System for controlling the thrust nozzle adjustment of dual cycle gas turbine jet propulsion engines

Claim 1

A method for controlling dual cycle gas turbine jet propulsion engines by means of pressure ratio closed loop control circuit which controls the adjustment of the opening angle of the thrust nozzle, comprising the following steps: (a) measuring the actual static pressure (P sD ) downstream of the radial outer compressore (1a) of the second flow circuit (K2), (b) measuring the actual static pressure (P sE ) of the air flowing into the propulsion engine, (c) forming an actual pressure ratio between the actual pressures measured insteps (a) and (b) to provide an actual pressure ratio value (π NVZ-I .sbsb.sT), (d) measuring the reduced revolutions per minute of the low pressure compressor (1) to provide a respective r.p.m. value (N r ), (e) storing in a first computor memory (21) rated pressure ratio values (π NVZ-Soll ) as a function of said reduced r.p.m. value (N r ) said rated pressure ratio values in said first computer memory taking into account as parameters steady state operating conditions without afterburning and acceleration state operating conditions without afterburning, (f) storing in a second computer memory (22) rated pressure ratio values (π NVZ-Soll ) as a function of said r.p.m. value (N r ), said rated pressure ratio values taking into account as parameters steady state operating conditions with afterburning and acceleration state operating conditions with afterburning, (g) providing to said computer memories a second signal for activating one or the other of the two memories depending on the on or off condition of an afterburner, (h) providing to said computer memories a first signal for activating one or the other of the two memories depending on the steady state operating condition parameter or the acceleration state operating condition parameter, and (i) comparing under the control of said first and second signals one of said stored rated pressure ratio functions with the actual pressure ratio value formed in step (c) from values measured insteps (a), (b) under corresponding operating conditions to determine a control deviation (επ), and controlling said thrust nozzle adjustment angle in response to said control deviation to return the control deviation substantially to a zero value under said operating conditions, whereby during steady state operation fuel consumption is minimized in the subsonic range while the thrust is maximized in the supersonic range, and whereby during the non-steady state of operation the stability between the two aerodynamic limits of the compressor surging on the one hand and of the afterburner chamber quenching on the other hand is assured.

Claim 2

A method for controlling dual cycle gas turbine jet propulsion engines by means of pressure ratio closed loop control circuit which controls the adjustment of the opening angle of the thrust nozzle, comprising the following steps: (a) measuring the actual static pressure (P sD ) downstream of the radial outer compressore (1a) of the second flow circuit (K2), (b) measuring the actual static pressure (P sE ) of the air flowing into the propulsion engine, (c) forming an actual pressure ratio between the actual pressures measured insteps (a) and (b) to provide an actual pressure ratio value (π NVZ-I .sbsb.sT), (d) measuring the reduced revolutions per minute of the low pressure compressor (1) to provide a respective r.p.m. value (N r ), (e) storing in a first computor memory (21) rated pressure ratio values (π NVZ-Soll ) as a function of said reduced r.p.m. value (N r ) said rated pressure ratio values in said first computer memory taking into account as parameters steady state operating conditions without afterburning and acceleration state operating conditions without afterburning, (f) storing in a second computer memory (22) rated pressure ratio values (π NVZ-Soll ) as a function of said r.p.m. value (N r ), said rated pressure ratio values taking into account as parameters steady state operating conditions with afterburning and acceleration state operating conditions with afterburning, (g) providing to said computer memories a second signal for activating one or the other of the two memories depending on the on or off condition of an afterburner, (h) providing to said computer memories a first signal for activating one or the other of the two memories depending on the steady state operating condition parameter or the acceleration state operating condition parameter, and (i) comparing under the control of said first and second signals one of said stored rated pressure ratio functions with the actual pressure ratio value formed in step (c) from values measured insteps (a), (b) under corresponding operating conditions to determine a control deviation (επ), and controlling said thrust nozzle adjustment angle in response to said control deviation to return the control deviation substantially to a zero value under said operating conditions, whereby during steady state operation fuel consumption is minimized in the subsonic range while the thrust is maximized in the supersonic range, and whereby during the non-steady state of operation the stability between the two aerodynamic limits of the compressor surging on the one hand and of the afterburner chamber quenching on the other hand is assured.