JP2010077930A - Bleed type gas turbine engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bleed type gas turbine increasing a bleed air flow rate and enabling stable operation. <P>SOLUTION: The bleed type gas turbine engine 1 is a device making an air flow in a compressor 10, making air compressed by the compressor 10 flow in a combustor 11 and taking out the ar as energy, and rotating a turbine 12 by combustion gas in the combustor 11, and includes a steam injection device 18 injecting steam to the turbine 12. An operating point of the compressor is moved to a direction increasing air flow rate by steam injection, and a bleed air flow rate is increased since a turbine flow rate characteristic line moves in air flow rate reduction direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an extraction type gas turbine engine that extracts compressed air from a compressor as energy to the outside of the engine.

Conventionally, as an extraction type gas turbine engine, as described in, for example, Japanese Patent Application Laid-Open No. 2006-213168, a part of the air compressed by a compressor is taken out to the outside, and the remaining compressed air is flowed into a combustor to produce fuel. Are known, and the turbine is rotated by the combustion gas. In this gas turbine engine, the extracted high-pressure air is used as energy to generate thrust by a thrust generator of a vertical take-off machine, thereby reducing the weight of the apparatus.
JP 2006-213168 A

  In the above-described extraction type gas turbine engine, if the flow rate of the compressed air taken out (extraction air flow rate) is increased to increase the thrust, the operating point of the compressor may enter the surge region, which is stable. There was a problem that it was difficult to secure the driving.

  Therefore, the present invention has been made to solve such a technical problem, and an object of the present invention is to provide a bleed-type gas turbine engine capable of increasing the bleed-air flow rate and enabling stable operation. .

  That is, in the extraction type gas turbine engine according to the present invention, air flows into the compressor, a part of the air compressed by the compressor flows into the combustor, the remaining compressed air is taken out as energy, and the combustion gas in the combustor In the extraction type gas turbine engine for rotating the turbine by means of the above, a steam supply means for supplying steam to the turbine is provided.

  According to the present invention, since the steam supply means is provided, the steam is supplied to the turbine by the steam supply means. By supplying this steam, the turbine flow rate characteristic line moves in the decreasing direction of the air flow rate, and the operating point of the compressor moves to the large flow rate side at the same turbine inlet temperature, so that the extraction air flow rate can be increased. Moreover, as a result of the operating point of the compressor moving in the direction of increasing the air flow rate, the operating point moves away from the surge line, and a surge can be avoided. Therefore, stable operation can be ensured.

  In the extraction type gas turbine engine according to the present invention, it is preferable that the steam supply means supplies steam to a communication path that connects the combustor and the turbine.

  Thus, the steam supply means supplies the steam to the communication path that communicates the combustor and the turbine, so that the steam is supplied upstream of the turbine, can be mixed uniformly with the combustion gas, and can flow into the turbine.

  The extraction type gas turbine engine according to the present invention allows air to flow into a compressor, a part of the air compressed by the compressor flows into the combustor, and the remaining compressed air is taken out as energy, and the turbine uses the combustion gas in the combustor. In the extraction type gas turbine engine for rotating the engine, moisture supply means for supplying moisture to the turbine is provided.

  According to the present invention, since the moisture supply means is provided, the moisture is supplied to the turbine by the steam supply means. By supplying moisture, the turbine flow rate characteristic line moves in the decreasing direction of the air flow rate, and the operating point of the compressor moves to the high flow rate side at the same turbine inlet temperature, so that the extraction air flow rate can be increased. Moreover, as a result of the operating point of the compressor moving in the direction of increasing the air flow rate, the operating point moves away from the surge line, and a surge can be avoided. Therefore, stable operation can be ensured.

  In the extraction type gas turbine engine according to the present invention, it is preferable that the moisture supply means supplies moisture to a communication path that connects the combustor and the turbine.

  Thus, the moisture supply means supplies moisture to the communication path that communicates the combustor and the turbine, so that the moisture is supplied upstream of the turbine, can be uniformly mixed with the combustion gas, and can flow into the turbine.

  ADVANTAGE OF THE INVENTION According to this invention, while increasing the extraction air flow rate, the extraction type gas turbine which enabled the stable driving | operation can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is a configuration diagram of an extraction type gas turbine engine according to a first embodiment of the present invention. As shown in FIG. 1, an extraction type gas turbine engine (hereinafter referred to as an extraction type gas turbine) 1 includes a compressor 10, a combustor 11, and a turbine 12, and the compressor 10 and the turbine 12 are connected by a rotary shaft 13. Has been. The compressor 10 takes in air from the atmosphere and compresses the taken-in air. The compressor 10 supplies the compressed high-pressure air to the combustor 11 through the internal pipe 14 and takes it out through the extraction pipe 15.

  The combustor 11 mixes and combusts the compressed air supplied from the compressor 10 and the fuel supplied from the fuel actuator 2 to generate high-temperature and high-pressure combustion gas. The combustor 11 communicates with the turbine 12 through an internal pipe 16 that is a communication path. The high-temperature and high-pressure combustion gas is supplied to the turbine 12 via the internal pipe 16. The turbine 12 is rotated by the flow of supplied combustion gas. The turbine 12 drives the compressor 10 via the rotating shaft 13 and exhausts the combustion gas to the outside. The fuel actuator 2 receives a fuel control signal from an engine control ECU (not shown) and supplies fuel into the combustor 11 in accordance with the fuel control signal.

  The extraction type gas turbine 1 further includes a steam injection device 18. The steam injection device 18 injects steam into the turbine 12 and communicates with the internal piping 16 via the injection piping 17. Therefore, the steam from the steam injection device 18 is injected upstream of the turbine 12 at a constant pressure via the injection pipe 17 and the internal pipe 16, mixed with the combustion gas, and flows into the turbine 12. Note that the steam here includes not only steam but also steam of other substances. The bleed-type gas turbine 1 generates no shaft output except for driving auxiliary equipment such as a fuel pump and a lubricating oil pump (not shown).

  Hereinafter, the operation of the extraction type gas turbine engine 1 will be described with reference to FIG. Prior to the description, the operation of the shaft output type gas turbine engine will be briefly described.

  The load control of the high-pressure air supply apparatus using the shaft output type gas turbine engine is normally performed by controlling the turbine inlet gas temperature T4. Since the upper limit value T4max of the turbine inlet gas temperature T4 is determined by the heat resistance of the turbine nozzle and the turbine blade, the amount of air that can be supplied is limited. Therefore, when a further large amount of high-pressure air is required, it is necessary to increase the output by another method other than the turbine inlet gas temperature T4.

  As a method for increasing the output of the shaft output type gas turbine engine, in addition to the control of the turbine inlet gas temperature T4, a method of increasing the output by steam injection such as a cogeneration cogeneration system can be considered. Although this steam injection can increase the output of the turbine inlet gas temperature upper limit value T4max or more, there is a risk that the operating point of the compressor approaches the surge line of the compressor and enters the surge region.

  FIG. 3 is a graph showing the characteristics of the pressure ratio and flow rate of the compressor of the shaft output type gas turbine engine. In FIG. 3, the horizontal axis represents the air flow rate, and the vertical axis represents the pressure ratio (compressor outlet air pressure P3 / atmospheric pressure P0). Line L7 is a pressure flow characteristic line of the compressor when the rotational speed is constant, and line L8 is a surge line of the compressor. Line L9 is a compressor operating line passing through the operating point b 'without steam injection, and line L10 is a compressor operating line when the turbine inlet gas temperature T4 is the upper limit value T4max without steam injection. The line L11 is a compressor operation line when steam injection is performed and the turbine inlet gas temperature T4 is the upper limit value T4max. These operation lines L9 to L11 are determined by the turbine flow rate characteristics.

  In the case of a simple cycle, the compressor is operated in a range between the operating point a ′ and the operating point b ′ by controlling the turbine inlet gas temperature T4 according to the load. The operating point a ′ is the maximum output point, and at this time, the turbine inlet gas temperature T4 becomes the upper limit value T4max. When steam is injected upstream of the turbine in this state, the steam flows through the turbine nozzle, so the air flow rate of the compressor decreases and the operating point moves to point c ′.

  Compressor work is reduced by reducing the air flow. In this case, the output increases at the same turbine inlet gas temperature T4, but the operating point approaches the surge line L8, and the compressor may enter the surge region. In particular, when saturated steam is used as injection steam, a large amount of steam flows in due to condensation of the steam, and the gas turbine engine may be misfired or damaged by a severe surge. Therefore, proper steam injection control is required to avoid surge.

  FIG. 2 is a diagram showing the characteristics of the pressure ratio and the flow rate of the compressor of the extraction type gas turbine engine. In FIG. 2, the horizontal axis represents the air flow rate, and the vertical axis represents the pressure ratio (compressor outlet air pressure P3 / atmospheric pressure P0). Line L5 is a pressure flow characteristic line of the compressor at a constant rotation speed, and line L6 is a surge line.

  Line L1 is a turbine flow rate characteristic line when steam injection is performed and the turbine inlet gas temperature T4 is the upper limit value T4max. Line L1 ′ is no steam injection and the turbine inlet gas temperature T4 is the upper limit value T4max. It is a turbine flow rate characteristic line when there is. Line L2 is a compressor operating line when steam injection is performed and the turbine inlet gas temperature T4 is the upper limit value T4max. Line L2 ′ is no steam injection and the turbine inlet gas temperature T4 is the upper limit value T4max. This is the compressor operating line.

  Line L3 is a compressor operating line passing through operating point c, and at this time, turbine inlet gas temperature T4 = T4c. Line L4 is a turbine flow rate characteristic line when the turbine inlet gas temperature T4 is T4c without steam injection. When the pressure ratio becomes constant, the difference ΔG1 in the air flow rate between the line L4 and the operating point c becomes the extraction flow rate of high-pressure air, that is, this ΔG1 can be extracted as high-pressure air.

  Since the extraction type gas turbine is in a choke state in the high pressure region, the turbine inflow gas flow rate G4, the turbine inlet gas temperature T4, and the turbine inlet gas pressure P4 satisfy the relationship of the formula (1).

  The total air flow rate G of the compressor is obtained by the equation (2), and the turbine inflow gas flow rate G4 is obtained by the equation (3). In equations (2) and (3), Ga is the flow rate of air flowing through the combustor, Gb is the bleed air flow rate, and Gf is the fuel flow rate. The unit of flow rate is kg / sec.

  Further, the turbine inlet gas pressure P4 can be obtained by Expression (4). In equation (4), ΔP is the combustor pressure loss.

  And if Formula (1)-(4) is deform | transformed, Formula (5), (6) will be obtained.

  Equation (5) corresponds to the compressor operating line L3, and equation (6) corresponds to the turbine flow rate characteristic line L4. Gb corresponds to the above-described extraction air flow rate ΔG1.

  In the case of a shaft output type gas turbine, since the extraction flow rate Gb = 0, G = Ga from the equation (2). Accordingly, the compressor operating line and the turbine flow rate characteristic line coincide, and the compressor operating line is determined by the turbine flow rate characteristic. On the other hand, in the case of the extraction type gas turbine, the turbine flow rate characteristic is smaller than that in the case of the shaft output type gas turbine, and the difference between the operating point of the compressor and the turbine flow rate can be extracted.

  In the case of the extraction type gas turbine, the amount of extraction increases as the turbine inlet gas temperature T4 rises, as in the case of the shaft output type gas turbine. In FIG. 2, when the turbine inlet gas temperature T4 is raised, the operating point moves from the operating point c to the large flow rate side (in the direction of increasing air flow), and moves to the operating point a at the turbine inlet gas temperature T4 upper limit value. be able to. On the other hand, the turbine flow rate characteristic line moves from the line L4 to the line L1 ′. Then, the difference ΔG2 in the air flow rate between the line L1 ′ and the operating point a becomes the extraction flow rate of high-pressure air, and this ΔG2 can be extracted as high-pressure air. Comparing ΔG2 and ΔG1, it is clear that the extraction air flow rate has increased.

  As the turbine inlet gas temperature T4 rises, the work of the turbine increases, and the compressor load also needs to increase for no output. Therefore, when the rotational speed of the compressor is constant, the operating point of the compressor moves in the direction in which the flow rate increases. Here, “no output” means that the turbine and the compressor are balanced, that is, the work of the turbine = compressor power + the work to the outside (in this case, 0).

  Next, the operation when steam is injected into the extraction type gas turbine 1 will be described.

  As described above, ΔG2 is the maximum extraction amount obtained by the operation at the operating point a when the turbine is at a simple cycle and the turbine inlet temperature T4 = T4max. When a larger amount of high-pressure air is required than this, it is possible to increase the amount of extraction at the same turbine inlet temperature by injecting steam upstream of the turbine in the same manner as the shaft output type gas turbine. is there.

  That is, when the steam is injected upstream of the turbine, the steam flows through the nozzle installed at the inlet of the turbine, so the turbine flow rate characteristic line L1 ′ shown in FIG. 2 moves to the small flow rate side by the amount of the injected steam, It becomes line L1. When the injection vapor amount is Gs, Ga is obtained by the equation (7).

  Comparing equation (7) and equation (3), it can be seen that Ga moves to the small flow rate side only by the amount of Gs.

  On the other hand, at the same turbine inlet temperature, the operating point of the compressor moves from the operating point a to the operating point b (that is, the large flow rate side) by steam injection. This is because the specific heat of the steam is larger than the specific heat of the combustion gas (the specific heat of the steam is about twice that of the combustion gas), and the turbine work increases even under the same turbine inlet temperature conditions. Due to this increase in turbine work, it is necessary to increase the compressor load from the non-output condition, and the compressor flow rate changes in the same rotational speed. A difference ΔG3 in the air flow rate between the line L1 and the operating point b is a high-pressure air extraction flow rate, and this ΔG3 can be extracted as high-pressure air.

  As a result of the steam injection, the operating point of the compressor moves in the increasing direction of the air flow rate, and the turbine flow rate characteristic line moves in the decreasing direction of the air flow rate. As a result, the amount of air that can be extracted increases from ΔG2 to ΔG3. The bleed air flow rate can be reliably increased. Moreover, as a result of the operating point of the compressor moving in the direction of increasing the air flow rate, the operating point moves away from the surge line, and a surge can be avoided. That is, in the case of a bleed gas turbine, the operating point moves to the small flow rate side by steam injection as in the shaft output gas turbine, and there is no risk of entering the surge region, so that stable operation can be ensured. Become.

  In addition, such a high-pressure air supply apparatus can control even a rapid increase in high-pressure air in a system that drives a fan or the like using high-pressure air. Furthermore, it is also possible for industrial use as a high-pressure air source.

(Second Embodiment)
Next, an extraction type gas turbine engine according to a second embodiment of the present invention will be described.

  FIG. 4 is a configuration diagram of an extraction type gas turbine engine according to the second embodiment. As shown in FIG. 4, the difference between the extraction type gas turbine 1a according to the second embodiment and the first embodiment is that two compressors are provided. That is, an engine compressor 20 is installed between the high-pressure air generating compressor 19 and the combustor 11, and the engine compressor 20 is communicated with the combustor 11 via the internal pipe 14. 11 is supplied with compressed air.

  On the other hand, the high pressure air generating compressor 19 compresses air and takes out the compressed air to the outside through the extraction pipe 15. The high-pressure air generating compressor 19 and the engine compressor 20 are connected by a rotary shaft 13 and are driven to rotate by the rotation of the rotary shaft 13 to take in air and compress the taken-in air. Since the operation of the bleed gas turbine 1a is the same as that of the first embodiment, a duplicate description is omitted.

  With such a configuration, the extraction type gas turbine 1a can obtain the same effects as those of the first embodiment, and can further increase the extraction air flow rate by providing the compressor 19 for generating high pressure air.

(Third embodiment)
FIG. 5 is a configuration diagram of an extraction type gas turbine engine according to the third embodiment. As shown in FIG. 5, the difference between the extraction type gas turbine 1 b according to the third embodiment and the first embodiment is that a high-pressure air / steam cogeneration system that recovers waste heat of the turbine 12 is used. Specifically, an exhaust boiler 21 is installed as a steam injection device, and the exhaust boiler 21 and the turbine 12 are communicated with each other by a pipe 22. The high-temperature combustion gas discharged from the turbine 12 flows into the exhaust boiler 21 via the pipe 22, heats the water vapor in the exhaust boiler 21, and then is exhausted to the outside via the pipe 23. Since the operation of this extraction type gas turbine 1b is the same as that of the first embodiment, the duplicated explanation is omitted.

  With such a configuration, the extraction type gas turbine 1b can obtain the same effects as those of the first embodiment, and can perform steam injection in the stable operation region of the compressor, so that it is possible to surplus without worrying about the dryness of the steam. It is possible to increase the extraction air flow rate using steam.

  In addition, embodiment mentioned above demonstrated an example of the extraction type gas turbine engine which concerns on this invention, and the extraction type gas turbine engine which concerns on this invention is not limited to what was described in this embodiment. For example, in the above-described embodiment, an example of a steam injection device that injects steam into the turbine has been described. However, a moisture injection device may be used instead of the steam injection device.

  For example, the moisture injection device injects mist-like water into the internal pipe 16 at a constant pressure. In this case, the same effect as the above embodiment can be obtained. In other words, the operating point of the compressor moves in the direction of increasing the air flow rate and the turbine flow rate characteristic line moves in the decreasing direction of the air flow rate due to the water injection, so that the extraction air flow rate can be increased. Further, as a result of the operating point of the compressor moving in the direction of increasing the air flow rate, the operating point moves away from the surge line, so that the surge can be avoided and stable operation can be ensured.

It is a block diagram of the extraction type gas turbine engine which concerns on 1st Embodiment of this invention. It is a figure which shows the characteristic of the pressure ratio and flow volume of the compressor of an extraction type gas turbine engine. It is a figure which shows the characteristic of the pressure ratio and flow volume of the compressor of a shaft output type gas turbine engine. It is a block diagram of the extraction type gas turbine engine which concerns on 2nd Embodiment. It is a block diagram of the extraction type gas turbine engine which concerns on 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b ... Extraction type gas turbine engine, 10 ... Compressor, 11 ... Combustor, 12 ... Turbine, 18 ... Steam injection apparatus, 21 ... Exhaust boiler.

Claims (4)

In an extraction type gas turbine engine in which air is introduced into a compressor, a part of the air compressed by the compressor is introduced into a combustor, the remaining compressed air is extracted as energy, and the turbine is rotated by combustion gas in the combustor. ,
A bleed type gas turbine engine characterized in that steam supply means for supplying steam to the turbine is provided.   The extraction type gas turbine engine according to claim 1, wherein the steam supply means supplies steam to a communication path that connects the combustor and the turbine. In an extraction type gas turbine engine in which air is introduced into a compressor, a part of the air compressed by the compressor is introduced into a combustor, the remaining compressed air is extracted as energy, and the turbine is rotated by combustion gas in the combustor. ,
An extraction type gas turbine engine characterized in that a water supply means for supplying water to the turbine is provided. The extraction type gas turbine engine according to claim 3, wherein the moisture supply means supplies moisture to a communication path that communicates the combustor and the turbine.

Images