Improvement of Turbine Vane Film Cooling Performance by Double Flow-Control Devices

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Hirokazu Kawabata ◽  
Ken-ichi Funazaki ◽  
Yuya Suzuki ◽  
Hisato Tagawa ◽  
Yasuhiro Horiuchi

This study deals with the studies of the effect of double flow-control devices (DFCDs) on turbine vane film cooling. Aiming for improving film effectiveness, two semispheroid DFCDs per pitch were attached to the vane surface upstream of the cooling hole. Although the DFCDs were successfully applied to the flat-plate film cooling in the previous study, the applicability to the turbine vane was to be investigated. In order to observe the flow field in detail, Reynolds-averaged Navier–Stokes (RANS) simulation was conducted first. The DFCDs were installed upstream of each cooling hole of the pressure and suction sides of the vane to investigate the effect of the device position. In this paper, the effects of blowing ratio and cooling hole pitch were also investigated. The results obtained by CFD showed that the vortex generated from DFCD suppressed lift-off of the secondary air. As a result, the film effectiveness became significantly higher than that without DFCD condition. Moreover, the improvement in the film effectiveness by DFCD was observed by both of the pressure and suction sides of the turbine vane. Based on the findings through RANS simulation, adiabatic effectiveness and total pressure loss coefficient measurement were performed in a linear cascade test facility. The experiment confirmed that the film effectiveness was improved when DFCDs existed.

Author(s):  
Hirokazu Kawabata ◽  
Ken-ichi Funazaki ◽  
Yuya Suzuki ◽  
Hisato Tagawa ◽  
Yasuhiro Horiuchi

This study deals with the studies of the effect of flow control double devices (DFCDs) on turbine vane film cooling. Aiming for improving film effectiveness, two semi-spheroid DFCDs per pitch were attached to the vane surface upstream of the cooling hole. Although the DFCDs were successfully applied to the flat plate film cooling in the previous study, the applicability to the turbine vane was to be investigated. In order to observe the flow field in detail, RANS simulation was conducted first. The DFCDs were installed upstream of each cooling hole of the pressure and suction sides of the vane to investigate the effect of the device position. In this paper, the effects of blowing ratio and cooling hole pitch were also investigated. The results obtained by CFD showed that the vortex generated from DFCD suppressed lift off of the secondary air. As a result, the film effectiveness became significantly higher than that without DFCD condition. Moreover, the improvement in the film effectiveness by DFCD was observed by both of the pressure and suction sides of the turbine vane. Based on the findings through RANS simulation, adiabatic effectiveness and total pressure loss coefficient measurement were performed in a linear cascade test facility. The experiment confirmed that the film effectiveness was improved when DFCDs existed.


Author(s):  
Ken-ichi Funazaki ◽  
Ryota Nakata ◽  
Hirokazu Kawabata ◽  
Hisato Tagawa ◽  
Yasuhiro Horiuchi

This paper deals with effects of double flow control devices (DFCDs) on flat plate film cooling performance. Aiming for further improvement of film effectiveness of discrete cooling holes, this new type of controlling method is invented and recently patented by the authors. The performance of base-type DFCDs, installed just upstream of cooling holes with conventional round or fan-shaped exits, is thoroughly investigated and reported in this study. Effects of the hole pitch are examined. Three hole-pitch cases, 3.0d, 4.5 d and 6.0 d are examined in this study to explore a possibility of reducing the cooling air by the application of DFCDs, where d is a hole diameter. In order to investigate the film effectiveness, a transient method using a high-resolution infrared camera is adopted. At the downstream of the cooling hole, the time-averaged temperature field is captured by a thermocouple rake and the time-averaged velocity field is captured by 3D Laser Doppler Velocimeter (LDV), respectively. Furthermore, the aerodynamic loss characteristics of the cooling hole with and without DFCDs are measured by a total pressure probe rake. The experiments are carried out for two blowing ratios, 0.5 and 1.0. It is found that DFCDs are quite effective in increasing the film effectiveness not only for round but also the fan-shaped holes. Starting from the base-type device, a robust optimization using Taguchi Method has been made by the present authors and will be reported as Part II.


2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Hirokazu Kawabata ◽  
Ken-ichi Funazaki ◽  
Ryota Nakata ◽  
Daichi Takahashi

This study deals with the experimental and numerical studies of the effect of flow control devices (FCDs) on the film cooling performance of a circular cooling hole on a flat plate. Two types of FCDs with different heights are examined in this study, where each of them is mounted to the flat plate upstream of the cooling hole by changing its lateral position with respect to the hole centerline. In order to measure the film effectiveness as well as heat transfer downstream of the cooling hole with upstream FCD, a transient method using a high-resolution infrared camera is adopted. The velocity field downstream of the cooling hole is captured by 3D laser Doppler velocimeter (LDV). Furthermore, the aerodynamic loss associated with the cooling hole with/without FCD is measured by a total pressure probe rake. The experiments are carried out at blowing ratios ranging from 0.5 to 1.0. In addition, numerical simulations are also made to have a better understanding of the flow field. LES approach is employed to solve the flow field and visualize the vortex structure around the cooling hole with FCD. When a taller FCD is mounted to the plate, the film effectiveness tends to increase due to the vortex structure generated by the FCD. As FCD is laterally shifted from the centerline, the film effectiveness increases, while the lift-off of cooling air is also promoted when FCD is put on the center line.


Author(s):  
Hirokazu Kawabata ◽  
Ken-ichi Funazaki ◽  
Ryota Nakata ◽  
Daichi Takahashi

This study deals with the experimental and numerical studies of the effect of flow control devices (FCDs) on the film cooling performance of a circular cooling hole on a flat plate. Two types of FCDs with different heights are examined in this study, where each of them is mounted to the flat plate upstream of the cooling hole by changing its lateral position with respect to the hole centerline. In order to measure the film effectiveness as well as heat transfer downstream of the cooling hole with upstream FCD, a transient method using a high-resolution infrared camera is adopted. The velocity field downstream of the cooling hole is captured by 3D Laser Doppler Velocimeter (LDV). Furthermore, the aerodynamic loss associated with the cooling hole with/without FCD is measured by a total pressure probe rake. The experiments are carried out at blowing ratios ranging from 0.5 to 1.0. In addition, numerical simulations are also made to have a better understanding of the flow field. LES approach is employed to solve the flow field and visualize the vortex structure around the cooling hole with FCD. When a higher FCD is mounted to the plate, the film effectiveness tends to increase due to the vortex structure generated by the FCD. As FCD is laterally shifted from the centerline, the film effectiveness increases, while the lift-off of cooling air is also promoted when FCD is put on the center line.


Author(s):  
Ken-ichi Funazaki

This study deals with CFD-based optimization of Double Flow Control Devices (DFCDs); a patented technology for enhancing film effectiveness using Taguchi method as a robust optimizing technique. This study adopts offset of the devices with respect to the centerline of the hole, which may happen in the manufacturing process, as a noise factor in the optimizing process. The aim of this study is to explore a possibility of DFCDs to improve the cooling performance of a sophisticated fan-shaped cooling hole called 7-7-7 shaped hole developed by Penn State University [9]. Aerodynamic and thermal performances of the optimized DFCD model were evaluated through the detailed experiments using IR camera and temperature rake.


2018 ◽  
Vol 2018 (0) ◽  
pp. OS8-10
Author(s):  
Tomohiro KAWAMURA ◽  
Ken-ichi FUNAZAKI ◽  
Suzuna SAITO

Author(s):  
Weiguo Ai ◽  
Thomas H. Fletcher

Numerical computations were conducted to simulate flyash deposition experiments on gas turbine disk samples with internal impingement and film cooling using a CFD code (FLUENT). The standard k-ω turbulence model and RANS were employed to compute the flow field and heat transfer. The boundary conditions were specified to be in agreement with the conditions measured in experiments performed in the BYU Turbine Accelerated Deposition Facility (TADF). A Lagrangian particle method was utilized to predict the ash particulate deposition. User-defined subroutines were linked with FLUENT to build the deposition model. The model includes particle sticking/rebounding and particle detachment, which are applied to the interaction of particles with the impinged wall surface to describe the particle behavior. Conjugate heat transfer calculations were performed to determine the temperature distribution and heat transfer coefficient in the region close to the film-cooling hole and in the regions further downstream of a row of film-cooling holes. Computational and experimental results were compared to understand the effect of film hole spacing, hole size and TBC on surface heat transfer. Calculated capture efficiencies compare well with experimental results.


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