Download or read book Interaction Between Secondary Flow Film Cooling Jets of a Realistic Annular Airfoil Cascade high Mach Number written by Cuong Quoc Nguyen and published by . This book was released on 2010 with total page 149 pages. Available in PDF, EPUB and Kindle. Book excerpt: Film cooling is investigated on a flat plate both numerically and experimentally. Conical shaped film hole are investigated extensively and contribute to the current literature data, which is extremely rare in the open public domain. Both configuration of the cylindrical film holes, with and without a trench, are investigated in detail. Design of experiment technique was performed to find an optimum combination of both geometrical and fluid parameters to achieve the best film cooling performance. From this part of the study, it shows that film cooling performance can be enhanced up to 250% with the trenched film cooling versus non-trenched case provided the same amount of coolant. Since most of the relevant open literature is about film cooling on flat plate endwall cascade with linear extrusion airfoil, the purpose of the second part of this study is to examine the interaction of the secondary flow inside a 3D cascade and the injected film cooling jets. This is employed on the first stage of the aircraft gas turbine engine to protect the curvilinear (annular) endwall platform. The current study investigates the interaction between injected film jets and the secondary flow both experimentally and numerically at high Mach number (M=0.7). Validation shows good agreement between obtained data with the open literature. In general, it can be concluded that with an appropriate film coolant to mainstream blowing ratio, one can not only achieve the best film cooling effectiveness (FCE or [eta]) on the downstream endwall but also maintain almost the same aerodynamic loss as in the un-cooled baseline case. Film performance acts nonlinearly with respect to blowing ratios as with film cooling on flat plate, in the other hand, with a right blowing ratio, film cooling performance is not affect much by secondary flow. In turn, film cooling jets do not increase pressure loss at the downstream wake area of the blades.
Download or read book Dossier Ushio Amagatsu written by and published by . This book was released on 1991 with total page 14 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 An Experimental and Numerical Study of Secondary Flows and Film Cooling Effectiveness in a Transonic Cascade written by James C. Kullberg and published by . This book was released on 2011 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many studies have been published on the subject of film cooling, but because of the difficulty and expense of simulating turbine realistic conditions, many authors introduce vast simplifications such as low speed conditions or linear cascades. These simplifications do not adequately represent the behavior of a turbine and therefore their results are of limited use. This study attempts to eliminate many of those simplifications.
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 Experimental Investigation of Air Film Cooling Applied to an Adiabatic Wall by Means of an Axially Discharging Slot written by S. Stephen Papell and published by . This book was released on 1959 with total page 68 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 1993 with total page 712 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 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 Evaluation of Film Cooling Superposition Method on the Suction Side of a Blade Model written by Christopher Yoon and published by . This book was released on 2018 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Film cooling is often used for turbine airfoil cooling, and there are numerous studies of the performance of a single row of holes. Typically, blades and vanes in gas turbine engines have multiple rows of holes that interact. Consequently, there is a need to develop techniques to predict film cooling performance with multiple rows of holes. One of the method is to superposition single row cooling effectiveness to predict combined effectiveness. Although there have been many studies of superposition techniques with multiple rows of cylindrical holes, there have been very few in which shaped holes were used with a typical turbine airfoil model. In this study, film effectiveness was measured on the suction side of a turbine blade model using two rows of 7-7-7 shaped holes, with pitch to diameter ratio of 6, and the two rows were more than 40 diameters apart. Measurements were made with each row operating independently, which provided the experimental data for superposition predictions. These predictions were evaluated with effectiveness measurements with both rows operational. For these combined row tests, two different upstream blowing ratios and a wide range of downstream blowing ratios were selected. The superposition predictions were reasonably accurate when the upstream blowing ratio was high with a corresponding smaller film effectiveness downstream (due to jet separation). However, when the upstream coolant holes were operated at optimum blowing ratio with maximum film effectiveness downstream, the superposition analysis predicted film effectiveness levels slightly lower than actual levels. These results indicate that there was an interaction between jets that resulted in higher film effectiveness than what the superposition method had predicted
Download or read book Prediction and Measurement of Film Cooling Effectiveness for a First stage Turbine Vane Shroud written by D. Granser and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: After compressor discharge air has initially been used to cool the heat shields of the hot gas inlet casing, it can subsequently be employed for film cooling of the first-stage vane shrouds. Since the flow field near these shrouds is three-dimensional, the film cooling effectiveness cannot be predicted correctly by common two-dimensional codes. The secondary flow transports the film from the pressure side to the suction side where it can even climb up the airfoil to cool its trailing section. Such film cooling effectiveness was first investigated experimentally in a linear vane cascade at atmospheric pressure. The temperatures and static pressure levels at the adiabatic shrouds, as well as the temperature measurements within the vane cascade, are reported for different cooling film blowing rates. In addition, the secondary flow was analysed numerically using a partially-parabolic computer code for 3D viscous flows. It involves mutual interaction of the boundary layer with the mainstream. The secondary flow can also be modelled with this algorithm, which requires less numerical effort than solving the fully 3D elliptic flow equations. The numerical results of the experiment and numerical predictions are compared. In addition, the application of these results to a high-temperature gas turbine is presented.
Download or read book Film Cooling with Ejection from a Row of Inclined Circular Holes written by Christian Liess and published by . This book was released on 1973 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrogen Film Cooling with Incident and Swept Shock Interactions in a Mach 6 4 Nitrogen Free Stream written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-04 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effectiveness of slot film cooling of a flat plate in a Mach 6.4 flow with and without incident and swept oblique shock interactions was experimentally investigated. Hydrogen was the primary coolant gas, although some tests were conducted using helium as the coolant. Tests were conducted in the Calspan 48-Inch Shock Tunnel with a nitrogen flow field to preclude combustion of the hydrogen coolant gas. A two-dimensional highly instrumented model developed in a previous test series was used. Parameters investigated included coolant mass flow rate, coolant gas, local free-stream Reynolds number, incident oblique shock strength, and a swept oblique shock. Both gases were highly effective coolants in undisturbed flow; however, both incident and swept shocks degraded that effectiveness. Olsen, George C. and Nowak, Robert J. Langley Research Center RTOP 506-43-31-03...
Download or read book Hydrogen Film Cooling with Incident and Swept shock Interactions in a Mach 6 4 Nitrogen Free Stream written by George C. Olsen and published by . This book was released on 1995 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Development of a High Speed Annular Sector Cascade for Film Cooling Measurements in Nozzle Guide Vanes with Contoured Endwalls written by Christian Landfester and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect on Gaseous Film Cooling of Coolant Injection Through Angled Slots and Normal Holes written by S. Stephen Papell and published by . This book was released on 1960 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
