KR20060135445A - Air collision type fuel nozzle - Google Patents

Abstract

An air collision type fuel nozzle is provided to prevent deterioration of fuel spray characteristics by permitting a piezoelectric transducer to quickly correspond to the relative variation of position between a fuel nozzle unit and an air nozzle unit caused due to thermal distortion occurred in a gas turbine combustor. An air collision type fuel nozzle comprises a fuel nozzle unit(110), a fuel collision unit(120), an air outlet unit(130), and a length varying unit(140). The fuel nozzle unit has an inner surface where a through hole(115) is formed in a lengthwise direction. The through hole has one side with a fuel inlet port(114) and the other side with a fuel outlet port(116). The fuel collision unit is spaced apart from the fuel outlet port, and has a fuel collision plate(124) where fuel injected from the fuel outlet port collides. The fuel collision unit is coupled to the fuel nozzle unit. The air outlet unit discharges air which collides against the fuel which has collided against the fuel collision unit. The length varying unit has a piezoelectric transducer formed by depositing at least one piezoelectric material of which displacement varies when an electrical signal is applied, so that the longitudinal distance between the fuel collision unit and the fuel outlet port is controlled.

Description

Air collision type fuel nozzle

1 is a sectional view schematically showing a conventional fuel nozzle for a gas turbine.

2 is a schematic cross-sectional view showing an air collision type fuel nozzle according to a preferred embodiment of the present invention.

3 to 5 are cross-sectional views showing an example of an operation of changing the separation distance between the fuel outlet port and the fuel impingement membrane of FIG. 2, respectively, and FIG.

4 is a cross-sectional view illustrating a case in which a separation distance between the fuel outlet port and the fuel collision membrane of FIG. 2 is increased.

FIG. 5 is a cross-sectional view illustrating a case in which a separation distance between the fuel outlet port and the fuel impingement membrane of FIG. 2 is shortened.

Explanation of symbols on the main parts of the drawings

100: air impingement fuel nozzle 110: fuel nozzle unit

114: fuel inlet 115: through hole

116: fuel outlet 120: fuel impact portion

124: fuel impingement plate 130: air discharge portion

140: length displacement portion 141: piezoelectric transducer

142: piezoelectric element L: liquid film

D: separation distance between fuel impingement plate and fuel outlet

The present invention relates to an air impingement fuel nozzle, and more particularly, to control spray characteristics such as flow rate and injection angle of fuel flowing into a combustor, and to use the gas turbine combustor having an active combustion control structure. And an air impingement type fuel nozzle.

In a gas turbine, compressed air must be combusted in a combustor in order to obtain high temperature and high pressure expansion air. In order to combust compressed air, fuel must be injected into the compressed air with a fuel nozzle, and at the same time, the fuel is ignited with a spark plug and then continuously injected with fuel.

Among the various types of fuel nozzles used in the gas turbine combustor, an air impingement fuel nozzle such as an air assist nozzle has a mechanism for converting pressure energy into atomized energy, and at the same time, it is excellent in low pressure using air. As a result of atomization performance, it is widely used in gas turbines, industrial combustors, and domestic boilers.

As shown in FIG. 1, a conventional air impingement fuel nozzle 10 used in a gas turbine combustor includes a fuel nozzle portion 11, a swing portion 20, and an air nozzle portion 30. The fuel nozzle part 11 injects fuel and sprays it to the outside. The revolving part 20 is provided with the liquid film plate 22 formed so as to collide with the fuel injected from the said fuel nozzle part 11. The air nozzle unit 30 is formed behind the liquid film plate 22 to inject air that collides with the fuel collided with the liquid film plate 22. Therefore, the fuel injected from the fuel nozzle unit 11 forms a liquid film L while colliding with the liquid film plate 22, and the liquid film L collides with the compressed air ejected from the air nozzle unit 30. They are atomized and injected into the combustor.

By the way, the above-mentioned conventional gas turbine fuel nozzle 10 has a constant length D from the fuel nozzle part 11 to the liquid film plate 22 at all times, and is thus ejected from the fuel nozzle part 11. The length of the liquid film L generated while colliding with the liquid film plate 22 becomes constant. This causes the following problems.

First, it becomes difficult to control spray performance. That is, when the positions of the fuel nozzle unit 11 and the liquid film plate 22 are fixed in the assembling process, as described above, the length of the liquid film L is always constant, so that the liquid film can not be adjusted according to the user's request. In general, when the length of the liquid film (L) is long, it is known that the amount of impingement air is increased to reduce the size of the droplets, thereby improving the overall spraying performance. In addition, under weak fuel supply pressure at start-up, it is possible to increase the length of the liquid film to improve the ignition performance, but it is impossible in the prior art in which the length of the liquid film is fixed.

Second, it becomes difficult to cope with the relative position change of the fuel nozzle unit 10 and the liquid film plate 22 due to thermal deformation. That is, the fuel nozzle including the fuel nozzle unit 10 and the liquid film plate 22 is a component located at the inlet of the gas turbine combustor, and is one of the representative components in which thermal deformation occurs under the influence of high temperature in the combustion chamber. Therefore, the performance during initial assembly and performance after a long time of operation occurs a lot, and if these performance changes accumulate, the pattern factor (Pattern Factor) is worsened, and may cause fatal damage to the engine. A representative thermal deformation of the air-impact fuel nozzle is a change in spraying performance due to separation of the initial assembly position due to thermal expansion of the metal material, and a constant distance (D) between the conventional fuel nozzle part 11 and the liquid film plate 22. There is no solution to this problem with fuel nozzles with).

Third, active combustion control is impossible. That is, one to several dozen fuel nozzles are used in one gas turbine combustor. If the atomizing performance of each fuel nozzle can be controlled at high speed and finely, technical difficulties such as not only the combustion performance improvement of the combustor but also the combustion instability phenomenon, etc. Can solve them. However, according to the prior art, it is impossible to change the spray characteristic of each fuel nozzle finely.

The present invention has been made to solve various problems including the above problems, and an object of the present invention is to provide an air collision type fuel nozzle having a structure capable of controlling spray characteristics such as fuel flow rate and injection angle.

Another object of the present invention is to provide an air impingement fuel nozzle having a structure in which the fuel nozzle portion and the air nozzle portion change relative positions due to thermal deformation.

It is still another object of the present invention to provide an air impingement fuel nozzle with easy active combustion control.

In order to achieve the above object, an air collision fuel nozzle according to a preferred embodiment of the present invention includes: a fuel nozzle portion having a fuel inlet and a fuel outlet formed in a lengthwise direction through-holes disposed at one side and the other side, respectively; A fuel impingement part having a separation distance from the fuel outlet and having a fuel impingement plate formed to collide with fuel injected from the fuel outlet, and coupled to the fuel nozzle part; An air discharge unit for discharging air colliding with the fuel hit by the fuel collision unit; And a piezoelectric transducer having a piezoelectric transducer in which at least one piezoelectric element whose displacement changes when an electrical signal is applied is changed so that the distance between the fuel impingement portion and the fuel outlet port in the longitudinal direction can be changed and controlled.

In the piezoelectric transducer, at least one piezoelectric element whose displacement is changed when an electrical signal is applied is preferably stacked.

In this case, the piezoelectric transducer is preferably polarized in the longitudinal direction of the through hole.

The fuel impingement part further includes a fuel guide plate which is bent from the fuel impingement plate and formed in the fuel nozzle direction. In this case, the piezoelectric transducer has one end portion and the other end portion of the fuel guide plate and the fuel nozzle, respectively. It is preferable to combine with a part.

The piezoelectric element is preferably made of LiNbO ₃ material.

Here, the fuel nozzle unit may include a protruding coupling portion protruding from the nozzle body in a radial direction to be joined to the length displacement portion.

On the other hand, the air collision type fuel nozzle is preferably used for a gas turbine combustor.

Hereinafter, with reference to an embodiment shown in the accompanying drawings the present invention will be described in more detail. In this case, hereinafter, for convenience of description, it is assumed that the air collision type fuel nozzle is used in the combustor of the gas turbine, but the present invention is not limited thereto. 2 is a cross-sectional view showing an air collision type fuel nozzle according to a preferred embodiment of the present invention.

Referring to FIG. 2, the air collision type fuel nozzle 100 according to the present invention includes a fuel nozzle unit 110, a fuel collision unit 120, an air discharge unit 130, and a length displacement unit 140. . The fuel nozzle part 110 is provided with the through-hole 115 formed in the longitudinal direction in the inside. The through hole 115 is a passage through which the fuel penetrates, and a fuel inlet 114 constituting the fuel inlet passage is formed at one side, and a fuel outlet 116 constituting the outlet passage of the fuel is formed at the other side. In this case, a swirler 118 may be formed in the through hole 115, and the swirler 118 functions to cause the fuel passing through the through hole 115 to pivot.

The fuel impingement part 120 has a distance D from the fuel outlet 116 and is combined with the fuel nozzle part 110 so that the fuel sprayed primarily from the fuel outlet 116 may collide. Is formed. In this case, the fuel collision part 120 may include a fuel guide plate 122 and a fuel collision plate 124. The fuel guide plate 122 is coupled to the fuel nozzle unit 110 and extends in the longitudinal direction of the through hole 115. The fuel impingement plate 124 is formed to be inclined with the longitudinal direction of the through hole 115 so that the fuel hits it. Therefore, the fuel discharged to the outside through the fuel outlet 116 strikes the fuel impingement plate 124 to form the liquid film L.

The air discharge unit 130 emits air colliding with the fuel hit by the fuel collision unit 120. This strong air stream collides with the liquid film L to form the final secondary spray. In this case, the air discharge unit 130 may be integrally formed with the fuel collision unit 120.

The present invention further includes a length displacement unit 140 capable of changing and controlling the distance D in the longitudinal direction between the fuel impingement plate 124 and the fuel outlet 116. As the separation distance D between the fuel impingement plate 124 and the fuel outlet 116 is changed, the time for the fuel sprayed from the fuel outlet 116 to impinge on the fuel impingement plate 124 is also changed. As a result, the length of the liquid film L generated by the fuel collision plate 124 is also changed.

As is known, the final spraying performance and spraying shape are different as the length of the liquid film L is changed. For example, as the length of the liquid film L increases, the surface area colliding with the air increases, so that the size of the generated droplets decreases. Therefore, under the weak fuel supply at the start of the gas turbine, the length displacement part 140 is formed such that the length of the liquid film L is long, so that the ignition performance can be improved.

In addition, when the gas turbine is used for a long time, thermal deformation occurs in the metal, which is the material of the fuel nozzle, under the influence of the high temperature in the combustor, thereby changing the initially set spray performance and spray formation. Therefore, in this case, the length displacement part 140 may have a constant spraying performance regardless of the passage of time by adjusting the separation distance between the fuel outlet 116 and the fuel impingement plate 124.

In addition, several to several dozen fuel nozzles are used in the gas turbine, and by adjusting the spray characteristics of each fuel nozzle, the combustion performance of the entire combustor can be improved, and combustion instability can be prevented.

In this case, the length displacement part 140 may be a piezoelectric transducer 141 made of at least one piezo-electric material 142, as shown in FIGS. 3 to 5. A piezoelectric element uses an inverse piezoelectric phenomenon, and is an object in which deformation occurs when a voltage is applied thereto. Here, the reverse piezoelectric phenomenon refers to a phenomenon in which the piezoelectric element is periodically stretched and contracted when a high frequency voltage is applied to an object having piezoelectricity.

In this case, the single piezoelectric element 142 typically has a displacement of up to several tens of micrometers and a response speed of several to several tens of microseconds. Accordingly, by forming the length displacement part 140 as the piezoelectric element 142, the separation distance D from the fuel outlet 116 to the fuel impingement plate 124 may be slightly changed. The piezoelectric transducer 141 used in the air collision type fuel nozzle according to the embodiment of the present invention preferably has displacement of 2 mm to 6 mm by applying an electromotive force of several tens to several hundred volts. The amount of displacement can be increased by stacking 142.

The piezoelectric element 142 may be formed of one of PZT, BTO (BaTiO ₃ ), PMN (Pb-Mg-Nb), SBT (SrBi ₂ Ta ₂ O ₉ ), LiNbO _3, or BaMgF ₄ . It is necessary to the piezoelectric element 142 is formed of an excellent material piezoelectric property even in high temperature of a gas turbine combustor, in particular preferred that the piezoelectric element 142 is made of a LiNbO ₃ material, which is a high temperature of the LiNbO ₃ material 1250 ℃ This is because it also has good piezoelectric properties. In this case, a power supply device for applying a voltage to the piezoelectric element 142 is disposed inside the fuel nozzle or outside the fuel nozzle.

In this case, as illustrated in FIGS. 3 to 5, the piezoelectric transducer 141 constituting the length displacement part 140 may be polarized in the longitudinal direction, and thus the fuel outlet 116 and the fuel impingement plate 124 may be polarized. A distance D of) may be extended or contracted in the longitudinal direction of the length displacement part 140.

By controlling the voltage applied to the piezoelectric element 142, the separation distance between the fuel outlet 116 and the fuel impingement plate 124 may be adjusted. That is, opposite voltages may be applied to one end portion adjacent to the fuel nozzle of the piezoelectric transducer 141 and the other end portion formed on the opposite side thereof. In this case, the one end portion is fixed to the fuel nozzle unit 110 in combination. Therefore, when a voltage is applied to the piezoelectric transducer 141, the other end portion extends in the lengthwise direction of the through hole 115 by the applied voltage, or is compressed to a fuel nozzle part side, so that the fuel outlet port 116 and the fuel are compressed. The separation distance D between the collision plates 124 may be changed.

For example, as shown in FIG. 3, the piezoelectric transducer 141 is disposed such that a positive electrode is formed at the other end and a negative electrode is formed at one end. In this case, when no voltage is applied to the piezoelectric transducer 141 from the power supply unit 160 disposed in the air collision fuel nozzle 100 or disposed outside the air collision fuel nozzle 100, the piezoelectric transducer is used. 141 has a reference length D_a.

In this case, as shown in FIG. 4, when a positive voltage is applied to the other end of the piezoelectric transducer 141 and a negative voltage is applied to one end of the piezoelectric transducer 141, the piezoelectric transducer 141 is a reverse piezoelectric phenomenon. Due to this, the stretching occurs to have a length D_b corresponding to the voltage. As a result, the length of the liquid film L is also changed.

In addition, when the voltage applied in the state of FIG. 4 is weakened, or as shown in FIG. 5, a negative voltage is applied to the other end and a positive voltage is applied to one end, the piezoelectric converter ( 141 corresponds to the voltage and the length D_c is reduced. As a result, the length of the liquid film L is changed again.

2, the fuel collision part 120 may further include a fuel guide plate 122. The fuel guide plate 122 is bent from the fuel impingement plate 124 to extend, and is formed in the direction of the fuel nozzle unit 110. The fuel guide plate 122 is formed in the longitudinal direction of the through hole 115 to have a cylindrical shape. In this case, the piezoelectric transducer 141 may be interposed between the fuel guide plate 122 and the fuel nozzle unit 110 to be coupled to the fuel guide plate 122 and the fuel nozzle unit 110. Accordingly, as the piezoelectric transducer 141 increases, the fuel guide plate 122 may be lengthened, thereby increasing the distance between the fuel outlet 116 and the fuel impingement plate 124, thereby increasing the piezoelectric transducer ( As the 141 decreases, the distance between the fuel outlet 116 and the fuel impingement plate 124 becomes smaller. In this case, since the fuel nozzle unit 110 is fixed, the piezoelectric transducer 141 extends toward the fuel guide plate 122, and thus the fuel guide plate 122 extends to the opposite side of the fuel nozzle unit 110. .

On the other hand, the fuel nozzle unit 110 may further include a protruding coupling portion 116. The protrusion coupling portion 116 protrudes from the body of the fuel nozzle in the radial direction of the through hole 115 so as to be bonded to the length displacement portion 140 in a cylindrical shape. That is, one end of the length displacement unit 140 may be coupled to the protruding coupling portion, and the other end thereof may be coupled to the fuel guide plate 122.

Hereinafter, the operation of the present invention having such a structure will be described. First, fuel is injected from the fuel outlet 116 of the fuel nozzle unit 110 toward the fuel impingement plate 124 to form a primary spray.

The primary sprayed fuel collides with the fuel impingement plate 124 inclined in the longitudinal direction of the through hole 115, so that a liquid film L of fuel is formed. In this case, since the spray characteristics and spraying performance are changed according to the length of the liquid film L, the length depends on whether the gas turbine is in an initial ignition state, whether it is used for a long time, whether it is thermally deformed, or whether the gas turbine outlet stabilizes flame. The displacement unit 140 may change the separation distance between the fuel impingement plate 124 and the fuel outlet 116.

Subsequently, the liquid film L collides with a strong air flow discharged from the air discharge unit 130, and the liquid film L develops as droplets due to the difference in speed between the liquid film L and the air flow. At the same time, the secondary spray is out of the fuel nozzle.

The secondary sprayed fuel is injected into a gas turbine combustor.

According to the present invention having the above-described structure, it is possible to control the physical characteristics of the droplets generated in the fuel collision plate by controlling the separation distance from the fuel outlet to the fuel collision plate. Therefore, spray characteristics such as fuel flow rate and injection angle can be controlled.

In addition, the piezoelectric transducer responds finely and quickly in response to changes in relative positions of the fuel nozzle unit and the air nozzle unit due to thermal deformation that may occur inside a gas turbine combustor operating at a high temperature. Can be prevented.

In addition, fine and rapid control of spray performance for each individual fuel nozzle enables active combustion control in the gas turbine combustor, resulting in improved gas turbine performance.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and any person skilled in the art to which the present invention pertains may have various modifications and equivalent other embodiments. Will understand. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (5)

A fuel nozzle unit having a fuel inlet and a fuel outlet formed in a lengthwise direction through-holes disposed at one side and the other side, respectively; A fuel impingement part having a distance from the fuel outlet and having a fuel impingement plate formed to collide with fuel injected from the fuel outlet, and coupled to the fuel nozzle part; An air discharge unit configured to discharge air colliding with the fuel collided with the fuel collision unit; And And a length displacement part having a piezoelectric transducer in which at least one piezoelectric element whose displacement changes when an electrical signal is applied to change and control a distance in the longitudinal direction between the fuel collision part and the fuel outlet is stacked. Air impingement fuel nozzle. The method of claim 1, And the piezoelectric transducer is polarized in the longitudinal direction of the through hole. The method of claim 1, The fuel impingement part further includes a fuel guide plate which is bent from the fuel impingement plate and formed in a direction of the fuel nozzle part. The piezoelectric transducer, one end and the other end of the air collision type fuel nozzle, characterized in that coupled to the fuel guide plate and the fuel nozzle unit, respectively. The method of claim 1, The piezoelectric element is an air collision type fuel nozzle, characterized in that made of LiNbO ₃ material. The method of claim 1, The fuel nozzle unit has an air collision type fuel nozzle, characterized in that it comprises a protruding coupling portion protruding in the radial direction of the through-hole from the nozzle body to be joined to the length displacement portion.

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