HIGH RESOLUTION NUMERICAL METHOD FOR PREDICTING SLOTS FILM‐COOLING USING THE COUPLED PARABOLIC/ELLIPTIC NAVIER‐STOKES SOLVER

1993 ◽  
Vol 3 (6) ◽  
pp. 531-544
Author(s):  
E.Y.‐K. NG
Keyword(s):  
High Resolution ◽  
Numerical Method ◽  
Film Cooling ◽  
Navier Stokes

Systematic Study on the Fluid Dynamical Behaviour of Streamwise and Laterally Inclined Jets in Crossflow

1997 ◽  
Author(s):  
R.-D. Baier ◽  
W. Koschel ◽  
K.-D. Broichhausen ◽  
G. Fritsch
Keyword(s):  
High Resolution ◽  
Film Cooling ◽  
Large Scale ◽  
Computational Study ◽  
Dynamical Behaviour ◽  
Temperature Fields ◽  
Navier Stokes ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Film Cooling Holes

The design of discrete film cooling holes for gas turbine airfoil applications is governed by a number of parameters influencing both their aerodynamic and thermal behaviour. This numerical and experimental study focuses on the marked differences between film cooling holes with combined streamwise and lateral inclination and film cooling holes with streamwise inclination only. The variation in the blowing angle was chosen on a newly defined and physically motivated basis. High resolution low speed experiments on a large scale turbine airfoil gave insights particularly into the intensified mixing process with lateral ejection. The extensive computational study is performed with the aid of a 3D block-structured Navier-Stokes solver incorporating a low-Reynolds-number k-ε turbulence model. Special attention is paid to mesh generation as a precondition for accurate high-resolution results. The downstream temperature fields of the jets show reduced spanwise variations with increasing lateral blowing angle; these variations are quantified for a comprehensive variety of configurations in terms of adiabatic film cooling effectiveness.

Development of a two-fluid based thermal-hydraulic subchannel analysis code with high-resolution numerical method

2021 ◽  
Vol 134 ◽  
pp. 103671
Author(s):  
Minyang Gui ◽  
Wenxi Tian ◽  
Di Wu ◽  
Ronghua Chen ◽  
Mingjun Wang ◽  
...  
Keyword(s):  
High Resolution ◽  
Numerical Method ◽  
Two Fluid ◽  
Subchannel Analysis

Computation of Discrete-Hole Film Cooling by a Near-Wall Second-Moment Turbulence Closure

1999 ◽  
Author(s):  
Hamn-Ching Chen ◽  
Gengsheng Wei ◽  
Je-Chin Han
Keyword(s):  
Film Cooling ◽  
Moment Closure ◽  
Navier Stokes ◽  
Closure Model ◽  
Complex Flow ◽  
Second Moment ◽  
Finite Analytic Method ◽  
Second Moment Closure ◽  
Effectiveness Prediction ◽  
Near Wall

Abstract A multiblock Favre-Averaged Navier-Stokes (FANS) method has been developed in conjunction with a chimera domain decomposition technique for investigation of flat surface, discrete-hole film cooling performance. The finite-analytic method solves the FANS equations in conjunction with a near-wall second-order Reynolds stress (second-moment) closure model and a two-layer k-ε model. Comparisons of flow fields and turbulence quantities with experimental data clearly demonstrate the capability of the near-wall second-moment closure model for accurate resolution of the complex flow interaction bewteen the coolant jet and the mainstream. The near-wall second-moment anisotropic model provides better agreement in adiabatic film effectiveness prediction than the two-layer k-ε model.

Film Cooling From Novel Sister Shaped Single-Holes

2014 ◽  
Author(s):  
Siavash Khajehhasani ◽  
Bassam Jubran
Keyword(s):  
Film Cooling ◽  
Three Dimensional ◽  
Lateral Spreading ◽  
Navier Stokes ◽  
The Novel ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Shaped Hole ◽  
Lift Off

A numerical investigation of the film cooling performance from novel sister shaped single-holes (SSSH) is presented in this paper and the obtained results are compared with a single cylindrical hole, a forward diffused shaped hole, as well as discrete sister holes. Three types of the novel sister shaped single-hole schemes namely downstream, upstream and up/downstream SSSH, are designed based on merging the discrete sister holes to the primary hole in order to reduce the jet lift-off effect and increase the lateral spreading of the coolant on the blade surface as well as a reduction in the amount of coolant in comparison with discrete sister holes. The simulations are performed using three-dimensional Reynolds-Averaged Navier Stokes analysis with the realizable k–ε model combined with the standard wall function. The upstream SSSH demonstrates similar film cooling performance to that of the forward diffused shaped hole for the low blowing ratio of 0.5. While it performs more efficiently at M = 1, where the centerline and laterally averaged effectiveness results improved by 70% and 17%, respectively. On the other hand, the downstream and up/downstream SSSH schemes show a considerable improvement in film cooling performance in terms of obtaining higher film cooling effectiveness and less jet lift-off effect as compared with the single cylindrical and forward diffused shaped holes for both blowing ratios of M = 0.5 and 1. For example, the laterally averaged effectiveness for the downstream SSSH configuration shows an improvement of approximately 57% and 110% on average as compared to the forward diffused shaped hole for blowing ratios of 0.5 and 1, respectively.

A CFD-Based Parametric Study on Modification of Discrete Sister Holes Location for the Film Cooling Flow

2014 ◽  
Author(s):  
Siavash Khajehhasani ◽  
Bassam Jubran
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Base Case ◽  
Spanwise Direction ◽  
Cooling Performance ◽  
Cooling Flow ◽  
Lift Off ◽  
The Individual

A numerical study on the effects of sister holes locations on film cooling performance is presented. This includes the change of the location of the individual discrete sister holes in the streamwise and spanwise directions, where each one of these directions includes 9 different locations, The simulations are performed using three-dimensional Reynolds-Averaged Navier Stokes analysis with the realizable k–ε model combined with the standard wall function. The variation of the sister holes in the streamwise direction provides similar film cooling performance as the base case for both blowing ratios of 0.5 and 1. On the other hand, the spanwise variation of the sister holes’ location has a more prominent effect on the effectiveness. In some cases, as a result of the anti-vortices generated from the sister holes and the repositioning of the sister holes in the spanwise direction, the jet lift-off effect notably decreases and more volume of coolant is distributed in the spanwise direction.

Leading Edge Film Cooling: Computations and Experiments Including Density Effects

1996 ◽  
Author(s):  
Pingfan He ◽  
Dragos Licu ◽  
Martha Salcudean ◽  
Ian S. Gartshore
Keyword(s):  
Experimental Data ◽  
Film Cooling ◽  
Stokes Equations ◽  
Leading Edge ◽  
Variable Density ◽  
Navier Stokes ◽  
Cooling Effectiveness ◽  
Stagnation Line ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio

The effect of varying coolant density on film cooling effectiveness for a turbine blade-model was numerically investigated and compared with experimental data. This model had a semi-circular leading edge with four rows of laterally-inclined film cooling orifices positioned symmetrically about the stagnation line. A curvilinear coordinate-based CFD code was developed and used for the numerical investigation. The code used a domain segmentation strategy in conjunction with general curvilinear grids to model the complex blade configuration. A multigrid method was used to accelerate the convergence rate. The time-averaged, variable-density, Navier-Stokes equations together with the energy or scalar equation were solved. Turbulence closure was attained by the standard k–ε model with a near-wall k model. Either air or CO2 was used as coolant in three cases of injection through single rows and alternatively staggered double raws of holes. Two different blowing rates were investigated in each case and compared with experimental data. The experimental results were obtained using a wind tunnel model, and the mass/heat analogy was used to determine the film cooling effectiveness. The higher density of the carbon dioxide coolant (approximately 1.5 times the density of air) in the isothermal mass injection experiments, was used to simulate the effects of injection of a colder air in the corresponding adiabatic heat transfer situation. Good agreement between calculated and measured film cooling effectiveness was found for low blowing ratio M ≤ 0.5 and the effect of density was not significant. At higher blowing ratio M > 1 the calculations consistently overpredict the measured values of film cooling effectiveness.

scholarly journals Heat Transfer on a Film-Cooled Rotating Blade

1999 ◽  
Author(s):  
Vijay K. Garg
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Three Dimensional ◽  
Leading Edge ◽  
Tip Clearance ◽  
Navier Stokes ◽  
Film Cooling Effectiveness ◽  
Film Cooling Holes

A multi-block, three-dimensional Navier-Stokes code has been used to compute heat transfer coefficient on the blade, hub and shroud for a rotating high-pressure turbine blade with 172 film-cooling holes in eight rows. Film cooling effectiveness is also computed on the adiabatic blade. Wilcox’s k-ω model is used for modeling the turbulence. Of the eight rows of holes, three are staggered on the shower-head with compound-angled holes. With so many holes on the blade it was somewhat of a challenge to get a good quality grid on and around the blade and in the tip clearance region. The final multi-block grid consists of 4784 elementary blocks which were merged into 276 super blocks. The viscous grid has over 2.2 million cells. Each hole exit, in its true oval shape, has 80 cells within it so that coolant velocity, temperature, k and ω distributions can be specified at these hole exits. It is found that for the given parameters, heat transfer coefficient on the cooled, isothermal blade is highest in the leading edge region and in the tip region. Also, the effectiveness over the cooled, adiabatic blade is the lowest in these regions. Results for an uncooled blade are also shown, providing a direct comparison with those for the cooled blade. Also, the heat transfer coefficient is much higher on the shroud as compared to that on the hub for both the cooled and the uncooled cases.

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