited Statement of Work written by and published by . This book was released on 2006 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this project was to initiate investigation of film cooling flow control in order to improve its performance through active excitation of the film-cooling jet. A theoretical analysis was conducted and mechanisms that can play a defining role in film cooling control were identified on the basis of fundamental fluid-dynamics, prior experiments and preliminary numerical simulations. A cold flow wind-tunnel experiment incorporating a scaled-up, single film-cooling jet on a flat wall with a 90 deg injection angle was designed and built. The theoretical analysis was used to identify a window of essential flow-modulation parameters (frequency, duty cycle, mean blowing ratio, blowing ratio amplitude) within which film-cooling flow performance is expected to improve. A flow-pulsing system was designed, built and dynamically characterized. Both the wind tunnel boundary layer and jet exit flows were characterized using constant temperature anemometry. A series of preliminary experiments were conducted using reactive, Mie-scattering, laser-sheet visualizations for three mean blowing ratios with nearly zero low blowing ratio in the cycle, two duty cycles and four pulsing frequencies. The visualization results indicate that for the transverse jet with 90 deg injection angle, low frequency pulsations of the jet flow tend to increase the lateral coverage of the jet relative to the benchmark steady case without causing substantial lift-off at a blowing ratio of 0.5 and duty cycle of 50%. The observations are encouraging as to the feasibility of controlling the film cooling jet through mass flow pulsation and are consistent with predictions from fundamental analysis in terms of anticipated favorable operating conditions.
Download or read book Numerical Analysis for Film Cooling Performance Under Different Jet Design Criteria written by Mohammed Aref Al-Hemyari and published by . This book was released on 2018 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Cooling gas turbine blades is a crucial technique to allow higher turbine inlet temperatures. A higher turbine inlet temperature allows boosting gas turbine efficiency, which reduces fuel consumption. One of the main cooling techniques of the turbine blades is film cooling where a relatively low air temperature is used to form a blanket of cool air around the blade to shield it from high temperature gases. Many complex interrelated geometry and flow parameters affect the effectiveness of the film cooling. The complex interrelations between these parameters are considered the main challenge in properly understanding the effect of these parameters on film cooling. Testing such cooling techniques under actual engine conditions is even more challenging due to difficulty of installing proper instrumentations. Numerical techniques are viable analysis techniques that are used to better understand film cooling techniques. In this study, a simplified 2D film cooling jet blown from the slot jet is investigated under multiple variable parameters, mainly, the blowing ratio, jet angle, density ratio and centrifugal force. The performance of the film cooling is reported using local and average adiabatic film effectiveness. The main contribution of this study is exploring the effect of the centrifugal force and wall material selection using conjugate heat transfer on film cooling effectiveness. The centrifugal force reduces the overall adiabatic film effectiveness. A correlation between the blowing ratio, density ratio and injection angle is developed in this work. The highest film cooling performance was founded at a blowing ratio of 0.8, an injection angle of 30° and density ratio of 1.2."--Abstract.
Download or read book The Effect of Bulk Flow Pulsations on Film Cooling from Two Rows of Holes written by Dong Kee Sohn and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the International Gas Turbine & Aeroengine Congress & Exhibition, Orlando, FL, Jun 2-Jun 5, 1997.
Download or read book Numerical Study of Film Cooling Influence on Performance of Transonic Vane Cascade written by Ahmad Mahmoud Alameldin and published by . This book was released on 2014 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Gas turbines are a major contributor to world power generation with applications ranging from electricity production to aircrafts propulsion. Their efficiency is subject to continuous research. A gas turbine's overall efficiency is directly proportional to flow inlet temperature. Various methods are implemented to protect hot gas path components from mainstream flow well above their melting temperature, namely, heat resistant coatings, internal cooling and film cooling. The latter is the subject of this work. A 3-D Computational Fluid Dynamics (CFD) model is solved using ANSYS CFX software and compared to experimental measurements of film cooled transonic vane cascade operating at a Mach number of 0.89; the experimental data used for validation is provided by Heat and Power Technology Department of the Royal Institute of Technology (Kungliga Tekniska Hogskolan, KTH) of Stockholm, Sweden. A new approach was used to model the film cooling holes, omitting the need to model both the coolant plenum and cooling tubes, resulting in 180% reduction in grid size and attributed computational cost interpreted in 300% saving in computation time. The new approach was validated on a basic flow problem (flat plate film cooling) and was found to give good agreement with experimental measurements of velocity and temperature at a blowing ratio (BR) of 1 and 2; the experimental data for the flat plate was provided by NASA's Glenn Research Center. The numerical simulation of the cooled vane cascade was compared to experimental measurements for different cooling configurations and different BRs. a) One row on pressure side at BR = 0.8, 0.96 and 2.5. b) Two rows on suction side (location 1) at BR = 0.8, 1.4 and 2.5. c) Two rows on suction side (location 2) at BR = 0.8. And d) Showerhead cooled vane at BR ranges between 1.98 and 5.84. The coolant was applied at the same temperature as the mainstream, to match experimental conditions. A good agreement with the experimental measurements was obtained for exit flow angle, vorticity downstream of the vane, pressure coefficients and aerodynamic loss. The proposed approach of coolant injection modeling is shown to yield reliable results, within the uncertainty of the measurements in most cases. Along with lower computational cost compared to conventional film cooling modeling approach, the new approach is recommended for further analysis for aero and thermal vane cascade flows.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1993 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation of Film Cooling Flows for Gas Turbine Applications written by Christopher A. Lemmon and published by . This book was released on 2000 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Jet Model for Slot Film Cooling with Effect of Free stream and Coolant Turbulence written by Frederick F. Simon and published by . This book was released on 1986 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Computational Study of Discrete Jet Film Cooling with Compound angle Injection written by Kevin Thomas McGovern and published by . This book was released on 1997 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Film Cooling in a Pulsating Wall Jet written by and published by . This book was released on 2000 with total page 39 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent wall jets have many important engineering applications. Much effort has been spent to investigate the plane turbulent wall jet without external stream (Launder and Rodi 1981,1983, Katz et al 1992, Wygnanski et al 1992) and with a relatively slow external stream (Zhou and Wygnanski 1993, Zhou et al 1996). However, many engineering applications seem to be described better by a wall jet embedded in a uniform stream of comparable velocity (the weak wall jet), for example, the cooling turbine blades and the flows over a wing equipped with a slotted flap (Fig. 1) represents such flows. The recently developed technique for separation control by periodic blowing/suction on the flap also belongs to category (Fig. 2). Thus, it is important to provide a better understanding of the development of these flows. For example: the possibility of flow similarity, normalization of the mean velocity fields, scaling laws for the governing parameters, as well as the various responses to external excitations. This report represents but a single facet of the general effort endeavoring to use the wall jet for boundary layer control, film cooling and the exertion of force on a body through the use of what is commonly known as the Coanda Effect.
Download or read book Effects of Geometry on Slot jet Film Cooling Performance written by and published by . This book was released on 1995 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Physics of film cooling for shaped, inclined slot-jets with realistic slot-length-to-width ratios is studied for a range of blowing ratio and density ratio parameters typical of gas turbine operations. Effect of inlet and exit shaping of the slot-jet on both flow and thermal field is isolated, and the dominant mechanisms responsible for differences in these items are documented. A computation method was used to study 4 configurations. Field results and surface phenomena are presented. Both adiabatic film effectiveness and heat transfer coefficient are vital in assessing film cooling performance. Performance of two popular turbulence models were studied to evaluate ability to handle highly elliptic jet/crossflow interaction type processes. The simulations were consistent.
