1、整理9FA燃气轮机压气机叶片断裂典型案例Failure of 9FA Gas Turbine Compressor A Unique Experience.9FA燃气轮机压气机叶片断裂-一个典型案例Dhabol power project of RGPPL, a Joint Venture of NTPC,GAIL & MSEB, consist of 6 numbers of GE make gas turbines and 3 number of GE make steam turbines with module configuration of 2 GT + 1 ST. Hence,
2、there are 3 module and known as block -I, block -II and block -III. RGPPL电厂,印度国家电力集团的合资企业,有GE制造的6台燃机和3台汽机,采用2拖1的模式,三台机组分别称为I、II、III机组。Though there are 6 numbers of GE make gas turbines but all 6 gas turbines are not identical so far the capacity, TIT and heat rate are concerned. As per the data avai
3、lable at site and Tractable (Consultant to Indian lenders) report, the gas turbine of block -I is suppose to be PG 9331 and gas turbine of block -II and block-III are PG 9351 version. As per GE technical literature PG 9331 is known as 9FA+ and PG 9351 is known as 9FA+e model. From the technical lite
4、rature available in internet, the technical specifications of 9FA+ & 9FA+e are as follows: 尽管有6台GE公司的燃机，但是到目前为止6台燃机的容量、透平入口温度、机组效率等不一致，根据机组收集的有用数据和印度的相关报告，I机组的燃机型号为PG9331，II、III机组的燃机型号为PG 9351。按照GE的技术通报文件PG9331称为9FA+，PG 9351称为9FA+e，从GE官方网站获取的9FA+和9FA+e参数如下：It can be seen from the technical specifica
5、tions mentioned above in the table that technically there is substantial difference between PG 9351 and PG 9331. Though Block-II and Block-III gas turbines of Dabhol Power Project are suppose to be PG 9351 but due to failure of compressor of GT 2B and failure of tie rod of GT#3A, gas turbine rotor o
6、f GT#2B has been replaced with spare refurbished rotor of block -I and GT#3A rotor has been replaced with GT-1B/1A used rotor. Therefore, with the present configuration, block -II and block-III consists of one GT of PG 9351 and one GT of PG 9331 version. 从上表所述的关于PG 9351 和PG 9331的不同点已很详细。尽管II、III机组为P
7、G9351燃机，但由于发生了压气机事故的为GT#2B和GT#3A的拉杆，燃机GT#2B转子更换为I机组的备用转子，GT#3A转子更换为GT-1B/1A使用过的转子。因此，目前的配置情况是，II和III燃机由PG 9351和PG 9331混合组成。The entire plant has been revived by GE experts and under their supervision. Not only this, before starting revival activities, GE carried out condition assessment of all 6 Gas
8、Turbines and based on assessment result GE recommended spares to be replaced for healthy running of the plant and all the spares recommended by GE have been replaced during the restoration of respective Gas Turbine. 整个计划在GE专家的领导和监督之下完成。除了这些，在检修完成之后再次启动前，GE对6台燃机进行了状态评估，根据评估结果，GE建议为了设备的健康运行对备品按计划进行更换，
9、因此，机组再次启动前对所有GE建议的备件进行了更换。But in-spite of this, RGPPL Dabhol has faced three catastrophic failure of 9 FA Gas Turbine Compressor with in a span of two years. And all three failures are of same nature that is High Cycle Fatigue. 但是让RGPPL电厂恼怒的是在两年之内发生了三起9FA压气机事故，三起压气机事故均是由于高周疲劳引起。It started with the f
10、ailure of GT#2B on 05th Jan-2007, GT#2A on 19th Jan-2008 and GT#3A on 8th Nov-2008. And failure of GT#3B avoided due to premature unscheduled inspection. GT#2B发生压气机事故的时间是2007年1月5日，GT#2A是2008年1月19日，GT#3A是2008年11月8日，GT#3B避免发生类似的事故是因为进行了之前未计划的检查。In all three happenings, machines were running absolutely
11、 normal. In-spite of all normal running parameters, stable grid frequency and at steady load, all on a sudden , Gas Turbines have tripped on Hi-Vibration Protection on auto with very high sound, Abnormal sound was coming from the compressor side and rotor stopped rotating did not come on turning gea
12、r. On cooling, Compressor rotor inspected from compressor IGV end and damage of compressor moving blades & vanes observed. 在发生的三起事故前机组运行完全正常，运行时无任何异常参数的变化、电网频率稳定、机组负荷稳定，然而出乎意料的是，机组轴振高保护跳闸，现场明显听见高分贝的声音，异音从压气机侧开始直至转子转速到零盘车投入。在盘车期间，压气机转子检查从IGV末端、损坏的压气机动叶和静叶进行观察。Compressor SectionOn opening the compress
13、or mid casing (Stage 2 to 12) upper half, catastrophic failure of Compressor Moving & Stationary blades from Row #2 to Last Stage in case of GT#2A& 3A and from R3 to Last Stage in case of GT#2B observed. The failure is so massive that failed moving & stationary blades have got melted and molten meta
14、llic debris(slag) deposited on compressor outlet area, air extraction lines and in blades/vanes cooling air duct as well as on entire the casing inner surface in case of GT#2A& 3A.压气机部分当打开压气机中缸上半部分时（第2至12级），GT#2A& 3A压气机动叶和静叶的灾难性事故从动叶和静叶第2列（R1、S1）到末级，GT#2B从R3到末级叶片。压气机动叶和静叶的损坏是巨大的，压气机出口区域聚集了大量熔化的金属碎屑，
15、GT#2A& 3A事故中压气机抽气管道和动/静叶片的冷却空气通道同样堆积了大量熔化的金属碎屑。损坏的叶片附在压气机上大量熔化的金属碎屑On close observation, it is found that the failures are due to impact and on further examining it has been found that all moving Blades and stationary vanes failed from root and all failed surface are so badly deformed that it is ver
16、y difficult to identify the primary failed blade. In case of GT#2A, on further observation, it was noticed that 2 nos. of moving blade of Row#2 failed from the platform but the failure pattern are different from the rest. Out of this two moving blades of row#2, one has failed from just above the pla
17、tform and one piece has failed 5-8 mm below the platform and failed surfaces were found to be less deformed. Similarly in case of GT#3A, 8 nos. of moving blades of row#2, have failed 5-8 mm below the platform and failed surfaces were found to be less deformed. But in case of GT#2B, one no. of moving
18、 blades of row#3, one has failed from just above the platform. 继续观察发现，损坏的叶片受严重的冲击影响，进一步的检查发现所有的动叶和静叶从根部断裂，所有损坏的叶片表面已经严重变形以至于难以辨认叶片断裂的根源。在GT#2A事故中，进一步的检查发现动叶第二列（R1）的2号叶片从叶台断裂，这种断裂形式跟剩余的叶片完全不同。从R1的两片动叶发现,一片刚好在叶台上部断裂，令一片在叶台往下5-8mm断裂，同时在这些断裂的叶片表面发现少许的变形。类似的出现于GT#3A 的动叶第二列（R1）的8号叶片，在叶台往下5-8mm处断裂，同时在这些断裂的
19、叶片表面发现少许的变形。但是GT#2B事故中的动叶第三列（R2），一片叶片刚好在叶台上部断裂。Gas Turbine冷却通道堵塞On opening the Turbine casing no major physical damage was found in the moving blade/ Vanes. But very huge metallic molten debris found in the cooling passage of vanes & blades of row#1 & Row#2. This is due the fact that the cooling air
20、 is extracted from the discharge of compressor and with the damage of compressor blades & vanes, very fine debris, have been carried by the cooling air, have entered in to cooling passages of blades and vanes and got deposited. 燃机透平打开燃机透平外壳后透平动叶/静叶未发现有明显的机械损伤，但是在第一级静叶、第一级动叶和第二级静叶、第二级动叶的冷却通道发现了非常多的金属
21、碎屑。这些碎屑来源于压气机排气的冷却空气，当压气机叶片断裂发生后，很多极细的碎屑随着冷却空气被带入透平动叶和静叶的冷却空气通道堆积堵塞。Root Cause Analysis of FailuresOn visual inspection of failed surface and material flow on the damage surface of the moving blades & vanes, it appeared that the blades and vanes of the compressor have failed due to impact. For impac
22、t failure, the components have to be hit with an object. The object may come from out side and hit the component causing damage to the components and this type of damage is popularly known as Foreign Object damage (FOD). Or the object may be generated within the turbine and may hit the component cau
23、sing damage to the components and this type of damage is known as Domestic Object damage (DOD). This is most common type of failure in gas turbine and takes place due to premature failure of gas turbine components. As mentioned above that the failure is due to impact and for impact failure, the mate
24、rial is to be hit by an object and this object may be external or internal, hence further investigation done on each and every stages of moving and stationary blades of compressor to identify the source of object. 叶片断裂根本原因分析基于叶片断裂表面的目视检查和出现在断裂叶片表面的物料，表明压气机叶片的断裂是受到了严重冲击。对于叶片断裂的冲击，部件必须受到目标的击打。击打目标可能来自
25、压气机外部，外物击打部件造成的损伤通常被称为外物损伤。也可能来源于压气机内部，内部击打部件造成的损伤通常被称为内部损伤。这两个是造成压气机损坏的常见原因，通常会造成压气机部件过早失效。综上所述，叶片断裂常常是由于发生冲击和受到击打，叶片受到击打的源头可能是外部或内部目标，因此下一步的调查主要是针对压气机动叶和静叶的每一级、每一片叶片寻找断裂的源头。Damage due to Foreign Object If the damage was due to foreign object, then the material has to travel from out side the Gas T
26、urbine, and it has to be entered in to the Gas turbine Compressor through Compressor inlet air plenum air flow path only. 外物击打损伤假设压气机损坏是由于外物的击打，那么，击打物肯定是从外部跟随气流进入压气机，当然，击打物要想进入压气机只有从压气机入口这一条路径进入。If the material entered through this path, then the object should have hit the IGV and 1st row i.e. R0 of
27、 compressor moving & stationary blades and those components would have damaged. But in all cases the IGV, Compressor moving blades of row#0 and stationary vanes of row#0 have been found to be OK(minute dent mark at trailing edge). FOD damage can not start from intermediate stage, hence the damage of
28、 compressor moving blades and vanes can not be due to the FOD. 如果外物沿着压气机入口进入，那么，击打应该从IGV和第一列开始，也就是压气机动叶和静叶第一列（R0、S0）这些部件也应损坏。但是在三起事故中，IGV、R0、S0均检查正常。外物击打不可能从中间级开始，因此，排除了压气机动叶和静叶损坏的外物击打可能性。Damage due to Domestic Object As the probability of damage due to FOD has already been ruled out therefore, the
29、damage has to be due to DOD, in order to find the source of Domestic Object, when the compressor mid casing was opened, it was found that all most all moving & stationary blades have failed from the root just above platform with massive deformations and failed surface are totally distorted (clockwis
30、e). Therefore, though a nos. of moving & stationary blades have failed still question arises which has/have failed first and whether they have failed of their own (due to any reason) or they have also been hit by an object and this object has be generated with in compressor. Now Domestic Object will
31、 generate only because of any one or combination of the following:内部击打损坏在排除了外物击打损坏的可能性后，压气机损坏事故只有内部击打导致了，为了寻找击打的源头，当压气机中压缸打开时发现大部分的动叶和静叶由于巨大的变形从叶台根部断裂，断裂的叶片表面已经完全变形（顺时针方向）。因此，尽管一系列动叶和静叶已损坏，问题的关键是哪一片是第一片断裂的叶片，不论是这些断裂叶片中的一片还是被击打导致叶片断裂，但这些击打物都是来自压气机。因此，击打物通常是已断裂叶片中的任何一片或者以下的一些组合：1. Something left durin
32、g last inspection 2. Failure of fixing material and hitting the other components 3. Dislodging of metallic piece from stationary blade and hitting the other components. 4. Dislodging of metallic piece from moving blades and hitting the other components. 5. Dislodging of metallic piece from moving and stationary blades and hitting the other components. In order to find the root cause, the factors mentioned above, theory of elimination have been applied to come to the final cause of failure. 1、上一次检查时遗留在压气机内部的物品。2、压气机的固定部件脱落击中了其他部件。3、压气机静叶中含金属物质的部件掉块击打了其他部件。4、压气机动叶中含金属物质的部
