Effects of film cooling hole locations on flow and heat transfer characteristics of impingement/effusion cooling at turbine blade leading edge

2018 ◽  
Vol 126 ◽  
pp. 192-205 ◽  
Author(s):  
Junfei Zhou ◽  
Xinjun Wang ◽  
Jun Li ◽  
Yandong Li
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Film Cooling ◽  
Leading Edge ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Cooling Hole ◽  
Blade Leading Edge

Numerical Study on Influencing Factors of Film Cooling on Turbine Blade Leading Edge Under Rotating State

2018 ◽  
Author(s):  
Yiwen Ma ◽  
Haiwang Li ◽  
Meisong Yang ◽  
Min Wu ◽  
Huimin Zhou
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Turbine Blade ◽  
Rotation Number ◽  
Film Cooling ◽  
Leading Edge ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Blade Leading Edge

Engine turbine blades operate at a high speed of rotation and are subjected to high temperature and pressure prevailing gas from the combustion chamber, making the working condition very harsh. In particular, the leading edge of the blade, which is directly subjected to high-temperature gas impacts, is the hottest part of the turbine. Therefore, it is of great importance to improve the protection of the blade leading edge and enhance the understanding of this part of the flow field and temperature field. This paper will focus on the phenomenon of wake deflection and study the film cooling characteristics of the turbine blade under rotating condition. The characteristics of pressure surface and suction surface of the blade are verified by numerical simulation. The contents cover the influence of the film hole diameter, pitch, blowing ratio, rotation number and the development process, the film cooling efficiency on the outflow of coolant film. The result shows that Coriolis force, centrifugal force and secondary flow induced by rotation will change the mainstream flow along the blade, which will lead to changes of pattern concerning the development of the film on the blade surface. In the process of wake development, deflection occurs in different directions at different positions, and the greater the rotation number is, the more obvious the degree of deflection will be. Studying the model with film holes on the leading edge of the blade, these phenomena can be observed along the downstream on the pressure and suction surfaces. Also, models with film holes independently set on the pressure and suction surfaces can be used as proof of these features. At the same time, this paper studies the flow and heat transfer characteristics of the leading-edge gas film under rotating condition and focuses on the influence of rotation on the outflow and the development processes of the wake. The gas film cooling models in rotating state of different film hole diameters and film hole radial spacing will also be compared to further understand the flow and heat transfer characteristics of film cooling on the leading edge of the blade.

Flow and Heat Transfer Characteristics in Models of Turbine Blade Tip-Walls With Three Kinds of Turning Vanes

2018 ◽  
Author(s):  
Bin Wu ◽  
Xing Yang ◽  
Lv Ye ◽  
Zhao Liu ◽  
Yu Jiang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Double Layer ◽  
Pressure Loss ◽  
Stokes Equations ◽  
Wall Heat Transfer ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Blade Tip

In this paper, effects of three kinds of turning vanes on flow and heat transfer of turbine blade tip-walls with a U-shaped channel have been numerically studied. Numerical simulations are performed to solve three-dimensional, steady, Reynolds-averaged Navier-Stokes equations with the standard k-ω turbulence model. The aspect ratio (AR) and the hydraulic diameter of the channel are 2 and 93.13 mm, respectively. The effects of single-layer, double-layer and double-layer dome-shaped turning vanes in the turn region on the tip-wall heat transfer and overall pressure loss of rectangular U-shaped channels are analyzed. Detailed flow and heat transfer characteristics over the tip-walls, as well as the overall performance, are presented and compared with each other. Results show that the tip-wall heat transfer coefficients with double-layer dome-shaped turning vanes are the highest among the three cases. Double-layer dome-shaped turning vanes can promote the lateral spreading of secondary flow and effectively increase the uniformity of heat transfer on the tip-wall. More importantly, this structure can make the cooling air expand and accelerate at the center region of the top of the U-shaped channel, resulting in more heat to be removed from the tip-wall. Additionally, double-layer dome-shaped turning vanes can effectively reduce the pressure loss of the channel.

Flow and Heat Transfer Characteristics in Channels With Groove–Protrusions and Combination Effect With Ribs

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Lu Zheng ◽  
Yonghui Xie ◽  
Di Zhang ◽  
Haoning Shi
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Rectangular Channel ◽  
Leading Edge ◽  
Small Scale ◽  
Combination Effect ◽  
Transfer Enhancement ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Flow And Heat Transfer

Passive flow control and heat transfer enhancement technique has become an attractive method for device internal cooling with low resistance penalty. In the present paper, the flow and heat transfer characteristics in the small scale rectangular channel with different groove–protrusions are investigated numerically. Furthermore, the combination effect with ribs is studied. The numerical results show that on the groove side, the flow separation mainly occurs at the leading edge, and the reattachment mainly occurs at the trailing edge in accordance with the local Nusselt number distribution. On the protrusion side, the separation mainly occurs at the protrusion back porch and enhances the heat transfer at the leading edge of the downstream adjacent groove. The rectangle case provides the highest dimensionless heat transfer enhancement coefficient Nu/Nu0, dimensionless resistance coefficient f/f0, and thermal performance (TP) with the highest sensitivity of Re. When ribs are employed, the separation bubble sizes prominently decrease, especially inside the second and third grooves. The Nu/Nu0 values significantly increase when ribs are arranged, and the one-row case provides the highest heat transfer enhancement by ribs. Besides, the two-row case provides the highest Nu/Nu0 value without ribs, and the three-row case shows the lowest Nu/Nu0 value whether ribs are arranged or not.

Net Heat Flux Reduction and Overall Effectiveness for a Turbine Blade Leading Edge

2005 ◽  
Author(s):  
Brian D. Mouzon ◽  
Elon J. Terrell ◽  
Jason E. Albert ◽  
David G. Bogard
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Turbine Blade ◽  
Film Cooling ◽  
Leading Edge ◽  
Cooling Performance ◽  
Net Heat Flux ◽  
Laboratory Models ◽  
Overall Effectiveness ◽  
Blade Leading Edge

The external cooling performance of a film cooled turbine airfoil can be quantified as a net reduction in heat transfer relative to the turbine airfoil without film cooling. This quantification is generally accomplished by using measurements of the adiabatic effectiveness and the change in heat transfer coefficients (hf/h0) for the film cooled surface to determine the net heat flux reduction (Δqr). Although measurement of Δqr for laboratory models give an indication of the ultimate film cooling performance, this does not show how much the surface temperature of the airfoil is reduced by film cooling. Measurement of scaled surface temperatures can be accomplished by using laboratory models constructed so that the Biot number is matched with that of the actual airfoil. These measurements provide a scaled temperature distribution on the airfoil that is referred to as the overall effectiveness, φ. For the current study, measurements of Δqr and φ have been made for a simulated turbine blade leading edge. The simulated leading edge incorporated shaped coolant holes, and had three rows of coolant holes. Improvements due to the shaped holes were determined by comparisons with previously measured round hole configurations. Spatially distributed hf/h0 show increases of 5% to 15% for M = 1.0 and 10% to 30% for M = 2.0. Results show that local variation in Δqr much greater than variation in φ, but laterally averaged Δqr distributions are reasonable predictors of the laterally averaged φ distributions.

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