Abstract:
A high response air angle probe to measure a flow direction in an air flow near or above Mach one. The probe is rotatably secured within an assembly with marking to indicate when a desired position of the probe within the air flow has been found. The probe includes a row of three high response pressure transducers on a leading edge region to detect when the probe is at a certain position within the air flow.

Description:
GOVERNMENT LICENSE RIGHTS 
     None. 
     CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to a high response air angle probe, and more specifically to a high response air angle probe used for testing airflow in a stator vane assembly. 
     2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98 
     In a gas turbine engine, a turbine section includes multiple stages or rows of stator vanes and rotor blades. A stage of stator vanes is located immediately upstream in the flow direction from a stage of rotor blades and function to guide the flow into the rotating blades for maximum efficiency. The stator vane assembly is designed for use in a specific engine with airfoils having a specific shape and angle and with a specific throat area formed between adjacent airfoils to control airflow and pressure. 
     A new design for a stator vane assembly requires testing of airflow through the vanes in order to determine if a proper design has been produced. Proper airflow testing of a stator vane assembly also requires the testing to be done with an adjacent stage or stages of rotor blades in order to account for the full effect of the airflow passing through the turbine. Airflow testing is required in order to validate the design of a new airfoil stator vane. 
     Currently, testing of airflow through a stator vane assembly is performed using low flows. Compressed air used for testing is stored in a pressure tank and then released to flow through the vane assembly where the airflow direction can be measured using standard air flow angle probes. This process for testing airflow is limited to low pressures because of the limit in the size and pressure of the compressed air storage tank. In order to test a vane assembly for high volume flows with high pressures, a number of high pressure compressors is required or a very large compressed air storage tank is required. A large tank capable or storing a large volume of compressed air at high pressures would be very cost prohibited, especially for a medium to small size testing facility. 
     BRIEF SUMMARY OF THE INVENTION 
     A high response air angle probe for use in testing airflow through a stator vane assembly in which a short burst of compressed air having a high pressure is used for testing. The high response angle probe is capable of quickly determining the air flow angle before the air flow is exhausted. The high response air angle probe includes one or more rows of high response pressure transducers positioned along the probe with one transducer centered and two on each side at equal and opposite angle. The transducers are in the natural frequency range of from 100 kHz to 1,000 kHz and preferably at around 300 kHz and can measure air angles in air flow near to or above Mach one. The probe is capable of measuring a total pressure, a static pressure, and an air flow angle. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  shows an isometric view of a first embodiment of a high response air angle probe assembly of the present invention. 
         FIG. 2  shows a cutaway view of the probe assembly of  FIG. 1 . 
         FIG. 3  shows a cross section view of the probe assembly of  FIG. 1 . 
         FIG. 4  shows a top view of the probe assembly of  FIG. 1 . 
         FIG. 5  shows an isometric view of a second embodiment of a high response air angle probe assembly of the present invention. 
         FIG. 6  shows an isometric view of the probe only of  FIG. 5 . 
         FIG. 7  shows a front view of the probe of  FIGS. 1 and 5  with an arrangement of three pressure transducers. 
         FIG. 8  shows an isometric view of the upper and lower mounting plates and the collar for the probe assembly of  FIG. 5 . 
         FIG. 9  shows an isometric view of the clocking plate for the probe assembly of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A high response air angle probe that is used for testing air flows through a stator vane assembly in which the testing period is a very short time because of the limit in the size of the compressed air storage tank used to supply the air flow. The probe is for use not with a steady-state test but for a very quick test commonly referred to as a blown-down test of around five seconds. Because of the high response time of the probe, high volume and pressure flow testing can occur using smaller compressed air storage tanks. 
       FIG. 1  shows a view of the high response air angle probe assembly in a first embodiment. The probe assembly includes a probe  11  having the high response pressure transducers mounted on a surface of the probe  11 , a clocking flange  12 , a mounting plate  13 , and a mounting disk  18  for the probe  11 . The probe  11  is secured to the mounting disk  18  against relative rotation.  FIG. 2  shows a cutaway view of the probe assembly. The mounting plate  13  includes a circular hole in which the probe  11  is rotatably secured. The mounting disk  18  and the clocking flange  12  both include annular grooves so that the clocking flange  12  can secure the mounting disk  18  to the mounting plate  13  while allowing for rotation of the mounting disk—and thus the probe  11 —relative to the mounting plate  13 . A number of bolts holes  14  are used to secure the clocking flange  12  to the mounting plate  13 . In this embodiment, four bolt holes  14  are used. When tightened, these bolts also clamp and hold the probe and mounting disk  18  from rotating. The angle of the probe is set to testing, but can be changed between tests by loosening the bolts and repositioning the mounting disk  18 . 
       FIG. 3  shows a cross section of the probe assembly with the probe  11  secured to the mounting disk  18  that is secured within the flange of the clocking plate  12 . The probe  11  includes three hypo-tube leads  15  that extend from a cavity formed above the mounting disk  18  and open onto the surface of the probe  11  on which the air flow will strike. The probe  11  also includes a transducer wire lead  16  and  17  for the high response pressure transducers that are mounted on the front side of the probe  11 . 
       FIG. 4  a top view of the probe assembly and includes markings  22  on the clocking plate  12  and a marking  21  on the mounting disk  18  of the probe  11 . The three hypo-tube leads  15  and the transducer wire lead  16  is shown opening onto the top of the mounting disk  18 . The markings  21  and  22  allow for the angle of the probe  11  to be determined in relation to the mounting plate  12 . The markings allow for easy probe alignment through a wide arc. 
       FIG. 7  shows a section of the probe  11  that the high response pressure transducers  28  are mounted to for both embodiments of the high response air angle probe of the present invention. The probe  11  includes a leading edge region with the three openings  29  of the hypo-tube leads  15 . A rectangular opening is formed in the probe surface to receive the three high response pressure transducers  28  so that they are mounted flush with the leading edge region surface of the probe  11 . The high response pressure transducers  28  include wires that extend through the transducer lead wires  17  that are connected to equipment outside of the probe assembly. The probe will use special pressure transducers that have a small foot print, high natural frequency, extreme resistance to vibration and shock, and a wide temperature range. The high response pressure transducers  28  used in the present invention are the LQ-062 series ultra miniature thin line IS pressure transducers supplied from KULITE Semiconductor Products, Inc. of Leonia, N.J. The transducer with a 300 kHz natural frequency has an input pressure of 3.5 bar and a pressure range of 50 psi. In the probe of the present invention, three high response pressure transducers  28  are used with one centered and two offset at equal angles of from 30 degrees to 45 degrees. In other embodiments, several rows of three transducers  28  can be used spaced along the axial length of the probe  11 . 
       FIG. 5  shows a second embodiment of the probe assembly of the present invention. In the  FIG. 5  embodiment, the probe  11  is formed with an integral cylinder  27  that has a flange on the upper side to engage the flange on a clocking plate. An O-ring groove  31  is formed on the outer surface of the cylinder  27  to receive an O-ring ( FIG. 6 ). A lower mounting plate  23  with a cylindrical collar  24  and an upper mounting plate  25  secured together and include a central opening in which the probe  11  and the cylinder  27  rotatable fit. The O-ring within the annular groove  31  forms a seal with an inner surface of the collar  24 . A clocking plate  26  is secured over the upper mounting plate  25  to rotatably secure the probe within the probe assembly. 
       FIG. 8  shows the cylindrical collar  24  positioned between the lower mounting plate  23  and the upper mounting plate  25 . These three pieces can be made separately and bonded together to form one integral unit or can be assembled together without bonding. The lower mounting plate includes holes for bolts to secure the probe assembly to a surface where the probe is to measure air flow direction. The upper mounting plate  25  includes two holes for the bolts that fit through the slots  30  in the clocking plate  26 . 
       FIG. 9  shows the clocking plate  26  with an annular flange facing downward that the flange on the cylinder  27  rotates within when the clocking plate  26  is secured to the upper mounting plate  25 . The clocking plate  26  includes two slots  30  to receive the bolts that secure the probe assembly together. The probe cylinder  27  includes a marking  21  and the clocking plate  26  includes several markings  22  so that the angle of the probe  11  with respect to the mounting plate can be determined. 
     The high response air angle probe is used to determine an air angle of flow over a wide Mach number range. The probe uses a number of high response pressure transducers to allow for high accuracy during short duration testing. The probe includes a variable and controllable probe angle relative to flow. The probe uses standard hypo-tube pressure sensors as a calibration or validation of high response sensor data. A probe may have transducers at multiple radial locations along the probe.