RU2347093C2 - Method for control of bypass two-shaft gas turbine engine of airplane and device for its realisation - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: inventions are related to methods for protection of bypass two-shaft gas turbine engines (GTE) of airplane against ingress of foreign objects and turbulent vortex flows to the inlet of high pressure compressor (HPC). Whenever GTE operates at idle and other reduced conditions of forward thrust, air relief gate valves of both groups are in open position. Contaminating particles that are separated in fan and low pressure compressor (LPC), through open gate valves of both groups are supplied to external circuit and further exhausted from GTE without its damage. During airplane landing pilot puts engine control lever (ECL) in position "Flight idle", relief gate valves of both groups are in open position. Then pilot switches on thrust reversal, after that ECL is changed over to position of "Maximum reverse thrust". GTE control lever position detector continuously measures value L_ecl, which is compared to L^threshold _ecl in unit of reversal switching signal generation. If L_ecl< L^threshold _ecl, signal I₂=1 (criterion of operation at reversal) is generated at the outlet of reversal switching signal generation unit, which arrives to inlet of commutator switch. If signal I₂=1 is available in commutator switch, control circuits of gate valves of both groups open, and independently on rotation frequency n_"ткпр" and velocity V_s, gate valves remain in open position, thus providing for reliable protection of engine against ingress of foreign objects and effect of "bound vortex" during airplane breaking. At the same time on appearance of signal I₂=1 regulation program is readjusted at pickup, at that higher surplus of fuel supply ΔGf to combustion chamber is provided compared to program of fuel supply Gf at pickup modes for forward thrust. Such method and device will make it possible to increase reliability of engine operation.

EFFECT: higher reliability of engine operation.

3 cl 1 dwg

Description

The invention relates to methods for protecting a double-circuit twin-shaft gas turbine engine (GTE) of an aircraft from the ingress of foreign objects and turbulent eddy flows at the entrance to a high pressure compressor (HPC).

Known automatic methods of protection against ingress of foreign particles and turbulent eddy flows at the entrance to the gas turbine engine, based on blowing high pressure air from the air intake [RU 2156369, F02C 7/05, 1998; RU 2138663, F02C 7/05, B64D 33/02, 1998].

A disadvantage of the known methods is the need for air sampling from the compressor, which reduces its efficiency. In addition, the use of systems for suppressing turbulent flows provides for the complexity of the design, which leads to an increase in the weight and cost of gas turbine engines.

A GTE control device is known, which is designed to improve its operating conditions by eliminating the ingress of foreign objects by accurately turning on the minimum reverse (reverse) thrust after braking the aircraft to a speed slightly higher than that at which the engines begin to suck foreign objects from the runway [RU 2031814, B64D 31/04, 1995].

The disadvantage of this device is the need for continuous visual control by the pilot over the speed of the aircraft during its braking.

There is also known a method of protecting a gas turbine engine and a device for its implementation, which provide the discharge of foreign particles into the external circuit of the engine through the air bypass flaps from the low pressure compressor (LPC), as well as the discharge of particles through the corresponding annular channel. At the same time, in all operating modes, pollutant particles are discharged through the annular channel, and when the engine is in reduced mode, through open bypass flaps into the external circuit of the gas turbine engine and then into the atmosphere [RU 2176333, F04D 27/02, 2000].

The known GTE protection device implementing the above method provides inertial separation of foreign particles and their subsequent discharge into the external GTE circuit due to special profiling of the compressor inlet channel [RU 2176333, F04D 27/02, 2000].

The main disadvantage of the analogue is the increased probability of the ingress of foreign particles during engine operation at maximum mode before the aircraft take-off and at the stage of braking.

Closest to the technical nature of the claimed is a method of controlling the gas turbine engine, preventing surging of the gas turbine compressor and increasing the accuracy of regulation of air bypass from the low pressure valve during the take-off of the aircraft before flight and during landing by increasing the reserves of gas-dynamic stability. The method is carried out by opening a group of air bypass dampers from low pressure valves at low gas turbine engine modes and closing them at high modes [RU 2109174, F04D 27/02, 1998].

The closest in technical essence to the claimed is a device for implementing the known method, which provides for the presence of two groups of air bypass flaps from KND. Before reaching the aircraft speed V _c ~ 60 ... 70 km / h, the flaps of the second group are open, providing increased reserves of gas-dynamic stability and protection of the engine from turbulent flows (“connected vortex”). At V _c ≥60 ... 70 km / h, when the air is sucked into the engine only in front, the flaps of the second group are closed, and the “attached vortex” disappears [RU 2109174, F04D 27/02, 1998].

A common disadvantage of the known method and device for its implementation is that when the aircraft brakes and the gas turbine engine operates at maximum reverse thrust (reverse is turned on), reliable engine protection is not fully provided under all expected operating conditions. So, when landing in difficult weather conditions (icing, snow, rain), with a short runway or not turning on the reverse of the thrust of another engine, an unfavorable combination of these and other operational factors, a longer operation of the engine on reverse is necessary to ensure the required path length to a stop. Including at speeds V _c , when the suction of foreign objects begins from the runway. In such a situation, the open shutters of the second group may not be enough to ensure reserves of gas-dynamic stability and a reliable discharge of foreign objects due to the fact that the area of the through sections of the shutters of the bypass of the second group is usually 5-6 times smaller than the first.

In addition, at V _c <80 ... 100 km / h, due to the aerodynamic effect of the reverse air flow directed along the course of the aircraft with an outflow speed of ~ 500 ... 550 km / h, intense snow / ice casting is possible, “raised” from the runway at the entrance of the gas turbine engine, which significantly increases the likelihood of compressor damage.

The technical problem solved by the claimed group of inventions is to increase engine reliability by preventing foreign objects and turbulent eddy flows from entering the high-pressure compressor, as well as reducing the braking time of the aircraft by arranging air bypass from the low-pressure compressor to the external channel through open air bypass flaps during engine operation in reverse mode with maximum reverse thrust.

In the inventive method for controlling a double-circuit twin-shaft gas turbine engine of an aircraft, including bypassing air from a low-pressure compressor through the air bypass flaps of the first and second groups and supplying fuel according to the pick-up program in direct thrust modes, according to the invention, an additional reverse signal is generated, according to which the bypass flaps are opened air of the first and second groups, regardless of the engine operating mode and aircraft speed, and the fuel is supplied to the combustion chamber acceleration program with an excess of fuel in the range of 10 ... 15% in comparison with the program on the pickup forward thrust.

In addition, according to claim 2, the formula measures the value of L _ores characterizing the position of the engine control lever, compares it with a threshold value L ^{threshold of} _ores, and when L _ores <L the ^{threshold of} _ores , a reverse enable signal is generated.

A device for implementing the inventive method for controlling a dual-circuit twin-shaft gas turbine engine of an airplane includes engine and speed parameters sensors connected to an air bypass damper control unit from a low pressure compressor, and according to the invention further comprises a position sensor of the engine control lever L _ores , a unit for setting a threshold value of the lever position control ^threshold L _ores forming unit incorporating reverse signal switch key provides switching chains flaps air bypass control, and automatic engine acceleration, the output of the sensor lever position control motor L _ores and output setting unit threshold value L ^threshold _ores are connected to the block forming inclusion reverse signal, which output is connected to the input-switch key and the input engine acceleration automaton .

The drawing shows a diagram of a device that implements the inventive method.

The device comprises a block 1 of sensors for gas turbine engine parameters, a block 2 for measuring the speed of the aircraft, a block 3 for generating control signals for the first and second groups of air bypass flaps, a block 4 - a sensor for positioning the control lever for a gas turbine engine L _ores , a block 5 for generating a threshold value L an _ore ^threshold , a comparator 6 switch key 7, overclocking machine 8.

Block 1 is a block of sensors of parameters of the gas turbine engine. As sensors of parameters of a gas turbine engine, an air temperature sensor at the inlet Т ^* _Вх in the gas turbine engine and a turbocharger speed sensor n _tk (gas turbine engine generator) are used.

Block 2 - block measuring the speed of the aircraft V _c .

Block 3 - block generating control signals of the first and second groups of air bypass flaps. Block 3 has two outputs connected respectively to the first and second groups of dampers (not shown). The formation of control signals I ^1gr ₁ and I ^2gr _{1 is} carried out as follows:

;- the signal to close the air bypass flaps of the first group (I ^1gr ₁ = 1) is generated at a reduced speed n _tk of the turbocharger rotor above a predetermined value, where

;

- a signal to close the air bypass flaps of the second group (I ^2gr ₁ = 1) is generated at I ^1gr ₁ = 1 and V _c ≥60 ... 70 km / h.

As the algorithms for generating signals I ^1gr ₁ and I ^2gr ₁ can be used algorithms of other known methods of controlling the dampers.

Block 4 - the position sensor of the control lever of the gas turbine engine L _ore .

Block 5 - block forming the threshold value L ^{threshold of} _ores , which characterizes the inclusion of a reversing device.

Block 6 is a block for generating a reverse enable signal (comparator). In block 6, L _ores are compared with L _ores ^threshold . When the engine is operating on a direct thrust, L _{ores are} greater than L _ores ^threshold ; therefore, a signal I ₂ = 0 is generated in block 6. When the engine is running on the reverse L _ores <L ^{threshold of} _ores , the control signal I ₂ = 1 is formed at the output of block 6 (sign of the operation of the gas turbine engine in reverse thrust mode).

The switch key 7 is designed to close / open the signal circuits I ^1gr ₁ and I ^2gr ₁ under the influence of the control signal I ₂ . When I ₂ = 0, the signals I ^1gr ₁ and I ^2gr _{1 are} switched directly to the output of the switch key 7. When I ₂ = 1, the signal circuits I ^1gr ₁ and I ^2gr ₁ are opened, ensuring the open state of the air bypass flaps of the first and second groups regardless GTE operation mode and aircraft speed.

The accelerator 8 has two acceleration programs. When I ₂ = 0, the acceleration program uses the acceleration program used in direct traction modes. When I ₂ = 1, the acceleration program 8 employs an acceleration program with an increase in fuel consumption ΔGt increased by 10 ... 15% compared to the acceleration program in direct traction modes.

Improving the dynamic characteristics of a gas turbine engine in reaching the maximum reverse thrust mode helps to reduce aircraft braking time and reduce the likelihood of compressor damage.

The program n _tk = f (n _{tk pr} ) was selected as the overclocking program. However, it is clear to technicians that any other can be selected as the pick-up program.

The method of controlling a double-circuit twin-shaft gas turbine engine of the aircraft is carried out using the inventive device as follows.

When the gas turbine engine is running on low gas and other low direct thrust modes, for example, when taxiing to an executive start or parking, the air bypass flaps of both groups are in the open position. Contaminating particles that are separated in the fan and KND due to centrifugal forces, through the open flaps of both groups enter the external circuit and are further ejected from the gas turbine engine without damaging it.

When the aircraft takes off (up to V _c <60 ... 70 km / h) and the gas turbine engine operates in the increased mode, the discharge of foreign particles is carried out through the open second group of air bypass flaps.

During take-off of the aircraft (starting from V _c ≥60 ... 70 km / h), as well as in climb and cruise mode, the air bypass flaps of both groups are in the closed position to provide traction and increase compressor efficiency, but it is obvious that foreign objects these flight stages are minimal.

When the aircraft lands, the pilot sets the engine control lever (ORE) to the "Small gas" position, the bypass flaps of both groups are in the open position. Further, the pilot includes reverse thrust, after which the throttle is switched to the position of “Maximum reverse thrust”, which leads to an increase in n _{TC, etc.} Block 4 constantly measures the value of L _ores , which in block 6 is compared with the L ^{threshold of} _ores . When L _ores <L, the ^{threshold of} _ores at the output of block 6 forms a signal I ₂ = 1 (a sign of reverse operation), which is input to the switch key 7.

If there is a signal I ₂ = 1 in block 7, the control circuits of the shutters of both groups open and, regardless of the rotational speed n _{tk pr} and the speed V _{c, the} shutters remain in the open position, providing reliable protection of the engine against foreign objects and the influence of the “connected vortex” when braking the plane.

Simultaneously with the appearance of the signal I ₂ = 1, the control program for throttle response is rebuilt, while an increased excess of fuel consumption ΔGt in the combustion chamber is provided in comparison with the fuel supply program Gt in the throttle response modes for direct thrust.

Improving the dynamic characteristics of a gas turbine engine reduces the braking time of the aircraft and reduces the likelihood of compressor damage.

Claims (3)

1. A method of controlling a double-circuit twin-shaft gas turbine engine of an aircraft, including bypassing air from a low-pressure compressor through the air bypass flaps of the first and second groups and supplying fuel according to the pick-up program in direct thrust modes, characterized in that they additionally generate a reverse enable signal, according to which the opening is performed air bypass flaps of the first and second groups, regardless of the engine operating mode and aircraft speed, and the fuel is supplied to the combustion chamber according to the program p azgon with an excess of fuel consumption in the range of 10 ... 15% compared with the pick-up program in direct traction modes. 2. The method for controlling a double-circuit twin-shaft gas turbine engine of an airplane according to claim 1, characterized in that they measure L _ores characterizing the position of the engine control lever, compare it with a threshold value L _ore ^threshold and when L _ore <L _ore ^threshold , a reverse enable signal is generated . 3. A device for controlling a double-circuit twin-shaft gas turbine engine of the aircraft, including sensors of engine parameters and speed of the aircraft, connected to the control unit of the air bypass flaps from the low pressure compressor, characterized in that it further comprises a position sensor of the engine control lever L _ores , a threshold value setting unit the position of the control lever L ^{threshold of} _ores , a block for generating a signal for turning on the reverse, a switch key providing switching of control circuits of the shutters air bypass and automatic engine acceleration, and the output of the engine control lever position sensor L _ores and the output of the threshold value setting unit L _ores ^{threshold are} connected to the reverse enable signal generation unit, the output of which is connected to the input of the switch key and the input of the engine acceleration automaton.