Effects of Cooling Configurations on the Aerothermal Performance of a Turbine Endwall With Jet Impingement and Film Cooling

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Hongyan Bu ◽  
Zhendong Guo ◽  
Liming Song ◽  
Jun Li
Keyword(s):  
Film Cooling ◽  
Design Space ◽  
Cooling System ◽  
Uniform Design ◽  
Jet Impingement ◽  
Hole Diameter ◽  
Performance Criteria ◽  
Channel Height ◽  
Inlet Temperature ◽  
Cooling Effectiveness

Abstract With the increase of turbine inlet temperature and the application of premixed combustion, turbine components, particularly the turbine endwall, work in a harsh environment and must be effectively cooled to ensure the component durability. Recently, new cooling schemes that employ both external film cooling and internal jet impingement cooling have drawn much attention due to their extraordinary performance. In this study, a numerical model of turbine endwall with jet impingement and film cooling was established and validated against the experiment. To investigate the effects of geometric parameters related to this cooling scheme, four parameters including impingement hole-to-hole pitch Pi, impingement hole diameter Di, impingement channel height H, and film hole diameter Df were selected to adjust within a reasonable range. The uniform design method was used to collect a database that represented the design space formed by the four parameters. Performance criteria including area-averaged overall cooling effectiveness, standard deviation of overall cooling effectiveness, and total pressure drop coefficient of the cooling system were evaluated through computational fluid dynamics (CFD) calculations. To explore and exploit the design space, a Kriging model was built from the database. Analysis of variance (ANOVA) was conducted afterward to investigate the main effect of each parameter and the correlation between parameters. Finally, based upon the knowledge obtained from ANOVA, typical designs were selected which yielded either best or poorest performances. Through detailed analysis of flow and heat transfer mechanisms of these designs, the influence of each parameter was illustrated clearly and suggestions for the design of similar cooling schemes were drawn.

Effects of Cooling Configurations on the Aerothermal Performance of a Turbine Endwall With Jet Impingement and Film Cooling

2020 ◽  
Author(s):  
Hongyan Bu ◽  
Zhendong Guo ◽  
Liming Song ◽  
Jun Li
Keyword(s):  
Surrogate Model ◽  
Film Cooling ◽  
Design Space ◽  
Cooling System ◽  
Design Method ◽  
Uniform Design ◽  
Jet Impingement ◽  
Channel Height ◽  
Inlet Temperature ◽  
Cooling Effectiveness

Abstract With the rapid increase of turbine inlet temperature and the application of premixed combustion, turbine components, particularly the turbine endwall, works in extremely harsh environment and must be effectively cooled to ensure the component durability. Recently, new cooling schemes that employ both external film cooling and internal jet impingement cooling have drawn much attention due to their extraordinary performance. In this study, a numerical model of turbine endwall with jet impingement and film cooling was established and validated against the experimental results. To investigate the effects of geometric parameters related with this cooling scheme, four parameters including impingement hole-to-hole pitch Pi, impingement hole diameter Di, impingement channel height H, film hole diamete Df, were selected to adjust within a reasonable range. The uniform design method was used to collect a database that represented the design space formed by the four parameters. Performance criterions including area-averaged overall cooling effectiveness, standard deviation of overall cooling effectiveness, total pressure drop coefficient of the cooling system were evaluated through CFD calculations. To explore and exploit the design space as much as possible, a Kriging surrogate model was built from the database. Analysis of variance (ANOVA) was conducted based upon the surrogate model to investigate the main effect of each parameter and the correlation between parameters. Finally, based upon the knowledge obtained from ANOVA, typical designs were selected from the database which yielded either best or poorest performances. Through detailed analysis of flow and heat transfer mechanisms of these typical designs, the influence of each parameter was illustrated clearly and suggestions for the design of similar cooling schemes were drawn.

Enhanced Cooling Effectiveness in Full-Coverage Film Cooling System With Impingement Jets

2008 ◽  
Author(s):  
Sang Hyun Oh ◽  
Dong Hyun Lee ◽  
Kyung Min Kim ◽  
Moon Young Kim ◽  
Hyung Hee Cho
Keyword(s):  
Film Cooling ◽  
Cooling System ◽  
Hole Diameter ◽  
Cooling Effectiveness ◽  
Cooling Plate ◽  
Film Cooling Effectiveness ◽  
Impingement Jet ◽  
Full Coverage ◽  
Cooling Hole ◽  
Film Cooling Holes

An experimental investigation is conducted on the cooling effectiveness of full-coverage film cooled wall with impingement jets. Film cooling plate is made of stainless steel, thus the adiabatic film cooling effectiveness and the cooling effect of impingement jet underneath the film cooling plate are comprised in the cooling effectiveness. Infra-red camera is used to measure the temperature of film cooled surfaces. Experiments are conducted with different film cooling hole angles, such as 35° and 90°. Diameters of both film cooling holes and impinging jet holes are 5 mm. The jet Reynolds number base on the hole diameter (Red) ranges from 3,000 to 5,000 and equivalent blowing ratios (M) varies from 0.3 to 0.5, respectively. The distance between the injection plate and the film cooling plate is 1, 3 and 5 times of the hole diameter. The streamwise and spanwise hole spacing to the hole diameter ratio (p/d) are 3 for both the film cooling hole plate and the impingement jet hole plate. The 35° angled film cooling hole arrangement shows higher film cooling effectiveness than the 90° film cooling hole arrangement. As the blowing ratio increases, the cooling effectiveness is enhanced for both the 35° almost constant regardless of H/d, while H/d = 1 shows a minimum value for the angled film cooling hole.

Effect of Array Jet on Cooling Effectiveness on Full-Coverage Film Cooled Surface

2009 ◽  
Author(s):  
Dong Hyun Lee ◽  
Sang Hyun Oh ◽  
Eui Yeop Jung ◽  
Kyung Min Kim ◽  
Hyung Hee Cho
Keyword(s):  
Stainless Steel ◽  
Film Cooling ◽  
Steel Plate ◽  
Jet Impingement ◽  
Hole Diameter ◽  
Stainless Steel Plate ◽  
Cooling Effectiveness ◽  
Impingement Jet ◽  
Full Coverage ◽  
Film Cooling Holes

In this study, the cooling effectiveness (Φ) was measured on full-coverage film cooled surface with and without array jet impingement cooing using an infra-red thermographic technique. Measurements were conducted with two test plates of different thermal conductivities. One was made of stainless steel (k = 16.3 W/m·K) and the other was made of polycarbonate (k = 0.2 W/m · K). The measured cooling effectiveness comprises the adiabatic film cooling effectiveness on the film cooled surfaces, the heat conduction through the test plates and convective heat transfer of array jet impingement underneath the test plates. The inclination angles of film cooling holes and impingement jet holes were 35° and 90°, respectively. The diameters of both film cooling and impingement jet cooling holes were 5 mm. The streamwise and spanwise hole spacing-to-hole diameter ratios (p/d) are 3 for both the effusion plate (film cooled plate) and the injection plate (impingement nozzle plate. The holes on each plate were arranged in an inline pattern, while the film cooling holes and jet holes were positioned in a staggered manner. The jet Reynolds number based on the hole diameter was 3,000 and the equivalent blowing ratio (M) was 0.3. The gap distance between the jet plate and the film cooling plate was varied from 1 to 5 times of the hole diameter. In addition, the cooling effectiveness without impingement was tested, too. The stainless steel plate shows relatively higher and uniform cooling effectiveness than the polycarbonate plate. The effect of H/d was not significant for both test plates. However, the cooling effectiveness without the impingement jets decreases significantly for the stainless steel plate, while it changed a little for the cooling effectiveness of the polycarbonate plate.

Total Cooling Effectiveness on a Staggered Full-Coverage Film Cooling Plate With Impinging Jet

2010 ◽  
Author(s):  
Eui Yeop Jung ◽  
Dong Hyun Lee ◽  
Sang Hyun Oh ◽  
Kyung Min Kim ◽  
Hyung Hee Cho
Keyword(s):  
Film Cooling ◽  
Jet Impingement ◽  
Hole Diameter ◽  
Test Plate ◽  
Cooling Effectiveness ◽  
Cooling Plate ◽  
Impingement Jet ◽  
Full Coverage ◽  
Jet Cooling ◽  
Cooling Hole

In the present study, total cooling performance was experimentally investigated on a full-coverage film cooling plate with an impingement jet cooling array. The detailed temperature distributions on the film cooled surface were measured using an infra-red thermographic technique. The test plate was made of polycarbonate (k = 0.2 W/m·K) and an array jet impinged underneath the test plates. The measured cooling effectiveness is a combined result of film cooling on the surface and convective heat transfer by a jet impingement array underneath the test plate. The diameter (d) of both film cooling and impingement jet cooling holes was 5 mm. Both the streamwise and spanwise hole spacing-to-hole diameter ratios (p/d) were 3 on the film cooled plate and impingement nozzle plate. The inclination angles of the film cooling holes and impingement jet holes were 35° and 90°, respectively. The holes on each plate were arranged in a staggered pattern. The jet Reynolds number based on the hole diameter varied from 3,000 to 7,000 and the equivalent blowing rate (M) changed from 0.3 to 0.7. The combined cooling effectiveness was measured by changing the gap distance between the jet plate and the film cooling plate from 1 to 5 times the hole diameter. The staggered film cooling hole arrangement showed a higher film cooling effectiveness than the inline film cooling hole arrangement. As the blowing rate increased, the cooling effectiveness decreased on the front part of film cooling plate for a fixed height to diameter ratio (H/d). The effect of H/d on the total cooling effectiveness was not significant for the fixed blowing rate (M) in the tested range.

Experimental and numerical investigations of overall cooling effectiveness on a vane endwall with jet impingement and film cooling

2019 ◽  
Vol 148 ◽  
pp. 1148-1163 ◽  
Author(s):  
Xing Yang ◽  
Zhansheng Liu ◽  
Qiang Zhao ◽  
Zhao Liu ◽  
Zhenping Feng ◽  
...  
Keyword(s):  
Film Cooling ◽  
Jet Impingement ◽  
Cooling Effectiveness ◽  
Numerical Investigations

scholarly journals Adiabatic Effectiveness and Heat Transfer Coefficient of Shaped Film Cooling Holes on a Scaled Guide Vane Pressure Side Model

2004 ◽  
Vol 10 (5) ◽  
pp. 345-354 ◽  
Author(s):  
Jan Dittmar ◽  
Achmed Schulz ◽  
Sigmar Wittig
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Film Cooling ◽  
Guide Vane ◽  
Inlet Temperature ◽  
Test Model ◽  
Pressure Side ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness

The demand of improved thermal efficiency and high power output of modern gas turbine engines leads to extremely high turbine inlet temperature and pressure ratios. Sophisticated cooling schemes including film cooling are widely used to protect the vanes and blades of the first stages from failure and to achieve high component lifetimes. In film cooling applications, injection from discrete holes is commonly used to generate a coolant film on the blade's surface.In the present experimental study, the film cooling performance in terms of the adiabatic film cooling effectiveness and the heat transfer coefficient of two different injection configurations are investigated. Measurements have been made using a single row of fanshaped holes and a double row of cylindrical holes in staggered arrangement. A scaled test model was designed in order to simulate a realistic distribution of Reynolds number and acceleration parameter along the pressure side surface of an actual turbine guide vane. An infrared thermography measurement system is used to determine highly resolved distribution of the models surface temperature. Anin-situcalibration procedure is applied using single embedded thermocouples inside the measuring plate in order to acquire accurate local temperature data.All holes are inclined 35° with respect to the model's surface and are oriented in a streamwise direction with no compound angle applied. During the measurements, the influence of blowing ratio and mainstream turbulence level on the adiabatic film cooling effectiveness and heat transfer coefficient is investigated for both of the injection configurations.

Numerical Investigation of the Cooling Performance on the Endwall With and Without Fillet

2018 ◽  
Author(s):  
Qingzong Xu ◽  
Qiang Du ◽  
Pei Wang ◽  
Jun Liu ◽  
Guang Liu
Keyword(s):  
Secondary Flow ◽  
Turbulence Model ◽  
Film Cooling ◽  
Computational Method ◽  
Inlet Temperature ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Numerical Predictions ◽  
Turbine Vane

High inlet temperature of turbine vane increases the demand of high film cooling effectiveness. Vane endwall region was extensively cooled due to the high and flat exit temperature distribution of combustor. Leakage flow from the combustor-turbine gap was used to cool the endwall region except for preventing hot gas ingestion. Numerical predictions were conducted to investigate the flow structure and adiabatic film cooling effectiveness of endwall region in a linear cascade with vane-endwall junction fillet. The simulations were completed by solving the three-dimensional Reynolds-Averaged Navier-Stokes(RANS) equations with shear stress transport(SST) k-ω turbulence model, meanwhile, the computational method and turbulence model were validated by comparing computational result with the experiment. Three types of linear fillet with the length-to-height ratio of 0.5, 1 and 2, named fillet A, fillet B and fillet C respectively, were studied. In addition, circular fillet with radius of 2mm was compared with linear fillet B. The interrupted slot, produced by changing the way of junction of combustor and turbine vane endwall, is introduced at X/Cax = −0.2 upstream of the vane leading edge. Results showed that fillet can significantly affect the cooling performance on the endwall due to suppressing the strength of the secondary flow. Fillet C presented the best cooling performance comparing to fillet A and fillet B because a portion of the coolant which climbs to the fillet was barely affected by secondary flow. Results also showed the effect of fillet on the total pressure loss. The result indicated that only fillet A slightly decreases endwall loss.

scholarly journals Cooling and Sealing Air System in Industrial Gas Turbine Engines

1996 ◽  
Author(s):  
A. W. Reichert ◽  
M. Janssen
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Gas Turbines ◽  
State Of The Art ◽  
Cooling System ◽  
Inlet Temperature ◽  
Turbine Inlet ◽  
Air System ◽  
Calculation System ◽  
Cooling Air

Siemens heavy duty Gas Turbines have been well known for their high power output combined with high efficiency and reliability for more than 3 decades. Offering state of the art technology at all times, the requirements concerning the cooling and sealing air system have increased with technological development over the years. In particular the increase of the turbine inlet temperature and reduced NOx requirements demand a highly efficient cooling and sealing air system. The new Vx4.3A family of Siemens gas turbines with ISO turbine inlet temperatures of 1190°C in the power range of 70 to 240 MW uses an effective film cooling technique for the turbine stages 1 and 2 to ensure the minimum cooling air requirement possible. In addition, the application of film cooling enables the cooling system to be simplified. For example, in the new gas turbine family no intercooler and no cooling air booster for the first turbine vane are needed. This paper deals with the internal air system of Siemens gas turbines which supplies cooling and sealing air. A general overview is given and some problems and their technical solutions are discussed. Furthermore a state of the art calculation system for the prediction of the thermodynamic states of the cooling and sealing air is introduced. The calculation system is based on the flow calculation package Flowmaster (Flowmaster International Ltd.), which has been modified for the requirements of the internal air system. The comparison of computational results with measurements give a good impression of the high accuracy of the calculation method used.

Conjugate Heat Transfer on Full-Coverage Film Cooling With Array Impingement Jets

2015 ◽  
Author(s):  
Eui Yeop Jung ◽  
Heeyoon Chung ◽  
Seok Min Choi ◽  
Ta-kwan Woo ◽  
Hyung Hee Cho
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Film Cooling ◽  
Steel Plate ◽  
Hole Diameter ◽  
Maximum Deviation ◽  
Stainless Steel Plate ◽  
Cooling Effectiveness ◽  
Impingement Jet ◽  
Film Cooling Holes

We report an investigation of the total cooling effectiveness of a film cooled surface with staggered array impingement jet cooling using infra-red thermography. Heat transfer experiments were carried out using three film cooled test plates of different thermal conductivities: stainless steel (with a thermal conductivity, k = 13.4 W/mK), Corian® (k = 1 W/mK), and polycarbonate (k = 0.2 W/mK). The effects of conduction through the test plates and convective heat transfer due to the arrayed impingement jets were analyzed. The inclination angle of the film cooling holes was 35° and that of the impingement jet holes was 90°. The film and impingement jet holes on each plate were arranged in a staggered pattern, and the film cooling holes and impingement jet holes were also positioned in a staggered pattern. The jet Reynolds number based on the hole diameter was Rejet = 3,000 and the equivalent blowing rate was M = 0.3. The ratio of the target surface height to the hole diameter was varied in the range 1 < H/d < 5. The diameter of both the film cooling holes and impingement jet holes was 5 mm. The total cooling effectiveness was investigated with and without the impingement jets. When the impingement jets were added to the internal cooling, the averaged total cooling effectiveness was enhanced about 8.4%. The stainless steel plate was found to exhibit better cooling performance with more uniform temperature distribution. The total cooling effectiveness was increased up to 0.87 in the stainless steel plate, and the maximum deviation of total cooling effectiveness in the stainless steel was reduced to 85% from that in polycarbonate plate along the lateral direction. The total cooling effectiveness was related to the Biot number of the film cooled plate, however, the effect of the H/d ratio was not significant.

Enhancement in Film Cooling Effectiveness Using Delta Winglet Pair

2020 ◽  
pp. 1-37
Author(s):  
Nirmal Halder ◽  
Arun Saha ◽  
Pradipta Panigrahi
Keyword(s):  
Film Cooling ◽  
Cross Flow ◽  
Hole Diameter ◽  
Stagnation Region ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Longitudinal Vortices ◽  
Blowing Ratio ◽  
Turbulent Statistics ◽  
Delta Winglet

Abstract A simulation study is performed to inspect the influence of delta winglet pair for improving the film cooling effectiveness of gas turbine blade. Incompressible continuity, momentum, energy and two equations - SST model have been used for investigating the nature of flow field, temperature field and turbulent statistics. Reynolds number based on the jet velocity and film cooling hole diameter is 4232. The jet to cross-flow blowing ratio has been varied as 0.5, 1.0 and 1.5. The corresponding Reynolds numbers based on cross-flow velocity and film-hole diameter are equal to 6462, 4229 and 3231 respectively. It is observed that common flow down configuration augments the film cooling effectiveness which attributed to the development of secondary longitudinal vortices. Longitudinal vortices annihilate the counter rotating vortex structures present in the baseline flow. The generation of hairpin vortices and boost of shear layer vortices are modified due to the implementation of Delta winglet pair. The overall turbulence intensity and vorticity get reduced due to the presence of Delta winglet pair. A maximum of 97.46% and a minimum of 61.50% enhancement in film cooling effectiveness is observed at blowing ratio of 1.5 and 0.5 respectively.Wake region of film cooling jet is modified due to Delta winglet pair leading to formation of stagnation region and lower mixing resulting in higher film cooling effectiveness.

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