Author: Publisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 156
Book Description
Full-coverage Film Cooling Heat Transfer Study
Author: Full-coverage Film Cooling Heat Transfer Study: Summary of Data for Normal-hole Injection and 30 Deg Slant-hole Injection
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 Heat Transfer Study
Author: 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.
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.
Full-coverage Film Cooling on Flat, Isothermal Surfaces
Author: Michael E. CrawfordPublisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 148
Book Description
An experimental and analytical study of the heat transfer and fluid mechanics characteristics of full-coverage film cooling has been under way since 1971. This report summarizes the results for flat, isothermal plates for three.
A Full Coverage Film Cooling Study
Author: Justin HodgesPublisher:
ISBN:
Category :
Languages : en
Pages : 118
Book Description
This thesis is an experimental and numerical full-coverage film cooling study. The objective of this work is the quantification of local heat transfer augmentation and adiabatic film cooling effectiveness for two full-coverage film cooling geometries. Experimental data was acquired with a scientific grade CCD camera, where images are taken over the heat transfer surface, which is painted with a temperature sensitive paint. The CFD component of this study served to evaluate how well the v2-f turbulence model predicted film cooling effectiveness throughout the array, as compared with experimental data. The two staggered arrays tested are different from one another through a compound angle shift after 12 rows of holes. The compound angle shifts from [beta]=-45° to [beta]=+45° at row 13. Each geometry had 22 rows of cylindrical film cooling holes with identical axial and lateral spacing (X/D=P/D=23). Levels of laterally averaged film cooling effectiveness for the superior geometry approach 0.20, where the compound angle shift causes a decrease in film cooling effectiveness. Levels of heat transfer augmentation maintain values of nearly h/h0=1.2. There is no effect of compound angle shift on heat transfer augmentation observed. The CFD results are used to investigate the detrimental effect of the compound angle shift, while the SST k-[omega] turbulence model shows to provide the best agreement with experimental results.
Heat Transfer to a Full-coverage, Film-cooled Surface with Compound-angle (30 Deg and 45 Deg) Hole Injection
Author: H. K. KimPublisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 164
Book Description
An experimental study of heat transfer was conducted on a turbulent boundary layer with full-coverage film cooling through an array of holes inclined at 30 degrees to the surface and 45 degrees to the flow direction.
Heat Transfer to a Full Coverage Film Cooled Surface with Thirty Degree Slant Hole Injection
Author: Stanford University. Thermosciences Division. Thermosciences DivisionPublisher:
ISBN:
Category :
Languages : en
Pages : 264
Book Description