JPH0612078B2 - Gas turbine engine surging prevention method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for preventing surging during engine operation in a two-shaft gas turbine engine, and particularly to predicting and detecting entry into a surging area. Regarding how to prevent entering.

[Conventional technology]

2. Description of the Related Art Conventionally, a two-shaft gas turbine engine is known in which a compressor turbine is rotationally driven by combustion gas and an output turbine is rotationally driven by gas from the compressor turbine. The structure of the two-shaft gas turbine engine is as shown in FIG. In FIG.
1 is a compressor, 2 is a heat exchanger, 3 is a fuel device, 4 is a fuel actuator, 5 is a compressor turbine, 6 is a variable nozzle, 7 is a variable nozzle actuator, and 8 is an output turbine. In operation, air is compressed by the compressor 1, heated to a higher temperature by the heat exchanger 2 and burned by the combustor 3 to produce high temperature gas, and the compressor turbine 5 is driven. Further, the gas passing through the compressor turbine 5 passes through the variable nozzle 6 and the output turbine 8 is driven. Here, as for the engine efficiency, the higher the turbine inlet temperature T _{4, the} better the thermal efficiency, so fuel control and variable nozzle control are performed.

The characteristics of such a gas turbine engine are as follows:
As shown in the figure, there is a surging region S corresponding to the gas generator rotation speed (engine rotation speed) N ₁ . When the engine enters the surging area S, the engine becomes inoperable and the pulsation of air adversely affects the impeller and the like. Therefore, it is necessary to prevent entry into the surging area S during engine operation.

Conventionally, as shown in FIG. 8, the surging is prevented by a pressure ratio P ₃ of the air flow rate G _a , the compressor outlet pressure P ₃ and the atmospheric pressure P _0.
By understanding the characteristics of the compressor in advance from the relationship with / P ₀ ,
The engine is controlled by controlling the variable nozzle actuator and the fuel actuator so that the engine is operated in a range away from the surging area S.

As another surging prevention method, the inlet pressure and the outlet pressure are measured (JP-A-52-8215, JP-A-59-28025, JP-A-59-108828), and the engine surging is performed based on the pressure change. It is conceivable to perform predictive detection and control the engine so as not to enter the surging range.

[Problems to be Solved by the Invention]

However, when the operating range of the conventional engine is set to a range considerably apart from the surging range, there is a problem that the performance of the engine must be suppressed to some extent.

Further, when the surging of the engine is predicted and detected from the pressure change of the inlet pressure and the outlet pressure to prevent the surging, the pressure change due to the acceleration / deceleration is also widened, and the surging may be erroneously determined.

An object of the present invention is to reliably prevent the occurrence of surging even when the operating region of the engine is set to a region close to the surging region, and to prevent the surging from being erroneously judged due to the influence of pressure change due to acceleration / deceleration. (EN) A high gas turbine engine surging prevention method.

[Means for Solving the Problems]

The method for preventing surging of a gas turbine engine according to the present invention for achieving the above object comprises the following methods. That is, a compressor that suction-compresses air, a combustor that mixes and burns compressed air with fuel, a compressor turbine that is driven to rotate by gas from the combustor, and a gas that controls the compressor turbine. A method for preventing surging of a two-shaft gas turbine engine, comprising: a variable nozzle; and an output turbine that is rotationally driven by gas controlled by the variable nozzle, comprising: an inlet pressure or an outlet pressure of a compressor; Measure and enter the number of the measured compressor inlet pressure or outlet pressure fluctuations, and use the calculator to set the compressor inlet pressure or outlet pressure fluctuations that correspond to engine speed changes during acceleration and deceleration to zero. Compensation and predicting and detecting surging when the time differential value of the corrected compressor inlet pressure or outlet pressure is greater than or equal to a predetermined value. Surging prevention method of the turbine engine.

[Action]

In the above-mentioned method of the present invention, of the detected inlet pressure of the compressor, change amount of the outlet pressure, after removing the fluctuation of the compressor inlet pressure or the outlet pressure due to the acceleration and deceleration of the engine, the inlet pressure or the outlet pressure. Since the differential value of is calculated and the surging is predicted and detected based on it, the erroneous determination of surging due to the influence of engine acceleration / deceleration can be avoided.

In addition, since the amount of change in pressure can be detected at the rising portion of the change in the inlet pressure and outlet pressure that is actually detected, it can be predicted and detected before actually entering the surging region, and the operating region of the engine Since it is possible to reliably prevent entry into the surging area, it is possible to bring the engine operating area closer to the surging line and enable high performance operation.

〔Example〕

A preferred embodiment of a surging prevention method for a gas turbine engine according to the present invention will be described below with reference to the drawings.

FIG. 1 shows the two-shaft gas turbine engine shown in FIG. 7 with the addition of a device for carrying out the method of the invention. That is, the inlet of the compressor 1 is provided with the detecting end 10 for detecting the inlet pressure, or the outlet is provided with the detecting end 11 for detecting the outlet pressure. As a more specific detection position, as shown in FIG. 2, the inlet pressure or the outlet pressure of the compressor 1 is measured at the position of the detection end 10 or 11. 12
Is a diffuser, 13 is a rotor shaft, and 14 is a housing. Since the other device arrangements are the same as or similar to those shown in FIG. 7, the same reference numerals are given and description thereof will be omitted.

Next, a control device for preventing surging in the present embodiment will be described. As shown in the block diagram of FIG. ₃ , the detected value of the inlet pressure P ₁ or the outlet pressure P ₃ of the compressor 1 is input to the calculator 16 or 17, respectively. at the same time,
The engine speed N ₁ is input to the calculator 16 or 17. The calculator 16 or 17 is connected to the differentiator 18 or 19, and the signal from the differentiator 18 or 19 is input to the calculator 20. In the present embodiment, the output signal from the calculator 20 controls the variable nozzle actuator 7 for adjusting the control amount of the variable nozzle 6 and the fuel amount to the combustor 3 to control the engine speed N ₁
Is input to both fuel actuators 4 for adjusting

In this embodiment, both the variable nozzle actuator 7 and the fuel actuator 4 are used as the surging prevention actuator, but either one may be used.

The method of the present invention is carried out using the above apparatus as follows.

The inlet pressure P ₁ or the outlet pressure P ₃ measured at the detection end 10 or 11 is input to the calculator 16 or 17, and the pressure fluctuations of P ₁ and P _{3 with} respect to the engine rotation during acceleration and deceleration are corrected to 0. The corrected P ₁ and P ₃ values from which the variation of the inlet pressure or the outlet pressure due to the acceleration and deceleration of the engine are removed
It is sent to 8 and 19, and as shown in FIGS. 5 and 6, it is time-differentiated and the rate of change is calculated. That is, the differentiator detects a sudden change in pressure of the corrections P ₁ and P ₃ .
Generally, when entering the surging region, P ₁ changes in the positive pressure direction and P ₃ changes in the negative pressure direction. Then, when entering the surging region, P ₁ and P ₃ change rapidly. Therefore, the differentiators 18 and 19 calculate the rate of change of the initial pressure (at the time of rising of the change) to obtain the change amounts ΔP ₁ and Δ
P ₃ is predictively detected. Here, the output of the differentiator 18, 19 is V
_{When 0} is set, V ₀ = K (dP / dt). K is a coefficient and is determined by experiment. The output of the differentiator 18, 19 is the calculator 20
When any _one of ΔP ₁ and ΔP ₃ exceeds a predetermined value, a signal from the arithmetic unit 20 is issued. Calculator 20
Then, the operation start time and control amount of the variable nozzle actuator 7 and the fuel actuator 4 are calculated, and the outputs are input to the variable nozzle actuator 7 and the fuel actuator 4 to control the variable nozzle 6 and the engine speed.

Next, FIG. 4 is an operation diagram (engine characteristic diagram) of this embodiment.
Indicates the operating state. When the variable nozzle 6 is controlled (opened) when entering the surging area S (point A) in the state of N1 = 70% gas generator rotational speed (engine rotational speed),
Although the operating region setting line T ₄ is lowered, the gas generator rotational speed is increased to the position of point B. Therefore, by controlling the fuel, N1 = 70% gas generator rotation speed (C
Point) to control the current gas generator speed while preventing surging.

In the above description, the control just before the point A enters the surging area S is shown. However, it is more desirable to predictably detect that the point A approaches the surging area S and control the operating area to the T ₄ line. Is easily performed by increasing the prediction detection accuracy of ΔP ₁ and ΔP ₃ .

〔The invention's effect〕

According to the present invention, it is possible to predict and detect that the operating region has approached the surging region before actually entering the surging region, so that the operating region is set to a region close to the surging region without entering the surging region. It is possible to improve the performance of the engine. In addition, the time differential value of the inlet pressure or the outlet pressure is detected, excluding the fluctuation of the compressor inlet pressure or the outlet pressure due to the acceleration and deceleration of the engine.
Since surging is predicted, erroneous judgment of surging due to the influence of engine acceleration and deceleration can be avoided.

[Brief description of drawings]

1 is a block diagram of a gas turbine engine for carrying out a method according to an embodiment of the present invention, FIG. 2 is a block diagram of a compressor section of the apparatus shown in FIG. 1, and FIG. 3 is a block diagram of FIG. 4 is a control block diagram of the apparatus, FIG. 4 is a characteristic diagram of a gas turbine engine showing control characteristics by the method of the present invention, and FIG. 5 is an inlet pressure and time showing a state of pressure change detection by the control apparatus of FIG. FIG. 6 is a relational diagram between outlet pressure and time showing a state of pressure variation detection by the control device of FIG. 3, FIG. 7 is a configuration diagram of a conventional gas turbine engine, and FIG. FIG. 4 is a characteristic diagram showing a surging region of the gas turbine engine. 1 ... Compressor 2 ... Heat exchanger 3 ... Combustor 4 ... Fuel actuator 5 ... Compressor turbine 6 ... Variable nozzle 7 ... Variable nozzle actuator 8 ... Output turbine 10, 11 ... Detection end 16 , 17 …… Calculator 18, 19 …… Differentiator 20 …… Calculator P ₁ …… Inlet pressure P ₃ …… Outlet pressure P ₀ …… Atmospheric pressure N ₁ …… Engine speed

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-52-8215 (JP, A) JP-A-59-28025 (JP, A) JP-A-59-108828 (JP, A) JP-A 61- 53426 (JP, A) JP 59-7049 (JP, B2)

Claims (1)

[Claims] 1. A compressor for suction-compressing air, a combustor for mixing compressed air with fuel and burning the same, a compressor turbine rotatably driven by gas from the combustor, and a gas from the compressor turbine. A method for preventing surging of a two-shaft gas turbine engine, comprising: a variable nozzle that controls the pressure of the compressor; and an output turbine that is driven to rotate by the gas controlled by the variable nozzle. Calculating the engine speed, inputting it, and calculating the pressure fluctuation of the compressor inlet pressure or the outlet pressure corresponding to the engine speed change during acceleration and deceleration among the measured fluctuations of the compressor inlet pressure or outlet pressure. Is corrected to 0, and when the time differential value of the corrected compressor inlet pressure or outlet pressure is equal to or greater than a predetermined value, the surging is predicted and detected. A characteristic method for preventing surging of a gas turbine engine.