Coating Rejuvenation: New Repair Technology for High Pressure Turbine Blades

2000 ◽  
Author(s):  
Jeffrey A. Conner ◽  
Michael J. Weimer
Keyword(s):  
High Pressure ◽  
Life Cycle ◽  
Wall Thickness ◽  
Life Cycle Cost ◽  
Protective Coatings ◽  
Turbine Blades ◽  
High Pressure Turbine ◽  
Aluminide Coatings ◽  
Patent Applications ◽  
Blade Repair

With the evolution of advanced directionally solidified and single crystal nickel base superalloy turbine blades, managing life cycle costs of high pressure turbine (HPT) blades has become increasingly more difficult. Today’s advanced high pressure turbine blades in aero and aero-derivative turbines feature thin walls (<.030 inches), complex internal geometries, three dimensional (3D) aerodynamic shapes, multiple protective coatings and complex film cooling schemes. A major contributor to blade life cycle cost is the ability to perform multiple repairs without compromising the integrity of these complex components. Repair of HPT blades has traditionally fallen into two categories: mini or partial repairs where blade tips are restored and coated, and full repairs where flowpath coatings are removed, blade tips restored and new coating(s) applied to flowpath surfaces. Historically, the number of full repairs allowed ranges from zero to two based on numerous design considerations, one of which is maintaining a minimum wall thickness. Removal of protective coatings during full repair reduces wall thickness which limits the number of times a full repair can be performed. Furthermore, blades that have sufficient design allowance to permit two full repairs typically have very low yields at the second full repair due to thinning of airfoil walls below minimum thickness limits. The life of a given HPT blade is therefore controlled to a large degree by at what shop visit a full repair is performed. GE Engine Services has developed a new blade repair approach — Coating Rejuvenation — which significantly extends blade life by restoring protective coatings and maintaining wall thickness. Included in the Coating Rejuvenation repair are technologies that allow: removal of physical vapor deposited (PVD) thermal barrier coatings from external surfaces and cooling holes without impacting the bond coat; removal of oxidation and corrosion products from engine exposed coatings without impacting adjacent intact coating; restoration of coating composition to optimize environmental resistance; and upgrade of existing aluminide coatings to platinum aluminide coatings without removal of the existing coating. Combined together, these technologies can be used to support a comprehensive blade repair workscope plan that dramatically increases the life of HPT blades and decreases the life cycle cost for these components. Overviews of these technologies are presented in this paper along with information on how the technology was matured. Due to pending patent applications with the US Patent & Trademark Office as well as pending patent applications in other countries, significant technical detail cannot be presented at this time.

Evaluation of Simple Aluminide and Platinum Modified Aluminide Coatings on High Pressure Turbine Blades After Factory Engine Testing

1991 ◽  
Author(s):  
Jeffrey A. Conner ◽  
David A. Moore ◽  
Roger D. Wustman
Keyword(s):  
High Pressure ◽  
Turbine Blades ◽  
Chemical Vapor ◽  
Pack Cementation ◽  
Operating Conditions ◽  
Nickel Base Superalloy ◽  
High Pressure Turbine ◽  
Aluminide Coatings ◽  
Deposition Processes ◽  
Engine Testing

This paper presents results from recent factory engine testing of simple aluminide coatings produced using pack cementation processes and platinum modified aluminide coatings produced using both pack cementation and chemical vapor deposition processes. These coatings were evaluated on DS nickel base superalloy high pressure turbine blades in a commercial high bypass turbofan engine. Operating conditions were such that turbine inlet air contained up to 3 ppb of sodium. Details of the factory engine testing, coating selection and application, and environmental protection provided by the coatings are highlighted. Future testing plans are also presented.

Evaluation of Simple Aluminide and Platinum Modified Aluminide Coatings on High Pressure Turbine Blades After Factory Engine Testing-Round II

1992 ◽  
Author(s):  
Jeffrey A. Connor
Keyword(s):  
High Pressure ◽  
Turbine Blades ◽  
Chemical Vapor ◽  
Pack Cementation ◽  
Nickel Base Superalloy ◽  
High Pressure Turbine ◽  
Engine Operation ◽  
Temperature Oxidation ◽  
Aluminide Coatings ◽  
Engine Testing

This paper presents results of factory engine testing of simple aluminide and platinum modified aluminide coatings. Simple aluminide coatings were produced using pack cementation processes. Platinum modified aluminide coatings were produced using three aluminiding processes; pack cementation, above-the-pack or out-of-contact processing, and chemical vapor deposition. These coatings were evaluated on both directionally solidified and single crystal nickel base superalloy turbine blades. These high pressure turbine blades were tested in a commercial high bypass turbofan engine operating predominantly in a high temperature oxidation environment. Included in this paper are discussions of coatings phase stability, coating growth due to diffusion during engine operation, comparison of coating performance and assessment of remaining coating life after engine testing.

Aerothermal Effect of Cavity Welding Beads on a Transonic Squealer Tip

2020 ◽  
Author(s):  
Joao Vieira ◽  
John Coull ◽  
Peter Ireland ◽  
Eduardo Romero
Keyword(s):  
High Pressure ◽  
Film Cooling ◽  
Turbine Blades ◽  
Reynolds Numbers ◽  
High Pressure Turbine ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Aerodynamic Loss ◽  
Blade Tip ◽  
Mass Flow Rates

Abstract High pressure turbine blade tips are critical for gas turbine performance and are sensitive to small geometric variations. For this reason, it is increasingly important for experiments and simulations to consider real geometry features. One commonly absent detail is the presence of welding beads on the cavity of the blade tip, which are an inherent by-product of the blade manufacturing process. This paper therefore investigates how such welds affect the Nusselt number, film cooling effectiveness and aerodynamic performance. Measurements are performed on a linear cascade of high pressure turbine blades at engine realistic Mach and Reynolds numbers. Two cooled blade tip geometries were tested: a baseline squealer geometry without welding beads, and a case with representative welding beads added to the tip cavity. Combinations of two tip gaps and several coolant mass flow rates were analysed. Pressure sensitive paint was used to measure the adiabatic film cooling effectiveness on the tip, which is supplemented by heat transfer coefficient measurements obtained via infrared thermography. Drawing from all of this data, it is shown that the weld beads have a generally detrimental impact on thermal performance, but with local variations. Aerodynamic loss measured downstream of the cascade is shown to be largely insensitive to the weld beads.

scholarly journals Evaluation of High Pressure Turbine Blade Coatings on an LM2500 Rainbow Rotor

1995 ◽  
Author(s):  
B. Nagaraj ◽  
G. Katz ◽  
A. F. Maricocchi ◽  
M. Rosenzweig
Keyword(s):  
High Pressure ◽  
Turbine Blades ◽  
Leading Edge ◽  
Service Evaluation ◽  
High Pressure Turbine ◽  
Barrier Coating ◽  
Marine Propulsion ◽  
Corrosion Resistant Coatings ◽  
Stage 1 ◽  
Plasma Sprayed

Two LM2500 rainbow rotors with repaired stage 1 and stage 2 high pressure turbine blades are being assembled for marine propulsion service evaluation by the US Navy. The blades have seen between 5,000 and 15,000 hours of service in the Navy’s Fleets. A number of corrosion resistant coatings including plasma sprayed CoCrAlHf (bill of material), composite plated CoCrAlHf, platinum aluminide, aluminum silicide, and physical vapor deposited yttria stabilized zirconia thermal barrier coating (PVD TBC) will be evaluated in the rainbow rotor. This paper will discuss the advantages and microstructures of the various coatings. Composite plated CoCrAlHf, and PVD TBCs were recently service evaluated in an industrial LM2500 rainbow rotor for 10,500 hours. Both these coatings performed well, although the PVD TBC had local spallation at the leading edge. This paper will review the details of performance of these two coatings in the industrial LM2500 application.

Using CFD to Reduce Resonant Stresses on a Single-Stage, High-Pressure Turbine Blade

2002 ◽  
Author(s):  
J. P. Clark ◽  
A. S. Aggarwala ◽  
M. A. Velonis ◽  
R. E. Gacek ◽  
S. S. Magge ◽  
...  
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Guide Vane ◽  
Turbine Blades ◽  
Suction Side ◽  
Lessons Learned ◽  
Single Stage ◽  
Navier Stokes ◽  
High Pressure Turbine ◽  
Time Resolved

The ability to predict levels of unsteady forcing on high-pressure turbine blades is critical to avoid high-cycle fatigue failures. In this study, 3D time-resolved computational fluid dynamics is used within the design cycle to predict accurately the levels of unsteady forcing on a single-stage high-pressure turbine blade. Further, nozzle-guide-vane geometry changes including asymmetric circumferential spacing and suction-side modification are considered and rigorously analyzed to reduce levels of unsteady blade forcing. The latter is ultimately implemented in a development engine, and it is shown successfully to reduce resonant stresses on the blade. This investigation builds upon data that was recently obtained in a full-scale, transonic turbine rig to validate a Reynolds-Averaged Navier-Stokes (RANS) flow solver for the prediction of both the magnitude and phase of unsteady forcing in a single-stage HPT and the lessons learned in that study.

Sign in / Sign up

Export Citation Format

Share Document