Control device of a variable section nozzle and the implementation method thereof

Abstract

The present disclosure provides a device for controlling a variable section ejection nozzle of a turbojet engine nacelle of an aircraft. The device includes a calculator adapted to determine a position setpoint of the nozzle and a management system of the servo-control of the position of the variable nozzle depending on the flow rate of the fuel supplying the turbojet engine. The management system includes at least one instantaneous flow rate sensor of the fuel and a management unit which is designed to compare the flow rate measured by the flow rate sensor with a theoretical fuel flow rate depending on the parameters of the flight of the aircraft, to determine a correction value of the position of the nozzle depending on the comparison of the measured flow rate and the theoretical fuel flow rate, and to correct the position setpoint of the nozzle according to the correction value.

Claims

1. A device for controlling a variable section ejection nozzle of a turbojet engine nacelle of an aircraft, the device comprising: a calculator that determines a theoretical position setpoint of the nozzle based on flight parameters of the aircraft; a device configured to actuate the nozzle and associated to said calculator, the device adapted to control a position of the nozzle according to the theoretical position setpoint; a measuring device for measuring the position of the nozzle; and a management system including at least one instantaneous flow rate sensor for measuring an actual flow rate of fuel supplied to a turbojet engine and a management unit, wherein the management unit: compares the actual flow rate measured by the at least one instantaneous flow rate sensor with a theoretical flow rate of fuel corresponding to the theoretical position setpoint of the nozzle; determines a correction value of the position of the nozzle based on a comparison of the actual flow rate and the theoretical flow rate of fuel; and corrects a position setpoint of the nozzle according to the correction value such that a difference between the theoretical flow rate and the actual flow rate is reduced to compensate for inaccuracies in the position of the nozzle due to manufacturing tolerance and wear of the nozzle during operation.

2. The control device according to claim 1, wherein the management unit is operable to vary the position of the nozzle in a plurality of positions and to measure the actual flow rate for the position of the nozzle to determine a position offering improved operation efficiency of the turbojet engine based on the theoretical flow rate such that the difference between the theoretical flow rate and the actual flow rate is reduced.

3. The control device according to claim 1, wherein the management system further includes a data storage unit which contains a data table of the theoretical flow rate depending on the parameters of flight of the aircraft.

4. The control device according to claim 3, wherein the data table is adapted to be updated.

5. The control device according to claim 3, wherein the data storage unit is adapted to record the correction value of the position of the nozzle during several flights.

6. The control device according to claim 1, wherein the management system further includes an integrator adapted to calculate an integral of the measured actual flow rate over time to refine an accuracy of the measured actual flow rate.

7. A method for implementation of a control device of a variable section ejection nozzle of a turbojet engine nacelle of an aircraft, said device being in accordance with claim 1, the method comprising: determining a theoretical position setpoint of the nozzle based on flight parameters of the aircraft; actuating the nozzle to a position according to the theoretical position setpoint; measuring the position of the nozzle; comparing a flow rate measured by a flow rate sensor and a theoretical flow rate; determining a correction value of the position of the nozzle based on the comparison of the measured flow rate and the theoretical flow rate; and correcting the position setpoint of the nozzle according to the correction value obtained in the determination step such that a difference between the theoretical flow rate and the measured flow rate is reduced to compensate for inaccuracies in the position of the nozzle due to manufacturing tolerance and wear of the nozzle during operation.

8. The method according to claim 7 further comprising determining an improved operation comprising: varying the position of the nozzle in a plurality of different positions according to different position setpoints of the nozzle; and measuring the flow rate corresponding to the position of the nozzle to determine an enhanced efficiency of a turbojet engine based on the theoretical flow rate.

9. The method according to claim 8, wherein the step of determining an improved operation comprises a recording phase which includes recording a position allowing improved efficiency according to the flight parameters.

Description

DRAWINGS

(1) In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:

(2) FIG. 1 is a cross-sectional view illustrating a turbojet engine nacelle equipped with a control device according to the teachings of the present disclosure.

(3) The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

DETAILED DESCRIPTION

(4) The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

(5) Referring to FIG. 1, schematically represented is a nacelle 10 which has a substantially tubular shape along a longitudinal axis A, and which comprises an upstream section 12 with an air inlet lip 14 forming an air inlet, a mid-section 16 surrounding a fan 18 of a turbojet engine 20 and a downstream section 22.

(6) The downstream section 22 comprises an inner structure 24 surrounding the upstream portion of the turbojet engine 20 and an outer structure 26 which may support a movable cowl including thrust reverser means.

(7) The inner structure 24 and the outer structure 26 delimit therebetween an annular flow path 28 allowing the passage of an air flow 30 penetrating the nacelle 10 at the air inlet.

(8) The nacelle 10 of the present disclosure is terminated by a variable ejection nozzle 32, comprising an outer module 34 and an inner module 36, the inner 36 and outer 34 modules delimiting therebetween a hot air flow channel 38 exiting from the turbojet engine 20.

(9) The nozzle 32 comprises movable flaps 40 disposed at the downstream end of the outer structure 26 and opposite to the annular flow path 30, each flap 40 being pivotally mounted so as to switch from an enlargement or reduction position of the section of the annular flow path 30.

(10) Without limitation, the flaps 40 may be flaps sliding along the longitudinal axis A of the nacelle 10.

(11) In order to drive the flaps 40 in movement, the nacelle 10 is equipped with actuating means 42 which comprise mechanical actuators of the cylinder, or ball screw type for example.

(12) In accordance with the present disclosure, the nacelle 10 includes a control device 44 of the variable nozzle 32.

(13) The control device 44 includes a calculator 46 which is adapted to determine a position setpoint of the variable nozzle 32 and which cooperates with the actuating means 42 in order to control the position of the nozzle 32 according to the position setpoint.

(14) For information purpose only, the term position of the nozzle 32 means the position of the movable flaps 40 of the nozzle 32 varying the ejection section of the nozzle 32.

(15) The position setpoint of the nozzle 32 is determined according to the flight parameters of the aircraft. These flight parameters gather several data among which the altitude of flight, the speed of the aircraft, the outside temperature, the external pressure, the regime of the turbojet engine, the speed of rotation of the drive shafts, etc.

(16) The control device 44 also comprises management system of the servo-control of the position of the variable nozzle 32 depending on of the flow rate of the fuel supplying the turbojet engine 20.

(17) To this end, the management system includes an instantaneous flow rate sensor 48 of the fuel consumed by the turbojet engine 20.

(18) In order to refine the accuracy of the measurement of the instantaneous flow rate, the management system include an integrator (not represented) which allows calculating over time the integral of the measured fuel flow rate.

(19) Furthermore, the management system includes an additional calculator forming a management unit 50 which is designed to compare the fuel flow rate measured by the flow rate sensor 48 with a theoretical fuel flow rate.

(20) The theoretical flow rate of the fuel to be compared with the measured flow rate is determined depending on the parameters of the flight of the aircraft and corresponds to a flow rate allowing an improved operation efficiency of the turbojet engine.

(21) Indeed, the efficiency of the turbojet engine 20 corresponds to the ratio between the theoretical flow rate and the measured flow rate of fuel.

(22) Furthermore, the management unit 50 allows determining a correction value of the position of the nozzle 32 depending on the comparison of the measured flow rate and the theoretical fuel flow rate.

(23) The correction value accordingly determined allows correcting the position setpoint of the nozzle 32, in order to increase or reduce the section of the nozzle 32.

(24) The correction value is calculated such that the actual fuel flow rate is as close as possible to the theoretical flow rate, in order to operate the turbojet engine 20 at an improved efficiency.

(25) Complementarily, the management system includes a data storage unit 52 which contains a data table of the theoretical fuel flow rate depending on the flight parameters of the aircraft and which allows updating the data table.

(26) The storage unit 52 is for example an electronic circuit integrated with the management unit 50.

(27) Advantageously, the data storage unit 52 allows recording the different correction values of the position of the nozzle 32 calculated for a flight phase and given flight parameters.

(28) This recorded data may be applied again to future flights encountering a flight phase and flight parameters corresponding to those previously encountered.

(29) In order to improve the reliability of the recorded correction values, the different correction values may be averaged over several flights and the values widely out of the average may be eliminated.

(30) Similarly, a more significant weighting to the most recent flights may be given so as to take into account the recent deteriorations of the nozzle 32 or of the turbojet engine 20.

(31) According to another aspect of the present disclosure, the management unit 50 allows varying the position of the nozzle 32 in a plurality of positions, the fuel flow rate being measured for each adopted position, in order to determine the position offering improved operation efficiency of the turbojet engine 20, with given flight parameters.

(32) This action allows researching and determining improved operation efficiency of the turbojet engine 20 by taking into account the state of wear of the turbojet engine 20.

(33) The position of the nozzle 32 may be either deduced according to the position setpoint transmitted to the actuating means 42 of the nozzle 32, or measured by a measuring means 54 of the position of the nozzle 32 provided for this purpose.

(34) The present disclosure also concerns a method for the implementation of the control device 44, previously described.

(35) The method includes a comparison step of the flow rate measured by the flow rate sensor 48 at a theoretical fuel flow rate depending on the parameters of the flight, by means of the management unit 50.

(36) The comparison step is followed by a determination step of the correction value of the position of the nozzle 32 depending on the comparison of the measured flow rate and the theoretical fuel flow rate made during the comparison step.

(37) Furthermore, the method includes a correction step of the position setpoint of the nozzle 32 according to the correction value obtained in the determination step.

(38) The corrected position setpoint is transmitted to the actuating means 42 of the nozzle 32 in order to reduce or increase the section of the nozzle 32.

(39) The correction value is calculated such that the actual fuel flow rate is as close as possible to the theoretical flow rate, in order to operate the turbojet engine 20 at an improved efficiency.

(40) According to one form, the method includes an additional research step of improved operation which includes varying the position of the nozzle 32 in a plurality of different positions, according to different position setpoints of the nozzle 32, and in measuring the fuel flow rate corresponding to each adopted position in order to determine improved efficiency of the turbojet engine 20.

(41) This research step also includes recording the position allowing improved efficiency according to the determined flight parameters, in the storage unit 52.

(42) Thus, the recorded data may be applied to future flights encountering a flight phase and flight parameters corresponding to those previously encountered.

(43) The research step may be carried out at regular intervals, for example once per flight.

(44) The control device 44 as well as its implementation method allow overcoming the inaccuracies of positions of the nozzle 32 due, in particular, to the manufacturing tolerances, the wear and the distortions under loads of the different parts constituting the variable nozzle 32.

(45) In particular, upon changing the nozzle 32 on a motor, adjustment may not be needed.

(46) The enhanced accuracy of the position of the nozzle allows improved operation of the propulsion unit constituted by the turbojet engine 20 and the nacelle 10.

(47) Advantageously, the reliability of the control device and the method according to the present disclosure is not impacted by the reliability of the different sensors and measuring means, as would be a closed loop system of the military aircraft or supersonic civil aircraft type.

(48) The regulation by measuring the fuel flow rate may also compensate other parameters of deterioration of the turbojet engine, such as the increase in the clearances at the compressor blade tips or the deterioration of the turbine blades.

(49) It will be noted that the mechanical wear of the turbojet engine may be characterized by an increase in the temperature of the exhaust gases of the primary flow, for a speed of rotation of the fan and the given flight parameters.

(50) The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.