Computational Analysis of Side-Wall Heat Transfer of a Turbine Blade Internal Cooling Passage With Truncated Ribs on Opposite Walls

2012 ◽  
Author(s):  
Shian Li ◽  
Gongnan Xie ◽  
Bengt Sundén ◽  
Weihong Zhang
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Thermal Stresses ◽  
Side Wall ◽  
Leading Edge ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Wall Heat Transfer ◽  
Cooling Passage ◽  
Internal Cooling Passage

A problem involved in the increase of the turbine inlet temperature of gas turbine engine is the failure of material because of excessive thermal stresses. This requires cooling methods to withstand the increase of the inlet temperature. Rib turbulators are often used in the mid-section of internal cooling ducts to augment the heat transfer from blade wall to the coolant. This study numerically investigates side-wall heat transfer of a rectangular passage with the leading/trailing walls being roughened by staggered ribs whose length is less than the passage width. Such a passage corresponds to the internal cooling passage near the leading edge of a turbine blade. The inlet Reynolds number is ranging from 12,000 to 60,000. The detailed 3D fluid flow and heat transfer over the side-wall are presented. The overall performances of several ribbed passages are evaluated and compared. It is found that the side-wall heat transfer coefficients of the passage with truncated (continuous) ribs on opposite walls are about 20%–27% (28%–43%) higher than those of a passage without ribs, while the pressure loss could be reduced compared to a passage with continuous ribs. It is suggested that the usage of truncated ribs is a suitable way to augment the side-wall heat transfer and improve the flow structure near the leading edge.

Computational Fluid Dynamics Modeling Flow Field and Side-Wall Heat Transfer in Rectangular Rib-Roughened Passages

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Gongnan Xie ◽  
Shian Li ◽  
Weihong Zhang ◽  
Bengt Sunden
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Gas Turbine ◽  
Side Wall ◽  
Leading Edge ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Wall Heat Transfer ◽  
Dynamics Modeling

In order to achieve higher thermal efficiency and power output, the gas turbine inlet temperature of gas turbine engine is continuously increased. However, the increasing temperature may exceed the melting point of the blade material. Rib turbulators are often used in the midsection of internal cooling ducts to augment the heat transfer from blade wall to the coolant. This study uses computational fluid dynamics (CFD) to investigate side-wall heat transfer of a rectangular passage with the leading/trailing walls being roughened by continuous or truncated ribs. The inlet Reynolds number is ranging from 12,000 to 60,000. The detailed three dimensional (3D) fluid flow and heat transfer over the side-wall are presented. The overall performances of ribbed passages are compared. It is suggested that the usage of truncated ribs is a suitable way to augment the side-wall heat transfer and improve the flow structure near the leading edge especially under the critical limitation of pressure drop.

Numerical Investigation of Rotation Effects on the Flow and Heat Transfer on the Turbine Blade Tip Underside With Bleed Hole at Different Locations

2019 ◽  
Author(s):  
Zhiqi Zhao ◽  
Lei Luo ◽  
Xiaoxu Kan ◽  
Dandan Qiu ◽  
Xun Zhou
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Structural Damage ◽  
Three Dimensional ◽  
Side Wall ◽  
Internal Cooling ◽  
Heat Transfer Augmentation ◽  
Smooth Channel ◽  
Blade Tip ◽  
Cooling Passage

Abstract High thermal load on the turbine blade tip surface leads to high temperature corrosion and severe structural damage. One common way is to deliver a part of coolant through bleed holes onto the tip portion for cooling purpose. In this study, numerical simulations are performed to investigate the effects of rotation on the internal tip heat transfer in a simplified rotating two-pass channel with a bleed hole, which is applicable to the internal cooling passage of typical gas turbine blade. The bleed hole is placed on the tip wall of a two-pass channel at different locations, i.e. the ratio of distance from the outlet-side wall to width of the tip wall is 0.07, 0.21, 0.5, 0.78, 0.93, respectively. A smooth channel without bleed hole is used as Baseline. The Reynolds number is fixed at 10,000. The Ro numbers are varied from 0 to 0.4. Results show that a three-dimensional vortex, which is induced by the Coriolis force, is found at the bend region. It transports the fluid from the trailing side to leading side, which is beneficial to enhance tip heat transfer. The middle-mounted hole shows a better heat transfer augmentation compared to other hole arrangement. The rotation have a notable effect on the heat transfer and flow structures. Compared to the smooth channel, the heat transfer augmentation is about 34%.

Numerical Investigation on the Modified Bend Geometry of a Rotating Multipass Internal Cooling Passage in a Gas Turbine Blade

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
Naris Pattanaprates ◽  
Ekachai Juntasaro ◽  
Varangrat Juntasaro
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Internal Cooling ◽  
Gas Turbine Blade ◽  
Reduced Pressure ◽  
Improve Heat Transfer ◽  
Cooling Passage ◽  
Internal Cooling Passage

Abstract The present work is aimed to investigate whether the modification to the bend geometry of a multipass internal cooling passage in a gas turbine blade can enhance heat transfer and reduce pressure drop. The two-pass channel and the four-pass channel are modified at the bend from the U shape to the bulb and bow shape. The first objective of the work is to investigate whether the modified design will still improve heat transfer with reduced pressure drop in a four-pass channel as in the case of a two-pass channel. It is found out that, unlike the two-pass channel, the heat transfer is not improved but the pressure drop is still reduced for the four-pass channel. The second objective is to investigate the rotating effect on heat transfer and pressure drop in the cases of two-pass and four-pass channels for both original and modified designs. It is found out that heat transfer is improved with reduced pressure drop for all cases. However, the modified design results in the less improvement on heat transfer and lower reduced pressure drop as the rotation number increases. It can be concluded from the present work that the modification can solve the problem of pressure drop without causing the degradation of heat transfer for all cases. The two-pass channel with modified bend results in the highest heat transfer and the lowest pressure drop for rotating cases.

Computation of Flow and Heat Transfer of a Blade Internal Cooling Passage With Truncated V-Shaped Ribs on Opposite Walls

2012 ◽  
Author(s):  
Shian Li ◽  
Gongnan Xie ◽  
Weihong Zhang ◽  
Bengt Sundén
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Turbine Engine ◽  
Flow And Heat Transfer ◽  
Cooling Passage ◽  
Internal Cooling Passage

The inlet temperature of gas turbine engine is continuously increased to achieve higher thermal efficiency and power output. To prevent from the temperature exceeding the melting point of the blade material, ribs are commonly used in the mid-section of internal blade to augment the heat transfer from blade wall to the coolant. In this study, turbulent flow and heat transfer of a rectangular cooling passage with continuous or truncated 45-deg V-shaped ribs on opposite walls have been investigated numerically. The inlet Reynolds numbers are ranging from 12,000 to 60,000 and the low-Re k-ε model is selected for the turbulent computations. The complex three-dimensional fluid flow in the internal coolant passages and the corresponding heat transfer over the side-walls and rib-walls are presented and the thermal performances of the ribbed passages are compared as well. It is shown that the passage with truncated V-shaped ribs on opposite walls is very effective in improving the heat transfer performance with a low pressure loss, and thus could be suggested to be applied to gas turbine blade internal cooling.

Experimental and Numerical Investigation of the Flow in a Trailing Edge Ribbed Internal Cooling Passage

2018 ◽  
Author(s):  
Seungchan Baek ◽  
Sangjoon Lee ◽  
Wontae Hwang ◽  
Jung Shin Park
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Sharp Edge ◽  
Internal Cooling ◽  
Mean Flow ◽  
Trailing Edge ◽  
Triangular Channel ◽  
The Mean ◽  
Cooling Passage ◽  
Internal Cooling Passage

The flow field in a ribbed triangular channel representing the trailing edge internal cooling passage of a gas turbine high pressure turbine blade is investigated via Magnetic Resonance Velocimetry (MRV) and Large Eddy Simulation (LES). Results are compared to a baseline channel with no ribs. LES predictions of the mean velocity fields are validated by the MRV results. In the case of the baseline triangular channel with no ribs, the mean flow and turbulence level at the sharp corner are small, which would correspond to poor heat transfer in an actual trailing edge. For the staggered ribbed channel, turbulent mixing is enhanced, and flow velocity and turbulence intensity at the sharp edge increase. This is due to secondary flow induced by the ribs moving toward the sharp edge in the center of the channel. This effect is expected to enhance internal convective heat transfer for the turbine blade trailing edge.

Experimental and Numerical Investigation of the Flow in a Trailing Edge Ribbed Internal Cooling Passage

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Seungchan Baek ◽  
Sangjoon Lee ◽  
Wontae Hwang ◽  
Jung Shin Park
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Sharp Edge ◽  
Internal Cooling ◽  
Mean Flow ◽  
Trailing Edge ◽  
Triangular Channel ◽  
The Mean ◽  
Cooling Passage ◽  
Internal Cooling Passage

The flow field in a ribbed triangular channel representing the trailing edge internal cooling passage of a gas turbine high-pressure turbine blade is investigated via magnetic resonance velocimetry (MRV) and large eddy simulation (LES). The results are compared to a baseline channel with no ribs. LES predictions of the mean velocity fields are validated by the MRV results. In the case of the baseline triangular channel with no ribs, the mean flow and turbulence level at the sharp corner are small, which would correspond to poor heat transfer in an actual trailing edge. For the staggered ribbed channel, turbulent mixing is enhanced, and flow velocity and turbulence intensity at the sharp edge increase. This is due to secondary flow induced by the ribs moving toward the sharp edge in the center of the channel. This effect is expected to enhance internal convective heat transfer for the turbine blade trailing edge.

Thermal Analysis of a Turbine Blade: Effect of Film Cooling and Internal Convective Cooling

2015 ◽  
Author(s):  
S. Sarkar ◽  
P. Gupta
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Leading Edge ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Suction Surface ◽  
Transfer Condition ◽  
Convective Cooling ◽  
Cooling Passage

Advanced gas turbines are designed to operate at increasingly higher inlet temperature that poses a greater challenge to the designer for more effective blade cooling strategies. In this paper, a generic high-pressure turbine (HPT) blade of a gas turbine, which is cooled by film cooling in conjunction with internal convective cooling, has been analysed by solving Navier-Stokes and energy equations. The intricate internal cooling passages and a series of holes on the suction surface are considered for the simulations. Large numbers of cell in different zones are used to truly replace the blade with cooling holes and the internal cooling passage. The CFD analysis with conjugate heat transfer condition is accomplished by Fluent, version 6.3. A detailed discussion has been made regarding the aerodynamics and heat transfer. In brief, the suction surface is well protected by film cooling, whereas, the pressure surface demands some additional protection for a longer life. The leading edge is under the metallurgical limit because of internal cooling for the present configuration.

Heat Transfer and Flow Phenomena in a Swirl Chamber Simulating Turbine Blade Internal Cooling

1998 ◽  
Author(s):  
C. R. Hedlund ◽  
P. M. Ligrani ◽  
H.-K. Moon ◽  
B. Glezer
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Internal Cooling ◽  
Vortex Pairs ◽  
Nusselt Numbers ◽  
Swirl Chamber ◽  
Flow Phenomena ◽  
Energy Balances

Heat transfer and fluid mechanics results are given for a swirl chamber whose geometry models an internal passage used to cool the leading edge of a turbine blade. The Reynolds numbers investigated, based on inlet duct characteristics, include values which are the same as in the application (18000–19400). The ratio of absolute air temperature between the inlet and wall of the swirl chamber ranges from 0.62 to 0.86 for the heat transfer measurements. Spatial variations of surface Nusselt numbers along swirl chamber surfaces are measured using infrared thermography in conjunction with thermocouples, energy balances, digital image processing, and in situ calibration procedures. The structure and streamwise development of arrays of Görtler vortex pairs, which develop along concave surfaces, are apparent from flow visualizations. Overall swirl chamber structure is also described from time-averaged surveys of the circumferential component of velocity, total pressure, static pressure, and the circumferential component of vorticity. Important variations of surface Nusselt numbers and time-averaged flow characteristics are present due to arrays of Görtler vortex pairs, especially near each of the two inlets, where Nusselt numbers are highest. Nusselt numbers then decrease and become more spatially uniform along the interior surface of the chamber as the flows advect away from each inlet.

scholarly journals A Computational Visualization of Three Dimensional Flow: Finding Optimum Heat Transfer and Pressure Drop Characteristics From Short Cross-Pin Arrays and Comparison With Two Dimensional Calculations

1999 ◽  
Author(s):  
E. E. Donahoo ◽  
C. Camci ◽  
A. K. Kulkarni ◽  
A. D. Belegundu
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Structural Integrity ◽  
Turbine Blades ◽  
Circular Cross Section ◽  
Internal Cooling ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
Spacing Ratio ◽  
Cooling Passage

There are many heat transfer augmentation methods that are employed in turbine blade design, such as impingement cooling, film cooling, serpentine passages, trip strips, vortex chambers, and pin fins. The use of crosspins in the trailing edge section of turbine blades is commonly a viable option due to their ability to promote turbulence as well as supply structural integrity and stiffness to the blade itself. Numerous crosspin shapes and arrangements are possible, but only certain configurations offer high heat transfer capability while maintaining taw total pressure loss. This study preseots results from 3-D numerical simulations of airflow through a turbine blade internal cooling passage. The simulations model viscous flow and heat transfer over full crosspins of circular cross-section with fixed height-to-diameter ratio of 0.5, fixed transverse-to-diameter spacing ratio of 1.5, and varying streamwise spacing. Preliminary analysis indicates that endwall effects dominate the flow and heat transfer at lower Reynolds numbers. The flow dynamics involved with the relative dose proximity of the endwalls for such short crosspins have a definite influeoce on crosspin efficiency for downstream rows.

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