scholarly journals Film Cooling on a Gas Turbine Rotor Blade

Author(s):  
Kenichiro Takeishi ◽  
Sunao Aoki ◽  
Tomohiko Sato ◽  
Keizo Tsukagoshi

The film cooling effectiveness on a low-speed stationary cascade and the rotating blade has been measured by using a heat-mass transfer analogy. The film cooling effectiveness on the suction surface of the rotating blade fits well with that on the stationary blade, but a low level of effectiveness appears on the pressure surface of the rotating blade. In this paper, typical film cooling data will be presented and film cooling on a rotating blade is discussed.

1992 ◽  
Vol 114 (4) ◽  
pp. 828-834 ◽  
Author(s):  
K. Takeishi ◽  
S. Aoki ◽  
T. Sato ◽  
K. Tsukagoshi

The film cooling effectiveness on a low-speed stationary cascade and the rotating blade has been measured by using a heat-mass transfer analogy. The film cooling effectiveness on the suction surface of the rotating blade fits well with that on the stationary blade, but a low level of effectiveness appears on the pressure surface of the rotating blade. In this paper, typical film cooling data will be presented and film cooling on a rotating blade is discussed.


Author(s):  
Shiou-Jiuan Li ◽  
Akhilesh P. Rallabandi ◽  
Je-Chin Han

Detailed film cooling effectiveness distributions along a modeled turbine rotor blade under combined effects of upstream trailing edge unsteady wake with coolant ejection are presented using the pressure sensitive paint (PSP) mass transfer analogy method. The experiment is conducted in a low speed wind tunnel facility with a five blade linear cascade. The exit Reynolds number based on the axial chord is 370,000. Unsteady wakes and trailing edge coolant jets are produced by a spoked wheel-type wake generator with hollow rods equipped with several coolant ejections from holes. The coolant-to-mainstream density ratios for both blade and trailing edge coolant ejection range from 1.5 to 2.0 for simulating realistic engine conditions. Blade blowing ratios studied are 0.5 and 1.0 on Suction surface and 1.0 and 2.0 on Pressure surface. Trailing edge jet blowing ratio and Strouhal number are 1.0 and 0.12, respectively. Results show the unsteady wake reduces overall film cooling effectiveness. However, the unsteady wake with trailing edge coolant ejection enhances overall effectiveness. Results also show that the overall filming cooling effectiveness increases by using heavier coolant for trailing edge ejection as well as for blade surface film cooling.


2012 ◽  
Vol 134 (6) ◽  
Author(s):  
Shiou-Jiuan Li ◽  
Akhilesh P. Rallabandi ◽  
Je-Chin Han

Detailed film cooling effectiveness distributions along a modeled turbine rotor blade under the combined effects of an upstream trailing edge unsteady wake with coolant ejection are presented using the pressure sensitive paint (PSP) mass transfer analogy method. The experiment is conducted in a low speed wind tunnel facility with a five blade linear cascade. The exit Reynolds number based on the axial chord is 370,000. Unsteady wakes and trailing edge coolant jets are produced by a spoked wheel-type wake generator with hollow rods equipped with several coolant ejections from holes. The coolant-to-mainstream density ratios for both the blade and trailing edge coolant ejection range from 1.5 to 2.0 for simulating realistic engine conditions. Blade blowing ratio studies are 0.5 and 1.0 on the suction surface and 1.0 and 2.0 on the pressure surface. The trailing edge jet blowing ratio and Strouhal numbers are 1.0 and 0.12, respectively. The results show that the unsteady wake reduces the overall film cooling effectiveness. However, the unsteady wake with trailing edge coolant ejection enhances the overall effectiveness. The results also show that the overall filming cooling effectiveness increases by using heavier coolant for trailing edge ejection and for blade surface film cooling.


2008 ◽  
Vol 131 (1) ◽  
Author(s):  
A. Suryanarayanan ◽  
S. P. Mhetras ◽  
M. T. Schobeiri ◽  
J. C. Han

Film cooling effectiveness measurements under rotation were performed on the rotor blade platform using a pressure sensitive paint (PSP) technique. The present study examines, in particular, the film cooling effectiveness due to purging of coolant from the wheel-space cavity through the circumferential clearance gap provided between the stationary and rotating components of the turbine. The experimental investigation is carried out in a new three-stage turbine facility, recently designed and taken into operation at the Turbomachinery Performance and Flow Research Laboratory (TPFL) of Texas A&M University. This new turbine rotor has been used to facilitate coolant injection through this stator-rotor gap upstream of the first stage rotor blade. The gap was inclined at 25deg to mainstream flow to allow the injected coolant to form a film along the passage platform. The effects of turbine rotating conditions on the blade platform film cooling effectiveness were investigated at three speeds of 2550rpm, 2000rpm, and 1500rpm with corresponding incidence angles of 23.2deg, 43.4deg, and 54.8deg, respectively. Four different coolant-to-mainstream mass flow ratios varying from 0.5% to 2.0% were tested at each rotational speed. Aerodynamic measurements were performed at the first stage stator exit using a radially traversed five-hole probe to quantify the mainstream flow at this station. Results indicate that film cooling effectiveness increases with an increase in the coolant-to-mainstream mass flow ratios for all turbine speeds. Higher turbine rotation speeds show more local film cooling effectiveness spread on the platform with increasing magnitudes.


Author(s):  
A. Suryanarayanan ◽  
S. P. Mhetras ◽  
M. T. Schobeiri ◽  
J. C. Han

Film cooling effectiveness measurements under rotation were performed on the rotor blade platform using a pressure sensitive paint (PSP) technique. The present study examines, in particular, the film cooling effectiveness due to purging of coolant from the wheel-space cavity through the circumferential clearance gap provided between the stationary and rotating components of the turbine. The experimental investigation is carried out in a new three-stage turbine facility, recently designed and taken into operation at the Turbomachinery Performance and Flow Research Laboratory (TPFL) of Texas A&M University. This new turbine rotor has been used to facilitate coolant injection through this stator-rotor gap upstream of the 1st stage rotor blade. The gap was inclined at 25° to mainstream flow to allow the injected coolant to form a film along the passage platform. The effects of turbine rotating conditions on the blade platform film cooling effectiveness were investigated at three speeds of 2550 rpm, 2000 rpm and 1500 rpm with corresponding incidence angles of 23.2°, 43.4° and 54.8° respectively. Four different coolant-to-mainstream mass flow ratios varying from 0.5% to 2.0% were tested at each rotational speed. Aerodynamic measurements were performed at the 1st stage stator exit using a radially traversed five-hole probe to quantify the mainstream flow at this station. Results indicate that film cooling effectiveness increases with an increase in the coolant-to-mainstream mass flow ratios for all turbine speeds. Higher turbine rotation speeds show more local film cooling effectiveness spread on the platform with increasing magnitudes.


Author(s):  
Zhan Wang ◽  
Jian-Jun Liu ◽  
Bai-tao An ◽  
Chao Zhang

The effects of axial row-spacing for double jet film-cooling (DJFC) with compound angle on the cooling characteristics under different blowing ratios were investigated numerically. First, the flow fields and cooling effectiveness of DJFC on flat plate with different axial row-spacing were calculated. Film-cooling with fan-shaped or cylindrical holes was also calculated for the comparison. The results indicate that a larger axial row-spacing is helpful to form the anti-kidney vortex and to improve the cooling effectiveness. The DJFC was then applied to the suction and pressure surface of a real turbine inlet guide vane. Comparisons of film-cooling effectiveness with the cylindrical and fan-shaped holes were also conducted. The results for the guide vane show that on the suction surface the DJFC with a larger axial row-spacing leads to better film coverage and better film-cooling effectiveness than the cylindrical or fan-shaped holes. On the pressure surface, however, the film-cooling with fan-shaped holes is superior to the others.


Author(s):  
Dianliang Yang ◽  
Zhenping Feng ◽  
Xiaobing Yu

The effect of the film cooling holes arrangements and the blowing ratio on the tip film cooling effectiveness in a rotating blade with the squealer tip was investigated by using numerical methods in this paper. The first stage rotor blade with squealer tip of GE-E3 engine high pressure turbine was adopted to perform this study. The tip clearance was specified as 1% of the blade height, and the groove depth was specified as 2% of the blade height. The different turbulence models were checked by Kim’s experiment data [1] in 1995, and the standard k-ε turbulence model was chosen to predict the film cooling effectiveness on the blade tip. The film holes were arranged at the tip camber line, the tip division line, the tip pressure side and the pressure surface near tip, respectively. The effect of the holes position on the tip film cooling effectiveness in the rotating blade was studied. The effect of the blowing ratio was analyzed for the cases that the film holes were placed at the tip division line and the pressure surface near tip. The results show that the area-averaged tip film cooling effectiveness reaches the highest when the film holes are placed along the tip division line, and the tip leakage mass flow rate can be reduced by placing the film holes on the pressure surface near tip.


2021 ◽  
pp. 1-20
Author(s):  
Jichen Li ◽  
Hui Ren Zhu ◽  
Cun Liang Liu ◽  
Lin Ye ◽  
Zhou Daoen

Abstract Gas turbines have been widely used. With the continuous improvement of the performance of gas turbines, the turbine inlet temperature has greatly exceeded the heat resistance limit of the turbine blade material, so advanced cooling technology is required. The film cooling effectiveness distribution over the blade under the effect of wake was obtained by Pressure Sensitive Paint (PSP) technique. The test blade has 5 rows of chevron film holes on the pressure side, 3 rows of cylindrical film holes on the leading edge and 3 rows of chevron film holes on the suction side. The mainstream Reynolds number is 130,000 based on the blade chord length, and the mainstream turbulence intensity is 2.7%. The upstream wake was simulated by the spoken-wheel type wake generator. The film cooling effectiveness was measured at three wake Strouhal numbers (0, 0.12 and 0.36) and three mass flux ratios (MFR1, MFR2 and MFR3). The results show that the increase of mass flux ratio leads a decrease of the film cooling effectiveness on the suction surface. In the wake condition, the effect of mass flux ratio is weakened. Wake leads a marked decrease of the film cooling effectiveness over most blade surface except for the surface near leading edge on the pressure surface. In the high mass flux ratio condition, the effect of wake on the film cooling effectiveness is weakened on the suction surface and strengthened on the pressure surface.


Author(s):  
B. Weigand ◽  
S. P. Harasgama

A numerical investigation of film cooling on a turbine rotor blade has been carried out. The computations were performed with a 3D-Navier-Stokes code utilizing an unstructured solution adaptive grid methodology (Dawes (1992)). The code uses a low Reynolds number k-epsilon model for prescribing the Reynolds stresses. The results show that there is a significant interaction between the coolant flow and the secondary flow near the hub and the tip of the turbine blade. It was observed that, by blowing on the pressure side of the blade, some of the cooling air was transported through the tip gap of the blade to the suction side of the blade where the coolant flow interacts with the secondary flow field. When radial inlet temperature distortion (RTD) is included, it was possible to show that there were some further modifications of the film cooling effectiveness on the rotating blade near the pressure side tip. This is believed to be mostly because of the changed secondary flow system due to the radial inlet temperature profile.


Author(s):  
Shuai-qi Zhang ◽  
Cun-liang Liu ◽  
Qi-ling Guo ◽  
Da-peng Liang ◽  
Fan Zhang

Abstract The film coverage of a turbine blade surface is determined by all the film cooling structures. The direct study of full coverage film cooling is relatively rare, especially for related research on turbine blades. In this paper, the pressure-sensitive paint (PSP) measurement technique is used to carry out experiments under different turbulence intensities and mass flux ratios, and the distribution of the film cooling effectiveness on the entire surface is studied in detail. In this study, a basic turbine blade and an improved turbine blade are investigated. The film cooling hole position distribution on the improved blade is the same as that on the basic blade, but the film cooling hole shape on the suction surface and the pressure surface is changed from cylindrical holes to laid-back fan-shaped holes. Both blades have 5 rows of cylindrical holes at the leading edge and 4 rows of film cooling holes on the suction surface and the pressure surface. The leading edge, suction surface, and pressure surface have their own coolant inlet cavities. This kind of design is not only close to the actual working conditions in a flow distribution but also conveniently eliminates the mutual interference caused by the uneven flow distribution between the pressure surface and the suction surface to facilitate the independent analysis of the pressure surface and the suction surface. In this paper, the film cooling effectiveness of two kinds of turbine blades under different turbulence intensities and mass flux ratios is studied. The results show that the average cooling effectiveness of the improved blade is much better than that of the basic blade. The laid-back fan-shaped hole rows improve the cooling effectiveness of the suction surface by 60% to 100% and 50% to 120% on the pressure surface. The increase in turbulence intensity will reduce the cooling effectiveness of the blade surface; however, the effect of the turbulence intensity becomes weaker with an increase in the mass flux ratio. Compared with the multiple rows of cylindrical holes, the cooling effectiveness of the laid-back fan-shaped holes is more affected by the turbulence intensity under the small mass flux ratio.


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