Turbine Blade Leading Edge Cooling With One Row of Normal or Tangential Impinging Jets

2017 ◽  
Author(s):  
Nian Wang ◽  
Andrew F. Chen ◽  
Mingjie Zhang ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Turbine Blade ◽  
Leading Edge ◽  
Jet Impingement ◽  
Test Surface ◽  
Test Model ◽  
Edge Region ◽  
Target Plate ◽  
Blade Leading Edge

Jet impingement cooling has been extensively used in the leading edge region of a gas turbine blade. This study focuses on the effect of jet impinging position on leading edge heat transfer. The test model is composed of a semi-cylindrical target plate, side exit slots, and an impingement jet plate. A row of cylindrical injection holes is located along the axis (normal jet) or the edge (tangential jet) of the semi-cylinder, on the jet plate. The jet-to-target-plate distance to jet diameter ratio (z/d) is 5 and the ratio of jet-to-jet spacing to jet diameter (s/d) is 4. The jet Reynolds number is varied from 10,000 to 30,000. Detailed impingement heat transfer coefficient distributions were experimentally measured by using the transient liquid crystal technique. To understand the thermal flow physics, numerical simulations were performed using RANS with two turbulence models: realizable k-ε (RKE) and shears stress transport k-ω model (SST). Comparisons between the experimental and the numerical results are presented. The results indicate that the local Nusselt numbers on the test surface increase with the increasing jet Reynolds number. The tangential jets provide more uniform heat transfer distributions as compared with the normal jets in the stream-wise direction. For the normal jet impingement and the tangential jet impingement, the RKE model provides better prediction than the SST model. The results can be useful for selecting a jet impinging position in order to provide the proper cooling distribution inside a turbine blade leading edge region.

Turbine Blade Leading Edge Cooling With One Row of Normal or Tangential Impinging Jets

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Nian Wang ◽  
Andrew F. Chen ◽  
Mingjie Zhang ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Turbine Blade ◽  
Leading Edge ◽  
Jet Impingement ◽  
Test Surface ◽  
Test Model ◽  
Edge Region ◽  
Target Plate ◽  
Blade Leading Edge

Jet impingement cooling has been extensively used in the leading edge region of a gas turbine blade. This study focuses on the effect of jet impinging position on leading edge heat transfer. The test model is composed of a semicylindrical target plate, side exit slots, and an impingement jet plate. A row of cylindrical injection holes is located along the axis (normal jet) or the edge (tangential jet) of the semicylinder, on the jet plate. The jet-to-target-plate distance to jet diameter ratio (z/d) is 5 and the ratio of jet-to-jet spacing to jet diameter (s/d) is 4. The jet Reynolds number is varied from 10,000 to 30,000. Detailed impingement heat transfer coefficient distributions were experimentally measured by using the transient liquid crystal (TLC) technique. To understand the thermal flow physics, numerical simulations were performed using Reynolds-averaged Navier–Stokes (RANS) with two turbulence models: realizable k–ε (RKE) and shear stress transport k–ω model (SST). Comparisons between the experimental and the numerical results are presented. The results indicate that the local Nusselt numbers on the test surface increase with the increasing jet Reynolds number. The tangential jets provide more uniform heat transfer distributions as compared with the normal jets. For the normal jet impingement and the tangential jet impingement, the RKE model provides better prediction than the SST model. The results can be useful for selecting a jet impinging position in order to provide the proper cooling distribution inside a turbine blade leading edge region.

Effects of Jetting Orifice Geometry Parameters and Channel Reynolds Number on Bended Channel Cooling for a Novel Internal Cooling Structure

2019 ◽  
Author(s):  
Wei He ◽  
Qinghua Deng ◽  
Juan He ◽  
Tieyu Gao ◽  
Zhenping Feng
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Leading Edge ◽  
Jet Impingement ◽  
Suction Side ◽  
Outer Wall ◽  
Internal Cooling ◽  
Cooling Effectiveness ◽  
Blade Leading Edge

Abstract A novel internal cooling structure has been raised recently to enhance internal cooling effectiveness and reduce coolant requirement without using film cooling. This study mainly focuses on verifying the actual cooling performance of the structure and investigating the heat transfer mechanism of the leading edge part of the structure, named bended channel cooling. The cooling performances of the first stage of GE-E3 turbine with three different blade leading edge cooling structures (impingement cooling, swirl cooling and bended channel cooling) were simulated using the conjugate heat transfer method. Furthermore, the effects of jetting orifice geometry and channel Reynolds number were studied with simplified models to illustrate the flow and heat transfer characteristics of the bended channel cooling. The results show that the novel internal cooling structure has obvious advantages on the blade leading edge and suction side under operating condition. The vortex core structure in the bended channel depends on orifice width, but not channel Reynolds number. With the ratio of orifice width to outer wall thickness smaller than a critical value of 0.5, the coolant flows along the external surface of the channel in the pattern of “inner film cooling”, which is pushed by centrifugal force and minimizes the mixing with spent cooling air. Namely, the greatly organized coolant flow generates higher cooling effectiveness and lower coolant demand. Both the Nusselt number on the channel surfaces and total pressure loss increase significantly when the orifice width falls or channel Reynolds increases, but the wall jet impingement distance appears to be less influential.

Numerical Study of Flow and Heat Transfer of Impingement Cooling on Model of Turbine Blade Leading Edge

2010 ◽  
Author(s):  
Zhao Liu ◽  
Zhenping Feng ◽  
Liming Song
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Numerical Study ◽  
Leading Edge ◽  
Jet Impingement ◽  
Target Surface ◽  
Nozzle Diameter ◽  
Impingement Cooling ◽  
Jet Nozzle ◽  
Blade Leading Edge

In this paper a numerical simulation is performed to simulate the impingement cooling on internal leading edge region, which is stretched by the middle cross section of the first stage rotor blade of GE-E3 engine high pressure turbine, and in the condition that jets flow is ejected from a row of four different diameter circular nozzles. The relative performances of three versions of turbulence models including the RNG κ-ε model, the standard κ-ω model and the SST κ-ω model in the simulation of a row of circle jet impingement heat transfer are compared with available experimental data. The results show that SST κ-ω model is the best one based on simulation accuracy. Then the SST κ-ω model is adopted for the simulation. The grid independence study is also carried out by using the Richardson extrapolation method. A single array of circle jets is arranged to investigate the impingement cooling and its effectiveness. Four different jet nozzle diameters are studied and seven different inlet flow Mach numbers of each jet nozzle diameter are calculated. The influence of the ratio of the spacing of jet nozzle from the target surface to the jet nozzle diameter on impingement cooling is also studied, in case of a constant ratio of jet spacing to jet nozzle diameter in different jet nozzle diameters. The results indicate that the heat transfer coefficient on the turbine blade leading edge increases with the increase of jet Mach number and jet nozzle diameter, the spanwise area weight average Nusselt number decreases with the increase of the ratio of the spacing of jet nozzle from the target surface to jet nozzle diameter, and a lower ratio of spacing of jet nozzle from the target surface to the jet nozzle diameter is desirable to improve the performance of impingement cooling on turbine leading edge.

Heat Transfer and Flowfield Measurements in the Leading Edge Region of a Stator Vane Endwall

1999 ◽  
Vol 121 (3) ◽  
pp. 558-568 ◽  
Author(s):  
M. B. Kang ◽  
A. Kohli ◽  
K. A. Thole
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Leading Edge ◽  
Reynolds Numbers ◽  
Secondary Flows ◽  
Edge Region ◽  
Leading Edge Vortex ◽  
Stator Vane ◽  
Edge Vortex ◽  
The Mean

The leading edge region of a first-stage stator vane experiences high heat transfer rates, especially near the endwall, making it very important to get a better understanding of the formation of the leading edge vortex. In order to improve numerical predictions of the complex endwall flow, benchmark quality experimental data are required. To this purpose, this study documents the endwall heat transfer and static pressure coefficient distribution of a modern stator vane for two different exit Reynolds numbers (Reex = 6 × 105 and 1.2 × 106). In addition, laser-Doppler velocimeter measurements of all three components of the mean and fluctuating velocities are presented for a plane in the leading edge region. Results indicate that the endwall heat transfer, pressure distribution, and flowfield characteristics change with Reynolds number. The endwall pressure distributions show that lower pressure coefficients occur at higher Reynolds numbers due to secondary flows. The stronger secondary flows cause enhanced heat transfer near the trailing edge of the vane at the higher Reynolds number. On the other hand, the mean velocity, turbulent kinetic energy, and vorticity results indicate that leading edge vortex is stronger and more turbulent at the lower Reynolds number. The Reynolds number also has an effect on the location of the separation point, which moves closer to the stator vane at lower Reynolds numbers.

Influence of converging conical hole angles on jet impingement blade cooling of gas turbine blade leading edge

2022 ◽  
Author(s):  
S. Sathish ◽  
S. Seralathan ◽  
Mohan Sai Narayan Ch ◽  
V. Mohammed Rizwan ◽  
U. Prudhvi Varma ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Turbine Blade ◽  
Leading Edge ◽  
Jet Impingement ◽  
Gas Turbine Blade ◽  
Blade Cooling ◽  
Blade Leading Edge

Novel Gas Turbine Blade Leading Edge Cooling Configuration Using Advanced Double Swirl Chambers

2015 ◽  
Author(s):  
Karsten Kusterer ◽  
Gang Lin ◽  
Takao Sugimoto ◽  
Dieter Bohn ◽  
Ryozo Tanaka ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Leading Edge ◽  
Gas Turbine Blade ◽  
Stagnation Line ◽  
Impingement Cooling ◽  
Cooling Technology ◽  
Cooling Air ◽  
Blade Leading Edge

The Double Swirl Chambers (DSC) cooling technology, which has been introduced and developed by the authors, has the potential to be a promising cooling technology for further increase of gas turbine inlet temperature and thus improvement of the thermal efficiency. The DSC cooling technology establishes a significant enhancement of the local internal heat transfer due to the generation of two anti-rotating swirls. The reattachment of the swirl flows with the maximum velocity at the center of the chamber leads to a linear impingement effect on the internal surface of the blade leading edge nearby the stagnation line of gas turbine blade. Due to the existence of two swirls both the suction side and the pressure side of the blade near the leading edge can be very well cooled. In this work, several advanced DSC cooling configurations with a row of cooling air inlet holes have been investigated. Compared with the standard DSC cooling configuration the advanced ones have more suitable cross section profiles, which enables better accordance with the real blade leading edge profile. At the same time these configurations are also easier to be manufactured in a real blade. These new cooling configurations have been numerically compared with the state of the art leading edge impingement cooling configuration. With the same configuration of cooling air supply and boundary conditions the advanced DSC cooling presents 22–26% improvement of overall heat transfer and 3–4% lower total pressure drop. Along the stagnation line the new cooling configuration can generate twice the heat flux than the standard impingement cooling channel. The influence of spent flow in the impinging position and impingement heat transfer value is in the new cooling configurations much smaller, which leads to a much more uniform heat transfer distribution along the chamber axial direction.

scholarly journals Full Coverage Shaped-Hole Film Cooling in an Accelerating Boundary Layer With High Freestream Turbulence

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
J. E. Kingery ◽  
F. E. Ames
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Film Cooling ◽  
Density Ratio ◽  
Leading Edge ◽  
Test Surface ◽  
Turbulence Level ◽  
Full Coverage ◽  
Lower Reynolds Number ◽  
Shaped Hole

Full coverage shaped-hole film cooling and downstream heat transfer measurements have been acquired in the accelerating flows over a large cylindrical leading edge test surface. The shaped holes had an 8 deg lateral expansion angled at 30 deg to the surface with spanwise and streamwise spacings of 3 diameters. Measurements were conducted at four blowing ratios, two Reynolds numbers, and six well documented turbulence conditions. Film cooling measurements were acquired over a four to one range in blowing ratio at the lower Reynolds number and at the two lower blowing ratios for the higher Reynolds number. The film cooling measurements were acquired at a coolant to free-stream density ratio of approximately 1.04. The flows were subjected to a low turbulence (LT) condition (Tu = 0.7%), two levels of turbulence for a smaller sized grid (Tu = 3.5% and 7.9%), one turbulence level for a larger grid (8.1%), and two levels of turbulence generated using a mock aerocombustor (AC) (Tu = 9.3% and 13.7%). Turbulence level is shown to have a significant influence in mixing away film cooling coverage progressively as the flow develops in the streamwise direction. Effectiveness levels for the AC turbulence condition are reduced to as low as 20% of LT values by the furthest downstream region. The film cooling discharge is located close to the leading edge with very thin and accelerating upstream boundary layers. Film cooling data at the lower Reynolds number show that transitional flows have significantly improved effectiveness levels compared with turbulent flows. Downstream effectiveness levels are very similar to slot film cooling data taken at the same coolant flow rates over the same cylindrical test surface. However, slots perform significantly better in the near discharge region. These data are expected to be very useful in grounding computational predictions of full coverage shaped-hole film cooling with elevated turbulence levels and acceleration. Infrared (IR) measurements were performed for the two lowest turbulence levels to document the spanwise variation in film cooling effectiveness and heat transfer.

Leading Edge Jet Impingement Under High Rotation Numbers

2012 ◽  
Author(s):  
Cassius A. Elston ◽  
Lesley M. Wright
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Rotation Number ◽  
Leading Edge ◽  
Jet Impingement ◽  
Target Surface ◽  
Test Cases ◽  
Nusselt Numbers ◽  
Supply Channel ◽  
Cooling Air

The effect of rotation on jet impingement cooling is experimentally investigated in this study. Pressurized cooling air is supplied to a smooth, square channel in the radial outward direction. To model leading edge impingement in a gas turbine, jets are formed from a single row of discrete holes. The cooling air from the first pass is expelled through the holes, with the jets impinging on a semi-circular, concave surface. The inlet Reynolds number varied from 10000–40000 in the square supply channel. The rotation number and buoyancy parameter varied from 0–1.4 and 0–6.6 near the inlet of the channel, and as coolant is extracted for jet impingement, the rotation and buoyancy numbers can exceed 10 and 500 near the end of the passage. The average jet Reynolds number varied from 6000–24000, and the jet rotation number varied from 0–0.13. For all test cases, the jet-to-jet spacing (s/djet = 4), the jet-to-target surface spacing (l/djet = 3.2), and the impingement surface diameter-to-diameter (D/djet = 6.4) were held constant. A steady state technique was implemented to determine regionally averaged Nusselt numbers on the leading and trailing surfaces inside the supply channel and three spanwise locations on the concave target surface. It was observed that in all rotating test cases, the Nusselt numbers deviated from those measured in a non-rotating channel. The degree of separation between the leading and trailing surface increased with increasing rotation number. Near the inlet of the channel, heat transfer was dominated by entrance effects, however moving downstream, the local rotation number increased and the effect of rotation was more pronounced. The effect of rotation on the target surface was most clearly seen in the absence of crossflow. With pure jet impingement, the deflection of the impinging jet combined with the rotation induced secondary flows offered increased mixing within the impingement cavity and enhanced heat transfer. In the presence of strong crossflow of the spent air, the same level of heat transfer is measured in both the stationary and rotating channels.

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