Author: Mark Kenneth HarringtonPublisher:
ISBN:
Category :
Languages : en
Pages : 236
Book Description
Adiabatic effectiveness for full coverage film cooling with normal holes on a flat plate
Author: Mark Kenneth HarringtonPublisher:
ISBN:
Category :
Languages : en
Pages : 236
Book Description
An investigation of the heat transfer for full coverage film cooling of a flat plate with normal holes
Author: Grady Blair KellyMeasurements of Adiabatic Effectiveness from Full Coverage Film Cooling on a Scaled Turbine Vane with Laidback Fanshaped Holes
Author: Owen Michael O'NealPublisher:
ISBN:
Category :
Languages : en
Pages : 206
Book Description
This study was focused on measurements of adiabatic effectiveness on a scaled turbine vane which made use of a contoured endwall to match engine conditions. The vane model featured a full coverage film-cooling configuration with five rows of cylindrical holes in the showerhead and ten rows of laidback fanshaped holes distributed on the pressure and suction sides. The vane model was tested across a wide range of blowing ratios in several different coolant configurations including: individual rows on the pressure and suction side, full coverage tests with and without showerhead cooling, and full coverage tests at low and high mainstream turbulence levels. Comparisons between these configurations were made in order to assess the effects of local curvature, showerhead cooling, and mainstream turbulence levels. Single row tests measured in areas of high convex curvature tended to have an improved performance relative to flat plate predictions, while the opposite was true for rows in areas of concave curvature. Overall, showerhead cooling did not provide any significant improvements in effectiveness far downstream on both the pressure and suction side. Increasing mainstream turbulence levels tended to diminish the film cooling effectiveness. The negative effect of higher mainstream turbulence was most significant at low blowing ratios, but became negligible at higher flow rates.
Surface Measurements and Predictions of Full-coverage Film Cooling
Author: Greg NatsuiPublisher:
ISBN:
Category :
Languages : en
Pages : 126
Book Description
Full-coverage film cooling is investigated both experimentally and numerically. First, surface measurements local of adiabatic film cooling eeffectiveness and heat transfer augmentation for four different arrays are described. Reported next is a comparison between two very common turbulence models, Realizable k-[epsilon] and SST k-[omega], and their ability to predict local film cooling effectiveness throughout a full-coverage array. The objective of the experimental study is the quantification of local heat transfer augmentation and adiabatic film cooling effectiveness for four surfaces cooled by large, both in hole count and in non-dimensional spacing, arrays of film cooling holes. The four arrays are of two different hole-to-hole spacings (P/D = X/D = 14.5; 19.8) and two different hole inclination angles ([alpha] = 30°; 45°), with cylindrical holes compounded relative to the flow ([beta] = 45°) and arranged in a staggered configuration. Arrays of up to 30 rows are tested so that the superposition effect of the coolant film can be studied. In addition, shortened arrays of up to 20 rows of coolant holes are also tested so that the decay of the coolant film following injection can be studied. Levels of laterally averaged effectiveness reach values as high as [eta with line above]= 0.5, and are not yet at the asymptotic limit even after 20-30 rows of injection for all cases studied. Levels of heat transfer augmentation asymptotically approach values of h=h0 [almost equal to] 1.35 rather quickly, only after 10 rows. It is conjectured that the heat transfer augmentation levels off very quickly due to the boundary layer reaching an equilibrium in which the perturbation from additional film rows has reached a balance with the damping effect resulting from viscosity. The levels of laterally averaged adiabatic film cooling effectiveness far exceeding [eta with line above]= 0.5 are much higher than expected. The heat transfer augmentation levels off quickly as opposed to the film effectiveness which continues to rise (although asymptotically) at large row numbers. This ensures that an increased row count represents coolant well spent. The numerical predictions are carried out in order to test the ability of the two most common turbulence models to properly predict full-coverage film cooling. The two models chosen, Realizable k-[epsilon] (RKE) and Shear Stress Transport k-[omega] (SSTKW), are both two-equation models coupled with Reynolds Averaged governing equations which make several gross physical assumptions and require several empirical values. Hence, the models are not expected to provide perfect results. However, very good average values are seen tobe obtained through these simple models. Using RKE in order to model full-coverage filmcooling will yield results with 30% less error than selecting SSTKW.
Gas Turbine Heat Transfer and Cooling Technology, Second Edition
Author: Je-Chin HanPublisher: CRC Press
ISBN: 1439855684
Category : Science
Languages : en
Pages : 892
Book Description
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.
Film Cooling on a Convex Wall
Author: Kokichi FuruhamaPublisher:
ISBN:
Category : Turbines
Languages : en
Pages : 196
Book Description
A Numerical Study of Discrete-hole Film Cooling
Author: Mulugeta K. BerheFull-coverage Film Cooling on Flat, Isothermal Surfaces: Data and Predictions
Author: Full Coverage Film Cooling Heat Transfer Studies: a Summary of the Data for Normal Hole Injection and 30 Degrees Slant Hole Injection
Author: Stanford University. Thermosciences Division. Thermosciences DivisionPublisher:
ISBN:
Category :
Languages : en
Pages : 110
Book Description
Full-coverage Film Cooling on Flat, Isothermal Surfaces
Author: Michael E. CrawfordPublisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 120
Book Description