RU2817059C1 - Method of controlling fuel dosing at ignition of combustion chamber of gas turbine engines - Google Patents

Abstract

FIELD: control or regulation of internal combustion engines.

SUBSTANCE: invention relates to automatic control of gas turbine engines (GTE) used as power units in gas and power industries. Proposed method consists in increasing supply of fuel and air compressed in compressor into combustion chamber. At transition to ignition of combustion chamber (CC), according to the "SC open" signal, the current temperature behind the turbine is memorized at start-up Ttstart and instantaneous increase in flow rate at ignition to preset value Gt start + R_Gt start, kg/h; then flow rate is increased at ignition with rate ((Gt end + R_Gt end) - (Gt start + R_Gt start))/Cit kg/h/s to preset value Gt end + R_Gt end, kg/h; wherein temperature Ttstart is controlled, at increase of Ttstart by ΔTtstarti relative to Ttstart at the moment of opening of "SC", the CC ignition sign is formed, if at the same time the current task for fuel consumption is more than the preset value Gt ig + R_Gt ig, then the task for consumption is instantly reduced to the setpoint Gt ig + R_Gt ig, kg/h; and transition to acceleration algorithm is performed, if, when forming the CC ignition feature, the current fuel consumption task is less than the predetermined value Gt ig + R_Gt ig, then the flow rate task continues to increase with a given rate to the setting Gt ig + R_Gt ig, when the setpoint is reached, a transition to the acceleration algorithm is performed, if at increase in the flow rate setting to the setpoint Gt end + R_Gt end and maintaining this flow rate for a period of time Δt_Gtend has not formed the CC ignition feature, then termination of CC non-ignition start-up is performed.

EFFECT: invention improves performance and reduces the number of non-ignition of GTE CC due to optimization of fuel consumption for ignition of combustion chamber in all operating conditions.

4 cl, 2 dwg

Description

The invention relates to the field of automatic control of gas turbine engines used as power units in the gas and energy industries.

From the prior art there is a known method for dosing fuel at the ignition of the combustion chamber (CC) of a gas turbine engine (GTE), in which the fuel supply law has the form: Gt=const (corrected for pressure and temperature at the inlet to the gas turbine engine) regardless of external conditions - rotor speed high pressure (HPC) at purge, voltage at the terminals of the ignition unit, technical condition of the gas turbine engine, and so on. The metering element of the fuel dispenser is installed at maximum speed on the ignition platform and is maintained in this position throughout the entire ignition. “Design and operation of power plants of IL-96-300, TU-204, IL-114 aircraft”: Textbook. manual for universities/B.A. Soloviev, A.A. Inozemtsev, A.A. Kulandin, I.A. Rozhkov, V.S. Akulenko; Ed. B.A. Solovyova. - M.: Transport, 1993. 171 p.

With such a fuel supply, ignition of the air-fuel mixture in the combustion chamber occurs at an almost constant ratio of air and fuel flow rates. Changes in operating conditions cause a change in the optimal fuel-air ratio, and, as a result, cause non-ignition of the air-fuel mixture (FA). With the existing fuel supply law, it is necessary to carry out a set of work to find and eliminate the malfunction, including adjusting fuel consumption. As a rule, adjustments are made to increase fuel consumption. In some cases, the combustion chamber is ignited only at very high settings, which leads to extreme surges in gas temperature behind the turboprop and termination of startup when a high temperature is reached.

The closest analogue in technical essence and adopted as a prototype is a method for controlling fuel consumption at the start of a gas turbine engine (Patent RU No. 2386836, IPC F02C9/00, published on April 20, 2010), which consists in additionally measuring the temperature of the air-fuel mixture (VTS) in the CS, if there is no increase in the temperature of the VTS within 1-2 seconds from the moment the spinning apparatus (A3) is turned on, the specified fuel consumption when igniting the CS is changed by alternating stepwise action with a frequency of 1-2 Hz and with an amplitude increasing in magnitude from zero with a discreteness of 5% of the value of the specified fuel consumption when igniting the compressor station.

The disadvantages of this method are that the change in the specified fuel consumption during ignition of the combustion chamber is implemented through alternating and stepwise effects with a sufficiently high frequency, which significantly reduces the possibility of ensuring the fuel assembly is ideal for ignition. A lean fuel assembly increases the likelihood of failure to ignite, and ignition of a rich fuel assembly leads to extreme surges in gas temperature behind the turbine and termination of startup when a high temperature is reached. In addition, the method does not describe the algorithm of actions in the event of failure to ignite the combustion chamber.

The technical problem, the solution of which is provided when implementing the proposed invention, and cannot be achieved when using a prototype, is a decrease in operational characteristics and an increased number of non-ignitions of the combustion chamber of a gas turbine engine when operating conditions change and the technical condition of the engine deteriorates, reducing the reliability of the gas turbine engine.

The technical task is to improve the performance characteristics and reduce the number of non-ignitions of the combustion chamber of a gas turbine engine, ensure optimization of fuel consumption for ignition of the combustion chamber in all operating conditions, and increase the reliability of the operation of the gas turbine engine.

The technical problem is solved due to the fact that in the method of controlling fuel dosing during ignition of the combustion chamber of gas turbine engines, which consists in increasing the supply of fuel and air compressed in the compressor into the combustion chamber, according to the invention, when switching to ignition of the combustion chamber, according to the signal “ Stop valve open”, the current temperature behind the turbine at startup Ttzap is stored and the flow rate on ignition is instantly increased to a predetermined value Gt start + R_Gt start, where Gt start is the nominal setting of the initial fuel consumption at ignition, kg/h, R_Gt start is the set point adjustment initial fuel consumption during ignition, kg/h; then the ignition flow rate is increased at a rate ((Gt con + R_Gt con) - (Gt start + R_Gt start))/Krt kg/h/s to the preset value Gt con + R_Gt con, where Gt con is the nominal final flow rate setting fuel during ignition, kg/h, R_Gt con - adjustment of the final fuel consumption setting during ignition, kg/h, Krt - coefficient of rate of change in fuel consumption, s; at the same time, the temperature Ttzap is controlled, with an increase in Ttzap by ΔTtzap relative to Ttzap at the moment of opening the “Stop valve”, where ΔTtzap is the setting for increasing Ttzap to determine ignition, °C, a sign of ignition of the combustion chamber is formed, if the current fuel consumption target is greater, than the preset value Gt rose + R_Gt rose, then the consumption target is instantly reduced to the setting Gt rose + R_Gt rose, where Gt rose is the nominal fuel consumption setting for stable combustion on ignition, kg/h, R_Gt rose is the adjustment of the fuel consumption set point for stable combustion on ignition, kg/h; and the transition to the acceleration algorithm is performed, if, when a sign of ignition of the combustion chamber is formed, the current task for fuel consumption is less than the preset value Gt rose + R_Gt rose, then the fuel consumption task continues to increase at a given rate until the set point Gt rose + R_Gt rose, when it reaches setting, a transition to the acceleration algorithm is performed, if, when increasing the flow rate target to the set point Gt con + R_Gt con and maintaining this flow rate for a time Δt_Gtcon, s, a sign of ignition of the combustion chamber is not formed, then the start is terminated due to non-ignition of the combustion chamber.

In addition, the rate of change coefficient of fuel consumption Krt is equal to 5…25⋅s.

In addition, the increase setting for determining ignition ΔTtzapr is 30...130°C.

In addition, the delay time at the final fuel consumption setting for ignition Δt_Gtkon is 1...5 s.

The technical solution makes it possible to improve the performance characteristics and reduce the number of non-ignitions of the combustion chamber of a gas turbine engine by optimizing fuel consumption for igniting the combustion chamber under all operating conditions and thereby increasing the reliability of the operation of the gas turbine engine.

The present invention is illustrated by drawings.

In fig. 1 shows a graphical explanation of the proposed method.

In fig. 2 is a block diagram illustrating the procedure for implementing the proposed method.

Block 1 is a memory block that remembers the temperature value Ttsap, °C at the moment the stop valve opens. The output signal I ₁ enters block 5 and serves as a setpoint for calculating the difference between the current temperature behind the turbine and the temperature Tsap at the moment the stop valve opens.

Block 2 is a summation block in which two values are added up, the amount of fuel consumption for stable combustion during ignition and its adjustment. The output signal I ₂ serves as the steady combustion flow rate setting for the comparison block 9 and the selection block 13.

Block 3 is a summation block in which two values are added, the value of the initial fuel consumption during ignition and its adjustment. The output signal I ₃ serves as the initial ignition flow rate setting for the calculation block 6 and the integrating block 8.

Block 4 is a summation block in which two values are added up, the value of the final fuel consumption during ignition and its adjustment. The output signal I ₄ serves as the final flow rate setting for ignition for the calculation block 6, the integrating block 8 and the comparison block 10.

Block 5 - is a subtractive block that determines the difference between the current temperature behind the turbine at startup Ttzap and the temperature value Ttzap at the moment the stop valve opens. The output signal I ₅ goes to the comparison block 7.

Block 6 - is a block that calculates the rate of change in fuel consumption during ignition from initial to final. The output signal I ₆ is supplied to the input of the integrating block 8.

Block 7 is a comparison block (comparator) that compares the difference between the current temperature behind the turbine at the start of Ttzap and the temperature value Ttzap at the moment of opening the stop valve with the setting of the ignition sign of the combustion chamber equal to ΔTtzap. When the temperature difference exceeds the set point, the output signal I ₇ =1 - “Ignition of the combustion chamber” is generated, which is supplied to block 11.

Block 8 is an integrating block that changes fuel consumption during ignition from the initial value I ₃ to the final value I ₄ at a rate of I ₆ in the presence of the “SC open” signal. The output signal I ₈ serves as the value of the current fuel consumption reference to the input of the comparison block 9, the comparison block 10 and the selection block 13.

Block 9 is a comparison block (comparator) that compares the value of the current fuel consumption target I ₈ with the steady combustion flow rate setting I ₂ , when the value of the current fuel consumption target exceeds the set value, the signal I ₉ =1 is generated. The output signal I ₉ goes to block 11.

Block 10 is a comparison block (comparator) that compares the value of the current fuel consumption setting I ₈ with the final ignition consumption setting I ₄ , when the value of the current fuel consumption setting exceeds the setting value, the signal I ₁₀ =1 is generated. The output signal I ₁₀ goes to block 12.

Block 11 is a logical multiplication (AND) block, which, in the presence of the signal “Sign of ignition of the combustion chamber” (I ₇ = 1) and the signal I ₉ , generates the signal I ₁₁ = 1 - “Transition to acceleration”. Also, the output signal I ₁₁ is supplied to block 13.

Block 12 - is a delay block (timer), if there is a signal I ₁₀ about the value of the current fuel consumption setting exceeding the value of the final consumption setting on ignition during the time Δt_Gtkon, the signal I ₁₂ = 1 - “Start Termination” is generated.

Block 13 is a selection block; in the absence of signal I ₁₁ - “Transition to acceleration”, the current fuel consumption setting from the integrating block 8 is issued to control the dispenser; in the presence of signal I _11, the steady combustion flow rate setting is issued to control the dispenser.

The following designations and names are used in the description:

SK - stop valve - a valve that supplies fuel to the metering element and then to the KS;

Ttzap is the temperature behind the turbine at startup, °C;

ΔTtzapr - setting for increasing Ttzap to determine ignition, 30…130°C;

GT rose - nominal fuel consumption setting for stable combustion on ignition, 150…300 kg/h;

R_Gт rose - adjustment of the fuel consumption setting for stable combustion on ignition, kg/h;

GT start - nominal setting of initial fuel consumption during ignition, 0…150 kg/h;

R_Gt start - adjustment of the initial fuel consumption setting for ignition, kg/h;

GT con - nominal setting for final fuel consumption during ignition, 300…400 kg/h;

R_Gt con - adjustment of the final fuel consumption setting during ignition, kg/h;

Krt - coefficient of rate of change in fuel consumption, 5...25 s.

Δt_Gtkon - delay time at the final fuel consumption set point during ignition, 1…5 s.

The values ΔTtzapr, Gt rose, Gt start, Gt con, Krt, Δt_Gtcon used in the invention are determined by calculation and experiment depending on the power of the gas turbine engine and the design of the combustion chamber, the values of R_Gt rose, R_Gt start, R_Gt con are determined by calculation and experiment depending on the state of the gas turbine engine and operating conditions.

The method is carried out as follows.

When switching to ignition of the combustion chamber, at the “SK open” signal in block 1, the current temperature behind the turbine Ttzap is stored and the ignition flow rate setting is instantly increased in integrating block 8 to the initial value Gt start, kg/h + R_Gt start, kg/h (integrator initial setting), which is calculated in block 3.

Next, in block 8, the ignition flow rate is increased at a rate ((Gt end, kg/h + R_Gt end, kg/h) - (Gt start, kg/h + R_Gt start, kg/h))/Krt kg/h /s, the rate of increase is calculated in block 6, up to a predetermined value Gt con, kg/h + R_Gt con, kg/h, which is calculated in block 4. At the same time, the temperature Tzap is controlled, with an increase in Tzap by ΔTzapr relative to Tzap at the moment of opening SK, the sign of ignition of the CS is formed, the difference between the current Ttzap and Tsap at the moment of opening the SK is calculated in block 5, comparison of the temperature difference with the setting ΔTtzapr and the formation of the sign of ignition of the CS is performed in block 7.

In block 9, a comparison is made of the value of the current fuel consumption setting I ₈ , which is calculated in block 8, with the steady combustion flow rate setting Gt rose, kg/h + R_Gt rose, kg/h, which is calculated in block 2. If the value of the current flow rate is exceeded fuel above the set value, the signal I ₉ =1 is generated.

If, when the ignition signal is generated, the current fuel consumption target is greater than the preset value Gt rose, kg/h + R_Gt rose, kg/h, then the fuel consumption task is instantly reduced to the set value Gt rose, kg/h + R_Gt rose, kg /h and the transition to the acceleration algorithm is performed. The signal for switching to the acceleration mode is generated in block 11, therefore, the signal in block 13 instantly reduces the flow rate to the set point Gt rose, kg/h + R_Gt rose, kg/h.

If, when the ignition sign is formed, the current fuel consumption task is less than the preset value Gt rose, kg/h + R_Gt rose, kg/h, then the consumption task continues to increase at a given rate until the set point Gt rose, kg/h + R_Gt roz, kg/h, when the setpoint is reached, a transition to the acceleration algorithm is performed, if by increasing the flow rate task to the setpoint Gt con, kg/h + R_Gt con, kg/h (the comparison is performed in block 10) and maintaining this flow rate over time Δt_Gtkon (the delay is implemented in block 12), the ignition sign of the combustion chamber has not been formed, then the start is terminated due to non-ignition of the combustion chamber.

Examples of implementation of the invention are given.

Example 1. No ignition

Gt start = 0 kg/h, R_Gt start = 0 kg/h, Gt end = 400 kg/h,

R_Gt con = 0 kg/h, Gt rose = 300 kg/h, R_Gt rose = 0 kg/h,

Krt = 25 s, ΔTtzapr = 130°C, Δt_Gtkon = 5 s.

According to the “SK open” signal, the current temperature behind the turbine was recorded at the start of Ttzap and the ignition flow rate was instantly increased to a predetermined value (Gt start + R_Gt start) = 0 kg/h, then the ignition flow rate was increased at a rate ((Gt end + R_Gt con) - (Gt start + R_Gt start))/Krt = 16 kg/h/s to a predetermined value (Gt con + R_Gt con) = 400 kg/h, maintaining this flow rate for a time Δt_Gt con s, at In this case, the temperature Ttzap was controlled, an increase in Ttzap by ΔTtzapr °C relative to Ttzap did not occur at the moment of opening the SC, the sign of ignition of the CS was not formed, after the time Δt_Gtkon the launch was terminated due to non-ignition of the CS.

Example 2. Late ignition

Gt start = 0 kg/h, R_Gt start = 0 kg/h, Gt end = 400 kg/h,

R_Gt con = 0 kg/h, Gt rose = 300 kg/h, R_Gt rose = 0 kg/h, Krt = 25 s,

ΔTtzapr = 130°C, Δt_Gtkon = 5 s.

According to the “SK open” signal, the current temperature behind the turbine at startup Ttzap was recorded and the ignition flow rate was instantly increased to a predetermined value (Gt start + R_Gt start) = 0 kg/h, then
the ignition flow rate was increased at a rate
((Gt end + R_Gt end) - (Gt start + R_Gt start))/Krt = 16 kg/h/s, while the temperature Ttzap was controlled. An increase in Ttzap by ΔTtzapr = 130°C relative to Ttzap at the moment of opening the SC and the formation of the sign of ignition of the CS occurred at the current fuel consumption target greater than the previously specified value (Gt rose + R_Gt rose) = 300 kg/h. When the sign of ignition of the combustion chamber was formed, the consumption target was instantly reduced to the set point (Gt rose + R_Gt rose) = 0 kg/h and a transition was made to the acceleration algorithm from this fuel consumption value, which made it possible to reduce the temperature overshoot.

Example 3. Early ignition

Gt start = 0 kg/h, R_Gt start = 0 kg/h, Gt end = 400 kg/h,

R_Gt con = 0 kg/h, Gt rose = 300 kg/h, R_Gt rose = 0 kg/h, Krt = 25 s,

ΔTtzapr = 130°C, Δt_Gtkon = 5 s.

According to the “SK open” signal, the current temperature behind the turbine was recorded at the start of Ttzap and the ignition flow rate was instantly increased to a predetermined value (Gt start + R_Gt start) = 0 kg/h, then the ignition flow rate was increased at a rate ((Gt end + R_Gt end) - (Gt start + R_Gt start))/Krt = 16 kg/h/s, while the temperature Ttzap was controlled. An increase in Ttzap by ΔTtzapr °C relative to Ttzap at the moment of opening the SC and the formation of a sign of ignition of the CS occurred at the current fuel consumption target less than the previously specified value (Gt rose + R_Gt rose) = 300 kg/h. When the sign of ignition of the combustion chamber was formed, the increase in fuel consumption continued at a rate ((Gt con + R_Gt con) - (Gt start + R_Gt start))/Krt = 16 kg/h/s to the set point (Gt rose + R_Gt rose) = 300 kg/ h, after which a transition was made to the acceleration algorithm from this fuel consumption value, which made it possible to avoid flameout and reduce the temperature rise due to fuel surge to ensure the required acceleration during acceleration.

The given algorithm for supplying fuel during ignition of the compressor station allows:

- perform ignition of the combustion chamber with an automatic search for optimal ignition conditions in the studied range of fuel consumption (from Gt start, kg/h + R_Gt start, kg/h to Gt end, kg/h + R_Gt end, kg/h). So, when two channels of the ignition unit operate with a frequency of 3 Hz, about 90 discharges occur on two spark plugs in 15 seconds. Thus, in 15 seconds of operation of the ignition unit, 90 ignition attempts are performed with a change in fuel consumption between attempts by ≈2.2 kg/h (with a difference between the initial and final consumption of 200 kg/h);

- reduce fuel consumption during ignition (when igniting at high flow rate) to the established norm, which reduces the maximum gas temperature behind the turbine;

- increase fuel consumption to increase the likelihood of flame transfer to the remaining flame tubes, when the starting flame tubes are ignited and there is no flame transfer at low fuel consumption.

A positive technical result was obtained in all cases of implementation of the invention on all engines developed by UEC-Aviadvigatel JSC, used as power units in the gas and energy industries.

Thus, the use of the proposed invention with the above distinctive features makes it possible to increase the performance characteristics and reduce the number of non-ignitions of the combustion chamber of a gas turbine engine by ensuring optimization of fuel consumption for igniting the combustion chamber under all operating conditions and thereby increasing the reliability of the operation of the gas turbine engine.

Claims (4)

1. A method for controlling fuel dosing during ignition of the combustion chamber of gas turbine engines, which consists in increasing the supply of fuel and air compressed in the compressor into the combustion chamber, characterized in that when switching to ignition of the combustion chamber, at the signal “Open stop valve”, the current temperature behind the turbine at startup Ttzap is memorized and the ignition flow rate is instantly increased to a predetermined value Gt start + R_Gt start, where Gt start is the nominal setting of the initial fuel consumption at ignition , kg/h, R_Gt start – adjustment of the initial fuel consumption setting for ignition, kg/h; then the ignition flow rate is increased at a rate ((Gt con + R_Gt con) – (Gt start + R_Gt start))/Krt kg/h/s to the preset value Gt con + R_Gt con, where Gt con is the nominal final flow rate setting fuel during ignition, kg/h, R_Gt con – adjustment of the final fuel consumption setting during ignition, kg/h, Krt – coefficient of rate of change in fuel consumption, s; at the same time, the temperature Ttzap is controlled, with an increase in Ttzap by ΔTtzap relative to Ttzap at the moment of opening the stop valve, where ΔTtzap is the setting for increasing Ttzap to determine ignition, a sign of ignition of the combustion chamber is formed, °C, if the current fuel consumption target is greater than in advance given value Gt rose + R_Gt rose, then the consumption target is instantly reduced to the set point Gt rose + R_Gt rose, where Gt rose is the nominal fuel consumption setting for stable combustion on ignition, kg/h, R_Gt rose is the adjustment of the fuel consumption set point for stable combustion on ignition, kg/h; and the transition to the acceleration algorithm is performed, if, when a sign of ignition of the combustion chamber is formed, the current task for fuel consumption is less than the preset value Gt rose + R_Gt rose, then the fuel consumption task continues to increase at a given rate until the set point Gt rose + R_Gt rose, when it reaches setting, a transition to the acceleration algorithm is performed, if, when increasing the flow rate target to the set point Gt con + R_Gt con and maintaining this flow rate for the time Δt_Gtcon, s, the sign of ignition of the combustion chamber is not formed, then the start is terminated due to non-ignition of the combustion chamber. 2. The method according to claim 1, characterized in that the coefficient of the rate of change in fuel consumption Krt is equal to 5...25 s. 3. Method according to claim 1, characterized in that that the increase setting for determining ignition ΔTtzapr is equal to 30...130°C. 4. Method according to claim 1, characterized in that that the delay time at the final fuel consumption setting for ignition Δt_Gtkon is 1-5 s.