DYNAMIC PRESSURE RESPONSE CALIBRATOR

MEASURING DYNAMIC PRESSURES IN TURBINE AND ROCKET ENGINES ARE OFTEN MADE BY SEPARATING THE TRANSDUCING ELEMENT FROM THE MEASUREMENT POINT WITH TUBING. THE TUBING IS USED FOR THERMAL ISOLATION AND/OR WHEN THERE ARE SIZE CONSTRAINTS. THE ACOUSTIC PROPERTIES OF THE TUBES REQUIRE THE TUBING AND SENSOR UNIT BE CALIBRATED TOGETHER AS A SYSTEM. CURRENT CALIBRATORS ARE RESTRICTED IN ULTIMATE PEAK PRESSURE, BANDWIDTH, ACCURACY, AND TYPE OF EXCITATION SOURCE. IT IS PROPOSED TO DESIGN, BUILD, AND TEST A LABORATORY-SCALE CALIBRATION SYSTEM WITH FLEXIBLE EXCITATION SOURCES (SWEPT-SINE OR RANDOM), HIGH BANDWIDTH (2-500 HZ), AND HIGH PEAK PRESSURE (1 PSI). THE CALIBRTOR WILL UTILIZE A HIGH-OUTPUT ACOUSTIC DRIVER WHOSE OUTPUT IS CONTROLLED BY A DIGITAL SERVO-CONTROLLER. IN ADDITION TO PROVIDING A PRECISELY CONTROLLED EXCITATION, A TWO-CHANNEL MEASUREMENT (SENSOR OUTPUT DUE TO DRIVING PRESSURE AT TUBING INPUT) WILL PRODUCE A VERY ACCURATE MEASUREMENT BOTH IN TERMS OF AMPLITUDE AND PHASE.