Effect of channel orientation on heat transfer in a rotating impingement cooling channel

2022 ◽  
Vol 187 ◽  
pp. 122493
Author(s):  
Hua Li ◽  
Hongwu Deng ◽  
Lu Qiu
Keyword(s):  
Heat Transfer ◽  
Cooling Channel ◽  
Impingement Cooling ◽  
Channel Orientation

Numerical Studies on Effect of Channel Orientation in a Rotating Smooth Wedge-Shaped Cooling Channel

2014 ◽  
Author(s):  
Balamurugan Srinivasan ◽  
Anand Dhamarla ◽  
Chandiran Jayamurugan ◽  
Amarnath Balu Rajan
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Cooling Channel ◽  
Transfer Enhancement ◽  
Trailing Edge ◽  
Pin Fins ◽  
Channel Orientation ◽  
The Heat Transfer Coefficient

The increasing demands of better efficiency of modern advanced gas turbine require higher turbine inlet temperatures, which gives great challenges to turbine blade designers. However, the temperature limits of turbine blade material are not high enough to ensure its survival in such incredible operating temperature. Hence, both internal and external cooling approaches have been developed and widely used in today’s turbine blade. To internal cooling problems, a variety of cooling enhancement approaches, such as impingement and turbulators, are employed in order to meet the different needs in leading, middle and trailing region. One of the most critical parts in turbine blade is trailing edge where it is hard to cool due to its narrow shape. Pin-fins are widely used to cool the trailing edge of rotor and stator blades of gas turbine engine. Pin-fins offer significant heat transfer enhancement, they are relatively easy to fabricate and offer structural support to the hollow trailing edge region. The flow physics in a pin-fin roughened channel is very complicated and three-dimensional. In this work, we have studied the effect of channel orientation on heat transfer in a rotating wedge-shaped cooling channel using numerical methods. Qiu [1] studied experimentally heat transfer effects of 5 different angles of wedge shaped channel orientation for the inlet Reynolds number (5100 to 21000) and rotational speed (zero to 1000 rpm), which results in the inlet Rotation number variation from 0 to 0.68. They observed that compared to the non-rotating condition, there is about 35% overall heat transfer enhancement under highest rotation number. The above said results are validated using current studies with Computational Fluid Dynamics (CFD) revealed that rotation increases significantly the heat transfer coefficient on the trailing surface and reduces the heat transfer coefficient on the leading surface. This is due to the higher velocities associated with the converging geometry near trailing surface.

Application and Design of Multi-Impingement Cooling Channel in Turbine Blade Trail Edge

2020 ◽  
Vol 37 (3) ◽  
pp. 241-256
Author(s):  
Longfei Wang ◽  
Fengbo Wen ◽  
Songtao Wang ◽  
Xun Zhou ◽  
Zhongqi Wang
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Impinging Jet ◽  
Surface Heat ◽  
Cooling Channel ◽  
Plate Surface ◽  
Impingement Cooling ◽  
Surface Heat Transfer ◽  
Pin Fins

AbstractThe numerical simulations are used to conduct the comparative study of pin-fins cooling channel and multi-impingement cooling channel on the heat transfer and flow, and to design the multi-impingement channel through the parameters of impinging distance and impingement-jet-plate thickness. The Reynolds number ranges from 1e4 to 6e4. The dimensionless impinging distance is 0.60, 1.68, 2.76, respectively, and the dimensionless impinging-jet-thickness is 0.5, 1.0, 1.5, respectively. The endwall surface, pin-fins surface, impinging-jet-plate surface are the three object surfaces to investigate the channel heat transfer performance. The heat transfer coefficient $h$ and augmentation factor $Nu/N{u_0}$ are selected to measure the surface heat transfer, and the friction coefficient $f$ is chosen to evaluate the channel flow characteristics. The impinging-jet-plate surface owns higher heat transfer coefficient and larger area than pin-fins surface, which are the main reasons to improve the heat transfer performance of multi-impingement cooling channel. Reducing the impinging distance can improve the endwall surface heat transfer obviously and enhance impingement plate surface heat transfer to some extent, decreasing the thickness of impinging-jet-plate can significantly increase its own heat transfer coefficient, which both all increase the cooling air flow loss.

Effect of Channel Orientation in a Rotating Smooth Wedge-Shaped Cooling Channel With Lateral Ejection

2013 ◽  
Author(s):  
Lu Qiu ◽  
Hongwu Deng ◽  
Zhi Tao
Keyword(s):  
Heat Transfer ◽  
Rotation Number ◽  
Copper Plate ◽  
Bulk Temperature ◽  
Cooling Channel ◽  
Transfer Coefficients ◽  
Critical Rotation ◽  
Fundamental Research ◽  
Channel Orientation ◽  
Better Than

The effect of channel orientation on heat transfer in a rotating wedge-shaped cooling channel is experimentally investigated in current work. In order to perform a fundamental research, all turbulators are removed away. The classical copper plate technique is employed to measure the regional averaged heater transfer coefficients. The inlet Reynolds number and rotational speed range from 5100 to 21000 and zero to 1000rpm respectively, which results in the inlet Rotation number varies from zero to 0.68. In order to study the effect of channel orientation, five different angles are selected in current study. Furthermore, details such as local bulk temperature calculation and local mass flow rate determination are discussed in current paper. Interestingly, a two-dimensional bulk temperature distribution is observed. Due to the experimental results, the most evident rotation effect on heat transfer happens in 90° configuration. Compared to the non-rotating condition, there is about 35% overall heat transfer enhancement under highest rotation number. However, the greatest leading-to-trailing heat transfer difference happens in 135° or 112.5° configuration which depends on Rotation number. The highest difference is up to 40%. Besides, at the realistic 135° channel orientation, a critical Rotation number is observed after which the decreasing trend of heat transfer is traversed. The inlet Rotation is better than local one to describe this critical point. With the inlet parameter, the critical Rotation number is about 0.3 at all the locations in this channel.

High Rotation Number Effect on Heat Transfer in a Leading Edge Cooling Channel With Three Channel Orientations

2012 ◽  
Author(s):  
Szu-Chi Huang ◽  
Yao-Hsien Liu
Keyword(s):  
Heat Transfer ◽  
Leading Edge ◽  
Local Heat Transfer ◽  
Reynolds Numbers ◽  
Local Heat ◽  
Cooling Channel ◽  
Height Ratio ◽  
Triangular Channel ◽  
Rotation Numbers ◽  
Channel Orientation

Heat transfer in a leading edge, triangular shaped cooling channel with three channel orientations under high rotation numbers is experimentally studied. Continuous ribs and V-shaped ribs, both at 45° rib angle of attack, are applied on the leading and trailing surfaces. For each rib case, three channel orientations (90°, 67.5°, and 45°) with respect to the plane of rotation are tested. The rib height to hydraulic diameter ratio (e/Dh) is 0.085 and the rib pitch to height ratio (P/e) is 9. Reynolds numbers are from 15000 to 25000, and the rotation numbers are from 0 to 0.65. Results show that the heat transfer variation is influenced by the combined effects of rib configuration and channel orientation. Effect of channel orientation influences local heat transfer distribution inside this triangular channel, and heat transfer is enhanced gradually on the leading surface when the channel orientation varies from 90° to 45° for both ribbed cases in this study.

High Rotation Number Effect on Heat Transfer in a Leading Edge Cooling Channel of Gas Turbine Blades With Three Channel Orientations

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Szu-Chi Huang ◽  
Yao-Hsien Liu
Keyword(s):  
Heat Transfer ◽  
Rotation Number ◽  
Turbine Blades ◽  
Leading Edge ◽  
Cooling Channel ◽  
Number Range ◽  
Gas Turbine Blades ◽  
Rotation Numbers ◽  
Mainstream Flow ◽  
Channel Orientation

Heat transfer in a leading edge, triangular-shaped cooling channel with three channel orientations under high rotation numbers is investigated in this study. Continuous ribs and V-shaped ribs (P/e = 9, e/Dh = 0.085), both placed at an angle (α = 45 deg) to the mainstream flow, are applied on the leading and trailing surfaces. The Reynolds number range is 15,000–25,000 and the rotation number range is 0–0.65. Effects of high rotation number on heat transfer with three angles of rotation (90 deg, 67.5 deg, and 45 deg) are tested. Results show that heat transfer is influenced by the combined effects of rib and channel orientation. When the rotation number is smaller than 0.4, rotation causes a decrease in the average Nusselt number ratios on the leading surface at a channel orientation of 90 deg. Heat transfer is enhanced gradually on the leading surface when the channel orientation varies from 90 deg to 45 deg for both ribbed cases. The highest heat transfer enhancement due to rotation is found at the highest rotation number of 0.65.

Effects of Turning Angle and Turning Internal Radius on Channel Impingement Cooling for a Novel Internal Cooling Structure

2020 ◽  
Author(s):  
Wei He ◽  
Qinghua Deng ◽  
Guoying Yang ◽  
Zhenping Feng
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Loss ◽  
Leading Edge ◽  
Geometrical Parameters ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Turning Angle ◽  
Impingement Cooling ◽  
Internal Radius

Abstract Leading edge multi-channel double wall design, a novel internal cooling structure, has been put forward recently to enable higher overall cooling effectiveness with less penalty of coolant mass flow and pressure loss. Our previous work has proved the advantages of the design under operating condition relative to conventional internal cooling methods including impingement cooling and swirl cooling. Channel impingement cooling structure, which is utilized at the turning region of the leading edge, is the critical factor to realize the high cooling performance of the design. Hence, the turning angle and turning internal radius of the cooling channel are two key parameters for the novel design, and this paper focuses on the effects of these two parameters on the flow and heat transfer characteristics of the channel impingement cooling structure. Nine simplified single-channel models with different turning angles (45°, 60°, and 75°) and radiuses (0.6 mm, 0.9 mm, and 1.2 mm) were adopted to conduct the study, and the jet Reynolds number ranges from 10,000 to 40,000. The results show that the turning angle and turning internal radius affect the jet form significantly for the same mechanism. Small turning angle means large impingement, which leads to stream-wise counter-rotational vortices and high turbulence intensity, but increasing turning internal radius transfers the jet form from impingement jet to laminar layer attaching the target surface with low heat transfer. The turning internal radius has stronger effect than turning angle. With higher jet Reynolds number, both the heat transfer and total pressure loss increase dramatically, and the effects of geometrical parameters are clearer.

Effects of Turning Angle and Turning Internal Radius on Channel Impingement Cooling for a Novel Internal Cooling Structure

2021 ◽  
pp. 1-43
Author(s):  
Wei He ◽  
Qinghua Deng ◽  
Gouying Yang ◽  
Zhenping Feng
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Pressure Loss ◽  
Single Channel ◽  
Geometrical Parameters ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Turning Angle ◽  
Impingement Cooling ◽  
Internal Radius

Abstract Recently, a novel internal cooling structure, namely multi-channel wall, has been put forward to enable higher overall cooling effectiveness with less coolant and pressure loss. Our previous work has proved the advantages of the design relative to conventional impingement cooling and swirl cooling. Channel impingement cooling structure, which is utilized at the turning region of the leading edge, is the critical factor to realize the high cooling performance of the design. Hence, the turning angle and turning internal radius of the cooling channel are two key parameters, and this paper focuses on the effects of these two parameters on the flow and heat transfer characteristics of the channel impingement cooling structure. Nine simplified single-channel models with different turning angles (45°, 60°, and 75°) and radiuses (0.6 mm, 0.9 mm, and 1.2 mm) were adopted to conduct the study, and the jet Reynolds number ranges from 10,000 to 40,000. The results show that the turning angle and turning internal radius affect the jet form significantly for the same mechanism. Small turning angle means large impingement, which leads to stream-wise counter-rotational vortices and high turbulence intensity, but increasing turning internal radius transfers the jet form from impingement jet to laminar layer attaching the target surface with low heat transfer. The turning internal radius has stronger effect than turning angle. With higher jet Reynolds number, both the heat transfer and total pressure loss increase dramatically, and the effects of geometrical parameters are clearer.

Effect of Channel Orientation in a Rotating Wedge-Shaped Cooling Channel With Pin Fins and Ribs

2012 ◽  
Author(s):  
Lu Qiu ◽  
Hongwu Deng ◽  
Zhi Tao
Keyword(s):  
Heat Transfer ◽  
Rotation Number ◽  
Reynolds Numbers ◽  
Cooling Channel ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Narrow Region ◽  
Pin Fins ◽  
Channel Orientation ◽  
Rotating Channel

Experiments are preformed to investigate the effect of channel orientation in a rotating wedge-shaped cooling channel with lateral flow extraction. The test section bears the following characteristics. Staggered ribs are arranged in the inner wide region of the channel, while the pin-fins are located in the outer narrow region. The regionally averaged heat transfer coefficients are obtained to study the characteristics of heat transfer variations in this channel under rotating and non-rotating conditions. The experiments are conducted under four inlet Reynolds numbers (6100, 15000, 25100, 33000), five rotational speeds (0, 300, 500, 800, 1000rpm) and three channel orientations (90°, 135°, 180° angle from the channel symmetry plan to the rotating plan). The inlet rotation number ranges from zero to 0.62. Finally, the experimental data demonstrates that the streamwise heat transfer variations under rotating condition are strongly affected by channel orientation in this configuration. Furthermore, compared with the data under two channel orientation 90° and 180° (the direction of rotation is perpendicular and parallel to the channel symmetry plan), the heat transfer characteristics under 135° configuration, which is regarded as the typical trailing edge orientation, approaches to the 180° one in this rotating channel. An evident critical rotation number, after which the nature of heat transfer changes abruptly, exists under 180° and 135° configuration but not under 90° one.

Numerical Aero-Thermal Analysis of a Rib-Roughened Trailing Edge Cooling Channel at Different Rotation Numbers and Channel Orientations

2014 ◽  
Author(s):  
Matteo Pascotto ◽  
Alessandro Armellini ◽  
Luca Casarsa ◽  
Sebastian Spring
Keyword(s):  
Heat Transfer ◽  
Working Conditions ◽  
Turbine Blades ◽  
Thermal Characterization ◽  
Cooling Channel ◽  
Trailing Edge ◽  
Smooth Channel ◽  
Channel Orientation ◽  
Channel Configuration ◽  
Rib Roughened

The present work considers the aero-thermal characterization of a rib-roughened cooling channel for the trailing edge of gas turbine blades, and is based on previous findings from a smooth channel configuration. The passage is characterized by a trapezoidal cross section with high aspect-ratio, radial inlet flow, and coolant discharge at both model tip and trailing side, where seven elongated pedestals are installed. In this study, heat transfer augmentation is achieved by placing inclined squared ribs on the channel central portion. RANS simulations with a SST turbulence model were performed using the commercial solver ANSYS CFX®v14. The numerical tool was first validated on the available experimental data and, subsequently, its capabilities were exploited in a wider range of working conditions, namely at higher rotation speed and different channel orientation. In this way it was possible to highlight the effects that ribs and working conditions have on the development of both flow and thermal fields. The results show that rotation and channel orientation produce contrasting effects. On the rib-roughened wall, rotation/orientation generates an increase/decrease of the heat transfer; conversely, on the trailing side region rotation/orientation has a negative/positive effect on the thermal field.

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