Augmented Heat Transfer of an Internal Blade Tip by Full or Partial Arrays of Pin-Fins

2011 ◽  
Vol 42 (1) ◽  
pp. 65-81 ◽  
Author(s):  
Gongnan Xie ◽  
Bengt Sunden ◽  
Lieke Wang ◽  
Esa Utriainien
Keyword(s):  
Heat Transfer ◽  
Pin Fins ◽  
Blade Tip

Heat Transfer Enhancement From a Blade Tip-Cap Using Metal Foams

2012 ◽  
Vol 134 (11) ◽  
Author(s):  
Owen Sengstock ◽  
Kamel Hooman
Keyword(s):  
Heat Transfer ◽  
Hot Spot ◽  
Metal Foams ◽  
Plate Temperature ◽  
Pin Fin ◽  
Heat Transfer Augmentation ◽  
Smooth Channel ◽  
Pin Fins ◽  
Blade Tip ◽  
Spot Temperature

3D numerical results are presented to compare the heat transfer augmentation from a plate by using pin fins and metal foams. It is observed that maximizing the inlet velocity and pores per inch maximizes the overall heat transfer rate. The thickness of the foam layer has minimal effect on overall rates of heat transfer, but great effect on the maximum plate temperature. It has been shown that an optimum thickness exists which minimizes the hot spot temperature. Hot spots are generally located in the corners where velocities are the lowest. While the pressure drop remains almost unaltered, the heat transfer increases by 146% and 12% compared with a smooth channel and the optimal pin-fin data available in the literature, respectively. Interestingly, the additional mass of the foams, to achieve this performance, is approximately one-quarter of the best pin-fin sink quoted above.

Conjugate Heat Transfer Enhancement of an Internal Blade Pin-Finned Tip-Wall

2009 ◽  
Author(s):  
Gongnan Xie ◽  
Bengt Sunde´n
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Conjugate Heat Transfer ◽  
Gas Flow ◽  
Turbine Blades ◽  
Thermal Design ◽  
Inlet Temperature ◽  
Computational Domain ◽  
Pin Fins ◽  
Blade Tip

To improve gas turbine performance, the operating temperature has been increased continuously. However, the heat transferred to the turbine blade is substantially increased as the turbine inlet temperature is increased. Cooling methods are therefore needed for the turbine blades to ensure a long durability and safe operation. The blade tip region is exposed to the hot gas flow and is difficult to cool. A common way to cool the tip is to use serpentine passages with 180-deg turn under the blade tip-cap taking advantage of the three-dimensional turning effect and impingement. Increasing internal convective cooling is therefore required to increase the blade tip life. In this paper, augmented heat transfer of a blade tip with internal pin-fins has been investigated numerically using a conjugate heat transfer approach. The computational model consists of a two-pass channel with 180-deg turn and an array of pin-fins mounted on the tip-cap. The computational domain includes the fluid region and the solid pins as well as the solid tip regions. Turbulent convective heat transfer between the fluid and pins, and heat conduction within pins and tip are simultaneously computed. The inlet Reynolds numbers are ranging from 100,000 to 600,000. Details of the 3D fluid flow and heat transfer over the tip surface are presented. A comparison of the overall performance of the two models is presented. It is found that due to the combination of turning impingement and pin-fin cross flow, the heat transfer coefficient of the pin-finned tip is a factor of about 3.0 higher than that of a smooth tip. This augmentation is achieved at the cost of a pressure drop penalty of about 7%. With the conjugate heat transfer method, not only the simulated model is close to the experimental model, but also the distribution of the external tip heat transfer can be relevant for thermal design of turbine blade tips.

Effect of Pin Base-Fillet on Heat Transfer Enhancement of an Internal Blade Pin-Finned Tip-Wall

2009 ◽  
Author(s):  
G. N. Xie ◽  
B. Sunde´n ◽  
L. K. Wang ◽  
E. Utriainen
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Computational Models ◽  
Casting Process ◽  
Reynolds Numbers ◽  
Transfer Enhancement ◽  
Pin Fin ◽  
Pin Fins ◽  
Blade Tip ◽  
Real Practice

A common way to cool the tip is to use serpentine passages with 180-deg turn under the blade tip-cap. Improving internal convective cooling is therefore required to increase the blade tip life. In this paper, augmented heat transfer of a blade tip has been investigated numerically. The computational models consist of a two-pass channel with 180-deg turn and pin-fins mounted on the tip-cap, and a smooth two-pass channel. On the other hand, In particular manufacture, the casting process does not make a perfect cylinder pin, a fillet needs to be placed at the endwall. In order to make the conditions of simulations as close to real practice as possible, it is desirable to examine the effect of fillet on the tip heat transfer. Therefore, in the present study, the effect of pin base-fillet on heat transfer enhancement of a blade pin-finned tip-wall is investigated numerically. Inlet Reynolds numbers are ranging from 100,000 to 600,000. The computations are 3D, steady, incompressible and stationary. It is found that the pin-fins make the counter-rotating vortices towards pin-fin surfaces, resulting in continuous turbulent mixing near the pin-finned tip. Due to the combination of turning, impingement and pin-fin crossflow, the heat transfer coefficient of the pin-finned tip is a factor of as much as 2.66 higher than that of a smooth tip. Besides, with base-fillets the heat transfer enhancement is increased by about 10% while almost no additional pressure loss is resulted. It is suggested that the pin-fins could be used to enhance blade tip heat transfer and cooling.

Augmented Heat Transfer of Internal Blade Tip Wall With Pin-Fins

2009 ◽  
Author(s):  
G. N. Xie ◽  
B. Sunde´n ◽  
L. Wang ◽  
E. Utriainen
Keyword(s):  
Heat Transfer ◽  
Computational Models ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Inlet Temperature ◽  
Gas Flows ◽  
Pin Fin ◽  
Pin Fins ◽  
Blade Tip

The heat transferred to the turbine blade is substantially increased as the turbine inlet temperature is increased. Cooling methods are therefore much needed for the turbine blades to ensure a long durability and safe operation. The blade tip region is exposed to the hot gas flows. A common way to cool the tip is to use serpentine passages with 180-deg turn under the blade tip cap taking advantage of the three-dimensional turning effect and impingement. Improving internal convective cooling is therefore required to increase the blade tip life. In this paper, augmented heat transfer of a blade tip has been investigated numerically. The computational models consist of a two-pass channel with 180-deg turn and an array of pin-fins mounted on the tip-cap, and a smooth two-pass channel. Inlet Reynolds numbers are ranging from 100,000 to 600,000. The computations are 3D, steady, incompressible and stationary. The detailed 3D fluid flow and heat transfer over the tip surfaces are presented. The overall performance of the two models is evaluated. It is found that the pin-fins make the counter-rotating vortices towards pin-fin surfaces, resulting in continuous turbulent mixing near the pin-finned tip. Due to the combination of turning, impingement and pin-fin crossflow, the heat transfer coefficient of the pin-finned tip is a factor of as much as 1.84 higher than that of a smooth tip. This augmentation is achieved at the expense of a penalty of pressure drop around 35%. It is suggested that the pin-fins could be used to enhance blade tip heat transfer and cooling.

Computational Analysis of Pin-Fin Arrays Effects on Internal Heat Transfer Enhancement of a Blade Tip Wall

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Gongnan Xie ◽  
Bengt Sundén ◽  
Esa Utriainen ◽  
Lieke Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Computational Models ◽  
Internal Heat ◽  
Transfer Enhancement ◽  
Pin Fin ◽  
Flow And Heat Transfer ◽  
Pin Fins ◽  
Blade Tip ◽  
Pin Fin Arrays

Cooling methods are strongly needed for the turbine blade tips to ensure a long durability and safe operation. Improving the internal convective cooling is therefore required to increase the blade tip life. A common way to cool the tip is to use serpentine passages with 180-deg turns under the blade tip cap. In this paper, enhanced heat transfer of a blade tip cap has been investigated numerically. The computational models consist of a two-pass channel with a 180-deg turn and various arrays of pin fins mounted on the tip cap, and a smooth two-pass channel. The inlet Reynolds number is ranging from 100,000 to 600,000. The computations are 3D, steady, incompressible, and nonrotating. Details of the 3D fluid flow and heat transfer over the tip walls are presented. The effects of pin-fin height, diameter, and pitches on the heat transfer enhancement on the blade tip walls are observed. The overall performances of ten models are compared and evaluated. It is found that due to the combination of turning, impingement, and pin-fin crossflow, the heat transfer coefficient of the pin-finned tip is a factor of 2.67 higher than that of a smooth tip. This augmentation is achieved at the expense of a penalty of pressure drop around 30%. Results show that the intensity of heat transfer enhancement depends upon pin-fin configuration and arrangement. It is suggested that pin fins could be used to enhance the blade tip heat transfer and cooling.

A213 A Study on the Effect of Angled Pin Fins on Endwall Heat Transfer(Gas Turbine-7)

2009 ◽  
Vol 2009.2 (0) ◽  
pp. _2-73_-_2-78_ ◽  
Author(s):  
Yusuke Motoda ◽  
Kenichiro Takeishi ◽  
Yutaka Oda ◽  
Yoshiaki Miyake
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Pin Fins

Influence of tip clearance and cavity depth on heat transfer in a cutback squealer tip

2020 ◽  
pp. 095441002096469
Author(s):  
Weijie Wang ◽  
Shaopeng Lu ◽  
Hongmei Jiang ◽  
Qiusheng Deng ◽  
Jinfang Teng ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Suction Side ◽  
High Heat ◽  
Tip Clearance ◽  
Tip Leakage Flow ◽  
Trailing Edge ◽  
Cavity Depth ◽  
High Heat Transfer ◽  
Blade Tip ◽  
High Heat Transfer Coefficient

Numerical simulations are conducted to present the aerothermal performance of a turbine blade tip with cutback squealer rim. Two different tip clearance heights (0.5%, 1.0% of the blade span) and three different cavity depths (2.0%, 3.0%, and 6.0% of the blade span) are investigated. The results show that a high heat transfer coefficient (HTC) strip on the cavity floor appears near the suction side. It extends with the increase of tip clearance height and moves towards the suction side with the increase of cavity depth. The cutback region near the trailing edge has a high HTC value due to the flush of over-tip leakage flow. High HTC region shrinks to the trailing edge with the increase of cavity depth since there is more accumulated flow in the cavity for larger cavity depth. For small tip clearance cases, high HTC distribution appears on the pressure side rim. However, high HTC distribution is observed on suction side rim for large tip clearance height. This is mainly caused by the flow separation and reattachment on the squealer rims.

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