Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 120
Book Description
Full-coverage Film Cooling on Flat, Isothermal Surfaces: Data and Predictions
Author: Full-coverage Film Cooling on Flat, Isothermal Surfaces
Author: Michael E. CrawfordPublisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 120
Book Description
Scientific and Technical Aerospace Reports
Author: 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.
Film Cooling and Turbine Blade Heat Transfer
Author: Publisher:
ISBN:
Category : Aircraft gas-turbines
Languages : en
Pages : 262
Book Description
Film Cooling on a Convex Wall
Author: Kokichi FuruhamaPublisher:
ISBN:
Category : Turbines
Languages : en
Pages : 196
Book Description
Advances in Heat Transfer
Author: Publisher: Academic Press
ISBN: 0080575706
Category : Science
Languages : en
Pages : 401
Book Description
Advances in Heat Transfer
ASME Technical Papers
Author: Publisher:
ISBN:
Category : Mechanical engineering
Languages : en
Pages : 438
Book Description
Full-coverage Film Cooling Heat Transfer Studies - a Summary of the Data for Normal-hole Injection and 30 Degree Stant-hole Injection
Author: M. E. CrawfordPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Results are presented from a study of heat transfer to a full-coverage, film-cooled turbulent boundary layer over a flat surface. The surface used in the investigation consists of a discrete hole test section, containing eleven.
Author: