Accession Number : ADD005774

Title :   Method and System of Controlling a Jet Engine for Avoiding Engine Surge.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON D C

Personal Author(s) : Harloff,Gary J

Report Date : 19 Dec 1978

Pagination or Media Count : 6

Abstract : A jet engine is controlled by placing time variant total pressure probes at the entry plane and the discharge plane of a jet engine fan. The pressure values at the probes are converted into electrical signals, filtered and then fed to meters where the root-mean-square (RMS) values of the electrical signals are determined. The RMS values are fed to a computer which computes the ratio of the two RMS values and this ratio is fed to a comparison circuit which generates a difference signal representing the difference between the RMS ratio and a predetermined limit value. If the RMS ratio equals the limit value, then the operating point of a fan is altered by either changing the nozzle area, changing the fan speed, or changing the altitude or Mach number. (Author)

Descriptors :   *Patents, *Engine surge, *Turbofan engines, Velocity, Control systems, Pressure transducers, Digital computers, Analog computers, Analog to digital converters, Variable area nozzles, Mach number, Altitude

Subject Categories : Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE