RU2725296C1 - Method for reducing fuel consumption of a gas turbine engine (gte) equipped with a starter - Google Patents

Abstract

FIELD: engine building.SUBSTANCE: invention relates to gas turbine engines for railway mainline locomotive. Method for reducing fuel consumption of gas turbine engine (GTE), equipped with electric starter, consists in the fact that during its operation at low modes and idling, forced rotation of GTE high-pressure rotor is provided. At that, it is possible to cut fuel gas supply into GTE combustion chamber at idle. Fuel supply is maintained only to provide combustion, i.e. GTE does not switch off, which allows rapid transition to other operating modes.EFFECT: technical result of using all significant features of invention consists in reduction of fuel consumption and temperature of gases during GTE operation at idle and low modes.1 cl, 5 dwg

Description

The invention relates to energy, and in particular to gas turbine engines, and more particularly to gas turbine engines for a railway main locomotive.

There is a method of reducing the fuel consumption of gas turbine engines (GTE) on low gas (idling is the term for a locomotive) by reducing the speed of its rotors. However, the magnitude of the reduction in mode and, accordingly, fuel consumption with a deep decrease in mode is limited by an increase in gas temperature to limit values due to a strong decrease in the efficiency of the turbine and compressor, and at some point the turbine power becomes less than the required compressor power. Autonomous operation of the engine becomes impossible, and the engine stops (see AL Klyachkin. Theory of jet engines, M, "Mechanical Engineering", 1969, p.449).

During start-up, such an unfavorable mode is excluded by the spinning of the rotor (or high-pressure rotor (HP) of a two- or three-shaft gas-turbine engine) of the engine with a starter (see AL Klyachkin. Theory of air-jet engines, M, "Mechanical Engineering", 1969, p. 452; Theory of Air-Jet Engines. Edited by Dr. of Technical Sciences S. M. Shlyakhtenko, M, "Mechanical Engineering", 1975, p. 457). During start-up, when the turbine’s power already significantly exceeds the compressor’s resistance, the starter shuts off (see A. Klyachkin. Theory of Aircraft Engines, M, Mashinostroenie, 1969, p. 452; Theory of Aircraft Engines. Under Edited by Doctor of Technical Sciences S. M. Shlyakhtenko, M, "Mechanical Engineering", 1975, p. 457, 458). An increase in starter power at the start favorably affects a decrease in the start time and a decrease in gas temperature.

For gas turbine aircraft engines and most ground-based engines, fuel consumption for small gas is not significant, since it is used for a limited time compared to the main modes.

For aircraft engines, the amount of small gas depends on the amount of thrust needed to allow the plane to taxi out at the aerodrome and on the minimum thrust that allows for safe landing and braking of the aircraft (see AL Klyachkin. Theory of jet engines, M, "Engineering", 1969, p. 219).

For ground-based engines (for example, NK-36ST with a capacity of 25 mW, operated on gas-pumping units), small gas at start-up is a through mode when the engine enters the warm-up mode. Idle gas is used only for cooling the engine for 5 minutes before stopping (see the NK-36ST 36.000.000 - 2RE Operation Manual, Section 3, page 13). For engines operated in power plants (for example, NK-37, with a capacity of 25 mW), small gas is used when synchronizing the frequency of the generator with the network and cooling the engine before stopping.

There is a method of increasing the resource and reducing fuel consumption of an engine with gas turbine supercharging, namely, that the engine is set at lower speeds compared to operational while reducing the speed and temperature of the exhaust gases of the engine (see RF patent No. 2342550, IPC F02D 23 / 00, F02D 29/02, B63H 23/06 (2006.01), 2007).

However, this solution applies to gas turbine diesel engines. The solution described in this patent cannot be implemented for gas turbine engines.

As an example, consider the NK-361 gas turbine engine powered by liquefied natural gas (LNG), which is designed and manufactured for the GT1h gas turbine locomotive developed by VNIKTI. Kolomna city. ( http://www.rzd-expo.ru/innovation/stock/locomotives_for_alternative_types_of_fuels/ ).

The idle speed on a gas turbine locomotive has a significant effect on the total fuel consumption in connection with the fundamental features of the distribution of modes over time. On a gas turbo locomotive, the idling time of a gas turbine engine is at least 50% of its total operating time, and the total fuel consumption at XX is no less than 25% of the total consumption, therefore, a decrease in idle consumption will greatly affect the total fuel consumption.

The ability to reduce idle fuel consumption is limited by rising gas temperatures.

Below are the experimental data obtained during the tests on the change in specific fuel consumption at extreme engine loading modes and on reducing idle fuel consumption by conventional means - by reducing the engine mode.

The power-supply parameters of a gas turbo locomotive: the maximum power of a gas turbo locomotive is: N = 7500 kW at a fuel consumption of G _T = 2300 kg / h, the minimum N is 300 kW at a fuel consumption of G _T = 700 kg / h and the rotational speed of the high-pressure rotor of the engine n _VD ≈ 6050 rpm

The specific fuel consumption is: at a maximum power of 0.307 kg / kW, and at a minimum power of 2.3 kg / kW. These specific costs differ by 7.5 times, which indicates a very low efficiency of the compressor and turbine at minimum power. The idle fuel consumption (XX) at a rotational speed of a free engine turbine n _CT = 3000 rpm and a rotational speed of a high-pressure rotor of an engine n _VD ≈ 4800 rpm is about 400 kg / h.

To start the engine, an electric starter with a power of 65 kW was used, powered by an auxiliary diesel generator or from batteries. In FIG. 1 shows the parameters of the engine during a typical course of starting. As you can see, after the starter is turned off, a slight temperature drop occurs. To reduce this cast in the area where the starter is turned off, the rate of increase in fuel consumption is reduced.

The operating time at the twentieth and the relative fuel consumption at the twentieth depend on: the track profile, the weight of the train, the capacities used and the parking time.

So, when driving a GT1h-002 on May 26, 2016 with a length of 302 km, the total idle time was 6 hours 42 minutes (60%), and the total fuel consumption for the twentieth made 2680 kg (27.5%). From these data it is clear that a decrease in idle fuel consumption should provide significant fuel savings.

In FIG. Figure 2 presents experimental data on the effect of a decrease in engine mode on a decrease in fuel consumption and a change in gas temperature. As can be seen from the graphs, simultaneously with a decrease in fuel consumption, an increase in gas temperature occurs. A decrease in fuel consumption below 300 kg / h is unacceptable due to a sharp increase in gas temperature. An increase in the temperature of gases to dangerous values will be promoted by an increase in the temperature of the air at the engine inlet and a deterioration of the engine parameters during continuous operation.

It was revealed that when the gas turbo-locomotives are idling and at idle, there is a large consumption of fuel gas - an average of 400 kg / h.

The technical problem solved by the invention is to reduce fuel consumption at idle and at low speeds.

The posed problem is solved due to the fact that a method has been developed to reduce the fuel consumption of a gas turbine engine (GTE) equipped with an electric starter, which consists in the fact that when it is operating at low modes and at idle, the GTE high-pressure rotor is forced to rotate.

Forced rotation of the high pressure rotor is provided by an electric starter.

The technical result from the use of all the essential features of the invention is to reduce fuel consumption and gas temperature during gas turbine engine operation at idle and low modes.

Ensuring the forced rotation of the high pressure rotor of the gas turbine engine when it is operating at low and idle speeds reduces the power transmitted to the compressor from the turbine by reducing the supply of fuel gas to the combustion chamber, which reduces fuel consumption and gas temperatures when the gas turbine engine is idling and low modes.

The use of an electric starter to force rotation of a high-pressure rotor of a gas turbine engine when it is operating at low and idle speeds reduces the power generated by the turbine and transmitted to the compressor from the turbine, and thus reduces fuel consumption and gas temperature at idle and low modes.

Using the invention will allow:

1. Reduce the total fuel gas consumption to 20%.

2. Reduce fuel gas consumption to 400% at idle.

4. To reduce the time of the transition process during the set of power at low modes of the gas turbine engine.

FIG. 1 - engine parameters during a typical course of starting the NK-361 engine on a gas turbine locomotive GT1h;

FIG. 2 - experimental data on the effect of reducing engine mode on reducing fuel consumption and changing gas temperatures;

FIG. 3 - Launch of NK-361 at GT1h-001 with reduced fuel idle consumption of 200 kg / h;

FIG. 4 - modes of operation of the starter while ensuring the forced rotation of the high-pressure rotor of the turbine engine when it is operating at low modes, idling and when a minimum power of 300 kW is set;

FIG. 5 is a block diagram of a gas turbine engine;

It is known that starting a gas turbine engine is a lengthy procedure, for which they use a starter that transmits torque to the shaft of a gas turbine engine (GTE). Torque means overcoming the resistance to rotation, which is caused by the aerodynamic resistance of the rotating parts, mechanical friction of the contacting parts and losses associated with fluid friction between the contacting parts immersed in the liquid medium of at least one hydraulic lubrication circuit and / or temperature control associated with said gas turbine engine. The electric starter gradually accelerates the gas turbine engine with acceleration, and when the specified rotation speed is reached, fuel injection and ignition are initiated in the combustion chamber of the gas turbine engine. Then, at another predetermined rotation speed, the action of the electric starter stops and the gas turbine engine continues to accelerate to idle speed due to the power that appears when the fuel is burned.

As you know, in a gas turbine engine, part of the power produced is used to rotate the compressor. Forced rotation of the high pressure rotor connecting the turbine and compressor by the starter idling allows the turbine power required to drive the compressor to be reduced, and thus the required amount of fuel supplied to the combustion chamber can be reduced, providing only its combustion.

A positive effect from the forced rotation of the high pressure rotor will be achieved if the amount of fuel that is needed to generate electricity for the electric starter is less than the amount by which the amount of fuel from the forced rotation of the high pressure rotor is reduced - the twist effect.

The implementation of the claimed method of reducing fuel consumption of a gas turbine engine equipped with an electric starter when operating at XX and low modes consists in connecting a starter for forced rotation of the high pressure rotor of the turbine engine when it is operating at low modes, idling and a minimum power of 300 kW. At the same time, at idle, it becomes possible to reduce the supply of fuel gas to the gas turbine combustion chamber. The fuel supply is only supported for combustion, i.e. The gas turbine engine does not turn off, which allows for a quick transition to other operating modes.

The graph (see Fig. 4) presents in a visual form the calculated parameters of the electric starter operating modes on cold scrolling, starting and during forced rotation of the high-pressure rotor of the gas turbine engine at idle, as well as when the minimum power is set to Ng = 300 kW (1st position ) in coordinates: electric starter torque (MKR st) - rotational speed of the rotor VD (n _VD ).

As can be seen from the graph, with a decrease in fuel consumption, the rotational speed of the VD rotor (n _VD ) also decreases. So, in the XX mode without forced rotation of the high pressure rotor of the gas turbine engine and fuel consumption Gt = 400 kg / h, the rotational speed of the rotor VD n _VD is 4800 rpm, with the forced rotation of the high pressure rotor gas turbine with an electric starter and fuel consumption Gt = 200 kg / hour the rotational speed of the rotor n _VD decreases to 3300 rpm, and at a fuel consumption of Gt = 100 kg / h, the rotational speed of the rotor n _VD , equal to 2700 rpm, approaches the rotational speed of the rotor VD during cold scrolling n _VD = 2200 rpm , i.e. the minimum mode is maintained, providing almost only fuel combustion in the combustion chamber.

The same graph shows the trajectory of the gas turbine engine power set from 0 kW to 300 kW at an initial fuel consumption of 100 kg / h with boosting the power of the electric starter to 100 kW.

The following is a description of the electric starter used to implement the method.

The figure 5 shows a functional block diagram of a gas turbine engine equipped with an electric starter.

A gas turbine engine includes a combustion chamber 1, a compressor 2, a turbine 3, a power turbine 4, a generator 5 and a drive from a turbine shaft through gears 6 and a gearbox 7 to an electric starter 8 (see Fig. 5). The electric starter 8 is made in the form of an electric machine with permanent magnets, the rotor of which is constantly connected through a kinematic connection with the high-pressure rotor of the gas turbine engine. The electric starter is controlled from the automatic control system according to the operator’s commands and information from the turbine speed sensor 9, which is kinematically connected to the high-pressure shaft and provides information on its rotation speed. The control of an electric machine (electric starter 8) in the motor mode (when starting the gas turbine engine) is carried out using the frequency conversion unit 10.

At idle and low modes, the high-pressure rotor of the gas turbine engine is forced to rotate (tighten) by the electric starter 8 as follows: reduce the gas supply to the combustion chamber 1, the turbine rotational speed decreases, the electric starter 8 switches from the generator mode to the engine mode and starts to rotate the high-pressure rotor with necessary effort, providing the required number of revolutions of the compressor shaft with reduced power transmitted to it from the turbine. Thus, there is a decrease in fuel consumption and at the same time, there is no critical increase in gas temperature.

In FIG. Figure 3 presents a preliminary check of the forced rotation mode of the high-pressure rotor of the gas turbine engine (twist) NK-361 on the 20th with a standard electric starter with a power of 60 ... 65 kW with an output of reduced fuel consumption of 200 kg / hour. The gas temperature during this start-up reached only 223 ° С, i.e. less than 200 ° C temperature drop during normal normal start-up.

Forced rotation of the high-pressure rotor of a gas turbine engine when the gas turbine engine is running at low speeds and idling with a starter will reduce fuel consumption on the XX from 400 kg / h to values of 200 ... 100 kg / h, which will lead to a decrease in total fuel consumption from 12 to 20%, at such an ultra-low mode, it will provide a low gas temperature in front of a free turbine, and will also help to maintain the rotor speed of the gas turbine engine and generator at an acceptable level.

Loading the minimum power Ng = 300 kW from the XX mode is a very slow process, therefore, the use of forced rotation of the high pressure rotor of the gas turbine engine (twist) during the transition process will also reduce fuel consumption.

In FIG. Figure 4 shows the modes of operation of the electric starter on cold scrolling, starting, idling with forced rotation of the rotor of the engine of the gas turbine engine, as well as when gaining a minimum power of Ng = 300 kW (1st position).

Using the invention allows:

- reduce the total fuel gas consumption to 25%,

- reduce fuel gas consumption to 400% at idle.

The practical implementation of this invention was tested on a gas turbine NK-361 gas turbine locomotive GT1. Field tests showed the effectiveness of the proposed solution on the engine operating mode on x.h. The proposed solution allows both standard operations for the electric start of the gas turbine engine, its cold scrolling, and forced rotation of the high-pressure rotor of the turbine engine when it is operating at low modes and idling, which can significantly reduce the consumption of gas turbine engines.

If the electric starter is powered by the energy of the batteries, then charging the batteries at high modes of the gas turbine engine, where the efficiency is much higher than at the minimum power mode, will have a positive effect. The gas turbine locomotive has rechargeable batteries charged from the main generator. At a maximum power of 7500 kW, the specific fuel consumption is 0.307 kg / kW, and at a minimum power of 300 kW it is 2.3 kg / kW, i.e. Efficiency differ by 7.5 times. Therefore, charging the batteries in high modes and returning the accumulated electricity to twist the rotor will have a significant effect.

In the case of installing an auxiliary gas engine with a generator of auxiliary needs (gas piston motor generator) on a gas turbine locomotive, which have sufficiently high efficiency, the additional fuel consumption of such a motor generator to drive an electric starter will also make up a small part of the reduced fuel consumption.

With a specific fuel consumption of a motor generator of 0.21 ... 0.26 kg / kWh (such a specific fuel consumption has a gas piston power station KG-200S with a capacity of 200 kW based on a KAMAZ 820.20-200 gas engine), additional fuel consumption with an electric starter power of 65 kW will total 14 ... 17 kg / h, and the fuel consumption for generating the same electricity at a minimum capacity of a gas turbine locomotive of 300 kW will be 150 kg / h. Which is about 10 times more.

The use of an electric starter for forced rotation of a high-pressure rotor of a gas turbine engine while reducing the power transmitted to the compressor from the turbine on a gas turbine during long-term parking allows minimizing the fuel supply and scrolling the turbine shaft for a long time, thereby maintaining the gas turbine installation in operable condition and at the same time ensuring prompt loading of the gas turbine if necessary .

The method can be applied on gas turbine engines for a railway trunk locomotive.

Claims (2)

1. A method of reducing fuel consumption of a gas turbine engine (GTE) equipped with an electric starter, which consists in the fact that when it is operating at low modes and idling, the GTE high pressure rotor is forced to rotate. 2. The method according to claim 1, characterized in that the forced rotation of the high pressure rotor is provided with a starter.

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