Fluidic Pressure Ratio Sensor.

Pressure ratio measurements are used to monitor and control core engine and by-pass air flow rates, compressor and fan performance, and engine thrust. The wide range of required operating pressure levels plus the severe environment vibration and temperature makes the use of discrete pressure sensors with electronic ratio computation extremely difficult. The fluidic approach avoids much of this difficulty and provides a simple, rugged, compact design. The design features, operation, bench evaluation testing and engine testing of a fluidic pressure ratio sensor are described. The sensor design is readily adaptable to measurement of any engine related pressure ratio, but it was specifically configured and developed for measuring burner inlet mach number corrected air flow for the Pratt and Whitney Aircraft ATEGG engine. The sensor was designed for direct engine mounting and uses compressor discharge air for the flow circuits. Sensor operation was tested for the range of burner inlet total pressures from 6.6 to 500 psia and sensor environmental temperatures from -65 to 750 F. Author