JP2024078998A - Fuel nozzle and gas turbine engine - Google Patents

Abstract

[Problem] To promote atomization of liquid fuel and suppress the generation of harmful emissions such as NOx. [Solution] A fuel nozzle 100 is provided, which includes a nozzle portion 10 for injecting liquid fuel toward a combustion chamber CC, an inner cylindrical portion 20 forming an inner flow passage IC for circulating combustion air CA between the nozzle portion 10 and the inner cylindrical portion 20, and an inner swirler 30 for applying a swirling force to the combustion air CA flowing through the inner flow passage IC, and the inner circumferential surface 20a of the inner cylindrical portion 20 forms a liquid film by adhering the liquid fuel injected from the nozzle portion 10, and the inner cylindrical portion 20 is formed so that the flow passage cross-sectional area does not increase as it approaches the combustion chamber CC along the axis X, and the wetted perimeter length in a cross section perpendicular to the axis X of the inner circumferential surface 20a of the inner cylindrical portion 20 increases as it approaches the combustion chamber CC along the axis X. [Selected Figure] Figure 1

Description

The present disclosure relates to fuel nozzles and gas turbine engines.

The mainstream fuel nozzles used in the combustors of aircraft engines are air blast nozzles that use a high-speed airflow to atomize liquid fuel (see, for example, Patent Document 1). Patent Document 1 discloses that a lip extender with gaps formed at multiple locations around the circumference is provided at the tip of the nozzle, and the thin film of fuel is mixed with the air flowing in through the gaps to promote atomization of the liquid fuel.

U.S. Pat. No. 1,031,7083

In recent aircraft engines, strict regulations have been imposed on harmful emissions such as NOx (nitrogen oxides). If the liquid fuel is not atomized sufficiently in the fuel nozzle, the fuel concentration inside the combustor becomes non-uniform, resulting in locally high-temperature combustion gas and increased NOx emissions. For this reason, there is a demand for further improvement in the atomization of liquid fuel.

The present disclosure has been made in consideration of these circumstances, and aims to provide a fuel nozzle that can promote atomization of liquid fuel and suppress the generation of harmful emissions such as NOx, and a gas turbine engine equipped with the same.

In order to solve the above problem, a fuel nozzle according to one aspect of the present disclosure includes a nozzle section that is arranged along an axis and injects liquid fuel from an injection hole toward a combustion chamber, a first tubular section that is formed in a cylindrical shape along the axis and is arranged on the outer periphery of the nozzle section, forming a first flow path for circulating combustion air between the nozzle section and the first swirler that is arranged in the first flow path and applies a swirling force to the combustion air flowing through the first flow path to rotate around the axis, and the inner circumferential surface of the first tubular section forms a liquid film by adhering the liquid fuel injected from the nozzle section, and the first tubular section is formed so that the flow path cross-sectional area does not increase as it approaches the combustion chamber along the axis, and the wetted perimeter length in a cross section perpendicular to the axis of the inner circumferential surface of the first tubular section increases.

The present disclosure provides a fuel nozzle that can promote atomization of liquid fuel and suppress the generation of harmful emissions such as NOx, and a gas turbine engine equipped with the same.

FIG. 1 is a vertical cross-sectional view showing a fuel nozzle according to a first embodiment of the present disclosure. 2 is a plan view of the tip side of the inner cylindrical portion shown in FIG. 1 as viewed from the combustion chamber side along the axis. FIG. 3 is a perspective view of a tip end side of an inner cylindrical portion shown in FIG. 2 . 2 is a cross-sectional view of the inner tubular portion and the outer tubular portion taken along a position X1 in FIG. 2 is a cross-sectional view of the inner cylindrical portion at position X0 in FIG. 1 . 3 is a cross-sectional view of the tip side of the inner tubular portion shown in FIG. 2 taken along the line AA. 3 is a front view of a tip end side of the inner cylindrical portion shown in FIG. 2 . 13 is a plan view of a tip side of an inner cylindrical portion of a second embodiment of the present disclosure, viewed from the combustion chamber side along an axis line. FIG. FIG. 11 is a plan view of a tip side of an inner cylindrical portion of a third embodiment of the present disclosure, as viewed from the combustion chamber side along an axis line. FIG. 13 is a development view of an inner tubular portion according to a fourth embodiment of the present disclosure, with the inner circumferential surface facing upward.

First Embodiment
A fuel nozzle 100 according to a first embodiment of the present disclosure will be described below with reference to the drawings. Fig. 1 is a vertical cross-sectional view showing a fuel nozzle 100 according to a first embodiment of the present disclosure.

The fuel nozzle 100 of this embodiment is provided in a combustor of a gas turbine engine used in, for example, an aircraft. A gas turbine engine having a combustor equipped with the fuel nozzle 100 of this embodiment includes a turbine driven by combustion gas generated in the combustor by burning liquid fuel, and a drive shaft driven by the driving force of the turbine. The driving force transmitted from the turbine to the drive shaft is used as power to rotate a propeller or the like connected to the drive shaft.

As shown in FIG. 1, the fuel nozzle 100 of this embodiment includes a nozzle section 10, an inner cylindrical section (first cylindrical section) 20, an inner swirler (first swirler) 30, an outer cylindrical section (second cylindrical section) 40, and an outer swirler (second swirler) 50.

The nozzle section 10 is a fuel nozzle that is arranged along the axis X and injects liquid fuel supplied from a liquid fuel supply source (not shown) from the injection hole 11 through the inner cylindrical section 20 toward the combustion chamber CC. The nozzle section 10 injects liquid fuel toward the inner circumferential surface 20a of the inner cylindrical section 20 along an injection direction ID that intersects with the axis X.

The inner cylindrical portion 20 is a cylinder formed in a cylindrical shape along the axis X and arranged coaxially on the outer periphery side of the nozzle portion 10. The inner cylindrical portion 20 forms an inner flow passage IC between the nozzle portion 10 and the inner cylindrical portion 20, through which the combustion air CA flows. The inner flow passage IC is formed in an annular shape around the axis X until it reaches X0 shown in FIG. 1, and is formed in a frustum shape from X0 to X2. The inner flow passage IC is supplied with the combustion air CA from a combustion air supply source (not shown).

The inner swirler 30 is a device that is disposed in the inner flow passage IC and applies a swirling force to the combustion air CA flowing through the inner flow passage IC to rotate about the axis X. The inner swirler 30 is disposed in an annular shape in the circumferential direction about the axis X.

The outer cylindrical portion 40 is a cylindrical body formed in a cylindrical shape along the axis X and arranged coaxially on the outer circumferential side of the inner cylindrical portion 20. The inner cylindrical portion 20 forms an outer flow passage OC between the inner cylindrical portion 20 and the outer cylindrical portion 40, through which the combustion air CA flows. The outer flow passage OC is a flow passage formed in an annular shape around the axis X. The combustion air CA is supplied to the outer flow passage OC from a combustion air supply source (not shown).

The outer swirler 50 is a device that is disposed in the outer flow passage OC and applies a swirling force to the combustion air CA flowing through the outer flow passage OC to cause it to swirl about the axis X. The outer swirler 50 is disposed in an annular shape in the circumferential direction about the axis X.

Here, we will explain the configuration in which the inner cylindrical portion 20 forms a liquid film LF to promote atomization of the liquid fuel discharged into the combustion chamber CC. As shown in FIG. 1, the inner peripheral surface 20a of the inner cylindrical portion 20 adheres a portion of the liquid fuel injected from the nozzle portion 10 to form a liquid film LF. The liquid film LF formed on the inner peripheral surface 20a gradually becomes thinner as it moves toward the tip portion 20b of the inner cylindrical portion 20 facing the combustion chamber CC. The liquid film LF discharged from the tip portion 20b into the combustion chamber CC is atomized by the shearing action of the combustion air CA discharged from the inner flow passage IC and the combustion air CA discharged from the outer flow passage OC.

The liquid fuel is discharged from the tip 20b into the combustion chamber CC and atomized into droplets. As it moves away from the tip 20b, the droplets become smaller and smaller and begin to evaporate. The evaporated fuel mixes with the combustion air CA and is guided downstream in the flow direction of the combustion chamber CC.

Next, the shape of the inner cylindrical portion 20 for promoting atomization of the liquid fuel discharged into the combustion chamber CC will be described. FIG. 2 is a plan view of the tip side of the inner cylindrical portion 20 shown in FIG. 1, viewed from the combustion chamber CC side along the axis X. FIG. 3 is a perspective view of the tip side of the inner cylindrical portion shown in FIG. 2. As shown in FIGS. 2 and 3, the inner peripheral surface 20a of the inner cylindrical portion 20 has an uneven shape (first uneven shape) in which the distance from the axis X periodically increases and decreases along the circumferential direction CD about the axis X. In addition, the outer peripheral surface 20c of the inner cylindrical portion 20 has an uneven shape (second uneven shape) in which the distance from the axis X periodically increases and decreases along the circumferential direction CD about the axis X.

At the tip 20b of the inner cylindrical portion 20, the inner peripheral surface 20a has a shape in which recesses 21 that are farther from the axis X than the radius R2 centered on the axis X and protrusions 22 that are farther from the axis X than the radius R2 centered on the axis X are alternately arranged along the circumferential direction CD. In Figures 2 and 3, the valleys 21a indicate the positions of the recesses 21 that are farthest from the axis X. The peaks 22a indicate the positions of the protrusions 22 that are farthest from the axis X.

2 and 3, the valley line VL is a line formed by plotting the position of the valley portion 21a of the inner tubular portion 20 in the circumferential direction CD. Since the inner tubular portion 20 of this embodiment has a substantially constant plate thickness t, the shape of the inner circumferential surface 20a and the shape of the outer circumferential surface 20c are consistent. Therefore, in FIGS. 2 and 3, the position of the valley line VL formed on the inner circumferential surface 20a is shown on the outer circumferential surface 20c. The valley line VL is formed so as to move along the circumferential direction CD as the position of the axial direction X of the inner tubular portion 20 progresses from X0 to X1 and from X1 to X2 shown in FIG. 1.

Figure 4 is a cross-sectional view of the inner tubular portion 20 and the outer tubular portion 40 at position X1 in Figure 1. The inner peripheral surface 20a of the inner tubular portion 20 at position X1 has a shape in which recesses 21 that are farther from the axis X than the radius R1 centered on the axis X and protrusions 22 that are farther from the axis X than the radius R1 centered on the axis X are alternately arranged along the circumferential direction CD. In Figure 4, the valleys 21a indicate the positions of the recesses 21 that are farthest from the axis X. The peaks 22a indicate the positions of the protrusions 22 that are farthest from the axis X.

The radius R1 shown in FIG. 4 is larger than the radius R2 shown in FIG. 2. Therefore, the flow path cross-sectional area of the inner flow path IC formed by the inner peripheral surface 20a of the inner cylindrical portion 20 at position X2 in FIG. 1 is smaller than the flow path cross-sectional area of the inner flow path IC formed by the inner peripheral surface 20a of the inner cylindrical portion 20 at position X1 in FIG. 1. Also, the wet perimeter length of the inner peripheral surface 20a of the inner cylindrical portion 20 at position X2 in FIG. 1 is longer than the wet perimeter length of the inner peripheral surface 20a of the inner cylindrical portion 20 at position X1 in FIG. 1. Here, the wet perimeter length is the length of the inner peripheral surface 20a of the inner cylindrical portion 20 in a cross section perpendicular to the axis X, and refers to the length of one revolution along the circumferential direction CD of the inner peripheral surface 20a.

Figure 5 is a cross-sectional view of the inner tubular portion 20 at position X0 in Figure 1. As shown in Figure 5, the inner circumferential surface 20a at position X0 on the axis X is a circle with a constant distance R0 from the axis X. The radius R0 shown in Figure 5 is larger than the radius R1 shown in Figure 4. Therefore, the flow path cross-sectional area of the inner flow path IC formed by the inner circumferential surface 20a of the inner tubular portion 20 at position X1 in Figure 1 is smaller than the flow path cross-sectional area of the inner flow path IC formed by the inner circumferential surface 20a of the inner tubular portion 20 at position X0 in Figure 1. In addition, the wetted perimeter length of the inner circumferential surface 20a of the inner tubular portion 20 at position X1 in Figure 1 is longer than the wetted perimeter length of the inner circumferential surface 20a of the inner tubular portion 20 at position X0 in Figure 1.

As described above, the inner cylindrical portion 20 is formed so that the flow passage cross-sectional area of the inner flow passage IC decreases as it approaches the combustion chamber CC along the axis X, and the wetted perimeter length of the inner peripheral surface 20a of the inner cylindrical portion 20 in a cross section perpendicular to the axis X increases.

In the above description, the radii R1 and R2 are set at positions where the distance to the valley 21a and the distance to the apex 22a are equal in the radial direction centered on the axis X. The distance from the circle of the radii R1 and R2 to the valley 21a is equal to the distance from the circle of the radii R1 and R2 to the apex 22a, and this distance is defined as the amplitude VA (see FIG. 4). It is desirable to determine the amplitude VA so as to satisfy the following formula (1).
0.15×(r−R)≦VA≦0.5×(r−R) (1)
Here, r is the distance from the inner peripheral surface 40a of the outer tubular portion 40 to the axis X at each position along the axis X. r at position X1 is r1. R is the radius of a circle set at a position in the radial direction centered on the axis X where the distance to the valley portion 21a is equal to the distance to the peak portion 22a. R at positions X1 and X2 are R1 and R2.

By setting the amplitude VA to 0.15 x (r-R) or more, an appropriate wetted edge length for promoting thin film formation of the liquid fuel can be ensured. In addition, by setting the amplitude VA to 0.5 x (r-R) or less, it is possible to prevent the amplitude VA from becoming excessively large and causing liquid fuel to pool in the recess 21.

In the above description, the inner flow passage IC of the inner cylindrical portion 20 is described as having a flow passage cross-sectional area that decreases as it approaches the combustion chamber CC along the axis X, but other configurations are also possible. For example, the inner flow passage IC of the inner cylindrical portion 20 may be formed to have a constant flow passage cross-sectional area regardless of the distance from the combustion chamber CC along the axis X. In other words, the inner flow passage IC of the inner cylindrical portion 20 may not have a flow passage cross-sectional area that increases as it approaches the combustion chamber CC along the axis X.

Next, the imparting of a first swirl angle α to the combustion air CA flowing through the inner flow passage IC by the uneven shape formed on the inner peripheral surface 20a of the inner cylindrical portion 20 will be described with reference to the drawings. FIG. 6 is a cross-sectional view of the tip end side of the inner cylindrical portion 20 shown in FIG. 2 taken along the arrow A-A. As shown in FIG. 6, the angle between the tangent direction TD of the valley line VL formed on the inner peripheral surface 20a of the inner cylindrical portion 20 and the direction in which the axis X extends is the first swirl angle α. The combustion air CA flowing into the tip end side of the inner cylindrical portion 20 is guided along the tangent direction TD and is imparted with the first swirl angle α.

In the example shown in FIG. 6, the first swirl angle α at position X0 along the axis X is α0, the first swirl angle α at position X1 along the axis X is α1, and the first swirl angle α at position X2 along the axis X is α2. For example, the first swirl angle α has a relationship of α0<α1<α2. An example of α0 is 70 degrees, and an example of α2 is 50 degrees. In this way, the uneven shape formed on the inner peripheral surface 20a of the inner cylindrical portion 20 is shaped to impart the first swirl angle α to the combustion air CA flowing through the inner flow passage IC.

As shown in FIG. 6, the first swirl angle α is specified to change continuously and gradually as it approaches the combustion chamber CC along the axis X. Therefore, compared to when the first swirl angle α is changed suddenly or in stages, it is possible to suppress the occurrence of pressure loss in the inner flow passage IC and separation of the combustion air CA flowing through the outer flow passage OC.

Next, the imparting of a second swirl angle β to the combustion air CA flowing through the outer flow passage OC by the uneven shape formed on the outer peripheral surface 20c of the inner cylindrical portion 20 will be described with reference to the drawings. FIG. 7 is a front view of the tip side of the inner cylindrical portion 20 shown in FIG. 2. As shown in FIG. 7, the angle between the tangent direction TD of the valley line VL formed on the outer peripheral surface 20c of the inner cylindrical portion 20 and the direction in which the axis X extends is the second swirl angle β. The combustion air CA flowing into the outer flow passage OC is guided along the tangent direction TD and is imparted with the second swirl angle β.

In the example shown in FIG. 7, the second swirl angle β at position X0 along the axis X is β0, the second swirl angle β at position X1 along the axis X is β1, and the second swirl angle β at position X2 along the axis X is β2. For example, the second swirl angle β has a relationship of β0<β1<β2. An example of β0 is 70 degrees, and an example of β2 is 50 degrees. In this way, the uneven shape formed on the outer peripheral surface 20c of the inner cylindrical portion 20 is shaped to impart the second swirl angle β to the combustion air CA flowing through the outer flow passage OC.

As shown in FIG. 7, the second swirl angle β is specified to change continuously and gradually as it approaches the combustion chamber CC along the axis X. Therefore, compared to when the second swirl angle β is changed suddenly or in stages, it is possible to suppress the occurrence of pressure loss in the outer flow passage OC and the occurrence of separation of the combustion air CA flowing through the outer flow passage OC.

In this embodiment, the inner tubular portion 20 has a substantially constant plate thickness t, so the shape of the inner circumferential surface 20a and the shape of the outer circumferential surface 20c match. Therefore, the first rotation angle α and the second rotation angle β are the same at each position in the direction of the axis X.

The uneven shape of the inner peripheral surface 20a of the inner cylindrical portion 20 in this embodiment is a shape in which the distance from the axis X periodically increases and decreases along the circumferential direction CD about the axis X. By making the shape uneven in this way, the area of the liquid film LF can be increased. The combustion air CA flowing through the inner cylindrical portion 20 applies an external force to the liquid film LF, changing the interface shape and promoting the atomization of the fuel. The atomized fuel mixes with the combustion air CA, thereby appropriately promoting the generation of a mixture in the combustion chamber CC.

Similarly, the uneven shape of the outer peripheral surface 20c of the inner cylindrical portion 20 in this embodiment is a shape in which the distance from the axis X periodically increases and decreases along the circumferential direction CD about the axis X. By guiding the combustion air CA in a direction gradually approaching the axis X along such an uneven shape, the combustion air CA flowing through the outer flow passage OC is discharged into the combustion chamber CC in a direction approaching the axis X, thereby appropriately promoting mixing of the thin-film liquid fuel and the combustion air CA.

In particular, the uneven shape of the inner peripheral surface 20a imparts a swirling force to the combustion air CA discharged from the inner flow passage IC to the combustion chamber CC in a direction away from the axis X, and the combustion air CA discharged from the outer flow passage OC to the combustion chamber CC in a direction approaching the axis X, thereby effectively promoting atomization of the liquid fuel.

The periodicity of the uneven shape of the inner circumferential surface 20a and the periodicity of the uneven shape of the outer circumferential surface 20c are preferably 3 or more and 20 or less. Here, the periodicity refers to the number of times that the uneven shape increases and decreases repeatedly during one revolution around the axis in the circumferential direction CD. By making the periodicity 3 or more, it is possible to ensure a sufficient wetted edge length in the cross section of the inner circumferential surface 20a perpendicular to the axis X, and to promote atomization of the thin film liquid fuel. In addition, by making the periodicity 20 or less, it is possible to prevent the length of the uneven shape in the circumferential direction CD from becoming excessively short, thereby preventing liquid fuel from puddling in the recesses 21.

The functions and effects of the fuel nozzle 100 of the present embodiment described above will be described.
According to the fuel nozzle (100) of the present embodiment, a portion of the liquid fuel injected from the injection hole 11 of the nozzle portion 10 into the combustion chamber CC mixes with the combustion air CA to which a swirling force is applied by the inner swirler 30, swirls, and adheres to the inner circumferential surface 20a of the inner cylindrical portion 20. Since the wetted perimeter length in a cross section perpendicular to the axis X of the inner circumferential surface 20a of the inner cylindrical portion 20 becomes longer as the liquid fuel approaches the combustion chamber CC along the axis X, the liquid fuel adhered to the inner circumferential surface 20a of the inner cylindrical portion 20 gradually becomes thinner as it approaches the combustion chamber CC, and merges with the combustion air CA discharged from the outer flow passage OC when it is discharged from the tip portion 20b of the inner cylindrical portion 20.

In addition, since the flow passage cross-sectional area of the inner cylindrical portion 20 does not increase as it approaches the combustion chamber CC along the axis X, the combustion air CA can be discharged from the tip of the inner cylindrical portion 20 without reducing the flow rate of the combustion air CA, which is a mixture of the combustion air CA and liquid fuel. Furthermore, since a swirling force is applied to the combustion air CA discharged from the outer flow passage OC by the outer swirler 50, the shear force generated between the combustion air CA discharged from the outer flow passage OC and the combustion air CA mixed with liquid fuel discharged from the inner flow passage IC can promote atomization of the thin film liquid fuel.

According to the fuel nozzle 100 of this embodiment, the combustion air CA flowing through the inner cylindrical portion 20 is discharged into the combustion chamber CC with a first swirl angle α due to the uneven shape of the inner circumferential surface 20a, which promotes mixing of the thin film liquid fuel and the combustion air compared to when the inner circumferential surface 20a does not have an uneven shape.

According to the fuel nozzle 100 of this embodiment, the combustion air CA flowing through the outer flow passage OC is discharged into the combustion chamber CC with a second swirl angle β due to the uneven shape of the outer peripheral surface 20c. Therefore, compared to a case where the outer peripheral surface 20c does not have an uneven shape, the shear force acting when the combustion air CA flowing through the outer flow passage OC and the combustion air CA flowing through the inner flow passage IC mix is larger, and the atomization of the liquid fuel can be effectively promoted.

According to the fuel nozzle 100 of this embodiment, the combustion air flowing through the inner cylindrical portion 20 is discharged into the combustion chamber CC with a swirl angle imparted by the uneven shape having a periodicity of three or more, so that the mixing of the thin-film liquid fuel and the combustion air CA can be appropriately promoted.

Second Embodiment
Next, a fuel nozzle 100A according to a second embodiment of the present disclosure will be described with reference to the drawings. This embodiment is a modified example of the first embodiment, and is the same as the first embodiment except as otherwise specifically described below, and therefore the description thereof will be omitted.

The inner cylindrical portion 20 of the fuel nozzle 100 of the first embodiment has a substantially constant plate thickness t, the shape of the inner peripheral surface 20a and the shape of the outer peripheral surface 20c are the same, and the first swirl angle α and the second swirl angle β are the same at each position in the direction of the axis X. In contrast, the inner cylindrical portion 20A of the fuel nozzle 100A of the present embodiment has a first cylindrical portion 20A1 that forms the inner flow passage IC and a second cylindrical portion 20A2 that forms the outer flow passage OC, each formed from a different member.

Figure 8 is a plan view of the tip side of the inner cylindrical portion 20A of the second embodiment of the present disclosure, viewed from the combustion chamber CC side along the axis X. As shown in Figure 8, the inner cylindrical portion 20A of the fuel nozzle 100A of this embodiment has a first cylindrical portion 20A1 and a second cylindrical portion 20A2. The structure of the first cylindrical portion 20A1 is the same as the structure of the inner cylindrical portion 20 of the first embodiment, so a description thereof will be omitted below. However, while the outer peripheral surface 20c of the inner cylindrical portion 20 of the first embodiment forms the outer flow passage OC, the outer peripheral surface of the first cylindrical portion 20A1 of this embodiment does not form the outer flow passage OC.

In the inner cylindrical portion 20A of the fuel nozzle 100A of this embodiment, the second cylindrical portion 20A2 is disposed outside the first cylindrical portion 20A1. The second cylindrical portion 20A2 is a cylindrical body formed in a truncated cone shape in which the distance from the axis X to the inner peripheral surface 20A2a gradually decreases from R3 to R4 from position X0 on the axis X to position X2. The second cylindrical portion 20A2 forms an outer flow passage OC with the outer peripheral surface 20A2b.

In a radial direction perpendicular to the axis X, if the distance from the inner surface 20A1a of the first cylindrical portion 20A1 to the outer surface 20A2b of the second cylindrical portion 20A2 is tL, the distance VA2 from the top 22a to the valley 21a of the first cylindrical portion 20A1 is set to satisfy the following equation (2).
0.15 × tL ≦ VA2 ≦ 0.85 × tL (2)

At position X0 on axis X, VA2 = 0.15 x tL. At position X2 on axis X, VA2 = 0.85 x tL. Distance VA2 is set so that the position along axis X gradually increases from position X0 to position X2.

The inner cylindrical portion 20A of the fuel nozzle 100A of this embodiment has a first cylindrical portion 20A1 that forms the inner flow passage IC and a second cylindrical portion 20A2 that forms the outer flow passage OC, each formed from a different member. Therefore, the outer flow passage OC is formed by the outer peripheral surface 20A2b of the second cylindrical portion 20A2, not the outer peripheral surface of the first cylindrical portion 20A1. The shape of the inner peripheral surface 20A1a of the first cylindrical portion 20A1 does not match the shape of the outer peripheral surface 20A2b of the second cylindrical portion 20A2.

Therefore, compared to the inner tubular portion 20 of the first embodiment in which the first swirl angle α and the second swirl angle β are the same angle at each position in the axial direction X, the shear force acting when the combustion air CA flowing through the outer flow passage OC and the combustion air CA flowing through the inner flow passage IC are mixed is larger. This can effectively promote the atomization of the liquid fuel.

In this embodiment, the first cylindrical portion 20A1 forming the inner flow path IC and the second cylindrical portion 20A2 forming the outer flow path OC are formed from separate members, but other configurations are also possible. For example, the first cylindrical portion 20A1 and the second cylindrical portion 20A2 may be formed as an integral member. Also, for example, the first cylindrical portion 20A1 and the second cylindrical portion 20A2 may be formed integrally from a solid member that seals the gap between the first cylindrical portion 20A1 and the second cylindrical portion 20A2.

Third Embodiment
Next, a fuel nozzle 100B according to a third embodiment of the present disclosure will be described with reference to the drawings. This embodiment is a modified example of the second embodiment, and is the same as the second embodiment except as otherwise specifically described below, and therefore the description thereof will be omitted.

The inner cylindrical portion 20A of the fuel nozzle 100 in the second embodiment includes a first cylindrical portion 20A1 and a second cylindrical portion 20A2 having a truncated cone shape. In contrast, the inner cylindrical portion 20B in this embodiment includes a third cylindrical portion 20B3 in addition to the first cylindrical portion 20B1 and the second cylindrical portion 20B2 having a truncated cone shape.

Figure 9 is a plan view of the tip side of the inner cylindrical portion 20B of the third embodiment of the present disclosure, viewed from the combustion chamber CC side along the axis X. As shown in Figure 9, the inner cylindrical portion 20B of the fuel nozzle 100B of this embodiment has a first cylindrical portion 20B1, a second cylindrical portion 20B2, and a third cylindrical portion 20B3. The first cylindrical portion 20B1 and the second cylindrical portion 20B2 have the same structures as the first cylindrical portion 20A1 and the second cylindrical portion 20A2 of the second embodiment, respectively, and therefore will not be described below.

The inner cylindrical portion 20B of the third embodiment of the present disclosure further includes a third cylindrical portion 20B3 on the outside of the second cylindrical portion 20B2. The outer peripheral surface 20B3a of the third cylindrical portion 20B3 has an uneven shape (second uneven shape) in which the distance from the axis X periodically increases and decreases along the circumferential direction CD about the axis X. The outer peripheral surface 20B3a has alternating convex portions 20B3a1 and concave portions 20B3a2 whose distance from the axis X is shorter than that of the convex portions 20B3a1 along the circumferential direction CD.

9, the position of the recess 21 of the first cylindrical portion 20B1 is different from the position (phase) of the protrusion 20B3a1 of the third cylindrical portion 20B3 in the circumferential direction CD, and the position of the protrusion 22 of the first cylindrical portion 20B1 is different from the position (phase) of the recess 20B3a2 of the third cylindrical portion 20B3 in the circumferential direction CD. By doing so, the position of the main stream of the combustion air CA dispersing in the circumferential direction CD flowing from the inner flow passage IC to the combustion chamber CC along the first cylindrical portion 20B1 can be made different from the position of the main stream of the combustion air CA dispersing in the circumferential direction CD flowing from the outer flow passage OC to the combustion chamber CC along the third cylindrical portion 20B3. This can satisfactorily increase the shear force acting between the combustion air CA flowing from the inner flow passage IC to the combustion chamber CC and the combustion air CA flowing from the outer flow passage OC to the combustion chamber CC.

In this embodiment, the first swirl angle α (see FIG. 6) imparted to the combustion air CA flowing through the inner flow passage IC by the uneven shape formed on the inner peripheral surface of the first cylindrical portion 20B1 and the second swirl angle β (see FIG. 7) imparted to the combustion air CA flowing through the outer flow passage OC by the uneven shape formed on the outer peripheral surface 20B3a of the third cylindrical portion 20B3 may be made different at each position on the axis X.

The first swirl angle α and the second swirl angle β may be made different at least at the discharge position into the combustion chamber CC (the tip of the inner tubular portion 20B on the combustion chamber CC side). By making the first swirl angle α and the second swirl angle β different at the discharge position into the combustion chamber CC, the shear force acting between the combustion air CA flowing from the inner flow passage IC to the combustion chamber CC and the combustion air CA flowing from the outer flow passage OC to the combustion chamber CC can be effectively increased.

In the inner cylindrical portion 20B shown in FIG. 9, the number of periods in the circumferential direction CD of the uneven shape of the first cylindrical portion 20B1 (5) is the same as the number of periods in the circumferential direction CD of the uneven shape of the third cylindrical portion 20B3 (5), but other configurations are also possible. For example, the number of periods in the circumferential direction CD of the uneven shape of the third cylindrical portion 20B3 may be made larger than the number of periods in the circumferential direction CD of the uneven shape of the first cylindrical portion 20B1, and the number of periods may be made different.

In this embodiment, the first cylindrical portion 20B1, the second cylindrical portion 20B2, and the third cylindrical portion 20B3 are formed as independent members, but other configurations are also possible. For example, the first cylindrical portion 20B1, the second cylindrical portion 20B2, and the third cylindrical portion 20B3 may be formed as an integral member. Also, for example, the first cylindrical portion 20B1 and the third cylindrical portion 20B3 may be formed integrally by a solid member that seals the gap between the first cylindrical portion 20B1 and the third cylindrical portion 20B3.

Fourth Embodiment
Next, a fuel nozzle according to a fourth embodiment of the present disclosure will be described with reference to the drawings. This embodiment is a modified example of the first embodiment, and is the same as the first embodiment except as otherwise specifically described below, and therefore the description thereof will be omitted.

In the first embodiment, the inner cylindrical portion 20 has the same number of periods in the circumferential direction CD of the uneven shape formed on the inner peripheral surface 20a and outer peripheral surface 20c of the inner cylindrical portion 20 at each position along the axis X. In contrast, in the inner cylindrical portion 20C of this embodiment, the number of periods in the circumferential direction CD of the uneven shape formed on the inner peripheral surface and outer peripheral surface of the inner cylindrical portion 20C increases as it approaches the combustion chamber CC along the axis X.

Figure 10 is an exploded view of the inner tubular portion 20C of this embodiment with the inner circumferential surface 20Ca facing upward. The inner tubular portion 20C forms a tubular body with one end 20C1 and the other end 20C2 in the circumferential direction CD at the same position.

As shown in FIG. 10, at position X0 along the axis X, the recesses 21C and the protrusions 22C are alternately arranged with a period of 4 along the circumferential direction CD of the inner tubular portion 20C. At position X1 along the axis X, the recesses 21C and the protrusions 22C are alternately arranged with a period of 6 along the circumferential direction CD of the inner tubular portion 20C. At position X2 along the axis X, the recesses 21C and the protrusions 22C are alternately arranged with a period of 12 along the circumferential direction CD of the inner tubular portion 20C.

As described above, the inner cylindrical portion 20C of this embodiment is shaped so that the number of periods in the circumferential direction CD of the uneven shape formed on the inner peripheral surface 20Ca and outer peripheral surface of the inner cylindrical portion 20C increases as it approaches the combustion chamber CC along the axis X. In addition, the uneven shape of the inner cylindrical portion 20C has a curved shape as shown in FIG. 10 so that the number of phases is smoothly switched when the number of periods in the circumferential direction CD is increased along the axis X.

In the fuel nozzle of this embodiment, the number of periods of the concave-convex shape of the inner cylindrical portion 20C is gradually increased as it approaches the combustion chamber CC, so that the number of divisions in the circumferential direction CD of the combustion air CA flowing through the inner flow passage IC gradually increases as it approaches the combustion chamber CC, further promoting the mixing of the thin-film liquid fuel and the combustion air.

The fuel nozzle described in each of the above-described embodiments can be understood, for example, as follows.
A fuel nozzle (100) according to a first aspect of the present disclosure includes a nozzle portion (10) arranged along an axis (X) and configured to inject liquid fuel from an injection hole (11) toward a combustion chamber (CC), a first tubular portion (20) formed in a cylindrical shape along the axis, arranged on the outer periphery of the nozzle portion, and forming a first flow path (IC) through which combustion air flows between the nozzle portion and the first tubular portion, and a first swirler (30) arranged in the first flow path and configured to apply a swirling force to the combustion air flowing through the first flow path to rotate about the axis, wherein an inner circumferential surface (20a) of the first tubular portion forms a liquid film by adhering the liquid fuel injected from the nozzle portion, and the first tubular portion is formed such that a flow path cross-sectional area does not increase as the first tubular portion approaches the combustion chamber along the axis, and a wetted perimeter length in a cross section of the inner circumferential surface of the first tubular portion perpendicular to the axis increases.

According to the fuel nozzle (100) of the present disclosure, a portion of the liquid fuel injected from the nozzle hole in the nozzle portion into the combustion chamber mixes with the combustion air to which a swirling force is applied by the first swirler, swirls, and adheres to the inner circumferential surface of the first cylindrical portion. As the liquid fuel approaches the combustion chamber along the axis, the wetted perimeter length in a cross section perpendicular to the axis of the inner circumferential surface of the first cylindrical portion becomes longer, so that the liquid fuel adhered to the inner circumferential surface of the first cylindrical portion gradually becomes a thinner film as it approaches the combustion chamber.

In addition, since the cross-sectional area of the flow passage of the first cylindrical section does not increase as it approaches the combustion chamber along the axis, the mixture of combustion air and liquid fuel can be discharged from the tip of the first cylindrical section without reducing the flow rate of the mixture. The shear force generated by the combustion air discharged from the first flow passage promotes atomization of the thin film of liquid fuel.

The fuel nozzle (100) according to the second aspect of the present disclosure is the first aspect, and further includes the following configuration: the inner circumferential surface of the first cylindrical portion has a first uneven shape that periodically repeats an increase and a decrease in distance from the axis along a circumferential direction about the axis, and the first uneven shape is a shape that imparts a first swirl angle (θ1) with respect to the axis to the combustion air flowing through the first cylindrical portion.
According to the fuel nozzle of the second aspect of the present disclosure, the combustion air flowing through the first cylindrical portion is discharged into the combustion chamber with a first swirl angle imparted thereto by the first uneven shape, thereby promoting mixing of the thin-film liquid fuel and the combustion air compared to a case in which the first uneven shape is not provided on the inner circumferential surface.

In the second aspect, the fuel nozzle (100) according to the third aspect of the present disclosure further includes the following configuration: That is, the fuel nozzle (100) includes a second cylindrical portion (40) that is formed in a cylindrical shape along the axis and is disposed on the outer circumferential side of the first cylindrical portion, and that forms a second flow passage (OC) between the first cylindrical portion and the second cylindrical portion, through which combustion air flows, and the outer circumferential surface of the first cylindrical portion has a second uneven shape that periodically repeats an increase and a decrease in distance from the axis along the circumferential direction, and the second uneven shape is shaped to impart a second swirl angle (θ2) with respect to the axis to the combustion air flowing through the second flow passage.
According to the fuel nozzle of the third aspect of the present disclosure, the combustion air flowing through the second flow passage is discharged into the combustion chamber with a second swirl angle imparted by the second uneven shape. Therefore, compared to a case in which the second uneven shape is not provided, the shear force acting when the combustion air flowing through the second flow passage and the combustion air flowing through the first flow passage mix is greater, and the atomization of the liquid fuel can be effectively promoted.

The fuel nozzle (100) according to the fourth aspect of the present disclosure is the third aspect, further comprising the following configuration: the first uneven shape and the second uneven shape are formed at a tip end portion of the first cylindrical portion on the combustion chamber side such that the first swirl angle and the second swirl angle are different from each other.
According to the fuel nozzle of the fourth aspect of the present disclosure, the first swirl angle and the second swirl angle are different at the tip of the first cylindrical portion on the combustion chamber side. Therefore, compared to when the first swirl angle and the second swirl angle are the same, the shear force acting when the combustion air flowing through the outer flow passage and the combustion air flowing through the first flow passage are mixed is larger, thereby effectively promoting atomization of the liquid fuel.

The fuel nozzle (100) according to a fifth aspect of the present disclosure is any one of the second to fourth aspects, further comprising the following configuration: That is, the first uneven shape has three or more periods of increase and decrease in the distance per revolution around the axis in the circumferential direction.
According to the fuel nozzle of the fifth aspect of the present disclosure, the combustion air flowing through the first cylindrical portion is discharged into the combustion chamber with a swirl angle imparted by the first uneven shape having a periodicity of three or more, thereby appropriately promoting mixing of the thin-film liquid fuel and the combustion air.

The fuel nozzle (100) according to the sixth aspect of the present disclosure is the fifth aspect, further comprising the following configuration: That is, the first concave-convex shape is formed such that the periodic number gradually increases as the first concave-convex shape approaches the combustion chamber along the axis.
According to the fuel nozzle of the sixth aspect of the present disclosure, the periodic number of the first uneven shape is formed to gradually increase toward the combustion chamber. Therefore, the number of circumferential divisions of the combustion air flowing through the inner flow passage gradually increases toward the combustion chamber, thereby further promoting mixing of the thin-film liquid fuel and the combustion air.

A gas turbine engine according to a seventh aspect of the present disclosure includes a combustor having a fuel nozzle according to any one of the first to sixth aspects, and a turbine driven by combustion gas generated by burning liquid fuel in the combustor.
According to the gas turbine engine according to the seventh aspect of the present disclosure, it is possible to provide a gas turbine engine equipped with a fuel nozzle capable of promoting atomization of liquid fuel and suppressing the generation of harmful emissions such as NOx.

10 nozzle portion 11 injection hole 12 period number 20, 20A, 20B, 20C inner cylindrical portion 20a, 20A1a, 20A2a, 20Ca, 40a inner peripheral surface 20c, 20A2b, 20B3a outer peripheral surface 20b tip portion 20A1, 20B1 first cylindrical portion 20A2, 20B2 second cylindrical portion 20B3 third cylindrical portion 20B3a1, 22, 22C convex portion 20B3a2, 21, 21C concave portion 20C1 one end portion 20C2 other end portion 21a valley portion 22a apex portion 30 inner swirler 40 outer cylindrical portion 50 outer swirler 100, 100A, 100B fuel nozzle CA combustion air CC combustion chamber CD circumferential direction IC inner flow path LF liquid film OC outer flow path R0, R1, R2 Radius TD Tangential direction VA Amplitude VA2 Distance VL Valley line X Axis line t Plate thickness α First rotation angle β Second rotation angle

Claims (7)

a nozzle portion that is disposed along the axis and that injects liquid fuel from an injection hole toward a combustion chamber;
a first cylindrical portion that is formed in a cylindrical shape along the axis and is disposed on an outer circumferential side of the nozzle portion, the first cylindrical portion forming a first flow passage between the nozzle portion and the first cylindrical portion, through which combustion air flows;
a first swirler that is disposed in the first flow path and applies a swirling force to the combustion air flowing through the first flow path so that the combustion air swirls about the axis;
the liquid fuel injected from the nozzle portion adheres to an inner circumferential surface of the first cylindrical portion to form a liquid film;
the first cylindrical portion is formed such that a flow passage cross-sectional area does not increase toward the combustion chamber along the axis, and a wetted perimeter length of the inner circumferential surface of the first cylindrical portion in a cross section perpendicular to the axis increases toward the combustion chamber along the axis. the inner circumferential surface of the first cylindrical portion has a first uneven shape in which a distance from the axis line periodically increases and decreases along a circumferential direction around the axis line,
2 . The fuel nozzle according to claim 1 , wherein the first uneven shape is a shape that imparts a first swirl angle with respect to the axis to the combustion air flowing through the first cylindrical portion. a second cylindrical portion that is cylindrically formed along the axis and that is disposed on an outer circumferential side of the first cylindrical portion, and that forms a second flow passage between the first cylindrical portion and the second cylindrical portion, through which combustion air flows;
an outer circumferential surface of the first cylindrical portion has a second uneven shape in which a distance from the axis line periodically increases and decreases along the circumferential direction;
3. The fuel nozzle according to claim 2, wherein the second uneven shape is a shape that imparts a second swirl angle with respect to the axis to the combustion air flowing through the second flow passage. The fuel nozzle according to claim 3, wherein the first uneven shape and the second uneven shape are formed at the tip of the first cylindrical portion on the combustion chamber side so that the first swirl angle and the second swirl angle are different. The fuel nozzle according to any one of claims 2 to 4, wherein the first uneven shape has three or more periods of increase and decrease in the distance per revolution around the axis in the circumferential direction. The fuel nozzle according to claim 5, wherein the first uneven shape is formed so that the number of periods gradually increases as the shape approaches the combustion chamber along the axis. A combustor comprising the fuel nozzle according to any one of claims 1 to 4;
a turbine driven by combustion gases produced by the combustor combusting a liquid fuel.