Two-dimensional film-cooling effectiveness prediction based on deconvolution neural network

2021 ◽  
Vol 129 ◽  
pp. 105621
Author(s):  
Yaning Wang ◽  
Wen Wang ◽  
Guocheng Tao ◽  
Xinshuai Zhang ◽  
Shirui Luo ◽  
...  
Keyword(s):  
Neural Network ◽  
Film Cooling ◽  
Two Dimensional ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Effectiveness Prediction

Effect of Hole Diameter on Nozzle Endwall Film Cooling and Associated Phantom Cooling

2015 ◽  
Author(s):  
Luzeng Zhang ◽  
Juan Yin ◽  
Kevin Liu ◽  
Moon Hee-Koo
Keyword(s):  
Film Cooling ◽  
High Speed ◽  
Leading Edge ◽  
Suction Side ◽  
Hole Diameter ◽  
Two Dimensional ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Injection Angle ◽  
Blowing Ratio

Flow fields near the turbine nozzle endwall are highly complex due to the passage vortices and endwall cross flows. Consequently, it is challenging to provide proper cooling to the endwall surfaces. An effective way to cool the endwall is to have film cooling holes forward of the leading edge, often called “inlet-film cooling”. This paper presents the results of an experimental investigation on how the film hole diameter affects the film effectiveness on nozzle endwall and associated phantom cooling effectiveness on airfoil suction side. The measurements were conducted in a high speed linear cascade, which consists of three nozzle vanes and four flow passages. Double staggered rows of film injections, which were located upstream from the nozzle leading edge, provided cooling to the contoured endwall surfaces. Film cooling effectiveness on the endwall surface and corresponding phantom cooling effectiveness on the airfoil suction side were measured separately with a Pressure Sensitive Paint (PSP) technique through the mass transfer analogy. Four different film hole diameters with the same injection angle and the same pitch to diameter ratio were studied for up to six different MFR’s (mass flow ratios). Two dimensional film effectiveness distributions on the endwall surface and two dimensional phantom cooling distributions on the airfoil suction side are presented. Film/phantom cooling effectiveness distributions are pitchwise/spanwise averaged along the axial direction and also presented. The results indicate that both the endwall film effectiveness and the suction side phantom cooling effectiveness increases with the hole diameter (as decreases in blowing ratio for a given MFR) up to a specific diameter, then starts decreasing. An optimal value of the film hole diameter (blowing ratio) for the given injection angle is also suggested based on current study.

Film Cooling Effectiveness and Heat Transfer of Rectangular-Shaped Film Cooling Holes

2002 ◽  
Author(s):  
Dong Ho Rhee ◽  
Youn Seok Lee ◽  
Hyung Hee Cho
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Lateral Spreading ◽  
Two Dimensional ◽  
Rectangular Hole ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Cylindrical Holes

An experimental study has been conducted to measure the local film-cooling effectiveness and the heat transfer coefficient for a single row of rectangular-shaped holes. The holes have a 35° inclination angle with 3 hole diameter spacing of rectangular cross-sections. Four different cooling hole shapes such as a straight rectangular hole, a rectangular hole with laterally expanded exit, a circular hole and a two-dimensional slot are tested. The rectangular cross-section has the aspect ratio of 2 at the hole inlet with the hydraulic diameter of 10 mm. The area ratio of the exit to the hole inlet is 1.8 for the rectangular hole with expanded exit, which is similar to a two-dimensional slot. A thermochromic liquid crystals technique is applied to determine adiabatic film cooling effectiveness values and heat transfer coefficients on the test surface. Both film cooling effectiveness and heat transfer coefficient are measured for various blowing rates and compared with the results of the cylindrical holes and the two-dimensional slot. The flow patterns inside and downstream of holes are calculated numerically by a commercial package. The results show that the rectangular holes provide better performance than the cylindrical holes. For the rectangular holes with laterally expanded exit, the penetration of jet is reduced significantly, and the higher and more uniform cooling performance is obtained even at relatively high blowing rates. The reason is that the rectangular hole with expanded exit reduces momentum of coolant and promotes the lateral spreading like a two-dimensional slot.

The Effect of Conjugate Heat Transfer on Film Cooling Effectiveness

Volume 4 ◽  
2004 ◽  
Author(s):  
Mahmood Silieti ◽  
Eduardo Divo ◽  
Alain J. Kassab
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Turbulence Models ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Effectiveness Prediction ◽  
Lift Off ◽  
Rsm Model

We investigate the numerical prediction of film cooling effectiveness of a two-dimensional gas turbine endwall for the cases of conjugate and adiabatic heat transfer models. Further, the consequence of various turbulence models employed in the computation are investigated by considering various turbulence models: ‘RNG’ k-ε model, Realizable k-ε model, Standard k-ω model, ‘SST’ k-ω model, and ‘RSM’ model. The computed flow field and surface temperature profiles along with the film effectiveness for one and two cooling slots at different injection angles and blowing ratio of one are presented. The results show the strong effect of the conjugate heat transfer on the film effectiveness compared to the adiabatic and analytically derived formulae and show that turbulence model used significantly affects the film effectiveness prediction when separation occurs in the film hole and some level of jet lift-off is present.

Flat-Plate Film Cooling With Steam Injection Through One Row and Two Rows of Inclined Holes

1986 ◽  
Vol 108 (1) ◽  
pp. 137-144 ◽  
Author(s):  
J. C. Han ◽  
A. B. Mehendale
Keyword(s):  
Flat Plate ◽  
Film Cooling ◽  
Steam Injection ◽  
Air Injection ◽  
Two Dimensional ◽  
Injection Hole ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Air Film

Experiments have been performed to investigate the film-cooling characteristics with steam injection through one row (7 tubes) and two rows (13 tubes) of holes, inclined at an angle of 35 deg, over a flat plate. The spacing between the holes as well as the distance between the rows is 2 1/2 hole diameters. Data have been obtained for both steam and air film-cooling effectiveness at different axial and lateral locations downstream of the injection holes. The blowing rate M varied from 0.2 to 1.5. In the case of one-row injection, the results show that the film-cooling effectiveness with steam injection is about 50 to 100 percent higher than that with air injection at downstream locations, depending upon the blowing rate; however, the increase in film-cooling effectiveness is reduced near the injection hole region at high blowing rates. In the case of two-row injection, the laterally averaged film cooling effectiveness η can be correlated with the two-dimensional film-cooling parameter ξ. The η with steam injection is about 80 to 100 percent higher than that with air injection at low blowing rates and/or at downstream locations (ξ ≥ 15). However, the increase in η with steam injection is reduced near the injection hole region and/or at high blowing rates (ξ ≤ 15).

Correlation and Prediction of Film Cooling From Two Rows of Holes

1989 ◽  
Vol 111 (4) ◽  
pp. 502-509 ◽  
Author(s):  
B. A. Jubran
Keyword(s):  
Velocity Field ◽  
Turbulence Model ◽  
Film Cooling ◽  
Two Dimensional ◽  
Cooling Effectiveness ◽  
Momentum Ratio ◽  
Film Cooling Effectiveness

This paper reports the correlation and prediction of film cooling effectiveness and the velocity field from two rows of holes inclined in the streamwise and spanwise directions. The correlation of film cooling from two rows of holes can be achieved by using a two-dimensional correlating group provided that account is taken of the momentum ratio I. The effectiveness and velocity field were predicted using the PHOENICS package. Two versions of k–ε turbulence model were explored for the film cooling predictions, which were successful at the centerlines and for low blowing rates. A nonisotropic k–ε model improved the prediction by allowing the jet to spread laterally.

Scalar Diffusion Equation Based Model to Predict 2-D Film Cooling Effectiveness of Shaped Hole

2021 ◽  
pp. 1-37
Author(s):  
Ziyu Chen ◽  
Yifei Li ◽  
Xinrong Su ◽  
Xin Yuan
Keyword(s):  
Diffusion Coefficient ◽  
Film Cooling ◽  
Effective Diffusion ◽  
Main Flow ◽  
Two Dimensional ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
One Dimensional ◽  
Cooling Design ◽  
Scalar Diffusion

Abstract One-dimensional laterally averaged adiabatic film cooling effectiveness η¯lat based correlations have been widely employed in the cooling design of the modern gas turbine and aero-engine; however, the flow field of the discrete film cooling is fully three-dimensional and thus the cooling effectiveness distribution on the solid surface is two-dimensional. Accurate prediction of the cooling effectiveness distribution in the lateral direction would help to optimize the film cooling design but few paid attention to this issue in the literature. In this work, a simple yet accurate scalar diffusion equation based model is proposed to extend the one-dimensional correlation into two-dimensional. The effective diffusion coefficient is modeled to represent the balance between the diffusion and the passive transportation by the main flow. Analyses conducted within typical experimental range show that the effective diffusion coefficient is only dependent on the velocity ratio and the main-flow turbulence. The current model can be efficiently solved within one second and the results have been validated against a series of experimental data. According to the accuracy analysis, the R2 value larger than 0.9 is obtained for all cases and the source of the prediction error is also analyzed. The proposed model is proved to be accurate and efficient, and results show that the 2-D distribution of coolant can be reasonably predicted with this simple model.

IMPROVING ADIABATIC FILM-COOLING EFFECTIVENESS BY USING AN UPSTREAM PYRAMID

2016 ◽  
Vol 8 (2) ◽  
pp. 135-146 ◽  
Author(s):  
Zineb Hammami ◽  
Zineddine Ahmed Dellil ◽  
Fadela Nemdili ◽  
Abbes Azzi
Keyword(s):  
Film Cooling ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness

The Effect of Using Ramps with Trench Cylindrical Holes on Film Cooling Effectiveness

2015 ◽  
Vol 3 (2) ◽  
pp. 15-27
Author(s):  
Ahmed A. Imram ◽  
Humam K. Jalghef ◽  
Falah F. Hatem
Keyword(s):  
Numerical Simulation ◽  
Film Cooling ◽  
Air Injection ◽  
Baseline Model ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Hot Air ◽  
Test Study ◽  
Cylindrical Holes

     The effect of introducing ramp with a cylindrical slot hole on the film cooling effectiveness has been investigated experimentally and numerically. The film cooling effectiveness measurements are obtained experimentally. A test study was performed at a single mainstream with Reynolds number 76600 at three different coolant to mainstream blowing ratios 1.5, 2, and 3. Numerical simulation is introduced to primarily estimate the best ramp configurations and to predict the behavior of the transport phenomena in the region linked closely to the interaction between the coolant air injection and the hot air mainstram flow. The results showed that using ramps with trench cylindrical holes would enhanced the overall film cooling effectiveness by 83.33% compared with baseline model at blowing ratio of 1.5, also  the best overall flim cooling effectevness was obtained at blowing ratio of 2 while it is reduced at blowing ratio of 3.

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