A Study of the Effects of Thermal Barrier Coating Surface Roughness on the Boundary Layer Characteristics of Gas Turbine Aerofoils

1988 ◽  
Vol 110 (1) ◽  
pp. 88-93 ◽  
Author(s):  
R. M. Watt ◽  
J. L. Allen ◽  
N. C. Baines ◽  
J. P. Simons ◽  
M. George
Keyword(s):  
Surface Roughness ◽  
Reynolds Number ◽  
Gas Turbine ◽  
Thermal Barrier Coating ◽  
Guide Vane ◽  
Thermal Barrier ◽  
Coating Surface ◽  
Barrier Coating ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

The effect of thermal barrier coating surface roughness on the aerodynamic performance of gas turbine aerofoils has been investigated for the case of a profile typical of current first-stage nozzle guide vane design. Cascade tests indicate a potential for significant extra loss, depending on Reynolds number, due to thermal barrier coating in its “as-sprayed” state. In this situation polishing coated vanes is shown to be largely effective in restoring their performance. The measurements also suggest a critical low Reynolds number below which the range of roughness tested has no effect on cascade efficiency. Transition detection involved a novel use of thin-film anemometers painted and fired onto the TBC surfaces.

Surface Roughness Measurement of Thermal Barrier Coating using Terahertz Waves

2017 ◽  
Vol 137 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Tetsuo Fukuchi ◽  
Norikazu Fuse ◽  
Mitsutoshi Okada ◽  
Tomoharu Fujii ◽  
Maya Mizuno ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Thermal Barrier Coating ◽  
Thermal Barrier ◽  
Roughness Measurement ◽  
Terahertz Waves ◽  
Surface Roughness Measurement ◽  
Barrier Coating

scholarly journals Progress in Novel Electrodeposited Bond Coats for Thermal Barrier Coating Systems

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4214
Author(s):  
Kranthi Kumar Maniam ◽  
Shiladitya Paul
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coating ◽  
Gas Turbines ◽  
High Performance ◽  
Turbine Engines ◽  
Thermal Barrier ◽  
Gas Turbine Engines ◽  
Potential Cost ◽  
Bond Coats ◽  
Barrier Coating

The increased demand for high performance gas turbine engines has resulted in a continuous search for new base materials and coatings. With the significant developments in nickel-based superalloys, the quest for developments related to thermal barrier coating (TBC) systems is increasing rapidly and is considered a key area of research. Of key importance are the processing routes that can provide the required coating properties when applied on engine components with complex shapes, such as turbine vanes, blades, etc. Despite significant research and development in the coating systems, the scope of electrodeposition as a potential alternative to the conventional methods of producing bond coats has only been realised to a limited extent. Additionally, their effectiveness in prolonging the alloys’ lifetime is not well understood. This review summarises the work on electrodeposition as a coating development method for application in high temperature alloys for gas turbine engines and discusses the progress in the coatings that combine electrodeposition and other processes to achieve desired bond coats. The overall aim of this review is to emphasise the role of electrodeposition as a potential cost-effective alternative to produce bond coats. Besides, the developments in the electrodeposition of aluminium from ionic liquids for potential applications in gas turbines and the nuclear sector, as well as cost considerations and future challenges, are reviewed with the crucial raw materials’ current and future savings scenarios in mind.

scholarly journals Evaluation of Impact Properties of Thermal Barrier Coating on Gas Turbine Components.

2000 ◽  
Vol 66 (650) ◽  
pp. 1841-1846
Author(s):  
Hiroshige ITOH ◽  
Kazuhiro SAITOH ◽  
Takahiro KUBO ◽  
Masashi TAKAHASHI ◽  
Hideo KASHIWAYA
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coating ◽  
Thermal Barrier ◽  
Impact Properties ◽  
Barrier Coating

A Method for Correlating the Influence of External Crossflow on the Discharge Coefficients of Film Cooling Holes

2000 ◽  
Vol 123 (2) ◽  
pp. 258-265 ◽  
Author(s):  
D. A. Rowbury ◽  
M. L. G. Oldfield ◽  
G. D. Lock
Keyword(s):  
Gas Turbine ◽  
Film Cooling ◽  
Discharge Coefficient ◽  
Guide Vane ◽  
Discharge Coefficients ◽  
Nozzle Guide Vane ◽  
Aero Engine ◽  
Nozzle Guide ◽  
Film Cooling Holes ◽  
Asme Paper

An empirical means of predicting the discharge coefficients of film cooling holes in an operating engine has been developed. The method quantifies the influence of the major dimensionless parameters, namely hole geometry, pressure ratio across the hole, coolant Reynolds number, and the freestream Mach number. The method utilizes discharge coefficient data measured on both a first-stage high-pressure nozzle guide vane from a modern aero-engine and a scale (1.4 times) replica of the vane. The vane has over 300 film cooling holes, arranged in 14 rows. Data was collected for both vanes in the absence of external flow. These noncrossflow experiments were conducted in a pressurized vessel in order to cover the wide range of pressure ratios and coolant Reynolds numbers found in the engine. Regrettably, the proprietary nature of the data collected on the engine vane prevents its publication, although its input to the derived correlation is discussed. Experiments were also conducted using the replica vanes in an annular blowdown cascade which models the external flow patterns found in the engine. The coolant system used a heavy foreign gas (SF6 /Ar mixture) at ambient temperatures which allowed the coolant-to-mainstream density ratio and blowing parameters to be matched to engine values. These experiments matched the mainstream Reynolds and Mach numbers and the coolant Mach number to engine values, but the coolant Reynolds number was not engine representative (Rowbury, D. A., Oldfield, M. L. G., and Lock, G. D., 1997, “Engine-Representative Discharge Coefficients Measured in an Annular Nozzle Guide Vane Cascade,” ASME Paper No. 97-GT-99, International Gas Turbine and Aero-Engine Congress & Exhibition, Orlando, Florida, June 1997; Rowbury, D. A., Oldfield, M. L. G., Lock, G. D., and Dancer, S. N., 1998, “Scaling of Film Cooling Discharge Coefficient Measurements to Engine Conditions,” ASME Paper No. 98-GT-79, International Gas Turbine and Aero-Engine Congress & Exhibition, Stockholm, Sweden, June 1998). A correlation for discharge coefficients in the absence of external crossflow has been derived from this data and other published data. An additive loss coefficient method is subsequently applied to the cascade data in order to assess the effect of the external crossflow. The correlation is used successfully to reconstruct the experimental data. It is further validated by successfully predicting data published by other researchers. The work presented is of considerable value to gas turbine design engineers as it provides an improved means of predicting the discharge coefficients of engine film cooling holes.

Field Evaluation of 2CaO-SiO2-CaO-ZrO2 Thermal Barrier Coating on Gas Turbine Vanes

1997 ◽  
Author(s):  
N. Mifune ◽  
Y. Harada ◽  
H. Taira ◽  
S. Mishima
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coating ◽  
Thermal Barrier Coatings ◽  
Field Evaluation ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Thermal Change ◽  
Barrier Coating ◽  
Turbine Vanes ◽  
Higher Temperature

Abstract Higher-temperature operation in a gas turbine has urged development of heat-resistant coatings and thermal barrier coatings. We have developed a 2CaO-SiO2-CaO-ZrO2 based thermal barrier coating. This coating should effectively prevent separation of the coating by relieving the shear stress generated due to thermal change of environment between layers with dissimilar properties. The coating was applied to stationary vanes of an actual gas turbine in a 25,000-hour test. This paper describes the results of the field test.

Optimized Thermal Barrier Coating for Gas Turbine Blades

2019 ◽  
Vol 11 ◽  
pp. 912-919 ◽  
Author(s):  
Vishnu Sankar ◽  
PB. Ramkumar ◽  
Deepak Sebastian ◽  
Doyel Joseph ◽  
Jithu Jose ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Thermal Barrier Coating ◽  
Turbine Blades ◽  
Thermal Barrier ◽  
Gas Turbine Blades ◽  
Barrier Coating
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