JPS5936103B2 - Jet engine exhaust nozzle control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an exhaust nozzle control device for an aircraft jet engine.

In general, jet engines for aircraft need to maintain stable operation without generating engine surge under any flight conditions.

When the air flowing into the engine is at low pressure, low temperature, or highly turbulent, such as during high-speed flight, high-altitude/low-speed flight, or irregular motion, the engine is likely to generate surges.

That is, conventional jet engines have a problem in that surges are likely to occur.

Such defects are caused by the fact that the cross-sectional area of the exhaust nozzle of conventional jet engines remains unchanged during flight conditions, or
This is due to the fact that it was not possible to control the cross-sectional area of the exhaust nozzle to accommodate changes in the surge margin.

The present invention was developed in view of the above circumstances, and its configuration is based on the output signals of the pressure sensor installed at the fan inlet of the jet engine, the pressure sensor installed at the fan outlet, and the Ryokawa force sensor. an arithmetic circuit that inputs a fan operating point pressure ratio signal, engine air flow rate, and aircraft side parameters and outputs a fan surge pressure ratio signal; a surge margin signal calculated from the fan surge pressure ratio signal and the fan operating point pressure ratio signal; An exhaust nozzle opening/closing judgment circuit that inputs an allowable surge margin signal calculated from the fan surge margin reference value and a preset fan surge margin reference value and outputs an exhaust nozzle opening/closing judgment signal. Exhaust nozzle area calculation circuit that calculates the area of the exhaust nozzle, an exhaust nozzle area increase/decrease determination circuit that inputs the output signal of the calculation circuit and an area margin signal calculated from the actual exhaust nozzle area and outputs an increase or decrease signal for the exhaust nozzle area, and exhaust. inputting the nozzle area increase/decrease signal and the exhaust nozzle open/close determination signal5;
An exhaust nozzle control device for a jet engine, comprising: an opening/closing mode switching circuit that selects and outputs a command to an exhaust nozzle drive device based on these signals; Since the fan's surge pressure ratio and operating point pressure are detected and the difference is used as a parameter for controlling the cross-sectional area of the exhaust nozzle, the fan surge margin can be measured directly and preset in flight conditions when no Afukuburner is used. By comparing and determining the exhaust nozzle area to prevent engine surges and reduce the exhaust nozzle area to improve engine performance, it is possible to increase the exhaust nozzle area to prevent engine surges and reduce the exhaust nozzle area to improve engine performance. This engine has the advantage of not causing engine surge under all conditions such as high-altitude, low-speed flight, irregular motion, etc., and the engine's maximum performance can always be demonstrated.

Next, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of an embodiment of the present invention, in which 1 is a jet engine, 2 is an exhaust nozzle, 3 is an air intake fan, 4 is an air compressor,
5 is a combustion chamber, 6 is a high-pressure turbine rotated by combustion gas, 7
is also a low pressure turbine, 8 is a pressure sensor at the inlet of the fan 3, 9 is a pressure sensor at the outlet of the fan 3, 10 is an exhaust nozzle area sensor, and 11 is a sensor for airframe parameters (
(e.g. flight conditions, air intake parameters, etc.); 12 is an exhaust nozzle control device for increasing/decreasing the cross-sectional area of the exhaust nozzle; 1;
Similarly, 3 is the exhaust nozzle 1 driving device.

Next, FIG. 2 is a block diagram showing the arithmetic control configuration in the exhaust nozzle control device 12, in which 14 is a fan/surge pressure ratio arithmetic circuit, 15 is a surge pressure ratio signal, 16 is a fan operating point pressure ratio signal, 17 is a surge margin signal, 18 is an allowable surge margin signal, 19 is an exhaust nozzle open/close determination circuit, 20 is an open/close determination signal, 21 is a maximum exhaust nozzle area calculation circuit, 22 is a maximum nozzle area signal, 2
3 is an area margin signal for the maximum area, 24 is a circuit for determining whether or not the exhaust nozzle area can be increased, 25 is a nozzle area increase signal, 26 is a calculation circuit for the minimum exhaust nozzle area, 2γ is a minimum nozzle area signal, and 28 is the area for the minimum area. Margin signal, 29 is a circuit for determining whether or not the exhaust nozzle area can be reduced, 30
3 is a nozzle area reduction signal, and 31 is an open/close mode switching circuit.

Arithmetic control within the exhaust nozzle control device of the above embodiment is performed by a digital computer or an analog circuit.

Next, the effects of the above embodiment will be explained.

This implementation train is in flight condition when Afukvarna is not used.
This system performs exhaust nozzle control that adapts to changes in engine surge margin, and as shown in Figure 1, fan pressure, exhaust nozzle area, flight conditions, and air intake parameters are controlled by pressure sensors 8, 9, Exhaust nozzle area sensor 1
0, detected by sensor 11, exhaust nozzle control device 1
2.

The exhaust nozzle control device 12 uses these input signals to perform arithmetic control as shown in FIG. 2, and determines a command to be sent to the exhaust nozzle drive device 13.

This exhaust nozzle area command is used by the exhaust nozzle drive device 13.
The exhaust nozzle area is controlled to the optimum state.

The flow of arithmetic control signals within the exhaust nozzle control device 12 will be explained as follows with reference to FIG.

Opening/closing of the exhaust nozzle 2 is determined by the sign of the allowable surge/massine.

The fan surge pressure ratio signal 15 is determined by the arithmetic circuit 14 from flight conditions, air intake parameters (mainly distortion), and engine air flow rate.

Engine air flow rate is calculated from the fan inlet pressure.

The fan operating point pressure ratio signal 16 is calculated as fan outlet pressure/fan population pressure.

The difference between the surge pressure ratio signal 15 and the operating point pressure ratio signal 16 is calculated as the surge margin signal 11.

The difference between this surge margin signal 11 and the surge margin reference [direct] is determined as an allowable surge margin signal 18.

In the nozzle opening/closing determination circuit 19, an opening/closing determination signal 20 is determined based on the positive/negative of the allowable surge margin signal 18, and is transmitted to the opening/closing mode switching circuit 31.

That is, if the allowable surge margin signal 18 is negative, the open signal 1
If 1111 is positive, a close signal tl OI+ is sent.

When the open/close discrimination signal 20 is 1'', a nozzle area increase signal 25 is sent to the exhaust nozzle and drive device 13 as a command to the device 13.

The nozzle area is controlled by feedback control of the nozzle area so as not to exceed the maximum allowable area.

That is, the maximum nozzle area calculation circuit 21 calculates the maximum nozzle area signal 22 scheduled for the flight conditions.
is calculated.

The difference between this allowable maximum nozzle area and the actual nozzle area is calculated as an area margin signal 23 for the maximum area.

In the nozzle area increase determination circuit 24, a determination is made based on the area margin signal 23, and it is determined whether the nozzle area can be increased.

That is, only when the area margin signal 23 is positive, the nozzle area increase signal 25 becomes 1'' and is sent to the exhaust nozzle driving device 13 as a signal to increase the area.

When the nozzle area increase signal 25 is 0'', the nozzle area remains unchanged.

When the open/close determination signal 20 is 0'', a nozzle area reduction signal 30 is sent as a command to the exhaust nozzle drive device.

In this case, the nozzle area is controlled so as not to fall below the allowable minimum area.

That is, the minimum nozzle area calculation circuit 26 calculates the minimum nozzle area signal 2γ scheduled for the flight condition.
is calculated.

The difference between the actual nozzle area and the minimum nozzle area signal 27 is calculated as an area margin signal 28 for the minimum area.

In the nozzle area reduction determination circuit 29, a determination is made based on the area margin signal 28, and it is determined whether the nozzle area can be decreased.

That is, only when the area margin signal 28 is positive, the nozzle area reduction signal 30 becomes +111, and is sent to the exhaust nozzle driving device 13 as a signal to reduce the area.

When the nozzle area reduction signal 30 is 0'', the nozzle area remains unchanged.

The above-described actions enable exhaust nozzle control that adapts to fan surge margin changes, resulting in the following effects.

1) If the surge margin becomes too small, increase the exhaust nozzle area to increase the surge margin and prevent engine surge.

Therefore, safety is also improved. 2) If there is sufficient surge margin, highly efficient engine operation can be achieved by reducing the exhaust nozzle area.

Therefore, performance is improved.

As specifically explained above with respect to the embodiment, the present invention detects the surge pressure ratio and the operating point pressure of the fan, uses the difference between them as a parameter for controlling the cross-sectional area of the exhaust nozzle, and also detects the flight condition when the afukuburner is not used. [Correction of fan surge margin] [By comparing direct and pre-set standards [direct], increase the exhaust nozzle area to prevent engine surges and reduce the exhaust nozzle area to improve engine performance. Compared to conventional jet engines, the engine has the advantage of not causing engine surge under all conditions such as high-speed flight, high-altitude/low-speed flight, irregular motion conditions, etc., and the engine's maximum performance can always be demonstrated. It is something that you have.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall structure of an embodiment of the present invention, and FIG. 2 is a diagram showing the arithmetic control structure of the exhaust nozzle control device 12 of the above embodiment. 1-11. ... Jet engine, 2 ... Exhaust nozzle, 3 ... Fan, 8, 9 ... Pressure sensor, 10 ... Exhaust nozzle area sensor, 1
DESCRIPTION OF SYMBOLS 1...Sensor, 12...Exhaust nozzle control device, 13...Exhaust nozzle drive device, 14.
... Arithmetic circuit, 19... Open/close judgment circuit, 21, 26... Arithmetic circuit, 24, 29...
. . . Possibility judgment circuit, 31 . . . Opening/closing mode switching circuit.

Claims (1)

[Claims] 1 Pressure sensor 8 provided at the fan inlet of the jet engine, pressure sensor 9 provided at the fan outlet, fan operating point pressure ratio signal 16 calculated from the output signals of the Ryogawa force sensors 8 and 9, engine air flow rate, and aircraft body an arithmetic circuit 14 that inputs side parameters and outputs a fan surge pressure ratio signal 15; a surge margin signal 1γ calculated from the fan surge pressure ratio signal 15 and the fan operating point pressure ratio signal 16; and a preset fan surge margin reference value. An exhaust nozzle opening/closing determination circuit 19 inputs the allowable surge margin signal 18 calculated from and outputs an exhaust nozzle opening/closing determination signal 20; Arithmetic circuit 2L 26, output signal 22 of arithmetic circuit 2L 26
. Increase/decrease signal 2
5.30 and the exhaust nozzle opening/closing determination signal 20 are input, and based on these signals, a command whose content is an instruction signal to increase or decrease the exhaust nozzle area to the exhaust nozzle driving device is selected and output. switching circuit 31
An exhaust nozzle control device for a jet engine, comprising: