Fluidic pressure ratio sensor

Claim 1

A pressure ratio detector connected between the compressor and the engine inlet of a turbojet engine, comprising: a housing with a fluid flow channel passing through the housing; said housing having an inlet at one end of the flow channel adapted to be connected to a compressor stage of a turbojet engine and an outlet at the other end of the flow channel adapted to be connected to inlet of said turbojet engine; an insert having an orifice for producing a pressure drop in the inlet of said flow channel; a plug in said flow channel; said plug having a flow spreader at the inlet end and a plurality of helical grooves in the outer surface to provide a plurality of helical flow paths in said flow channel; means, between said plug and said outlet, for subjecting the flow to a sudden expansion and inducing a nutation in the flow; means, responsive to the acoustic nutational frequency in the region of said expansion, for converting the acoustic nutational frequency to an electrical output signal; and means, for measuring the temperature of flow at the inlet end of the flow channel.