Enhancement of Film Effectiveness of Cooling Holes With Fan-Shaped Exit Geometry by the Application of Double Flow-Control Devices: Optimization in Consideration of Device Offset

2017 ◽  
Author(s):  
Ken-ichi Funazaki
Keyword(s):  
Taguchi Method ◽  
Flow Control ◽  
State University ◽  
Ir Camera ◽  
Cooling Performance ◽  
Flow Control Devices ◽  
Penn State ◽  
Cooling Hole ◽  
Shaped Hole ◽  
Control Devices

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.

Improvement of Flat-Plate Film Cooling Performance by Double Flow Control Devices: Part I — Investigations on Capability of a Base-Type Device

2014 ◽  
Author(s):  
Ken-ichi Funazaki ◽  
Ryota Nakata ◽  
Hirokazu Kawabata ◽  
Hisato Tagawa ◽  
Yasuhiro Horiuchi
Keyword(s):  
Flow Control ◽  
Flat Plate ◽  
Film Cooling ◽  
Laser Doppler Velocimeter ◽  
Pressure Probe ◽  
Cooling Performance ◽  
Flow Control Devices ◽  
Type Device ◽  
Cooling Hole ◽  
Control Devices

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.

Experimental and Numerical Investigations of Effects of Flow Control Devices Upon Flat-Plate Film Cooling Performance

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Hirokazu Kawabata ◽  
Ken-ichi Funazaki ◽  
Ryota Nakata ◽  
Daichi Takahashi
Keyword(s):  
Flow Field ◽  
Flow Control ◽  
Flat Plate ◽  
Vortex Structure ◽  
Film Cooling ◽  
Pressure Probe ◽  
Cooling Performance ◽  
Flow Control Devices ◽  
Cooling Hole ◽  
Control Devices

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.

Experimental and Numerical Investigations of Effects of Flow Control Devices Upon Flat-Plate Film Cooling Performance

2013 ◽  
Author(s):  
Hirokazu Kawabata ◽  
Ken-ichi Funazaki ◽  
Ryota Nakata ◽  
Daichi Takahashi
Keyword(s):  
Flow Field ◽  
Flow Control ◽  
Flat Plate ◽  
Vortex Structure ◽  
Film Cooling ◽  
Pressure Probe ◽  
Cooling Performance ◽  
Flow Control Devices ◽  
Cooling Hole ◽  
Control Devices

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.

Improvement of film cooling performance by flow control devices

2018 ◽  
Vol 2018 (0) ◽  
pp. OS8-10
Author(s):  
Tomohiro KAWAMURA ◽  
Ken-ichi FUNAZAKI ◽  
Suzuna SAITO
Keyword(s):  
Flow Control ◽  
Film Cooling ◽  
Cooling Performance ◽  
Flow Control Devices ◽  
Control Devices

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
Keyword(s):  
Flow Control ◽  
Film Cooling ◽  
Test Facility ◽  
Rans Simulation ◽  
Flow Control Devices ◽  
Turbine Vane ◽  
Cooling Hole ◽  
Control Devices ◽  
Secondary Air ◽  
Lift Off

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.

scholarly journals Prediction of flow-control devices' noise with modified acoustic perturbation equations

2020 ◽  
Vol 22 (3) ◽  
pp. 619-627
Author(s):  
Luca Fenini ◽  
Stefano Malavasi
Keyword(s):  
Flow Control ◽  
Fluid Dynamic ◽  
International Standards ◽  
The Other ◽  
Computational Time ◽  
Noise Prediction ◽  
Acoustic Perturbation ◽  
Flow Control Devices ◽  
Control Devices ◽  
Perturbation Equations

Abstract Fluid-dynamic noise emissions produced by flow-control devices inside ducts are a concerning issue for valve manufacturers and pipeline management. This work proposes a modified formulation of Acoustic Perturbation Equations (APE) that is applicable to industrial frameworks where the interest is addressed to noise prediction according to international standards. This formulation is derived from a literature APE system removing two terms allowing for a computational time reduction of about 20%. The physical contribution of the removed terms is discussed according to the literature. The modified APE are applied to the prediction of the noise emitted by an orifice. The reliability of the new APE system is evaluated by comparing the Sound Pressure Level (SPL) and the acoustic pressure with the ones returned by LES and literature APE. The new formulation agrees with the other methods far from the orifice: moving over nine diameters downstream of the trailing edge, the SPL is in accordance with the other models. Since international standards characterize control devices with the noise measured 1 m downstream of them, the modified APE formulation provides reliable and faster noise prediction for those devices with outlet diameter, d, such that 9d < 1 m.

The Application of Shape Memory Alloy as Vortex Generators and Flow Control Devices for Enhanced Convective Heat Transfer

2007 ◽  
Author(s):  
Mohd. S. Aris ◽  
Ieuan Owen ◽  
Chris. J. Sutcliffe
Keyword(s):  
Heat Transfer ◽  
Flow Control ◽  
Shape Memory ◽  
Convective Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Convective Heat ◽  
Vortex Generators ◽  
Transfer Enhancement ◽  
Flow Control Devices ◽  
Control Devices

This paper is concerned with convective heat transfer enhancement of heated surfaces through the use of vortex generators and flow control devices. A preliminary proof-of-concept investigation has been carried out into the use of active vortex generators and flow control elements, both manufactured from Shape Memory Alloys (SMAs) which are activated at set temperatures. The vortex generators change their shape to intrude further into the flow at high temperature to enhance heat transfer, while they maintain a low profile at low temperatures to minimise flow pressure losses. One set of vortex generators was made from pre-alloyed powders of SMA material in an advanced rapid prototyping process known as Selective Laser Melting (SLM). Another set of devices was also made from commercially available flat annealed thin SMA sheets for comparison purposes. The flow control elements are devices that preferentially guide the flow to heated parts of a surface, again using temperature-activated SMAs. Promising results were obtained for both the vortex generator and flow control device when their temperatures were varied from 20° to 85°C. The vortex generators responded by increasing their angle of attack from 20° to 35° while the wavy flow control elements straightened out at higher temperatures. As the designs were two-way trained, they regain their initial position and shape at a lower temperature. The surface temperature of the heated plate on which the active devices were positioned reduced between 8 to 51%, indicating heat transfer enhancement due to the generated vortices and changes in air flow rates.

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