RU2601712C2 - Noise-immune self-tuning of gas turbine engine gas temperature meter - Google Patents

Abstract

FIELD: engines and pumps.

SUBSTANCE: invention can be used in systems for measuring temperature of gas turbine engines (GTE). First proportional link of this meter is connected with its input to differentiator output while its output is connected to second input of second multiplier unit. Meter also comprises series-connected second proportional link with input connected to output of second multiplier unit and third adder with second input connected to output of integrator and with output connected to second input of second adder.

EFFECT: increase of noise immunity of gas temperature meter of gas turbine engine.

1 cl, 5 dwg

Description

The invention relates to the field of gas temperature measuring systems of a gas turbine engine (GTE).

A self-adjusting device for measuring temperature is known, comprising primary and secondary thermal converters connected respectively to the primary and secondary corrective links, a comparison unit whose inputs are connected to the output of the primary thermal converter and the output of the auxiliary corrective link, and the output is connected to an actuator whose outputs are connected to the control the inputs of the corrective links [Shukshunov V.E. Corrective links in non-stationary temperature measuring devices. M., Energy, 1970, p. 97, fig. 62].

The disadvantages of this device are low dynamic accuracy and poor noise immunity.

There is also another self-adjusting device for measuring rapidly changing temperatures, containing a series-connected thermocouple, a second adder, a first differentiator, a first multiplication unit, a first adder, the second input of which is connected to the output of the second adder, the output of which is a value, the indirect temperature determination unit is connected in series, the unit comparison, the second input of which is the output value from the first adder, the second differentiator, the second block is multiplied Ia, the second input of which is the output of the first differentiator, an integrating amplifier, whose output is connected to the second input of the first multiplier, a filter connected in series, the input of which is the output of the second differentiator, the output of which is connected to the second input of the second adder. In this device, self-tuning is carried out according to the signal from the device output and the signal from the indirect temperature determination unit [Kudryavtsev A.V., Petunin V.I., Shaimardanov F.A. On increasing the dynamic accuracy of determining the temperature of gases behind a turbine of a gas turbine engine. - Abstracts dokl. All-Union Scientific conferences Methods and means of machine diagnostics of gas turbine engines and their elements, vol. 2, Kharkov, 1980, p. fifty].

However, this device has a low quality transient adjustment of the time constant of the correction link under various initial conditions. In addition, the device has low noise immunity, which adversely affects the quality of temperature measurement processes.

A thermocouple can be considered as an inertial link with a transfer function [B. Cherkasov Automation and regulation of jet engines. - M.: Mechanical Engineering, 1988. - 360 p., Integrated Systems for Automatic Control of Aircraft Power Plants / Ed. A.A. Shevyakova. - M.: Mechanical Engineering, 1983. - 283 p.]:

,

,

where K _t - transfer coefficient of the thermocouple;

T _t - the time constant of the thermocouple.

With a change in the operation mode of the gas turbine engine and flight conditions, the thermocouple time constant T _t changes in accordance with the change in the flow rate of the gas flowing around it G _g :

, где T_тр и G_гр - расчетные значения.

where T _Tr and G _gr - calculated values.

For conventional shielded thermocouples with a gas flow installed on a gas turbine engine, the time constant in starting conditions is within (1.5 ... 4) s.

To compensate for the dynamic error of the thermocouple in the measurement circuit after the thermocouple, it is necessary to introduce a serial thermocouple inertia compensator (KIT) with the transfer function:

,

,

where K _to - the transmission coefficient of the CIT;

T _t - time constant KIT;

τ _to << T _to .

Then the transfer function of the entire temperature meter:

,

,

where K _and = K _t K _k .

When compensating for the dynamic error of the thermocouple close to ideal

(T _to = T _t ), we obtain

where K _and - meter transfer coefficient;

τ _to - the time constant of the CIT.

In other cases, there will be either undercompensation (T _k <T _t ), or overcompensation (T _k > T _t ), and undercompensation leads to an overflow of gas temperature, and overcompensation leads to undersupply of thrust in a closed gas turbine self-propelled gun during transient processes.

The fulfillment of condition (1) at various gas-turbine engine modes and under different flight conditions is possible only due to a change in Т _к in a self-tuning gas temperature meter.

When constructing self-tuning gas temperature meters, indirect measurements of various gas-turbine engine parameters are used.

Consider a self-adjusting device for measuring rapidly changing parameters [Kudryavtsev A.V., Shaimardanov F.A., Frid A.I., Ryzhov I.D. Self-adjusting device for measuring rapidly changing temperatures, Copyright certificate No. 1122904].

(

- значение температуры на выходе корректирующего звена), последовательно соединенные блок 7 косвенного определения температуры, блок 5 сравнения, вторым входом которого является выходное значение с первого сумматора 4, второй дифференциатор 10, второй блок 11 умножения, второй вход которого является выходом первого дифференциатора 2, интегрирующий усилитель 6, выход которого подключен ко второму входу первого блока умножения 3, последовательно соединенные фильтр 8, входом которого является выход второго дифференциатора 10, выход которого подключен ко второму входу второго сумматора 9.The device comprises a series-connected thermal converter 1, a second adder 9, a first differentiator 2, a first multiplication unit 3, a first adder 4, the second input of which is connected to the output of the second adder 9, the output of which is the value

(

is the temperature value at the output of the correction unit), the indirect temperature determination unit 7, the comparison unit 5, the second input of which is the output value from the first adder 4, the second differentiator 10, the second multiplier 11, the second input of which is the output of the first differentiator 2, are connected in series an integrating amplifier 6, the output of which is connected to the second input of the first multiplication unit 3, connected in series to a filter 8, the input of which is the output of the second differentiator 10, the output of which is under is connected to the second input of the second adder 9.

The device generates a value of T _k according to the law:

where λ is a constant value;

- производная по времени сигнала

на выходе термопреобразователя;

- time derivative of the signal

at the output of the thermal converter;

- производная величины

, где

- значение сигнала, вырабатываемого блоком косвенного определения температуры.

- derivative of the quantity

where

- the value of the signal generated by the indirect temperature determination unit.

и выхода сумматора 4, который является одновременно и выходом устройства, формирует сигнал рассогласовании

. После дифференцирования во втором дифференциаторе 10 сигнал

умножается в блоке 11 на сигнал

, поступающий с выхода дифференциатора 2, и далее поступает на вход интегрирующего усилителя 6 с коэффициентом усиления λ. С выхода усилителя 6 сигнал T_k, пропорциональный величине (2), подается на вход блока 3 умножения, при этом постоянная времени корректирующего звена устанавливается равной постоянной времени термопреобразователя.Block comparison 5 for signals from the output of block 7 indirect temperature determination

and the output of the adder 4, which is both the output of the device, generates a mismatch signal

. After differentiation in the second differentiator 10 signal

multiplied in block 11 by the signal

coming from the output of the differentiator 2, and then goes to the input of the integrating amplifier 6 with a gain of λ. From the output of amplifier 6, a signal T _k proportional to (2) is supplied to the input of the multiplication unit 3, while the time constant of the correction link is set equal to the time constant of the thermal converter.

формируется сумматором 4 по сигналам с выхода первого блока 3 умножения и с выхода второго сумматора 9.Output signal

formed by the adder 4 according to the signals from the output of the first block 3 of multiplication and from the output of the second adder 9.

When using a device for measuring the gas temperature of a gas turbine engine in an automatic control system, the casting over the gas temperature decreases almost 3 times, which makes it possible to more accurately reach the steady state gas turbine engine operation [Kudryavtsev A.V., Shaimardanov F.A., Frid A.I. , Ryzhov I.D. Self-adjusting device for measuring rapidly changing temperatures, Copyright certificate No. 1122904].

; ДТ - датчик температуры; Д - дифференциатор; БУ - блок умножения; НП - нелинейный преобразователь; И - интегратор. [Петунин В.И. Определение температуры газа ГТД с помощью косвенных измерений // Изв. вузов. Авиационная техника. 2008. №1. - С. 51-55]. В предложенной схеме используется МТ-модель температуры газа, описываемая, например, в [Гуревич О.С., Гольберг Ф.Д. Интегрированное управление силовой установкой многорежимного самолета / О.С. Гуревич, Ф.Д. Гольберг, О.Д. Селиванов. Под общ. ред. О.С. Гуревича. - М.: Машиностроение, 1994. - 304 с.].The closest technical result achieved, chosen for the closest analogue, is a self-tuning gas temperature meter of a gas turbine engine built on the principle of closed self-tuning systems (SSS) with a reference model, where a gas-temperature gas channel model is used as a reference model

; DT - temperature sensor; D - differentiator; BU - multiplication block; NP - non-linear converter; And - an integrator. [Petunin V.I. Determination of gas temperature of a gas turbine engine using indirect measurements // Izv. universities. Aircraft technology. 2008. No. 1. - S. 51-55]. The proposed scheme uses the MT-model of gas temperature, described, for example, in [Gurevich OS, Golberg F.D. Integrated control of the power plant of a multi-mode aircraft / OS. Gurevich, F.D. Golberg, O.D. Selivanov. Under the total. ed. O.S. Gurevich. - M.: Mechanical Engineering, 1994. - 304 p.].

The following self-tuning circuit algorithm is used for this meter:

In order to increase the dynamic accuracy of the meter in the considered SNA, along with a closed loop of self-tuning, an open loop of self-tuning of the correcting link time constant by the high-pressure rotor speed n _{2 is also used} (through the NP, in accordance with the dependence of T _к1 on n ₂ , an approximate value of the correcting link T _K1 ). A more accurate adjustment of the time constant of the correction link T _{k is} carried out using the time constant T _k2 in the tuning loop, i.e. the time constant of the corrective link is the sum of two values of T _to = T _to1 + T _to2 .

The disadvantage of the considered gas temperature gauges GTD [Kudryavtsev A.V., Shaimardanov F.A., Frid A.I., Ryzhov I.D. Self-adjusting device for measuring rapidly changing temperatures, Copyright certificate No. 1122904, V. Petunin Determination of gas temperature of a gas turbine engine using indirect measurements // Izv. universities. Aircraft technology. 2008. No. 1. - S. 51-55, Figure 1] is low noise immunity, since the presence of two differentiators leads to additional interference in the circuits.

As a prototype, consider the meter [V. Petunia Determination of gas temperature of a gas turbine engine using indirect measurements // Izv. universities. Aircraft technology. 2008. No. 1. - S. 51-55, figure 1].

The task to which the claimed invention is directed is to build such a meter that is not inferior in quality of transients to similar gas temperature meters of a gas turbine engine, but has a higher noise immunity than known analogues.

The technical result is to increase the noise immunity of a gas temperature meter of a gas turbine engine.

The solution of this problem and the technical result are achieved by the fact that in a noise-free self-adjusting gas temperature meter of a gas turbine engine containing a gas temperature sensor, a differentiator, a first multiplication unit and a first adder, the second input of which is connected to the gas temperature sensor output, and a rotation speed sensor is connected in series high pressure rotor, non-linear transformation unit and a second adder, the output of which is connected to the second input of the first unit multiplication, series-connected low-pressure rotor speed sensor, gas temperature model, comparison element, second multiplication unit and integrator, high-pressure rotor speed sensor output connected to the second input of the gas temperature model, the ambient temperature sensor output connected to the third model input gas temperature, the output of the ambient pressure sensor is connected to the fourth input of the gas temperature model, the output of the first adder is connected to the second input of the comparison element , in contrast to the prototype, the first proportional link is added, the input of which is connected to the output of the differentiator, and the output is connected to the second input of the second multiplication unit, the second proportional link is connected in series, the input of which is connected to the output of the second multiplication unit and the third adder, the second input of which is connected with the output of the integrator, and the output is connected to the second input of the second adder.

The essence of the scheme is illustrated by drawings.

In FIG. 1 shows a block diagram of a gas temperature meter for a gas turbine engine; in FIG. 2, FIG. 3 - simulation results of transients of the prototype and the proposed meter at various time constants of the thermocouple (T _t = 5 s in Fig. 2 and T _t = 1 s in Fig. 3). From FIG. 2, FIG. 3 shows that the circuit of the proposed gas temperature meter is not inferior to the prototype in terms of the quality of transients. In FIG. 4, FIG. Figure 5 presents the simulation results of the same two meters in the presence of interference, from which the advantages of the proposed scheme are visible.

A noise-resistant self-tuning gas temperature meter for a gas turbine engine containing a gas temperature sensor (1), a differentiator (2), a first multiplication unit (3) and a first adder (4), a series-connected high-speed rotor speed sensor (5), a nonlinear block transformations (6) and the second adder (7), the output of which is connected to the second input of the first multiplication unit (3), the low-pressure rotor speed sensor (8) connected in series, the gas temperature model (9), electric comparison point (10), the second multiplication unit (11) and the integrator (12), the output of the high-pressure rotor speed sensor (5) is connected to the second input of the gas temperature model (9), the output of the ambient temperature sensor (13) is connected to the third the input of the gas temperature model (9), the output of the ambient pressure sensor (14) is connected to the fourth input of the gas temperature model (9), the output of the first adder (4) is connected to the second input of the comparison element (10), characterized in that it further comprises the first proportional link (15), the input of which о is connected to the output of the differentiator (2), and the output is connected to the second input of the second multiplication unit (11), the second proportional link (16) connected in series, the input of which is connected to the output of the second multiplication unit (11), and the third adder (17), the second input of which is connected to the output of the integrator (12), and the output is connected to the second input of the second adder (7).

The proposed gas temperature meter gas turbine engine operates as follows. Consider the intermediate point a (Fig. 1)

,

,

Where

;ε is a mismatch equal to

;

k ₁ - gain of the first proportional link;

- значение температуры на выходе термопары.

- the temperature value at the output of the thermocouple.

Then at the output of the third adder we get the following:

,

,

Where

k ₂ is the gain of the integrator;

k ₃ - gain of the second proportional link.

Thus, at the output of the first adder, we obtain the expression:

;

;

;

;

,

,

Where

T _k1 - the value of the time constant of the correction link obtained by the open correction circuit.

At the output of the correction loop, the control of the value of the time constant of the correction link is formed:

;

;

Self-tuning circuit algorithm:

Since the inventive gas temperature meter circuit of a gas turbine engine uses only one differentiating device and an isodromic link in the self-tuning circuit, it is more noise-resistant.

и

. Получим выражения для значения

в обоих измерителях.Consider the proposed scheme and the prototype of the gas turbine gas temperature meter, from the point of view of the influence of interference arising at the output of the differentiator. Let interference ƒ ₁ occur at the output of the differentiator in the proposed circuit. In the prototype [Petunin V.I. Determination of gas temperature of a gas turbine engine using indirect measurements // Izv. universities. Aircraft technology. 2008. No. 1. - P. 51-55] uses two differentiator, so the output of the first differentiator interference occurs ƒ _1, the output of the second differentiator interference ƒ ₂ described uniform distribution law, with a mean of 0 and a variance of 0.01. In consideration, it is assumed that

and

. Get the expressions for the value

in both meters.

в прототипе выглядит следующим образом:Expression for value

in the prototype is as follows:

We linearize expression (5):

Where

- базовое значение помех на выходе первого дифференциатора;

- the base value of the interference at the output of the first differentiator;

Δƒ ₁ is the deviation of the interference value from the base value at the output of the first differentiator;

- базовое значение постоянной времени термопары в замкнутом контуре самонастройки;

- the basic value of the thermocouple time constant in a closed loop of self-tuning;

ΔT _k2 - deviation of the value of the thermocouple time constant from the base value in a closed loop of self-tuning.

The expression for the value of T _{k2 is} as follows:

.

.

After linearization:

Where

ε ₀ is the base value of ε;

Δε is the deviation of the value of ε from the base value;

- базовое значение помех на выходе второго дифференциатора;

- the base value of the interference at the output of the second differentiator;

Δƒ ₂ is the deviation of the interference value from the base value at the output of the second differentiator.

We write expression (7) using the Laplace transform.

Where

p is the differentiation operator.

We substitute expression (8) into (6):

.

.

и

, то ε₀=0, и

.As

and

, then ε ₀ = 0, and

.

:We get the following expression for

:

,

,

.

.

Then

Expression (9) describes the effect of interference on the output signal in the prototype.

в предложенной схеме:Similarly, we get the expression for the value

in the proposed scheme:

We linearize expression (10) and obtain expression (11):

Where

- базовое значение помех на выходе дифференциатора;

- the base value of the interference at the output of the differentiator;

Δƒ ₁ - deviation of the interference value from the base value at the output of the differentiator;

- базовое значение постоянной времени термопары в замкнутом контуре самонастройки;

- the basic value of the thermocouple time constant in a closed loop of self-tuning;

ΔT _k2 - deviation of the value of the thermocouple time constant from the base value in a closed loop of self-tuning.

The expression for the value ΔT _{k2 is} as follows:

,

,

,

,

Where

ε ₀ is the base value of ε;

Δε is the deviation of the value of ε from the base value.

, где p - оператор преобразования Лапласа.Since the behavior of the system “in the small” is considered, we replace the integral with

, where p is the Laplace transform operator.

We substitute expression (12) into (11):

.

.

и

, то ε₀=0, и

.As

and

, then ε ₀ = 0, and

.

:We get the following expression for

:

,

,

.

.

Then

можно пренебречь на высоких частотах (характерных для помех), тогда выражение для

(13) упростится до (14):With an increase in the coefficient k ₃ value

can be neglected at high frequencies (characteristic of interference), then the expression for

(13) simplifies to (14):

Expression (14) describes the effect of noise at the output of the differentiator on the output signal in the proposed scheme.

From a comparison of (9) and (13), it can be seen that in the proposed scheme, the larger the values of the coefficients k ₁ and k ₃ , the more noise is suppressed, i.e. the greater the noise immunity in comparison with the prototype.

In FIG. 2, FIG. Figure 3 shows the transients with a single jump in gas temperature in the prototype and the proposed gas temperature meter of the gas turbine engine, with a thermocouple time constant equal to T _t = 5 s and T _t = 1 s, from which it is clear that the quality of the transients of the proposed meter circuit is not inferior to the quality prototype. Curve 1 - transient at the meter output, corresponding to the circuit [V. Petunin Determination of gas temperature of a gas turbine engine using indirect measurements // Izv. universities. Aircraft technology. 2008. No. 1. - S. 51-55]. Curve 2 - transient at the output of the meter, corresponding to the proposed scheme. The output to the set value of the two meters is almost the same. In steady state, curves 1 and 2 also behave approximately the same.

In FIG. 4, FIG. 5 presents the simulation results of the same meters in the presence of interference, from which it is clear that the proposed circuit has greater noise immunity than the prototype. The curves show that under the influence of interference, the proposed scheme (curve 2) is the most noise-resistant at a thermocouple time constant equal to T _t = 5 s and T _t = 1 s.

Conclusion

Thus, in the proposed meter, instead of two differentiators (see prototype), only one differentiator is used together with the isodromic link in the self-tuning circuit. As a result, the level of interference in the proposed meter is reduced and, as a result, the noise immunity of the meter as a whole is increased.

Claims (1)

A noise-resistant self-adjusting gas temperature meter for a gas turbine engine, comprising a gas temperature sensor, a differentiator, a first multiplication unit and a first adder, a second input of which is connected to an output of a gas temperature sensor, a high-pressure rotor speed sensor, a nonlinear conversion unit and a second adder, the output of which is connected to the second input of the first multiplication unit, the rotor speed sensor n low pressure, gas temperature model, comparison element, second multiplication unit and integrator, the output of the high-pressure rotor speed sensor is connected to the second input of the gas temperature model, the output of the ambient temperature sensor is connected to the third input of the gas temperature model, the output of the ambient pressure sensor to the fourth input of the gas temperature model, the output of the first adder is connected to the second input of the comparison element, characterized in that it further comprises a first proportional o, whose input is connected to the output of the differentiator, and the output is connected to the second input of the second multiplication unit, the second proportional link is connected in series, the input of which is connected to the output of the second multiplication unit, and the third adder, the second input of which is connected to the integrator output, and the output is connected to the second input of the second adder.

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