Thermal Analysis in a Film Cooling Hole with Thermal Barrier Coating

2009 ◽  
Vol 23 (4) ◽  
pp. 843-847 ◽  
Author(s):  
Dong Hyun Lee ◽  
Kyung Min Kim ◽  
Sangwoo Shin ◽  
Hyung Hee Cho
Keyword(s):  
Thermal Analysis ◽  
Thermal Barrier Coating ◽  
Film Cooling ◽  
Thermal Barrier ◽  
Barrier Coating ◽  
Cooling Hole

Effects of Surface Deposition, Hole Blockage, and Thermal Barrier Coating Spallation on Vane Endwall Film Cooling

2006 ◽  
Vol 129 (3) ◽  
pp. 599-607 ◽  
Author(s):  
N. Sundaram ◽  
K. A. Thole
Keyword(s):  
Thermal Barrier Coating ◽  
Film Cooling ◽  
Gas Turbines ◽  
Large Scale ◽  
Leading Edge ◽  
Thermal Barrier ◽  
Cooling Effectiveness ◽  
Barrier Coating ◽  
Cooling Hole ◽  
Alternate Fuels

With the increase in usage of gas turbines for power generation and given that natural gas resources continue to be depleted, it has become increasingly important to search for alternate fuels. One source of alternate fuels is coal derived synthetic fuels. Coal derived fuels, however, contain traces of ash and other contaminants that can deposit on vane and turbine surfaces affecting their heat transfer through reduced film cooling. The endwall of a first stage vane is one such region that can be susceptible to depositions from these contaminants. This study uses a large-scale turbine vane cascade in which the following effects on film cooling adiabatic effectiveness were investigated in the endwall region: the effect of near-hole deposition, the effect of partial film cooling hole blockage, and the effect of spallation of a thermal barrier coating. The results indicated that deposits near the hole exit can sometimes improve the cooling effectiveness at the leading edge, but with increased deposition heights the cooling deteriorates. Partial hole blockage studies revealed that the cooling effectiveness deteriorates with increases in the number of blocked holes. Spallation studies showed that for a spalled endwall surface downstream of the leading edge cooling row, cooling effectiveness worsened with an increase in blowing ratio.

Effect of Thermal Barrier Coating and Gas Radiation on Film Cooling of a Corrugated Surface

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Kuldeep Singh ◽  
B. Premachandran ◽  
M. R. Ravi
Keyword(s):  
Mach Number ◽  
Thermal Barrier Coating ◽  
Film Cooling ◽  
Heat Transfer Analysis ◽  
Thermal Barrier ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Corrugated Surface ◽  
Gas Radiation ◽  
Barrier Coating

In this work, a numerical study is conducted to investigate film cooling of a corrugated surface. A conjugate heat transfer analysis is carried out, accounting for the presence of thermal barrier coating (TBC) and gas radiation. The Mach number of mainstream flow is maintained at Ma = 0.6, while cold stream Mach number is varied from 0.3 to 0.58, and density ratio is kept 4. From this study, it is observed that the overall film cooling effectiveness increases by a value ranging from 0.10 to 0.15 with the use of TBC. The hot side metallic wall temperature increases in the range of 100–150 °C when the effect of gas radiation is considered. It is also found that the film cooling effectiveness decreases with decrease in the cold side Mach number.

Experimental and Computational Investigation of Integrated Internal and Film Cooling Designs Incorporating a Thermal Barrier Coating

2021 ◽  
Author(s):  
Matthew J. Horner ◽  
Christopher Yoon ◽  
Michael Furgeson ◽  
Todd A. Oliver ◽  
David G. Bogard
Keyword(s):  
Film Cooling ◽  
Velocity Ratio ◽  
Thermal Barrier ◽  
Internal Cooling ◽  
Barrier Coating ◽  
Component Design ◽  
Turbine Component ◽  
Cooling Hole ◽  
Optimum Velocity ◽  
Overall Effectiveness

Abstract Few studies in the open literature have studied the effect of thermal barrier coatings when used in combination with shaped hole film cooling and enhanced internal cooling techniques. The current study presents RANS conjugate heat transfer simulations that identify trends in cooling design performance as well as experimental measurements of overall effectiveness using a flat-plate matched-Biot number model with a simulated TBC layer of 0.42D thickness, where D is the film cooling hole diameter. Coolant is fed to the film cooling holes in a co-flow configuration, and the results of both smooth and rib-turbulated channels are compared. At a constant coolant flow rate, enhanced internal cooling was found to provide a 44% increase in spatially-averaged overall effectiveness, ϕ ̿ , without a TBC. The results show that the addition of a TBC can raise ϕ ̿ on a film-cooled component surface by 47%. The optimum velocity ratio was found to decrease with the addition of enhanced cooling techniques and a TBC as the film provided minimal benefit at the expense of reduced internal cooling. While the computational results closely identified trends in overall system performance without a TBC, the model over-predicted effectiveness on the metal-TBC interface. The results of this study will inform turbine component design as material science advances increase the reliability of TBC.

Experimental Simulation of a Film Cooled Turbine Blade Leading Edge Including Thermal Barrier Coating Effects

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Jonathan Maikell ◽  
David Bogard ◽  
Justin Piggush ◽  
Atul Kohli
Keyword(s):  
Thermal Barrier Coating ◽  
Turbine Blade ◽  
Film Cooling ◽  
Leading Edge ◽  
Experimental Simulation ◽  
Thermal Barrier ◽  
Stagnation Line ◽  
Barrier Coating ◽  
Overall Effectiveness ◽  
Blade Leading Edge

For this study, a simulated film cooled turbine blade leading edge, constructed of a special high conductivity material, was used to determine the normalized “metal temperature” representative of actual engine conditions. The Biot number for the model was matched to that for operational engine conditions, ensuring that the normalized wall temperature, i.e., the overall effectiveness, was matched to that for the engine. Measurements of overall effectiveness were made for models with and without thermal barrier coating (TBC) at various operating conditions. This was the first study to experimentally simulate TBC and the effects on overall effectiveness. Two models were used: one with a single row of holes along the stagnation line, and the second with three rows of holes straddling the stagnation line. Film cooling was operated using a density ratio of 1.5 and for range of blowing ratios from M=0.5 to M=3.0. Both models were tested using a range of angles of attack from 0.0 deg to ±5.0 deg. As expected, the TBC coated models had significantly higher external surface temperatures, but lower metal temperatures. These experimental results provide a unique database for evaluating numerical simulations of the effects of TBC on leading edge film cooling performance.

A Study of Deposition on a Turbine Vane With a Thermal Barrier Coating and Various Film Cooling Geometries

2013 ◽  
Vol 136 (4) ◽  
Author(s):  
F. Todd Davidson ◽  
David A. Kistenmacher ◽  
David G. Bogard
Keyword(s):  
Thermal Barrier Coating ◽  
Film Cooling ◽  
Stokes Number ◽  
Thermal Barrier ◽  
Transfer Coefficients ◽  
Cooling Performance ◽  
Heat Transfer Coefficients ◽  
Barrier Coating ◽  
Turbine Vane ◽  
Engine Components

Recent interest has been shown in using synthetic gaseous (syngas) fuels to power gas turbine engines. An important issue concerning these fuels is the potential for increased contaminant deposition that can inhibit cooling designs and expedite the material degradation of vital turbine components. The purpose of this study was to provide a detailed understanding of how contaminants deposit on the surface of a turbine vane with a thermal barrier coating (TBC). The vane model used in this study was designed to match the thermal behavior of real engine components by properly scaling the convective heat transfer coefficients as well as the thermal conductivity of the vane wall. Four different film cooling configurations were studied: round holes, craters, a trench, and a modified trench. The contaminants used in this study were small particles of paraffin wax that were sprayed into the mainstream flow of the wind tunnel. The wax particles modeled both the molten nature of contaminants in an engine as well as the particle trajectory by properly matching the expected range of Stokes number. This study found that the presence of film cooling significantly increased the accumulation of deposits. It was also found that the deposition behavior was strongly affected by the film cooling configuration that was used on the pressure side of the vane. The craters and trench performed the best in mitigating the accumulation of deposits immediately downstream of the film cooling configuration. In general, the presence of deposits reduced the film cooling performance on the surface of the TBC. However, the additional thermal insulation provided by the deposits improved the cooling performance at the interface of the TBC and vane wall.

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