Abstract:
An exemplary laser instrumentation bracket includes a support structure providing a recess configured to receive a collar of a laser housing. The laser housing has a main body extending axially through an aperture of the support structure when the recess receives the collar.

Description:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     This invention was made with government support under Contract No. F33657-91-C-0007 awarded by the United States Air Force. The Government has certain rights in this invention. 
    
    
     BACKGROUND 
     This disclosure relates generally to a laser instrumentation system and, more particularly, to adjustably supporting components of the laser instrumentation system. 
     Laser-based thermometry systems are a type of laser instrumentation system. In laser-based thermometry systems, a laser emitter communicates a laser to a laser receiver. Temperatures are then measured using the laser. 
     In some examples, laser-based thermometry systems are used to measure temperatures within a turbomachine, such as temperatures within a gas path of an augmentor igniter. In such examples, the laser emitter and laser receiver are located on opposing radial sides of the gas path. Aligning the laser emitter relative to the laser receiver is challenging. 
     SUMMARY 
     A laser instrumentation bracket according to an exemplary embodiment of the present disclosure includes, among other things, a support structure providing a recess configured to receive a collar of a laser housing. The laser housing has a main body extending axially through an aperture of the support structure when the recess receives the collar. 
     In a further non-limiting embodiment of the foregoing laser instrumentation bracket, the support structure may be a first support structure configured to be secured to a second support structure to clamp the collar between the first support structure and the second support structure when the recess receives the collar. 
     In a further non-limiting embodiment of either of the foregoing laser instrumentation brackets, the laser housing may extend axially through an aperture of the second support structure when the collar is clamped between the first support structure and the second support structure. 
     In a further non-limiting embodiment of any of the foregoing laser instrumentation brackets, the laser housing may extend axially through the aperture of the second support structure toward a flowpath of a turbomachine. 
     In a further non-limiting embodiment of any of the foregoing laser instrumentation brackets, the laser housing may comprise a laser receiver housing. 
     In a further non-limiting embodiment of any of the foregoing laser instrumentation brackets, a radial position of the laser housing may be adjusted when the laser housing extends axially through the aperture. 
     In a further non-limiting embodiment of any of the foregoing laser instrumentation brackets, the collar may extend radially from the main body. 
     In a further non-limiting embodiment of any of the foregoing laser instrumentation brackets, the recess may be oversized relative to the collar and the aperture may be oversized relative to the main body such that the collar is radially adjustable away from a centered position within the recessed area. 
     In a further non-limiting embodiment of any of the foregoing laser instrumentation brackets, the collar may contact a floor of the recess to limit axial movement of the laser housing through the aperture. 
     A laser instrumentation system according to another exemplary embodiment of the present disclosure includes, among other things, a laser emitter assembly, a laser receiver assembly configured to receive at least one laser from the laser emitter assembly, and a bracket that supports the laser emitter assembly or the laser receiver assembly within a recessed area. The supported one of the laser emitter assembly or laser receiver assembly is adjustable within the recessed area relative to the other one of the laser emitter assembly or laser receiver assembly. 
     In a further non-limiting embodiment of the foregoing laser instrumentation system, the laser emitter assembly and the laser receiver assembly may be located on opposing radial sides of a flowpath within a turbomachine. 
     In a further non-limiting embodiment of either of the foregoing laser instrumentation systems, the laser emitter assembly and the laser receiver assembly may be located within any exhaust system hardware of a turbomachine. 
     In a further non-limiting embodiment of any of the foregoing laser instrumentation systems, the laser may communicate through any exhaust system hardware. 
     In a further non-limiting embodiment of any of the foregoing laser instrumentation systems, the laser emitter assembly and the laser receiver assembly may be portions of a laser thermometry system. 
     A laser alignment method according to another exemplary embodiment of the present disclosure includes, among other things, holding a laser housing in a first position within a recess of a bracket, moving the laser housing to a second position within the recess of the bracket, and holding the laser housing in the second position. A laser emitter and a laser receiver are misaligned when the laser housing is in the first position, and the laser emitter and the laser receiver are aligned when the laser housing is in the second position. 
     In a further non-limiting embodiment of any of the foregoing laser alignment methods, the method may include measuring a temperature using a laser communicated from the laser emitter to the laser receiver. 
     In a further non-limiting embodiment of any of the foregoing laser alignment methods, the temperature may be a temperature of a flowpath within a turbomachine. 
     In a further non-limiting embodiment of any of the foregoing laser alignment methods, a collar of the laser housing may contact a floor of the recess to hold the laser housing in the first position and the second position. 
    
    
     
       DESCRIPTION OF THE FIGURES 
       The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows: 
         FIG. 1  shows a schematic side view of an example turbomachine. 
         FIG. 2  shows a schematic view of an example laser instrumentation system. 
         FIG. 3  shows a side view of the laser instrumentation system of  FIG. 2  within the turbomachine of  FIG. 1 . 
         FIG. 4  shows a close-up side view of a laser receiver system of  FIG. 3 . 
         FIG. 5  shows a perspective view of the laser receiver system of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an example turbomachine  10  includes a fan section  12 , a compressor section  14 , a combustor section  16 , a turbine section  18 , an augmentor section  20 , and an exhaust section  22 . The compressor section  14 , combustor section  16 , and turbine section  18  are generally referred to as the core engine. An axis A extends longitudinally through the turbomachine  10 . 
     Although depicted as a two-spool gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with such two-spool designs. That is, the teachings may be applied to other types of turbomachines and gas turbine engines, including three-spool architectures. 
     In the example turbomachine  10 , flow moves from the fan section  12  to a bypass flowpath. Flow from the bypass flowpath generates forward thrust. The compressor section  14  drives flow along a core flowpath. Compressed air from the compressor section  14  communicates through the combustor section  16 . The products of combustion are expanded through the turbine section  18 . 
     In some examples, the turbomachine  10  may incorporate a geared architecture  24  that allows a fan of the fan section  12  to rotate at a different speed than a turbine that is driving the fan. The geared architecture  24  may include an epicyclic geartrain, such as a planetary geartrain, or some other gear system. 
     Referring now to  FIG. 2  with continuing reference to  FIG. 1 , an example laser instrumentation system  50  may be incorporated into the turbomachine  10 . In this example, the laser instrumentation system  50  measures temperatures. 
     The laser instrumentation system  50  includes a laser emitter assembly  54  and a laser receiver assembly  58 . One or more light emitting lenses may be integrated into the laser emitter assembly  54  and the laser receiver  58  assembly. 
     The example laser instrumentation system  50  also includes a laser table  70  having a tunable diode laser  74  and high frequency detectors  78 . A fiber-optic cable  82  operatively links the tunable diode laser  74  to the laser emitter assembly  54 . A fiber-optic cable  84  operatively links the laser receiver assembly  58  to the high frequency detectors  78 . A computer  88  and a lock-in amp  92  are operatively connected to the tunable diode laser  74  and the high frequency detectors  78 . 
     During operation, one or more lasers  62  propagates from the laser emitter assembly  54 . The lasers  62  are received by the laser receiver assembly  58  when the system  50  and when the laser emitter assembly  54  are aligned with the laser receiver assembly  58 . 
     In this example, the laser  62  is communicated across a flowpath  96  within the augmentor section  20  of the turbomachine  10 . The laser emitter assembly  54  is mounted to an exhaust system component  106 , and the laser receiver assembly  58  is mounted to a radially inner wall  102 . 
     When the laser  62  is received by the laser receiver assembly  58 , the laser instrumentation system  50  is used to measure real-time temperatures within the flowpath  96  of the operating turbomachine  10 . A person having skill in this art and the benefit of this disclosure would comprehend how to measure real-time temperatures utilizing the laser instrumentation system  50 . 
     Referring now to  FIGS. 3-5  with continuing reference to  FIGS. 1 and 2 , the laser emitter assembly  54 , in some examples, includes four separate laser housings  104  each configured to communicate a laser beam through an exhaust system component  106  extending radially across the flowpath  96 . The individual laser beams from the laser housings  104  are received by four laser housings  110  of the laser receiver assembly  58 . 
     Notably, after the laser housings  104  of the laser emitter assembly  54  are secured relative to the exhaust hardware  106 , it can be difficult to adjust the laser housings  110  of the laser receiver assembly  58  into an appropriate laser receiving position. Similarly, if the laser housings  110  of the laser receiver assembly  58  are secured relative to the inner wall  102 , it can be difficult to adjust the laser housings  104  of the laser emitter assembly  54  into an appropriate laser propagating position. The example laser instrumentation system  50  includes a laser instrumentation bracket assembly  112  that permits adjustments of the laser housings  110 . 
     The example bracket assembly  112  includes three separate support structures  116 ,  118 , and  120 . The structures  118  and  120  are fastened directly to the radially inner wall  102  with mechanical fasteners, such as rivets, or another suitable attachment strategy. This example attachment strategy rivets the structure  120  to a doubler plate  123 . The support structure  116  is fastened directly to the support structure  118  using mechanical fasteners  122 . 
     The laser housings  110  each extend longitudinally along an axis A 1 . The laser housings  110  each include collars  124  extending radially from a main body portion  128  of the laser housings  110 . In this example, the collars  124  of the laser housings  110  are clamped between the support structure  116  and the support structure  118  when the support structure  116  is fastened to the support structure  118 . 
     When the laser receiver assembly  58  is installed, the example collars  124  are each received within recessed areas  132  of the support structure  116 . The collars  124  directly contact floors  140  of the recessed areas  132  to limit axial movement of the laser housings  110  in a first direction. Axial, in this example, is with reference to the axis A 1 . The opposing side of the collars  124  directly contacts the support structure  118  to limit axial movement of the laser housings  110  in a second, opposite direction. The support structure  118  may include recessed areas instead of, or in addition to, the support structure  116 . The recessed areas  132  may be non-circular or circular. Any number of the recessed areas  132  may be used. 
     The example recessed areas  132  are oversized relative to the collars  124 . That is, the radial width of the recessed areas  132  is greater than the diameter of the collar  124  received within that recessed area  132 . In some specific examples, the collars  124  are able to radially move within the recessed area  132  away from a centered position within the recessed area  132 . 
     When the laser receiver assembly  58  is installed, the main body portions  128  of each of the laser housings  110  extend through both an aperture  138  in the support structure  116  and an aperture  142  in the support structure  118 . The main body portions  128  extend through the apertures  142  toward the flowpath  96 . The main body portions  128  terminate near the flowpath  96 . Notably, no attachment features extend to the flowpath  96 , which would potentially disturb flow and cause measurement inaccuracies. 
     The apertures  138  and  142  are each oversized relative to the received one of the main body portions  128  of the laser housings  110 . That is, the respective diameters of the apertures  138  and  142  are both greater than the diameter of the main body portions  128  of the laser housings  110 . In some specific examples, each of the laser housings  110  is able to be moved radially away from a center of the apertures  138  and  142 . 
     In this example, each of the laser housings  110  is moved radially while the collar  124  is within the recessed area  132  until the laser housing  110  is in a position appropriate for receiving a laser beam from an associated laser housing  104  of the laser emitter assembly  54 . The mechanical fasteners  122  are then fully tightened to secure the support structure  116  to the support structure  118  and prevent movement of the laser housings  110  relative to the bracket assembly  112  during engine operation. 
     Although the example bracket assembly  112  is shown supporting the laser housings  110 , the bracket assembly  112  could also be used to adjustably hold the laser housings  104  associated with the laser emitter assembly  54 . 
     The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims.