The coating is intended to reduce the compressor rotor tipclearance, and is expected to increase the compressor efficiency by a range of 0. Thermally sprayed abradable coating technology for sealing in gas turbines the use of thermal spray technology has revolutionised turbomachinery sealing technology by being able to tailor design abradable thermal spray powders and spray them to a designated hardness range, using thermal spray technology to high levels of microstructural control. Abradable coating removal in turbomachines archive ouverte hal. Apr, 2018 an abradable coating is a coating made of an abradable material meaning if it rubs against a more abrasive material in motion, the former will be worn whereas the latter will face no wear. Aug 15, 2017 improvements in abradable coatings require various tests, extending from powder fabrication up to choosing the maximum thermal spray procedure. Oxidation behaviour of a conicralyhbn based abradable coating. Axial iii abradable coatings can be applied with consistent quality at high feed rate and deposition efficiency. Abradable coating acts as a seal between the blades and casing of aircraft or gas turbine engine. Johnston this paper reports recent research on abradable materials employed for aeroengine applications. An abradable coating is a coating made of an abradable material meaning if it rubs against a more abrasive material in motion, the former will be worn whereas the latter will face no wear. Jun 23, 2019 abradable coatings are a type of coating made using abradable substances. The main role of abradable coatings is to allow an automatic adjustment in clearance to accommodate thermal scenarios or physical interaction events when a device is operating.
Abradable coatings development and validation testing for. Pdf the aim of this work was to characterise the microstructure of recently developed abradable materials for providing a sealing between. Effect of simulated high hydrogen content combustion. The sensitivity of abradable coating residual stresses to varying material properties r. Thermal spray abradable materials for clearance control. There are a number of different abradable coating types, to cater for different operating temperatures, corrosive environments and mating materials. As the perfect skirt shape is approached, the oil film develops uniform loading across an enlarged contact area, and. The clearance between the blades and casing should be as. Candidate coatings were evaluated as abradable coatings used in gas turbine labyrinth seals. Surface and coatings technology, elsevier, 2007, 202, pp.
Modeling of abradable coating removal in aircraft engines. These coatings are designed to exhibit controlled removal of material in thin layers when the turbine blades sweep through the coating, which protects the mechanical integrity of the turbine blade. Thermal conductivity of alsipolyester abradable coatings. Abradable materials are widely used as a coating within compressor and turbine stages of modern aircraft engines in order to reduce operating.
Abradable materials were evaluated for the highpressure radial compressor and the axial high. Abradable thermal spray applications and technology thermal. An abradable coating is a coating made of an abradable material meaning if it rubs against a more abrasive material in motion, the former will be worn whereas the latter will face no wear abradable coatings are used in aircraft jet engines in the compressor and turbine sections where a minimal clearance is needed between the blade tips and the casing. Phenomenological modeling of abradable wear in turbomachines. Such thermal spray coatings are used extensively within the gas turbine, applied to the inner surface of. Abradability, erosion and steam oxidation tests were conducted on commercial and experimental abradable coatings in order to evaluate their suitability for applications in steam turbines. Timemarching strategies where the abradable removal is modeled through plasticity are available but another angle of attack is proposed in this work.
The proposed algorithms embedding unilateral contact conditions together with abradable coating removal are subsequently introduced and validated through a systematic analysis of 1 the nonlinear. Dear all i encounter a abradable coating failuresome top coating peeled off but didnt know why, please see attachment. Improvements in abradable coatings require various tests, extending from powder fabrication up to choosing the maximum thermal spray procedure. Thermal spray abradable coatings have low structural integrity so they are readily abraded when they come into contact with a moving surface with higher structural integrity. All prepared samples were ground using a manual polishing ma. Nov 20, 2015 save some money by coating your pistons with abradable powder coatings rescue me. As the gasturbine blades rotate at 300010,000 rpm and higher during operation, rotating blade tips may rub the stationary casing, due to either thermal expansion, misalignment or rotationinduced strains. Whether for aviation gas turbines, or power generation gas or steam turbines, we have abradable materials for your clearance control applications. Overview of sulzer metco compressor and turbine abradable technology scott wilson 8th international charles parsons turbine conference 05 sep 2011 08 sep 2011, university of. Pdf freestanding abradable coating manufacture and tensile test. Applying abradable coating on the casing of turbomachines has been widely recognized as a robust solution advantageously combining the adjustment of operating clearances with the reduction of potential nonrepairable damages. Pdf improvement of thermally sprayed abradable coating by. Pdf thermal conductivity of alsipolyester abradable.
Us5434210a thermal spray powders for abradable coatings. Save some money by coating your pistons with abradable powder. The part had an abradable coating the removal of which signified that replacement was necessary. First, the high porosity of the abradable coating was carefully characterised in order to. Abradable coatings increase gas turbine engine efficiency. The effects of the degree of melting of the sprayed particles, which depends on. Freestanding abradable coating manufacture and tensile test. Thermal spray abradable materials for clearance control coatings abradable coating solutions improve safety and reduce fuel consumption and emissions in turbomachinery. Abradable polymer labyrinth seals flyer quadrant plastics. Jan 25, 2014 the oem and vac aero agreed to work cooperatively to develop an improved abradable coating for these applications. This results in abradable coating recognition by engine manufacturers. Introduction to abradable powder coatings distribution, quotations and duplications in any form is only permitted upon prior written consent of line2line, inc. Highefficiency gas turbines require hightemperature sealing by use of abradable porous ceramic coatings to increase engine efficiency. All of these are done in order to simulate field trials and laboratory testing.
When we refer to the abradability of a coating, we are talking about its wear resistance in comparison to a more abrasive material that rubs against that coating. Very porous with many unreacted or unmelted particles which would by normal standards be considered as a very poor coating produced by very careful. Abradable coatings have long been used by aircraft engine manufacturers as sacrificial. Thermally sprayed abradable coating technology for sealing. It describes two families of coatings which have evolved for use at higher temperature.
Accepted practice for nicralbentonite abradable coatings. September learn how and when to remove this template message. L2l needs your finished bore sizes fbs, the manufacturers recommended piston to wall clearance rpwc, and the target coating thickness tct. The first half of this work performs an experimental validation of how the thz signal variation is affected by the porous abradable top coat. When sliding over the surface of an abradable, the blade tip strikes the coating particles which are protruding from the surface of the coating. The microstructure is essentially a composite material consisting of an alsi metal matrix, containing a solid lubricant phase of hbn hexagonal boron nitride bound to the matrix using an organic adhesive. Investigation of abradable seal coating performance using scratch testing. The main role of abradable coatings is to allow an automatic adjustment in clearance to accommodate thermal scenarios or physical interaction events when a device is. Investigation of abradable seal coating performance using scratch testing xiao ma, allan matthews to cite this version. Abradable polymer labyrinth seals quadrant plastics. Abradable coating an overview sciencedirect topics.
Tribological behaviour of wearresistant and abradable plasma sprayed coatings applied to aeroengines proc. It is assumed that the removal of abradable liners shares similarities with machine tool chatter encountered in manufacturing. Thermal spray abradable materials for clearance control coatings. The various applications of the coatings require different levels of porosity, from an optimized minimum level up to 50% in abradable coatings matejicek et al. Thermal spraying, optimization and characterization of. The use of thermal spray technology has revolutionised turbomachinery sealing tech nology by being able to tailor design abradable thermal spray powders and. Overview of sulzer metco compressor and turbine abradable technology scott wilson 8th international charles parsons turbine conference 05 sep 2011 08 sep 2011, university of portsmouth, portsmouth, uk. Aug 23, 2001 a good abradable accommodates different wear mechanisms created by changing rub conditions, namely blade material, temperature, blade tip velocity and incursion rate. Overview of sulzer metco compressor and turbine abradable. Abradable seal coatings are engineered to minimise the clearance between blade tips and casing to enhance gasturbine performance. Various lowtemperature abradable coatings for applications reaching 482c were evaluated with the purpose of being applied onto the compressor spacers of an 11 mw landbased gas turbine engine. The sensitivity of abradable coating residual stresses to. Microstructure and properties of porous abradable alumina.
The information and opinions in this report were prepared by line2line, inc. Method of producing a profiled abradable coating on a substrate in which an abradable ceramic coating composition is applied to a substrate using directwrite technology, or plasma sprayed onto the substrate through a mask or by use of a narrow footprint plasma gun. Investigation of abradable seal coating performance using. Accepted practice nicralbentonite abradable coatings. Thermally sprayed abradable seals have been used in the compressor section of jet engines since the late 1960s. Steam oxidation tests were carried out on freestanding top coat samples as well as coating systems consisting of a bond and an abradable top coat. Application of abradable seal to improve compressor. Abradable coatings are used in aircraft jet engines in the compressor and turbine sections where a minimal clearance is needed between the blade tips and. Abradable coating when we refer to the abradability of a coating, we are talking about its wear resistance in comparison to a more abrasive material that rubs against that coating. Thermally sprayed abradable coating technology for. Materials normally used in sacrificial coatings for gas path seals include sintered metalpowder segments, sintered metalfiber segments, metallic honeycomb filled and unfilled, elastomers and thermally sprayed abradable coatings. Abradable coating bond strength if the crosshead speed of the tensile test is faster than it needs to be then that condition may be occuring. Please enter or choose at least one search criteria to display out special repairs. Abradable powder coatings apc, also known as additive abradable powder coatings aapcs, are a class of abradable materials that are applied using standard powder coating technology.
Abradable polymer labyrinth seals deformation under load coef. Do not alter metal to metal clearances to accommodate apc. Abradable coatings formed by thermal spraying the powders abrade readily to form abradable seals. Using abradable powder coatingstm line2line coatings. Abradable coatings for lowtemperature applications thermal. They are used for clearance control, sealing and lubrication over a wide range of temperatures in oiled and dry devices. Thermally sprayed abradable coating technology for sealing in. An adhoc model was developed to correlate the signal amplitude variations in an experimental cscan image with the density of voids over slices of the abradable coating. Thanks to recent innovations in coating technology, its now possible to coat a piston instead of replacing it.
Alsi coating, which contains no additional secondary filler, only showed acceptable. Pdf on nov 1, 2015, yazid fizi and others published modeling of the mechanical behaviour of abradable coatings for the aeronautical. Air plasma sprayed aps abradable coatings are used in the turbine hot section to reduce the statorrotor gap, minimizing gas leakage. Numerical simulation of toolabradable material interaction. Abradable material is applied to the inside surface of the compressor and turbine shroud sections using thermal spray methods, coating the periphery of the. Thermal spray powders are characterized by the presence of a matrixforming component, a solid lubricant component and a plastic component.
Abradable coatings used for gas path seals in turbine engines. This article provides an overview of key abradable thermal spray coating systems based on predominant function and key design criteria. Thus, the modeling of this material is a growing field of investigation. The influence of composition and microstructure on the. Modelling route for abradable coatings request pdf.
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