Download or read book Measurements in Film Cooling Flows with Periodic Wakes written by and published by . This book was released on 2008 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Film cooling flows subject to periodic wakes were studied experimentally. The wakes were generated with a spoked wheel upstream of a flat plate. Cases with a single row of cylindrical film cooling holes inclined at 35 deg to the surface were considered at blowing ratios of 0.25, 0.50, and 1.0 with a steady freestream and with wake Strouhal numbers of 0.15, 0.30, and 0.60. Temperature measurements were made using an infrared camera, thermocouples, and constant current (cold-wire) anemometry. Hot-wire anemometry was used for velocity measurements. The local film cooling effectiveness and heat transfer coefficient were determined from the measured temperatures. Phase locked flow temperature fields were determined from cold-wire surveys. Wakes decreased the film cooling effectiveness for blowing ratios of 0.25 and 0.50 when compared to steady freestream cases. In contrast, effectiveness increased with Strouhal number for the 1.0 blowing ratio cases, as the wakes helped mitigate the effects of jet lift-off. Heat transfer coefficients increased with wake passing frequency, with nearly the same percentage increase in cases with and without film cooling. The time resolved flow measurements show the interaction of the wakes with the film cooling jets. Near-wall flow measurements are used to infer the instantaneous film cooling effectiveness as it changes during the wake passing cycle.

Download or read book Combined Effects of Wakes and Jet Pulsing on Film Cooling written by and published by . This book was released on 2008 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pulsed film cooling jets subject to periodic wakes were studied experimentally. The wakes were generated with a spoked wheel upstream of a flat plate. Cases with a single row of cylindrical film cooling holes inclined at 35 deg to the surface were considered at blowing ratios B of 0.50 and 1.0 with jet pulsing and wake Strouhal numbers of 0.15, 0.30, and 0.60. Wake timing was varied with respect to the pulsing. Temperature measurements were made using an infrared camera, thermocouples, and constant current (cold wire) anemometry. The local film cooling effectiveness and heat transfer coefficient were determined from the measured temperatures. Phase locked flow temperature fields were determined from cold-wire surveys. With B0.5, wakes and pulsing both lead to a reduction in film cooling effectiveness, and the reduction is larger when wakes and pulsing are combined. With B1.0, pulsing again causes a reduction in effectiveness, but wakes tend to counteract this effect somewhat by reducing jet lift-off. At low Strouhal numbers, wake timing had a significant effect on the instantaneous film cooling effectiveness, but wakes in general had very little effect on the time averaged effectiveness. At high Strouhal numbers, the wake effect was stronger, but the wake timing was less important. Wakes increased the heat transfer coefficient strongly and similarly in cases with and without film cooling, regardless of wake timing. Heat transfer coefficient ratios, similar to the time averaged film cooling effectiveness, did not depend strongly on wake timing for the cases considered.

Download or read book Active Flow and Combustion Control 2021 written by Rudibert King and published by Springer Nature. This book was released on 2021-11-12 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book reports on the latest theoretical and experimental findings in the field of active flow and combustion control, in the context of energy conversion for power and propulsion systems. It covers new developments in actuator technology and sensing, robust and optimal open- and closed-loop control, model reduction for control purposes, and unsteady turbine cooling and performance, among other relevant topics. Gathering contributions to the Active Flow and Combustion Control (AFCC 2021), held virtually on September 28-29, 2021, from the Technische Universität Berlin, Germany, this book describes research that has been carried out within, and supported by, the collaborative research center SFB 1029 on “Substantial efficiency increase in gas turbines through direct use of coupled unsteady combustion and flow dynamics”, and funded by the German Research Foundation (DFG). It highlights theoretical and practical aspects, and corresponding solutions, that are important for the development of future energy conversion systems, thus offering a timely guide for researchers and practitioners in the field of aeronautics, turbomachinery, control and combustion.

Download or read book Gas Turbine Heat Transfer and Cooling Technology Second Edition written by Je-Chin Han and published by CRC Press. This book was released on 2012-11-27 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive reference for engineers and researchers, Gas Turbine Heat Transfer and Cooling Technology, Second Edition has been completely revised and updated to reflect advances in the field made during the past ten years. The second edition retains the format that made the first edition so popular and adds new information mainly based on selected published papers in the open literature. See What’s New in the Second Edition: State-of-the-art cooling technologies such as advanced turbine blade film cooling and internal cooling Modern experimental methods for gas turbine heat transfer and cooling research Advanced computational models for gas turbine heat transfer and cooling performance predictions Suggestions for future research in this critical technology The book discusses the need for turbine cooling, gas turbine heat-transfer problems, and cooling methodology and covers turbine rotor and stator heat-transfer issues, including endwall and blade tip regions under engine conditions, as well as under simulated engine conditions. It then examines turbine rotor and stator blade film cooling and discusses the unsteady high free-stream turbulence effect on simulated cascade airfoils. From here, the book explores impingement cooling, rib-turbulent cooling, pin-fin cooling, and compound and new cooling techniques. It also highlights the effect of rotation on rotor coolant passage heat transfer. Coverage of experimental methods includes heat-transfer and mass-transfer techniques, liquid crystal thermography, optical techniques, as well as flow and thermal measurement techniques. The book concludes with discussions of governing equations and turbulence models and their applications for predicting turbine blade heat transfer and film cooling, and turbine blade internal cooling.

Download or read book Measurements in Film Cooling Flows written by and published by . This book was released on 1996 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hot-wire anemometry of simulated film cooling was used to study the influence of freestream turbulence intensity and film cooling hole length-to-diameter ratio on mean velocity and turbulence intensity. Measurements were made in the zone where the coolant and freestream flows mix. Flow from one row of film cooling holes with a streamwise injection of 35° and no lateral injection and with a coolant- to-freestream flow velocity ratio of 1.0 was investigated under freestream turbulence levels of 0.5 and 12%. Coolant-to-freestream density ratio was unity. Two length-to-diameter ratios for the film cooling holes, 2.3 and 7.0, are tested. Results show that under low freestream turbulence conditions, pronounced differences exist in the flowfield between L/D=7.0 and 2.3; the differences are less prominent at high freestream turbulence intensities. Generally, short-L/D injection results in ''jetting'' of the coolant further into the freestream flow and enhanced mixing. Other changes in the flowfield attributable to a rise in freestream turbulence intensity to engine- representative conditions are documented. 15 figs, 2 tabs, refs.

Download or read book Full coverage Film Cooling written by S. Yavuzkurt and published by . This book was released on 1979 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Heat Transfer written by and published by Academic Press. This book was released on 2017-11-11 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Heat Transfer, Volume 49 provides in-depth review articles from a broader scope than in traditional journals or texts. Topics covered in this new volume include Heat Transfer in Rotating Cooling Channel, Flow Boiling and Flow Condensation in Reduced Gravity, Advances in Gas Turbine Cooling, and Advanced Heat Transfer Topics in Complex Duct Flows. While the articles in this series will be of great interest to mechanical, chemical and industrial engineers working in the field of heat transfer, the book is also ideal for those in graduate schools or industry, and even non-specialists interested in the latest research. Compiles the expert opinions of leaders in the industry Fills the information gap between regularly scheduled journals and university-level textbooks by providing in-depth review articles over a broader scope than in traditional journals or texts Essential reading for all mechanical, chemical and industrial engineers working in the field of heat transfer, or in graduate schools or industry

Download or read book Measurements in Film Cooling Flows with Lateral Injection written by Richard W. Kaszeta and published by . This book was released on 1998 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Proceedings Of The International Heat Transfer Conference written by Lee and published by CRC Press. This book was released on 1998-11-01 with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt: This year's set of papers includes 23 Keynote Papers and 537 refereed General Papers, in seven volumes. Experts from around the world have combined to address the leading edge of research and practical innovations in convection, combustion, heat exchangers, two-phase flow, and much more. Whether one is involved in mechanical, chemical, nuclear, or energy engineering the quantity, international scope, and high quality of the contents make access to these volumes essential.

Download or read book Advanced Fluid Mechanics and Heat Transfer for Engineers and Scientists written by Meinhard T. Schobeiri and published by Springer Nature. This book was released on 2022-01-17 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current book, Advanced Fluid Mechanics and Heat Transfer is based on author's four decades of industrial and academic research in the area of thermofluid sciences including fluid mechanics, aero-thermodynamics, heat transfer and their applications to engineering systems. Fluid mechanics and heat transfer are inextricably intertwined and both are two integral parts of one physical discipline. No problem from fluid mechanics that requires the calculation of the temperature can be solved using the system of Navier-Stokes and continuity equations only. Conversely, no heat transfer problem can be solved using the energy equation only without using the Navier-Stokes and continuity equations. The fact that there is no book treating this physical discipline as a unified subject in a single book that considers the need of the engineering and physics community, motivated the author to write this book. It is primarily aimed at students of engineering, physics and those practicing professionals who perform aero-thermo-heat transfer design tasks in the industry and would like to deepen their knowledge in this area. The contents of this new book covers the material required in Fluid Mechanics and Heat Transfer Graduate Core Courses in the US universities. It also covers the major parts of the Ph.D-level elective courses Advanced Fluid Mechanics and Heat Transfer that the author has been teaching at Texas A&M University for the past three decades.

Download or read book Measurements of Mean Flow and Eddy Transport Over a Film Cooling Surface written by and published by . This book was released on 1996 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 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Particle image Velocimetry Measurements of Film Cooling Flows written by Wilhelm Jessen and published by . This book was released on 2008 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Investigation of Approach Flow Parameters Scaling Factors and Measurement Accuracy for Film Cooling Effectiveness and Heat Transfer Coefficient Measurements written by Joshua Brian Anderson and published by . This book was released on 2017 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: Film cooling is widely used in gas turbine engines to manage temperatures within the hot section of the engine. In this work, several investigations are described, all of which studied how fundamental hydrodynamic and thermal parameters influence the performance of film cooling. The first investigation studied the impact of freestream turbulence, boundary layer thickness, Reynolds number, and Mach number on film cooling performance, using axial shaped film cooling holes. The second study considered a similar set of parameters, and investigated their impact on compound-angle oriented film cooling holes. Both of these studies utilized measurements of adiabatic effectiveness and heat transfer coefficient augmentation. In general, the parameters had effects which were dependent on the coolant flow rate and density ratio. The final study considered methods to reduce the experimental uncertainty which arises from conduction and radiation errors in thermal measurements. A careful evaluation of the thermal boundary layer was used to validate these corrections

Download or read book Effects of Hole Length Supply Plenum Geometry and Freestream Turbulence on Film Cooling Performance written by and published by . This book was released on 2000 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Flow field Measurements in Supersonic Film Cooling Including the Effects of Shock Wave Interaction written by K. A. Juhany and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 3D Velocity and Scalar Field Measurements of Discrete Hole Film Cooling Flows written by Emin Issakhanian and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional mean velocity field measurements from magnetic resonance velocimetry (MRV) are used to study the flow fields in the interaction region between the film cooling jet and the mainflow, as well as inside the film cooling hole, for different film cooling hole inclination angles and velocity ratios. The vorticity field created by the interaction of the in-hole vorticity and surface boundary layer vorticity is discovered to resemble a streamwise series of horseshoe vortices inclined in the forward direction. A streamwise-normal view of this field reveals the traditionally identified counter-rotating vortex pair (CVP) which is detrimental to film cooling. The in-hole flow feature of a counter-rotating vortex pair, which affects the main flow field, is also identified for inclined film cooling holes. Tracking of the coolant exiting the film cooling hole is achieved through 3D measurement of the coolant concentration in the mainflow using magnetic resonance concentration (MRC). Through the scalar analogy, concentration measurements are related to temperatures and the adiabatic surface effectiveness of the tested film cooling cases is measured. Shallower inclination angles and low velocity ratio jets are seen to produce coolant jets which remain closer to the surface and provide good film cooling. However, low velocity ratios correspond to low coolant flux which limits cooling performance due to high turbulent mixing. It is desirable to produce a film cooling hole which creates similarly advantageous flow fields at higher velocity ratios which increase coolant flux and endure more mixing before falling below effective cooling levels. This is attempted through shaped holes. MRV studies of three traditionally shaped film cooling holes, which diffuse laterally and/or in the forward direction over a final length of the hole, are done to evaluate the flowfield developed by different diffusion angles and diffusive section lengths. Increased exit area is seen to reduce the momentum of the exiting jet and produce coolant flows which remain closer to the surface. However, in-hole measurements of the two more conservative diffuser-shaped holes show uneven flow through the diffusing section of the hole and room for improvement. The most extreme diffuser-shaped hole shows marked decrease in the strength of the mainfield CVP. In addition to conventional film cooling holes, MRV is done on novel hole shapes to ascertain whether they will perform well as film cooling holes. A round hole which lofts into an exit section modeled on two intersecting yawed holes is studied, which creates a pair of CVPs which lead to central vortices spinning counter to a conventional CVP. Two non-circular cross-section holes, a spanwise-stretched oval and a rounded triangle pointing streamwise, are tested in hopes of decreasing streamwise vorticity in the mainflow. The rounded triangle shapes leads to a very lifted coolant jet and increased vorticity, but the oval shape creates a coolant jet with a more complex vorticity field which remains attached and creates a beneficial velocity profile along the surface. MRC was done on the oval shaped hole, because of the promising flow features observed in the MRV results. Comparison of the surface effectiveness to all round hole cases and a single diffuser-shaped hole case show marked improvement in film cooling using an oval shaped hole over traditional round and diffuser-shaped holes.