Abstract:
A defect in a splitter fairing of a turbine engine is repaired by removing a forward portion of the splitter fairing and salvaging the remaining original portion of the splitter fairing. The forward portion includes an inner flange and outer surface that create a channel. A replacement ring is provided and welded to the original portion. The replacement ring has minimum dimensions equal to the maximum height and width of the removed forward portion. Material from the replacement ring is then removed to obtain a profile with essentially the same profile for the inner flange, outer surface, and channel as the original dimensions of the splitter fairing before the defect occurred.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to the repair of turbine engine components, and in particular to the repair of the front portion of a splitter fairing section located at the front of the low pressure compressor. 
         [0002]    During operation of a turbine engine, the engine components can be damaged. Engine operating stresses frequently lead to fatigue cracks or similar defects in gas turbine engines parts. Repairs must be done to the defects caused during normal operation. One part that may require repair is the splitter fairing. The splitter fairing supports the first stage stators of the low pressure compressor. Particularly, the front hook section as an engagement groove for the airseal on the splitter fairing can become worn. The inner flange of the hook becomes damaged, and must be repaired so that the part can function as originally anticipated. 
         [0003]    Traditional repair techniques, such as weld build up or plasma coating of the groove, are difficult to perform. Also, such repairs impose a debit to the structural capability, which will produce a repair with properties inferior to the original part. Currently, there is no known repair for the splitter fairing of an engine that assures the part will be restored to serviceable condition and airworthiness standards. The entire part is replaced. Replacement is done to assure part integrity. However, the cost associated with replacement is large. What is absent in the art is a repair that eliminates the need for total part replacement. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    In one embodiment, a defect in a splitter fairing of a turbine engine is repaired. A forward portion of the splitter fairing, the forward portion comprising an inner flange and outer surface that create a channel, is removed. An original portion of the splitter fairing is salvaged. A replacement ring is welded to the original portion. Material from the replacement ring is removed to obtain a profile with essentially the same profile for the inner flange, outer surface, and channel as the original dimensions of the splitter fairing before the defect occurred. 
         [0005]    In another embodiment, a defect in a generally cylindrical component turbine engine component is repaired. The component is removed from the engine, and a generally hook-shaped forward portion of the component is removed. A replacement ring having minimum dimensions equal to the maximum height and width of the removed forward portion is welded to the original portion. Material from the replacement ring is removed to obtain a new hook-shaped forward portion with essentially the same profile as the generally hook-shaped forward portion of the component prior to the defect. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a cross-sectional view of a gas turbine engine. 
           [0007]      FIG. 2  is a perspective view of a splitter fairing of a turbine engine. 
           [0008]      FIG. 3  is a cross-sectional view of the splitter fairing taken along line  3 - 3  illustrated in  FIG. 2 . 
           [0009]      FIG. 4  is a perspective view of the splitter fairing with a front portion removed, along with a replacement ring. 
           [0010]      FIG. 5  is a cross-sectional view of the remaining portion of the front splitter fairing joined to the replacement ring. 
           [0011]      FIG. 6  is a cross-sectional view of the repaired portion of the splitter fairing ring. 
       
    
    
     DETAILED DESCRIPTION 
       [0012]      FIG. 1  is a cross-sectional view of a gas turbine engine  10 . Engine  10  has an inlet fan  12 , a compressor section  14 , a combustion section  16 , and a turbine section  18 . Compressor section  14  has a low pressure compressor  20  and a high pressure compressor  22 . Air is taken in through fan inlet  12  and a portion is directed to the compressor section  14 . The air is then compressed by a series of rotating blades and static vanes in the compressor section. The compressed air is mixed with fuel, and then ignited in the combustion section  16 . The combustion exhaust is then directed towards the turbine section  18 , which is also comprised of blades and vanes. The blades extract kinetic energy from the exhaust to turn a shaft  24 , which provides power output for the engine. 
         [0013]    After air enters the fan inlet  12 , splitter fairing  26  directs a portion to the low pressure compressor  20 . The rest of the air flows through a bypass duct  27 . The air from bypass duct  27  will be bled off through an opening  28  to be used for cooling the components of the high pressure compressor  22 , combustion section  16 , and turbine section  18 . 
         [0014]      FIG. 2  is a perspective view of splitter fairing  26  of a turbine engine  10 . Splitter fairing  26  is generally cylindrical or frustaconical in shape and includes a forward portion  30 , a body  32 , and an aft portion  34  containing several apertures  36 . Splitter fairing  26  is typically constructed from aluminum or similar light weight metal, including AL 6061. Splitter fairing  26  is a forged component of turbine engine  10 ; forging assures structural strength for the part. Splitter fairing  26  operates in an environment of minimally enhanced temperatures, typically operating at just slightly above ambient temperature. 
         [0015]    Forward portion  30  contains a front edge  38 , which is used to direct the flow of fluids. Front edge  38  is forged in an acute angle, and may contain a rounded fillet to facilitate smooth air flow. Aft portion  34  is used to connect the splitter fairing  26  to the inner casing of the turbine engine  10 . Apertures  36  are fastener holes for securing the splitter fairing  26  within the turbine engine  10 . 
         [0016]      FIG. 3  is a cross-sectional view of splitter fairing  26  taken along line  3 - 3  illustrated in  FIG. 2 . In this view, the aft portion  34  is illustrated as being thicker than the adjacent body  32 . The additional thickness provides support for the apertures  36 . Aperture  36  contains a hole  40  and a countersink  42 . Countersink  42  allows for placing a fastener into the aperture  36  while keeping a flush surface along the splitter fairing  26 . A smooth surface promotes fluid flow through the bypass duct  27 . Aft portion  34  also contains an inner surface  44  perpendicular to the hole  40 . 
         [0017]    Forward portion  30  has a hook shape with an inner flange  46  and an outer edge  48 . The space between the inner flange  46  and outer edge  48  is used to attach low pressure compressor components. Forward portion  30  has general dimensions of height h and width w. In the embodiment illustrated, an aft edge  50  of the inner flange  46  contains damage that must be remedied. 
         [0018]    To initiate the repair, the splitting fairing  26  is removed from turbine engine  10 . Forward portion  30  of the splitter fairing  26  is then removed along a line  49  by a process such as laser cutting or machining, or similar material removal methods known in the art. The cut is made along a line such as line  49 . The angle of the cut is derived from the geometry of a replacement piece that will be attached to the remaining portion of splitter fairing  26 . 
         [0019]      FIG. 4  is a perspective view of the splitter fairing  26  with the forward portion  30  removed, leaving an original portion  54 , which contains the majority of body  32  and aft portion  34  with the apertures  36 . Also illustrated is a replacement ring  56 . Replacement ring  56  is constructed from the same or similar material as the original portion  54 , such as AL 6061. Replacement ring may be a forged part. 
         [0020]      FIG. 5  is a cross-sectional view of the original portion  54  of splitter fairing  26  joined to replacement ring  56 . Replacement ring  56  has a height H and width W, which are greater than the dimensions h and w of the original forward portion  30 . Replacement ring  56  is welded to the original portion  54 . 
         [0021]      FIG. 6  is a cross-sectional view of a repaired forward portion  30  of the splitter fairing  26 . Replacement ring  56  has been machined down to obtain the original dimensions for the forward portion  30 , including the inner flange  46  and outer edge  48 . The machining also creates a channel  60  which allows for the attachment of low pressure compressor components to the splitter fairing  26 . Inner flange  46  contains a round fillet on aft edge  50 , which promotes fluid flow past the surface. 
         [0022]    To summarize the repair process, the splitter fairing  26  is removed from the turbine engine. The damage is located during regular maintenance and inspection of the engine. The damaged section forward section is removed by machining or a similar process. Measurements are taken and recorded for the average wall thickness, inner diameter, and overall axial height to cut-off. Material removal is kept to a minimum. The cut plane location illustrated in  FIG. 3  is placed to accommodate a second section replacement, should one be necessary in the future. 
         [0023]    Next, the fairing is cleaned and the surfaces are prepped for welding by machining the original portion to a bright metal condition. Measurements are taken and recorded for the average wall thickness, inner diameter, and overall axial height to cut-off. 
         [0024]    A locally manufactured replacement ring is fabricated. The replacement ring is welded to the original portion by a welding process such electron beam (EB) welding, plasma arc welding (PAW), or gas tungsten arc welding (GTAW). If the EB procedure is to be performed, the locally fabricated replacement ring is machined ensuring a proper EB joint fit-up of 0.003 inch maximum gap. Similarly, if PAW procedure is to be performed, the replacement ring is fabricated to ensure a proper PAW joint fit. If GTAW is performed, additional filler material may be required. 
         [0025]    The replacement ring is cleaned after machining, and nondestructive inspection, such as Fluorescent Penetrant Inspection (FPI) is performed on the replacement ring and original portion to assure no defects are present prior to welding. The weld is performed. After welding, a visual inspection of the weld joint is done to assess is any re-welding operations that must be performed. If re-welding is required, no more than 25% of the length of the weld should be redone. If more that 25% of the length required rewelding, the repair process should be started again. 
         [0026]    A further inspection is done after the initial visual inspection. 
         [0027]    Known nondestructive inspection (NDI) techniques, such as flourescent penetrant inspection (FPI), eddy current inspection, ultrasonic inspection and x ray inspection, etc. can be used. After inspection, the part is stress-relieved if needed. Also, heat treatment may be applied to the completed part. 
         [0028]    Next, the replacement ring and adjacent weld are machined to meet the original tolerances of the part. The machining assures incorporation of critical design features present in the original section of the part. The original hole and perpendicular edge can be used as datum points for determining the amount of material to remove. The attaching weld must be flush to 0.010 inch above adjacent parent material. The original surface treatment on the part is removed, and a new surface treatment is applied. The part is again cleaned. Finally, the part is measured to assure all dimensions are within tolerances. The part is then ultimately returned to the engine. 
         [0029]    The current repair will not degrade the fatigue life of the part, and thus the life of the part is renewed with the forward section replacement. The fatigue life of the repaired part with the replacement ring and original section is substantially restored to that of the original part. The repair eliminates the need for replacement with a new part, which is more costly that utilizing the aforementioned repair. 
         [0030]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.