Based on eulerianlagrangian method and finnie rebound model, the urgent spe. Our study was performed on the real turbine blade worked in the industry. Study of solid particle erosion behaviour of ss 304 at room. Failures due to untimely valve maintenance include. Standard test method for conducting erosion tests by solid particle impingement using gas jets this standard is under the jurisdiction of astm committee g02 on wear and erosion and is the responsibility of subcommittee g02.
Based on the erosion rate models and the particle rebound models of blade materials obtained through the accelerated erosion test under high temperature. Article information, pdf download for mechanisms of steam turbine. Research on characteristics of solid particle erosion in. Therefore, they have been protected by the surface treatments such as ion nitriding, boriding and chrome carbide high velocity oxygen fuel hvof spray.
Solid particle erosion of steam path surfaces is a major concern in steam turbines. D106618e1 standard practice for sampling steam steam boilers saturated steam steam purity superheated steam. Water droplet erosion is one of major concerns in the design of modern large fossil steam turbines because it causes serious operational problems such as performance degradation and reduction of service life. Erosion prediction in turbomachinery resulting from. Solid particle erosion moisture erosion steam path deposits foreign object damage ges efficiency upgrades usually consist of sealing improvements and highperformance steam path components that recover the degradations, leading to an improved efficiency up to 16% and significantly extending the turbine. The influence of nozzle chamber structure and partialarc admission on the erosion characteristics of solid particles in the control stage of a supercritical steam turbine energy, vol.
In the gas turbines compressor, fines and particle ingestion damage is mostly related to fouling buildup of solid matter on the blades and erosion. The particle trajectories and the erosion regions were discussed. From individual components to turbine subsystems or total machine redesigns. Erosion, and in some cases, failure of the valve stems due to solid particle erosion failures of the main steam stop valve screen or strainer. Solid iron oxides particles formed on the surfaces of boiler tubes and steam pipes. Oct 05, 1993 the present invention relates to apparatus and methods for minimizing or eliminating solid particle erosion damage in doubleflow steam turbines and particularly relates to apparatus and methods for eliminating or minimizing such damage in the reheat tubs of doubleflow steam turbines by providing additional axial setback of the firststage. Reducing the solid particle erosion of blades is crucial to increasing the. Analysis on solid particle erosion in the governing stage of. Although several factors influence the formation of deposits on turbine components, the general. Solid particle erosion in the reheat stage seriously affects the safe and economic operation of the steam turbine. Schematic for the water droplet formation, which leads to erosion in steam turbines 8.
Other apparatus and methods for minimizing or eliminating solid particle erosion in steam turbines include solid particle erosion resistant coatings such as disclosed in u. This builds up, spalls and travels along with the steam causing erosion in areas where steam velocities are the highest. Oct 11, 1988 this invention relates to reducing solid particle erosion hereinafter spe in axial flow fluid turbines, such as steam turbines, and more particularly, to reducing erosion of the trailing, or downstream, edge of stationary spaced apart nozzle partitions, which are used to define passageways, or nozzles, therebetween for directing steam flow. Solid particle erosion moisture erosion steam path deposits foreign object damage ges efficiency upgrades usually consist of sealing improvements and highperformance steam path components that recover the degradations, leading to an improved efficiency up. Solid particle erosion in some cases, spe is a useful phenomenon, as in sandblasting and high speed abrasive waterjet cutting, but it is a serious problem in many. Us2111878a means for draining moisture from steam in steam. Solidparticle erosion and protective layers for steam. Erosion resistant coatings for turbine blade applications initial results are available from eprifunded research to evaluate potential coatings to combat solid particle erosion and liquid droplet erosion of steam and gas turbine blades. Apparatus and methods for minimizing or eliminating solid. The unit turbine at abc plant has experienced solid particle erosion spe which has increased the. On the base of the original geometry of the outlet channel of nozzle box, four different geometry of the outlet channel were constructed. Improving the capacity or output of a steam turbine. Solid particle erosion spe damage can be found on steam turbine stages. Prior to supplying steam to the turbine, the steam supply pipelines have to be drained and heated up.
Solid particle erosion in some cases, spe is a useful phenomenon, as in sandblasting and high speed abrasive waterjet cutting, but it is a serious problem in many engineering systems, including steam and gas turbines. The solid particle erosion on the control stage nozzle of supercritical steam turbines can be reduced by using suitable nozzle passage design to control the particle impacting velocity and impacting angle. Jan 04, 2007 the solid particle erosion on the control stage nozzle of supercritical steam turbines can be reduced by using suitable nozzle passage design to control the particle impacting velocity and impacting angle. To restore aging industrial steam turbines to modern standardseven after 20 to 40 years of operation ges industrial steam turbines team developed engineered advanced technology component packages that can be adapted to your specific plant needs. Reduce solid particle erosion in nuclear power plants the elimination of stress cracking in lp steam turbines is a major reason for upgrading. Performance deterioration of the governing stage nozzle. Solid particle impact erosion has been receiving increasing attention. Solid particle erosion in the reheat stage of the steam turbine. The technological approach to erosion testing is discussed.
Solid particle erosion in a steam turbine is minimized by diverting through holes in appendages of outer rings of the diaphragms, a portion of the steam from the steam flow path thereby bypassing downstream rotating components. Although the erosion resistance of nozzle is improved by the use of protective coatings, the developing of the blade material and the design of antisolid particle erosion spe steam passage, the decline of the unit efficiency caused by the eroded nozzle still very serious. Some examples of solid particle erosion in the gas turbine. This led to a steam path that not only is more efficient but also has a greater, sustained efficiency. Erosionresistant coatings for turbine blade applications initial results are available from eprifunded research to evaluate potential coatings to combat solid particle erosion and liquid droplet erosion of steam and gas turbine blades. In this chapter, evolution of thermal sprayed coating, erosion testin. Turbine bucket and nozzle materials are damaged by the solid particles within usc steam conditions. The strainer is exposed to large pressure drops when clogged, i. May 22, 2012 influence of valve governing mode on solid particle erosion and efficiency in governing stage of steam turbine energy, vol.
This is mainly due to the formation of magnetite on the inside of boiler tubes. Keywords erosion, life extension, main stop valve, numerical simulation, solid particles trajectories, steam turbine solid particle erosion spe of steam turbine components, such as nozzles, blades, radial spillstrips, and control valves, has been a problem of concern to utilities for several years as. The results have been published in an epri report entitled program on technology. The effects of surface treatments on solid particle erosion. Combating of the solid particle erosion in a steam. Analysis on solid particle erosion in the governing stage. The influence of the spe on the rotor due to the notch eroded was. In the solid particle erosion test in which materials were evaluated based on mass loss, for example, balinit turbine pro demonstrated more than five times higher erosion protection than other pvd coatings, including titanium nitride tin. In this paper, two nozzle designs with tip endwall contouringan aftloaded vane profile respectively are presented. This invention relates to reducing solid particle erosion hereinafter spe in axial flow fluid turbines, such as steam turbines, and more particularly, to reducing erosion of the trailing, or downstream, edge of stationary spaced apart nozzle partitions, which are used to define passageways, or nozzles, therebetween for directing steam flow. Solid particle erosion in electric power plants springerlink. Improvement of service life of turbine blade in wet region ts002 pdf 218kb improvement of drain erosion resistance for last stage blade te009 pdf 238kb repair of damaged rotor journal portion cts025 pdf 485kb 1st stage nozzle.
Erosion and corrosion resistant coatings also will be investigated. Steam turbine problems and their field monitoring jonas inc. But solid particle erosion spe, water droplet erosion wde, corrosion and fouling degrade performance, trigger outages. The solid particle erosion spe of flow passage is a universal problem in modern highparameter steam turbines. Influence of solid particle erosion spe on safety and. Sep 20, 2016 solid particle erosion spe damage can be found on steam turbine stages. New features of solid particle erosion damage of control stage blades in supercritical steam turbine liuxi cai, jingru mao, shunsen wang, and zhenping feng proceedings of the institution of mechanical engineers, part a. Steam turbine upgrades improve reliability power engineering. Applying numerical cfd simulations excessive solid particle erosion damage of the blades tenons, wheel filets, rotor labyrinth seals and main stop valves were studied and steam solid particles flow conditions which play a main role in the erosion process determined. New features of solid particle erosion damage of control.
Chapter 18 steam turbine deposition, erosion, and corrosion. Numerical modeling of wet steam flow in steam turbine. With the continuous improvement of the working parameters of the steam turbine, the problem of spe is becoming more serious. A solid particle of a given density and size that is carried by the flow in a compressor or turbine ideally follows the flow streamline and should never impact with any statorsrotor blades or walls. The present invention relates to apparatus and methods for minimizing or eliminating solid particle erosion damage in doubleflow steam turbines and particularly relates to apparatus and methods for eliminating or minimizing such damage in the reheat tubs of doubleflow steam turbines by providing additional axial setback of the firststage. Volume 2, issue 10, april 20 mechanism, characterization. Solid particle erosion of thermal sprayed coatings. Study of solid particle erosion behaviour of ss 304 at. Reducing solid particle erosion on steam turbine stages turbo. Solid particle erosion of blades 10 93 hiope solid particle erosion valve body in the boiler blowdown system. In case of turbines with cooling water preheating and lowpressure lp bypass, prior to supplying steam the regeneration and dumping systems have to be. There are two kinds of erosion in steam turbines, one is the solid particle erosion that occurs at the inlet stage of the steam turbine, and the other is the waterdroplet erosion that occurs in the latter stages of the lowpressure turbine where moving blades are operated in a wet steam region.
Erosion is one of the major problems in many engineering system including power generation units, steam jet turbines, chemical processing equipments, and air craft engines. In this paper, tensile stress distribution in the surface of highparameter steam turbine blade anti erosion boride coatings under single particle impact was investigated using a nonlinear finite. Solid particle erosion analysis and protection design for. Us2111878a means for draining moisture from steam in. Close tolerances in the turbines, the use of highstrength steels, and impure steam all contribute to these conditions.
One of the particular serious consequences resulting from the presence of liquid in steam turbines is blad e erosion. At present, repairing or replacing the eroded nozzle is not easy due to the limits of the maintenance period. Reducing solid particle erosion on steam turbine stages. Means and method for reducing solid particle erosion in turbines. Steam turbines in both process industries and power generation experience both solid particle and water droplet erosion in service. Erosion was found to be one of the reasons for such failure. In the present study erosion test were conducted using airjet erosion test rig on boiler tube steel ss 304. Although various methods of coating are tried and used for protection against erosion, thermal sprayed coating for such purpose is the most widely used method. Numerical modeling of wet steam flow in steam turbine channel. The effects of surface treatments on solid particle. Round robin conducted in 1982 formed basis for current. Improving the capacity or output of a steam turbine generator.
Round robin conducted in 1982 formed basis for current standard test method. Astm d1066 18e1 standard practice for sampling steam. Combating of the solid particle erosion in a steam turbines. Aug 17, 2017 the solid particle erosion spe of flow passage is a universal problem in modern highparameter steam turbines.
When the steam turbine used for long time, the steam path is deteriorated, and both output and efficiency of the turbine will decrease. Development of a water droplet erosion model for large steam. Furthermore, anti erosion performances of these two nozzles for a. The present study aims to make clear the relations between nozzle loss and surface degradation, aerodynamic parameters, as well as the shape, location, and size of the. Numerical study of erosion due to solid particles in steam turbine. Based on the erosion rate model and particle rebound model of blade materials obtained through accelerated erosion test under high temperature, erosion characteristics of flaky particles in control stage of a typical supercritical steam turbine were. Solid particle erosion is an important material degradation mechanism. Redesign of a steam strainer division of solid mechanics. It is well known that in steam turbines, and especially in the low pressure stages thereof, part of the steam is condensed and that the water of condensation thus formed has a deteriorating action on the blades.
These solid particles are caused by the exfoliation of iron oxides formed on the inner surfaces of both boiler tubes and steam pipes which are exposed to elevated temperature. The sources of impurities in the steam can include boiler water carryover. Steam turbine materials for ultra supercritical coal power. Nozzle passage aerodynamic design to reduce solid particle erosion of a supercritical steam turbine control. Solid particle erosion on shield surface of a helicopter rotor blade using computational fluid dynamics.
Influence of solid particle erosion spe on safety and economy of steam turbines author links open overlay panel lihua cao chaoyu tu pengfei hu shuang liu show more. In their case study for turbine failure at dresden power plant. This protects the stem from high velocity steam containing erosive solid particles. In some cases solid particle erosion is a useful phenomenon, as in sandblasting and highspeed abrasive water jet cutting, but it is a serious problem in many engineering systems, including steam and jet turbines, pipelines and valves carrying particulate matter. Pvd coatings extend life of igt and steam turbine components. Successful operations rely upon continuous, peak efficiency service from their steam turbines. Using the eulerlagrange method, the flow characteristics of solid particles in the five different channels were numerical simulated. Boiler blowdown in order to limit the concentration of solids in boiler water, some of the concentrated boiler water is discharged blowdown and replaced with feedwater having lower solids. Reducing solid particle erosion of blades is one of the most urgent problems for highparameter steam turbine power generation technology. Development of a water droplet erosion model for large. This invention relates to means for draining moisture from steam in steam turbines. Solid particle erosion and mechanical damage free download as. In their case study for turbine failure at dresden power plant, chynoweth et al 20 performed a root cause analysis for observed lp blade failures.
Erosion and deposition in turbomachinery journal of. Furthermore, antierosion performances of these two nozzles for a. Erosionresistant coatings for turbine blade applications. Coupled with the supply of a solid rotor elimination of the rotor bore, the sustained efficiency results in a turbine section that should not require internal repair or inspection for ten or more years. Erosion is one of the major problems in many engineering system including power generation units, steamjet turbines, chemical processing equipments, and air craft engines. In this paper, tensile stress distribution in the surface of highparameter steam turbine blade antierosion boride coatings under single particle impact was investigated using a nonlinear finite. Improvement of the turbine main stop valves with flow. Turbine losses 5 116 hiope the nozzle and bucket profiles have been manufactured with a specified surface finish and with strict tolerance. Solid particle erosion spe of governing stage has been proved to be great threat to steam turbine per formance. The solid particles interaction parameters entrained in steam flow vary in a wide range azevedo, 2009. Application of diffusion treatment against solid particle.
Objective the overall objective of this project is to contribute to the development of materials technology for use in power plant steam turbines capable of operating in pcfired. The solid particle erosion on the control stage nozzle of supercritical steam turbines can be reduced by using suitable nozzle passage design to control the particle impacting velocity and. In this study, we want to identify different areas caused by particle impact erosion and also express a permanent impression using experimental method. This article presents a numerical study of solid particle erosion spe on the nozzle of the first stage steam turbine.
Reducing the solid particle erosion spe of blades is one of the most important problems for highparameter steam turbine. In this chapter, solid particle erosion will be discussed. In the present study erosion test were conducted using airjet erosion test rig on. Solid particle erosion and mechanical damage turbine erosion. These particles and objects will cause solid particle erosion in the actual turbine if they pass by. Influence of solid particle erosion spe on safety and economy of. Other systems in which liquid droplets of substantial size may impact material surfaces causing damage are also subject to erosive attack, an example would be a fuel injection device. Solid particle erosion in the reheat stage of the steam. The development of modern, highefficiency steam turbines has led to an increase in deposition, erosion, and corrosion problems. Us7296964b2 apparatus and methods for minimizing solid. Erosion due to solid particle impact on the turbine blade. A new erosion model has been developed in the present study for the prediction of water droplet erosion of rotor blades operated in wet steam conditions.
Water droplet erosion of stainless steel steam turbine blades. However, the stellite protection eventually erodes, leaving the stem vulnerable to high velocity steam erosion. That value increased to more than 40x when compared to uncoated titanium and even more for steel. Mechanisms of steam turbine blade particle erosion and crucial. Analysis of solid particle surface impact behavior in. The hole through the first stage appendage lies in communication with a passage through a downstream outer ring of a following stage such that the diverted solid. An erosion model has been used to analyze the erosion behavior of cocr alloy coated steam turbine blades of composite material. They presented some causes and effects leading to the failure. The temperature of the steam in the turbines is increased in order to deliver more.
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