scholarly journals Numerical and experimental investigations on film cooling with single film hole diameter wide trench for improved cooling performance

2019 ◽  
Vol 1240 ◽  
pp. 012079
Author(s):  
V G Krishna Anand ◽  
K M Parammasivam
Keyword(s):  
Film Cooling ◽  
Hole Diameter ◽  
Experimental Investigations ◽  
Cooling Performance

Experimental Investigations of the Effect of Scheme Exit Height and Double Row Injection on the Film Cooling Performance of a Micro Tangential Jet Scheme: Part I — Pressure Side

2015 ◽  
Author(s):  
O. Hassan ◽  
I. Hassan
Keyword(s):  
Film Cooling ◽  
Density Ratio ◽  
Suction Side ◽  
Average Density ◽  
Hole Diameter ◽  
Experimental Investigations ◽  
Pressure Side ◽  
Thermochromic Liquid Crystal ◽  
Double Row ◽  
Cooling Performance

This paper presents experimental investigations of the effect of scheme exit height and double jet injection on the film cooling performance of a Micro-Tangential-Jet (MTJ) scheme. The investigations were conducted over a gas turbine vane pressure side using the transient Thermochromic Liquid Crystal technique. The suction side investigations are presented in Part II of the present paper. The MTJ scheme is a micro-shaped scheme designed so that the micro-sized secondary jet is supplied tangentially to the vane surface. The scheme combines the benefits of micro jets and tangential injection. In order to investigate the effect of scheme exit height, one row of the MTJ scheme with 1.0 hole diameter exit height and another row with 1.5 hole diameter exit height were investigated. Meanwhile, to investigate the effect of double injection, one row of the MTJ scheme in staggered arrangement with one row of fan-shaped scheme was investigated. The investigations were conducted at various blowing ratios, calculated based on the scheme exit area. The average density ratio, turbulence intensity and Reynolds number were 0.93, 8.5, and 1.4E+5, respectively. The investigations showed that the smaller the exit height, the better the film cooling performance. Meanwhile, double injecting the secondary stream from MTJ and shaped schemes did not result in significant film cooling enhancement due to the enhanced turbulence over the vane surface.

Experimental Investigations of the Film Cooling Performance of a Micro-Tangential-Jet Scheme on a Gas Turbine Vane: Part 1 — Effectiveness

2012 ◽  
Author(s):  
O. Hassan ◽  
I. Hassan
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Density Ratio ◽  
Suction Side ◽  
Experimental Investigations ◽  
Stream Velocity ◽  
Pressure Side ◽  
Cooling Performance ◽  
Film Cooling Effectiveness ◽  
Turbine Vane

This paper presents experimental investigations of the film cooling effectiveness performance of a Micro-Tangential-Jet (MTJ) Film cooling scheme on a gas turbine vane using transient Thermochromic Liquid Crystal (TLC) technique. The MTJ scheme is a micro-shaped scheme designed so that the secondary jet is supplied tangentially to the vane surface. The scheme combines the benefits of micro jets and tangential injection. The film cooling performance of one row of holes on both pressure and suction sides were investigated at a blowing ratio ranging from 0.5 to 1.5 on the pressure side and 0.25 to 0.625 on the suction side. The average density ratio during the investigations was 0.93, and the Reynolds Number was 1.4E+5, based on the free stream velocity and the main duct hydraulic diameter. The pitch to diameter ratio of the cooling holes is 5 on the pressure side and 6.5 on the suction side. The turbulence intensity during all investigations was 8.5%. Minor changes in the Mach number distribution around the airfoil surface were observed due to the presence of the MTJ scheme, compared with the case with no MTJ scheme. The investigations showed great film cooling performance for the MTJ scheme, high effectiveness values, and excellent lateral jet spreading. A 2-D coolant film was observed in the results, which is a characteristic of the continuous slot schemes only. The presence of this 2-D film layer helps minimize the rate of mixing between the main and coolant streams and provides uniform thermal loads on the surface. Furthermore, it was noticed that the rate of effectiveness decay on the suction side was less than that on the pressure side, while the lateral jet spreading on the pressure side was better than that of the suction side. The main disadvantage of the MTJ scheme is the increased pressure drop.

Optimal Design of Novel Laminated Cooling System Considering Cooling Effectiveness and Thermomechanical Performance

2021 ◽  
Author(s):  
Honglin Li ◽  
Lei Li ◽  
Wenjing Gao ◽  
Zhonghao Tang ◽  
Chunlong Tan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Optimal Design ◽  
Film Cooling ◽  
Pressure Loss ◽  
Maximum Stress ◽  
Hole Diameter ◽  
Loss Coefficient ◽  
Cooling Effectiveness ◽  
Cooling Performance ◽  
Pin Fin

Abstract Laminated cooling is deemed as one of the most potential and novel cooling technologies for turbine blade to increase turbine inlet temperature, which combines the superiority of film cooling, pin fin cooling and impingement cooling. To realize optimal design, the multidisciplinary design optimization of laminated cooling configuration is conducted considering cooling performance under acceptable pressure loss and thermomechanical performance. A coupled multidisciplinary analysis model is established to perform aerodynamical analysis, heat transfer analysis and thermomechanical analysis. Based on parametrized laminated model and Design of Experiments method, the cooling effectiveness, pressure loss coefficient and maximum stress can be obtained under different design parameters and their dominated design variables can be clarified. Using these sampling points, a Kriging approximation surrogate model can be established to replace real numerical calculation process and balance the efficiency and fidelity. Finally, the multi-island genetic algorithm is used to find the maximum cooling effectiveness and minimum pressure loss under the constraint of maximum stress. Results shows that, the dilation of film hole diameter, pin fin diameter and impingement hole diameter and the reduction of target plate thickness can effectively improve cooling performance and meanwhile decrease maximum stress, which can be up to 17.68% and 4.96% separately under the acceptable poressure loss coefficient raise of 16.8%. That can be attributed to the enhancement of inner heat transfer and improvement of outer film cooling.

Experimental Investigations of the Effect of Scheme Exit Height and Double Row Injection on the Film Cooling Performance of a Micro Tangential Jet Scheme: Part II — Suction Side

2015 ◽  
Author(s):  
O. Hassan ◽  
I. Hassan
Keyword(s):  
Film Cooling ◽  
Density Ratio ◽  
Suction Side ◽  
Average Density ◽  
Experimental Investigations ◽  
Stream Velocity ◽  
Thermochromic Liquid Crystal ◽  
Double Row ◽  
Cooling Performance ◽  
Staggered Arrangement

This paper presents experimental investigations of the effect of scheme exit height and double jet injection on the film cooling performance of a Micro-Tangential-Jet (MTJ) scheme on the suction side of a gas turbine vane using the transient Thermochromic Liquid Crystal (TLC) technique. In part I of the present paper the investigations over the pressure side are presented. The MTJ scheme is a micro-shaped scheme designed so that the micro-sized secondary jet is supplied tangentially to the vane surface. In order to investigate the effect of scheme exit height, one row of the MTJ scheme with exit height of 1.5 hole diameters was investigated and compared with the case of 1.0 hole diameter scheme exit height. Meanwhile, to investigate the effect of double injection, one row of the MTJ scheme in staggered arrangement with one row of fan-shaped scheme was investigated. The investigations were conducted at a blowing ratio, calculated based on the scheme exit area, ranging from 0.25 to 0.625. The average density ratio during the investigations was 0.93, and the Reynolds Number was 1.4E+5, based on the free stream velocity and the main duct hydraulic diameter. The pitch to diameter ratio of the cooling holes is 6.5, and the turbulence intensity during all investigations was 8.5%. The increase in the MTJ scheme exit height did not result in significant change in the Mach number distribution. Moreover, increasing the scheme exit height resulted in enhanced effectiveness performance. The enhanced effectiveness was accompanied with Heat Transfer Coefficient (HTC) ratio augmentation as well. As a result, a reduction in the Net Heat Flux Reduction (NHFR) accompanied increasing the scheme exit height from 1.0 to 1.5 hole diameters. Besides, adding a row of shaped schemes in front of the MTJ scheme result in significant effectiveness reduction, compared to the case of single row injection. The latter was attributed to the presence of the shaped scheme inclination angle that result in enhanced secondary stream loss due to the perpendicular momentum component to the vane surface accompanying the shaped scheme secondary jet.

Sign in / Sign up

Export Citation Format

Share Document