Wind turbine tower section and connecting device therefor

Abstract

A tower section for a wind turbine is provided. The tower section includes an annular wall portion defining a tower section axis and having an annular connecting flange portion, where the annular connecting flange portion defines a first array of bolt holes. An annular flange reinforcement is located on the annular connecting flange portion, the annular flange reinforcement defining a second array of bolt holes, each bolt hole in the first array of bolt holes being aligned with a respective bolt hole in the second array of bolt holes. A plurality of mechanical fasteners is provided, each of the plurality of mechanical fasteners extending through a respective bolt hole of the first and second arrays of bolt holes. Advantageously, the annular flange portion and the annular flange reinforcement are configured to define an annular gap therebetween. The annular void provides a degree of flexibility to the annular flange reinforcement, which changes the stiffness ratio between the flange portion and the mechanical fastener. Advantageously, this improves the stressability of the interface between the mechanical fasteners that clamp the annular flange reinforcement to the annular flange connection portion.

Description

Technical Field

[0001] The present disclosure generally relates to methods, techniques, and approaches for constructing wind turbines, and particularly to methods, techniques, and approaches for joining adjacent tower sections of a wind turbine together at a flange joint. Background Art

[0002] The current trend is to design wind turbines to be larger in order to capture more energy from the wind. As a result, wind turbine towers need to be taller and built more robustly to accommodate the required operating loads.

[0003] Typically, wind turbine towers are constructed of steel or concrete and are generally formed of multiple tower sections that are stacked vertically and secured together at connecting flanges. Such construction is well known to those skilled in the art.

[0004] Larger wind turbines impose greater loads on the tower, which increases the stress experienced at the flange joint. Although the tower sections can be designed to have thicker material sections and flanges, this would be more expensive and would significantly increase the mass of the tower sections, thus also affecting transportation issues. Therefore, it is desirable to increase the connection strength of a wind turbine tower without significantly increasing the tower mass. It is in this context that the present invention has been designed. Summary of the Invention

[0005] According to one aspect of the present invention, there is provided a tower section for a wind turbine. The tower section includes an annular wall portion that defines a tower section axis and has an annular connecting flange portion, wherein the annular connecting flange portion defines a first bolt hole array. An annular flange reinforcement device is located on the annular connecting flange portion, the annular flange reinforcement device defining a second bolt hole array, and each bolt hole in the first bolt hole array is aligned with a corresponding bolt hole in the second bolt hole array. A plurality of mechanical fasteners are provided, each of the plurality of mechanical fasteners extending through a corresponding bolt hole in the first bolt hole array and the second bolt hole array. Advantageously, the annular flange portion and the annular flange reinforcement device are configured to define an annular gap therebetween.

[0006] The annular gap provides a degree of flexibility to the annular flange reinforcement device, which changes the stiffness ratio between the flange portion and the mechanical fasteners. This means that the annular flange reinforcement device can be slightly bent or deflected into the space provided by the annular gap. Advantageously, this improves the stress capacity of the interface between the mechanical fasteners that clamp the annular flange reinforcement device to the annular flange connection portion.

[0007] It is conceivable that the annular flange reinforcement means is most conveniently implemented as an annular plate. The annular plate can be a single part or can be formed by a plurality of partial annular plates. The partial annular plates can be joined together in a suitable manner.

[0008] The annular gap can be at least partially defined by a recess defined in the annular connecting flange portion. Alternatively, the annular gap can be at least partially defined by a recess formed in the annular flange reinforcement means. This can be a more convenient method when retrofitting the reinforcement means to an existing wind turbine tower section.

[0009] The invention can also be expressed as a flange connection structure for a wind turbine, which wind turbine comprises a first or upper tower section and a second or lower tower section. The upper tower section comprises a wall portion and a first / upper connecting flange portion. The lower tower section comprises a wall portion and a second / lower connecting flange portion. The lower connecting flange portion and the upper connecting flange portion are joined together by an array of mechanical fasteners.

[0010] A first annular flange reinforcement means, which can be in the form of an annular plate, is clamped to the upper connecting flange portion by mechanical fasteners. Similarly, a second annular flange reinforcement means is clamped to the upper connecting flange portion by mechanical fasteners. A first annular gap is defined between the upper connecting flange portion and the upper annular flange reinforcement means. Correspondingly, a second annular gap is defined between the lower connecting flange portion and the lower annular flange reinforcement means.

[0011] Furthermore, the invention also includes a method of reinforcing a tower section of a wind turbine, the tower section comprising an annular wall portion which defines a tower section axis and has an annular connecting flange portion, wherein the annular connecting flange portion defines a first array of bolt holes and corresponding fasteners pass through the first array of bolt holes. The method comprises: removing at least some of the fasteners from the annular connecting flange portion; arranging an annular flange reinforcement means on the annular connecting flange portion, the annular flange reinforcement means defining a second array of bolt holes, each bolt hole in the first array of bolt holes being aligned with a corresponding bolt hole in the second array of bolt holes; and installing fasteners through the corresponding bolt holes in the first array of bolt holes and the second array of bolt holes so as to clamp the annular flange reinforcement means to the annular flange portion. The annular connecting flange portion and the annular flange reinforcement means are configured to define an annular gap therebetween.

[0012] The method can further comprise: forming a recess in the annular flange reinforcement means before arranging the annular flange reinforcement means on the annular connecting flange portion, so as to define an annular gap when the two components are placed together. As an alternative, the annular gap can be formed by forming a recess in the annular connecting flange portion before arranging the annular flange reinforcement means on the annular connecting flange portion.

[0013] It should be noted that the annular flange strengthening device can be formed by a plurality of individual parts. Accordingly, the step of arranging the annular flange strengthening device on the annular connecting flange part may further include: positioning a first part annular strengthening device part of the plurality of part annular strengthening device parts on the annular connecting flange part and fixing the first part annular strengthening device using corresponding mechanical fasteners; and subsequently repeating the positioning and fixing steps for other part annular strengthening devices of the plurality of part annular strengthening devices.

[0014] Optional features of aspects of the invention are set forth in the dependent claims. Note that these optional features may be combined with each other without limitation, except in cases where specific limitations are explicitly discussed in the following discussion. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more fully understand the present invention, the present invention will now be described by way of example only with reference to the following drawings, in which like features are assigned like reference numerals and in which:

[0016] Figure 1 is a front view of a wind turbine tower and includes an illustration showing a flange joint between adjacent sections of the tower;

[0017] Figure 2 shows from a different perspective Figure 1 a partial cross-sectional view of the flange joint in

[0018] Figure 3 is a cross-section through Figure 2 a part of the flange joint in

[0019] Figures 4a to 4d schematically shows a retrofit operation that can be implemented using an embodiment of the present invention;

[0020] Figure 5 is a plan view of a flange joint between tower sections, which shows a part annular plate according to the present invention applied to a connecting flange. DETAILED DESCRIPTION

[0021] Generally speaking, embodiments of the present invention provide a method for increasing the strength of a flange joint between wind turbine tower sections, which method improves the strength of the entire wind turbine tower. This means that the wind turbine tower can be constructed to have increased strength characteristics without significantly increasing its mass. One advantage is that the method can be applied to wind turbine towers that have already been built. This means that the strength of the wind turbine tower can be increased, which may be useful in retrofit operations to upgrade the power generation capacity of a specific wind turbine.

[0022] To provide the background of the present invention, Figure 1 A typical horizontal axis wind turbine 2 is shown, which includes a nacelle 4 mounted on top of a tower 6, and the nacelle 4 supports a forward rotor 8 including a plurality of coplanar blades 10. Although not shown in Figure 1 , the rotor 8 is connected to a power train or drive train housed within the nacelle 4. The drive train includes the components necessary to convert the rotation of the rotor 8 into electricity, and these components include a generator, a gear system, and a controller, but for the sake of brevity, these components are not shown or described in detail in Figure 1 . Although Figure 1 shows a horizontal axis wind turbine, which is a common configuration of a wind turbine, it should be noted that the present invention can be applied to other wind turbine configurations.

[0023] Generally, the tower 6 can be made of steel or concrete, and the choice of steel or concrete depends on many factors, such as the expected load conditions, hub height, and location, to name just a few. Hybrid towers of concrete and steel are also known.

[0024] The tower is constructed from annular or tubular tower sections 20, as can be seen in Figure 1 . Due to the slight taper of the tower 6, in this example, each annular tower section is slightly frustoconical. In the example shown, the annular tower section 20 can be considered to be made entirely or mostly of steel, which is a common construction material for wind turbine towers.

[0025] In the wind turbine 2 shown, there are two tower sections, which include a lower tower section 22 and an upper tower section 24. Note that the tower 6 can include more than two tower sections, for example between three and ten tower sections.

[0026] Each tower section 20 is connected together by a flange joint or "coupling" 25. A portion of the flange joint 25 between the lower tower section 22 and the upper tower section 24 can be seen in the illustration in Figure 1 , and can also be seen in Figure 2 and Figure 3 , and will now also be referred to in Figure 2 and Figure 3 .

[0027] As can be seen, the upper tower section 24 includes an annular wall portion 26 which terminates at its lower end at a first annular connecting flange portion 28. Similarly, the lower tower section 22 includes an annular wall portion 30 which terminates at its upper end in a corresponding second annular connecting flange portion 32. Such flanged connecting portions may also be referred to as L-shaped flanges, mainly due to their cross-sectional shape, and are generally known in the art. Other possibilities are substantially T-shaped flange joints, where the flange extends radially inwards from its corresponding wall portion and also extends radially outwards from the corresponding wall portion. T-shaped flanges are also known in the art. As shown, the flange portion is integral with the wall portion, but in principle the flange portion can be separate from the wall portion and welded to the wall portion to form an integral component.

[0028] The upper tower section 24 and the lower tower section 22 define a central tower axis A. In addition, the corresponding wall portions 26, 30 extend around the tower axis A and are generally aligned parallel to the tower axis A.

[0029] Regarding the upper tower section 24, it should be noted that the first annular connecting flange portion 28 extends in a direction substantially perpendicular to the annular wall portion 26. Thus, the annular wall portion 26 and the first annular connecting flange portion 28 define an L-shape in a vertical section, as shown. In the example shown, the first annular flange connecting portion 28 and the second annular flange connecting portion 32 engage each other at corresponding contact surfaces 35, 37.

[0030] Similarly, regarding the lower tower section 22, it should be noted that the second annular connecting flange portion 32 extends in a direction substantially perpendicular to the annular wall portion 30. Thus, the annular wall portion 30 and the second annular connecting flange portion 32 define an L-shape in a vertical section, as shown.

[0031] A circular array of mechanical fasteners 40 in the form of bolts extends circumferentially around the flange joint 25 and is used to join the first annular connecting flange portion 26 and the second annular connecting flange portion 32 together. As Figure 3 shown, the mechanical fastener 40 is a headed bolt having a T-shaped cross-section, thus defining an upper bolt head 42 integral with a shank portion 44. A corresponding nut 46 is fixed on the shank portion 44 of the bolt 40 and is suitably tightened to engage the flange joint 25. In principle, the diameter of the tower section can be of any size, but the invention is envisaged as being most suitable for large-diameter tower sections where the "bolt circle diameter" or BCD of the fasteners exceeds 3 m, for example between 3 m and 10 m, and more preferably between 3.5 m and 8 m.

[0032] The mechanical fastener 40 is also typically inverted such that the bolt head 42 is located below the second annular connection flange portion 32 and the nut 46 is located above the first annular connection flange portion 28. Moreover, the mechanical fastener 40 may alternatively be in the form of a stud bolt that does not have a fixed head but has a first removable nut and a second removable nut, as will be well understood by those skilled in the art.

[0033] The flange joint 25 between the tower sections 22, 24 also includes a strengthening structure 50 that is configured to be located between the mechanical fastener 40 and the annular connection flange portions 28, 32. As will be described, the strengthening structure 50 is used to change the stiffness ratio between the material of the fastener 40 and the material of the annular flange connection portions 28, 32. One way it is achieved is by being selected as a material whose Young's modulus is between the Young's moduli of the materials of the fastener 40 and the annular connection flange portions 26, 32. Another way to achieve this effect is to have a geometry that imparts structural flexibility at the interface between the fastener 40 and the annular connection flange portions 28, 32.

[0034] Although the general construction of the flange joint 25 is shown in Figure 1 and Figure 2 the flange joint 25 is also shown in more detail in Figure 3 .

[0035] The strengthening structure 50 in the illustrated embodiment includes a pair of annular flange strengthening devices 52, 56 that are positioned to sandwich the flange joint 25 therebetween, one on each side.

[0036] In another, not shown, embodiment, the strengthening structure 50 includes a single annular flange strengthening device 52, 56 that is positioned on one side of the flange joint 25.

[0037] Thus, the pair of annular flange strengthening devices includes a first (upper) annular flange strengthening device 52 on the upper surface 54 of the first annular connection flange portion 28 and a second (lower) annular flange strengthening device 56 on the lower surface 58 of the second annular connection flange portion 32. In the example shown, the annular flange strengthening devices 52, 56 are in the form of relatively flat plates and, for the sake of brevity, from now on they will be referred to as "plates". However, it should be understood that the annular plates 52, 56 need not strictly be in the form of plates. It should also be noted that in the specific example described herein, the annular plates 52, 56 are single components that are circular when viewed in plan view so as to be complementary to the shape of the flange joint 25. However, it should be understood that each of the annular plates 52, 56 may also be composed of a plurality of partial annular sections rather than being a monolithic component.

[0038] The upper annular plate 52 is in Figure 2It is seen in a partially cut-away form. Note that it is envisaged that the upper annular plate 52 and the lower annular plate 56 have the same or comparable external dimensions, although this does not rule out some differences.

[0039] Thus, in this form, the upper annular plate 52 and the lower annular plate 56 actually sandwich the first annular connection flange portion 28 and the second annular connection flange portion 32 therebetween. As will be seen Figure 3 particularly clearly in, each of the annular plates 52, 56 defines a corresponding array of bolt holes 52a, 56a. Each bolt hole in the bolt hole arrays 52a, 56a is aligned with a corresponding bolt hole in the bolt hole arrays 28a, 32a defined in the first connection flange portion 28 and the second connection flange portion 32.

[0040] Thus, the mechanical fasteners 40 pass through the aligned bolt holes in the annular plates 52, 56, the first connection flange portion 28 and the second connection flange portion 32 to join these components together. As will be seen Figure 3 in, a bushing, gasket or washer 60 is provided as a load displacement device between the ends of the mechanical fasteners 40 and the mating surfaces of the annular plates 52, 56.

[0041] As a temporary fixing device, auxiliary mechanical fasteners 63 may be provided to fix the corresponding annular plates 52, 56 to the annular connection flange portion 32 before the main fasteners 40 are applied.

[0042] From Figure 3 it can be seen that a first annular gap 70 is defined between the first annular plate 52 and the first annular connection portion 28. Similarly, a second annular gap 72 is defined between the second annular plate 56 and the second annular connection portion 32.

[0043] In the illustrated embodiment, each of the first annular gap 70 and the second annular gap 72 may be considered the same, and thus for the sake of brevity only one of them will be described in further detail. However, it should be understood that this description will apply to both annular gaps 70, 72.

[0044] On this basis, and referring to the upper part of the two annular gaps 70, 72 as shown in Figure 3 it should be noted that the first annular gap 70 is at least partially defined by the first connection flange portion 28 and / or at least partially by the first annular plate 52. In this particular embodiment, the shape of the first annular gap 70 is provided by an annular groove, recess or channel 74 defined in the upper surface 54 of the first connection flange portion 28.

[0045] As will be seen from Figure 3It is understood that when considered in the radial direction, the annular groove 74 is relatively wide, but when considered in the depth direction along the tower axis A, the annular groove 74 is shallow. The dimension of the annular groove 74 in the radial direction is smaller than the corresponding dimension of the annular plate 72. Therefore, the annular plate 72 overlaps or straddles above the top of the annular void 74. The position of the annular void 70 below the annular plate 52 means that the annular plate 52 can deflect slightly during cyclic loading on the tower so as to bend or deflect into the space provided by the annular void 70. Thus, the relatively hard high-strength bolt steel of the mechanical fastener 40 is provided with a relatively elastic mounting point when it abuts against the corresponding annular plate 52. Therefore, it is considered that the relative flexibility of the annular plate 52 provides a stress relief function compared with the known method of simply directly bolting the mechanical fastener 40 to the annular connection flange portions 28, 32.

[0046] As can be seen Figure 3 from, the dimension of the annular plate 52 in the radial direction, i.e., its width dimension (shown here as W1), is close to but slightly smaller than the width of the adjacent annular connection flange 28 (shown here as W2). It is conceivable that in some examples, the width of the annular plate will be greater than 80% of the width of the annular connection flange 28, although currently it is preferred to provide some clearance between the annular plate 52 and the wall portion 26 to address the fillets and other manufacturing tolerances at the corner points between the wall portion 26 and the connection flange portion 28.

[0047] Similarly, the width W3 of the annular void 70 is relatively large with respect to the width W2 of the annular connection flange portion 28. As shown here, the width W3 of the annular void 70 is greater than 30% of the width of the annular connection flange portion 28, preferably greater than 50%, and more specifically, about 70%. In some embodiments, the width W3 of the annular void 70 is such that it extends beyond the radial expansion of the washer 60.

[0048] As can be seen from the figure, the annular void 70 is shallow in its depth dimension taken along the tower axis A. It is currently contemplated that the cross-sectional shape of the annular void 70 taken in the radial direction is substantially rectangular and uniform around the entire annular void 70, and the depth is less than 10 mm. In some examples, the depth is between 5 mm and 10 mm, and in other examples, the depth is less than 5 mm, such as between 2 mm and 4 mm.

[0049] From the above discussion, it should be understood that the cross-sectional shape of the annular void 70 is relatively wide and shallow. Therefore, the ratio of the depth of the annular void to the radial width W3 of the annular void 70 can be between 1:30 and 1:60.

[0050] As can be seen Figure 3It is also understood that the annular plate 52 is configured such that its thickness T1 is less than the thickness T2 of the annular flange connection portion 28. The thickness T1 of the annular plate is preferably 50% or less, more preferably 25% or less, of the thickness T2 of the annular flange connection portion 28.

[0051] At this point, it should be emphasized that although in the illustrated embodiment, the annular gap 70 is defined by the annular groove 74 defined in the annular connecting flange portion 28, the annular gap 70 can also be defined by a groove machined in the lower side of the annular plate 52, or by a combination of grooves complementary formed in the annular connecting flange portion 28 and the annular plate 52. An alternative annular groove formed in the annular plate is shown at 74' in Figure 3 as follows.

[0052] A significant benefit of the present invention is that providing the annular gap below the annular plate means that the strength of the flange joint 25 between the tower sections 22, 24 is enhanced without increasing the mass and size of the flange joint. In fact, the inventors believe that a 10% to 15% increase in load capacity can be achieved in this way.

[0053] The principle of the present invention can also be applied to existing wind turbines. For example, it may be desirable to retrofit an existing wind turbine with the flange reinforcement structure 50 according to an example of the present invention in order to increase the load capacity of the flange joints within the wind turbine tower.

[0054] Such a retrofit process for strengthening a wind turbine tower is shown in Figures 4a to 4d as follows. Figures 4a to 4d The overall construction of the tower sections in Figure 2 and Figure 3 is comparable to the overall construction of the tower sections shown in

[0055] Therefore, the same reference numerals will be used to refer to corresponding parts, and for the sake of brevity, the complete discussion of each component will not be repeated. Figure 4a As can be seen from

[0056] a conventional flange joint 25 is provided between the lower tower section 22 and the upper tower section 24.

[0057] To carry out the method for strengthening the flange joint 25, the first step is to remove the array of mechanical fasteners 40, as shown in Figure 4b as follows. Here, the lower nut in the nut 46 is removed from the fastener 40 so that the fastener 40 can be pulled out of the corresponding hole in the upward direction.

[0058] It is contemplated that for a plurality of fasteners extending around a predetermined arc (e.g., between a thirty-degree and a ninety-degree arc) of the flange joint 25, the fastener removal process will be repeated. Once a predetermined number of fasteners 40 have been removed, the annular plate can be assembled onto the flange joint 25, which extends around the corresponding arc.

[0059] This is shown in Figure 5 which shows, Figure 5 in a plan view, the flange joint 25, in which a first subgroup 80 of the mechanical fasteners 40 has been removed. The partial annular plate portion 52' can then be provided to the flange joint 25 and placed in the position shown by the dashed line. Here, the partial annular plate portion 52' is one of four such plate portions (the other three not shown), which together form the four quarter circles of the complete annular plate 52 (not shown). The individual partial annular plate portions 52' can be joined together in some suitable manner, such as by a connecting bracket or similar means.

[0060] Forming the annular plate 52 from a plurality of partial annular plate portions 52' in this way provides a convenient way to retrofit the annular plate onto the flange joint 25 in order to strengthen the connection, without having to remove all the mechanical fasteners 40 from the connecting flange 25, and thus without having to disassemble the tower section or support the tower section with a crane during operation. Thus, a staged retrofit can be achieved, which is beneficial because at least some of the mechanical fasteners 40 always remain engaged with the flange joint 25 and are properly tensioned.

[0061] Returning to Figure 4c , here is shown the flange joint 25, in which the upper partial annular plate portion 52 and the lower partial annular plate portion 56 are placed in position. Although not shown here, temporary or permanent fasteners 63 ( Figures 4a to 4d not shown in Figure 3 ) can be used, as shown in

[0062] Figure 4d to hold the partial annular plate portions 52, 56 to the flange joint 25 before installing the mechanical fasteners 40.

[0063] In the foregoing discussion, various alternative examples of the illustrated embodiments have been mentioned. Other variations and examples will be apparent to those skilled in the art.

[0064] For example, in the above discussion, the stiffening structure 50 has been described as including an upper annular plate 52 and a lower annular plate 56, which are respectively clamped to the upper annular connection flange 28 and the lower annular connection flange 32. This arrangement is understood to be useful for the flange joint 25 between two tower sections 20, 22, 24 in the column of tower sections. However, it is contemplated that the stiffening structure 50 may include only a single one of the annular plates 52, 56. This may be because one of the annular flange portions of the flange joint is larger and thus stronger than the other annular flange portion, so that only one of them needs to be strengthened in the manner of the present invention.

Claims

1. A tower section (24) for a wind turbine, the tower section (24) comprising: An annular wall portion (26) that defines a tower section axis and has an annular connection flange portion (28), wherein the annular connection flange portion defines a first bolt hole array (28a); An annular flange reinforcement device (52) located on the annular connection flange portion (28), the annular flange reinforcement device (52) defining a second bolt hole array (52a), each bolt hole in the first bolt hole array being aligned with a corresponding bolt hole in the second bolt hole array; A plurality of mechanical fasteners (40), each of the plurality of mechanical fasteners (40) extending through a corresponding bolt hole in the first bolt hole array and the second bolt hole array, Wherein the annular flange connection portion (28) and the annular flange reinforcement device (52) are configured to define an annular gap (70) therebetween.

2. The tower section according to claim 1, wherein, The annular gap (70) is at least partially defined by a recess (74) defined in the annular connection flange portion (28).

3. The tower section according to claim 1 or 2, wherein, The annular gap (70) is at least partially defined by a recess (74') formed in the annular flange reinforcement device (52).

4. The tower section according to any one of the preceding claims, wherein, The annular gap (70) extends in the radial direction by more than 30%, and preferably more than 50%, of the radial length of the annular flange portion.

5. The tower section according to any one of the preceding claims, wherein, The annular flange reinforcement device (52) has a thickness (T1) defined along the tower section axis, wherein the thickness of the annular plate is less than 50%, and preferably less than 25%, of the thickness of the annular flange connection portion (28).

6. The tower section according to any one of the preceding claims, wherein, The annular gap (70) has a depth (D) along the tower section axis, wherein the depth is less than 10 mm.

7. The tower section according to any one of claims 1 to 5, wherein, The annular gap (70) has a depth (D) along the tower section axis, wherein the depth is less than 5 mm.

8. The tower section according to any one of claims 6 and 7, wherein, The ratio of the depth (D) of the annular gap (70) to the radial width (W3) of the annular gap (70) is between 1:30 and 1:

60.

9. The tower section according to any one of the preceding claims, wherein, The annular flange reinforcement device (52) is in the form of an annular plate.

10. The tower section according to claim 10, wherein, The annular plate is formed by a plurality of partial annular plate portions (52a).

11. A method of strengthening a tower section (20) of a wind turbine, the tower section comprising an annular wall portion (26) which defines a tower section axis and has an annular connecting flange portion (28), wherein, The annular connection flange portion defines a first bolt hole array (28a), and corresponding fasteners (40) pass through the first bolt hole array (28a); Wherein the method includes: Removing at least some of the fasteners (40) from the annular connection flange portion (28); Arranging an annular flange reinforcement device (52) on the annular connection flange portion (28), the annular flange reinforcement device defining a second bolt hole array (52a), each bolt hole in the first bolt hole array being aligned with a corresponding bolt hole in the second bolt hole array; Installing fasteners (40) through the corresponding bolt holes in the first bolt hole array and the second bolt hole array to clamp the annular flange reinforcement device (52) to the annular connection flange portion (28); Wherein, the annular flange connection portion (28) and the annular flange reinforcement device (52) are configured to define an annular gap (70) therebetween.

12. The method according to claim 11, wherein, The method includes: Forming a recess (74') in the annular flange reinforcement device (52) before arranging the annular flange reinforcement device on the annular connection flange portion (28).

13. The method according to claim 11 or 12, wherein, The method includes: Forming a recess (74) in the annular connection flange portion (28) before arranging the annular flange reinforcement device (52) on the annular connection flange portion.

14. The method according to claims 11 to 13, wherein, Arranging the annular flange reinforcement device (52) on the annular connection flange portion (28) includes: Positioning a first partial annular reinforcement device portion (52') of a plurality of partial annular reinforcement device portions on the annular connection flange portion and securing the first partial annular reinforcement device (52') using a corresponding mechanical fastener (40); and Subsequently repeating the positioning and securing steps for additional partial annular reinforcement devices (52') of the plurality of partial annular reinforcement devices.

15. The method according to any one of claims 11 to 14, wherein The annular flange reinforcement device (52) includes an annular plate.

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