Download or read book Flow Field and Thermal Measurements in Film Cooling written by Rohit Anand Oke and published by . This book was released on 1998 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Full coverage Film Cooling written by S. Yavuzkurt and published by . This book was released on 1979 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Thermal and Flow Field Investigations of a Micro Tangential Jet Film Cooling Scheme on Gas Turbine Components written by Othman Hassan and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 3D Velocity and Scalar Field Diagnostics Using Magnetic Resonance Imaging with Applications in Film cooling written by Michael John Benson and published by Stanford University. This book was released on 2011 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new Magnetic Resonance Imaging (MRI) technique was developed to measure the three-dimensional, time-averaged scalar concentration distributions in turbulent mixing applications. The diagnostic was initially developed and tested in a turbulent free shear layer experiment where it was validated using planar laser induced fluorescence (PLIF) experiments. The remainder of the study examined a three-dimensional mixing flow motivated by trailing edge film cooling of an aircraft gas turbine blade. A modern slotted trailing edge cutback geometry was added in which coolant was discharged from rectangular slots separated by tapered lands. Water, and water with copper sulfate were the working fluids, and the MR-based experiments were conducted at Reynolds numbers based on airfoil chord and bulk velocity from 100,000-250,000. The magnetic resonance concentration (MRC) technique was further refined in the film cooling apparatus to reduce the uncertainty to under 6.0% in concentration and to provide robust measurement of the surface concentration. Combined magnetic resonance velocimetry (MRV) and MRC measurements were acquired for a generic trailing edge cutback geometry. The effect of variations in the blowing ratio and Reynolds number were examined. Reynolds number was found to have no significant effect while the variations in blowing ratio produced relatively small changes. Combined MRV and MRC data sets were analyzed in detail for insight into the mean flow structures primarily responsible for rapid mixing of the mainstream and coolant flows. Longitudinal vortices formed inside the slot feed channels and at the edges of the lands played a critical role as did the separation bubble behind the slot lip. Three modifications to the breakout geometry were designed with the goal of minimizing the adverse effects of these flow structures. Performance improvements with the redesigned trailing edge geometries indicate as much as a 40% improvement in the averaged surface effectiveness using a non-dimensional performance parameter.

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 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 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 A Detailed Investigation of the Fluid Dynamics and Heat Transfer Related to Injection from a Compound Angled Shaped Film Cooling Hole written by Shane Haydt and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas turbines are used around the world to provide thrust for airplanes and to generate electricity. Designers and operators are constantly chasing higher thermal efficiency, and even an incremental increase is considered an achievement. Higher thermal efficiency begets higher turbine inlet temperatures, and the parts that are exposed to these temperatures require sophisticated cooling technologies. One such cooling method is shaped film cooling, which ejects low momentum coolant with the goal of it staying attached to the wall, spreading laterally, and providing a lower driving temperature for convection.In some film cooling manufacturing processes, the meter and diffuser are created in separate steps with separate machines, and an offset can occur in that process. A study was designed to quantify the change in adiabatic effectiveness for five offset directions: fore, fore-left, left, aft-left, and aft. All offset directions caused a detriment to film cooling performance, except for the fore offset, which improved adiabatic effectiveness relative to a no offset case. CFD helped show that the fore offset created a separation in the region of the film cooling metering section where jetting occurs, which decreased the high momentum and made the cooling jet more likely to remain attached to the surface. This study resulted in a patent.A large range of area ratios and blowing ratios were examined in a study designed to isolate the effect of area ratio by lengthening the diffuser of a shaped hole. Very high area ratios were generated that resulted in significant cooling potential. It was shown that at each area ratio there is an optimal blowing ratio beyond which the effectiveness will decrease or plateau. This was reduced to an optimal effective blowing ratio, M/AR, which was shown through CFD to be the condition when the coolant jet core has similar velocity magnitude to the mainstream flow. This results in a weak shear layer and a weak counter-rotating vortex pair.In an axially oriented hole, the mainstream flows over the top of a cooling jet and around the sides, in equal measure, creating a symmetric flowfield. In a compound angled shaped hole, the mainstream flows primarily around the leeward side, creating a strong shear layer and an asymmetric streamwise vortex. Compound angled shaped holes are used commonly in gas turbines, but there has been no work examining the adiabatic effectiveness and heat transfer coefficient augmentation at a range of compound angles, and there are no flowfield measurements. A comprehensive study of the flowfield, cooling effectiveness, and heat transfer coefficient were obtained for compound angled shaped holes for compound angles ranging from 0-60 in 15 increments. It is shown that asymmetry and vorticity magnitude increase with increasing compound angle and increasing blowing ratio. Holes with high compound angles can maintain jet attachment at high blowing ratios because the streamwise component of blowing ratio is reduced, which leads to high effectiveness. The most important contribution of this work was showing that the streamwise vortex increases heat transfer coefficient in a region adjacent to the jet, where very little coolant coverage exists. For this reason, compound angled shaped holes can cause local regions of increased heat flux relative to an uncooled surface, which may be an issue for some designs if not properly accounted for. Heat transfer coefficient augmentation increases as compound angle and blowing ratio increase. Designs that promote jet interaction, such as holes with a smaller pitchwise spacing or holes with significant lateral motion, cover the entire endwall in coolant and lessen the negative effects of high heat transfer coefficient augmentation.

Download or read book Thermal Measurements in Electronics Cooling written by Kaveh Azar and published by CRC Press. This book was released on 2020-08-26 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filled with careful explanations, step-by-step instructions, and useful examples, this handbook focuses on real-world considerations and applications of thermal measurement methods in electronics cooling. Fifteen experts in thermal engineering combine their expertise to create a complete guide to this complex topic. This practical reference covers all aspects of thermal characterization in electronics cooling and thermal management. The first part of the book introduces the concept of electronics cooling and its associated thermal phenomenon and explains why experimental investigation is required. Subsequent chapters explain methods of measuring different parameters and introduce relevant examples. Sources for locating needed equipment, tables, checklists, and to-do lists are included. Sample calculations and methodologies for error analysis ensure that you can put this valuable information to use in your work.

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 Full coverage Film Cooling on Flat Isothermal Surfaces written by Michael E. Crawford and published by . This book was released on 1980 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Experimental Methods in Heat Transfer and Fluid Mechanics written by Je-Chin Han and published by CRC Press. This book was released on 2020-05-20 with total page 383 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental Methods in Heat Transfer and Fluid Mechanics focuses on how to analyze and solve the classic heat transfer and fluid mechanics measurement problems in one book. This work serves the need of graduate students and researchers looking for advanced measurement techniques for thermal, flow, and heat transfer engineering applications. The text focuses on analyzing and solving classic heat transfer and fluid mechanics measurement problems, emphasizing fundamental principles, measurement techniques, data presentation, and uncertainty analysis. Overall, the text builds a strong and practical background for solving complex engineering heat transfer and fluid flow problems. Features Provides students with an understandable introduction to thermal-fluid measurement Covers heat transfer and fluid mechanics measurements from basic to advanced methods Explains and compares various thermal-fluid experimental and measurement techniques Uses a step-by-step approach to explaining key measurement principles Gives measurement procedures that readers can easily follow and apply in the lab

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.

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 Gas Turbine Heat Transfer and Cooling Technology written by Je-Chin Han and published by Taylor & Francis. This book was released on 2012-11-27 with total page 865 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive reference for engineers and researchers, this second edition focuses on gas turbine heat transfer issues and their associated cooling technologies for aircraft and land-based gas turbines. It provides information on state-of-the-art cooling technologies such as advanced turbine blade film cooling and internal cooling schemes. The book also offers updated experimental methods for gas turbine heat transfer and cooling research, as well as advanced computational models for gas turbine heat transfer and cooling performance predictions. The authors provide suggestions for future research within this technology and includes 800 illustrations to help clarify concepts and instruction.

Download or read book Statistical Analysis of Multi row Film Cooling Flow Fields written by Craig Patrick Fernandes and published by . This book was released on 2017 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results show good agreement with effectiveness measurements of a previous study at a higher density ratio. However, to accurately draw the comparison, effectiveness measurements should be conducted at a density ratio of 1. Recommendations were made to further the study of multi-row film cooled boundary layers. The scope includes a CFD component, other flowfield measurement techniques, and surface effectiveness studies using N2 as the coolant for a much broader picture of this flowfield.