METHOD FOR MANUFACTURING A WIND TURBINE BLADE AND MOLD ARRANGEMENT

Abstract

A method for manufacturing a wind turbine blade is provided, including arranging a first and second mandrel and an upper mold on a lower mold, wherein a fiber lay-up is arranged in the lower mold, the upper mold and between the first and second mandrels for molding a lower shell, an upper shell and a shear web of the blade, respectively, and wherein the first and/or second mandrels includes one or more sensors arranged at an outer surface thereof and adjacent the fiber lay-up provided for molding the shear web, infusing the fiber lay-up with resin and curing the resin, and monitoring the infusion and/or curing of the resin by the one or more sensors.

Claims

1. A method for manufacturing a wind turbine blade, comprising the steps of: a) arranging a first and a second mandrel and an upper mold on a lower mold, wherein a fiber lay-up is arranged in the lower mold, the upper mold and between the first and second mandrels for molding a lower shell, an upper shell and a shear web of the blade, respectively, and wherein the first and/or second mandrels comprise one or more sensors arranged at an outer surface thereof and adjacent the fiber lay-up provided for molding the shear web, b) applying vacuum to a space between the upper and lower molds and the mandrels, c) infusing the fiber lay-up with resin and curing the resin, and d) monitoring the infusion and/or curing of the resin by the one or more sensors.

2. The method according to claim 1, wherein the outer surface is a molding surface configured for molding the shear web and/or a connection region between the shear web and a spar cap of the blade.

3. The method according to claim 1, wherein the first and second mandrels comprise mating outer surfaces defining a gap for accommodating the fiber lay-up for molding the shear web, and wherein at least one of the one or more sensors is arranged at one of the mating surfaces.

4. The method according to claim 1, wherein at least one of the one or more sensors is arranged, with respect to a vertical direction of the molds pointing from the lower to the upper mold, in a middle portion of the first and second mandrels.

5. The method according to claim 1, wherein the first and second mandrels comprise several of the sensors, and the several sensors are arranged spaced apart from each other in a vertical direction of the molds pointing from the lower to the upper mold, and/or the several sensors are arranged spaced apart from each other in a longitudinal direction of the molds.

6. The method according claim 1, comprising the steps of creating one or more recesses in the outer surface of the first and/or second mandrels and arranging each of the one or more sensors in one of the recesses.

7. The method according to claim 1, comprising the step of covering each of the first and second mandrels including the one or more sensors with a vacuum bag.

8. The method according to claim 1, wherein in step d) a temperature at the position of the one or more sensors, an arrival of the resin at the position of the one or more sensors, and/or a curing state of the resin is monitored.

9. The method according to claim 1, wherein the one or more sensors comprise a temperature sensor and/or a capacitive sensor.

10. The method according to claim 1, wherein the one or more sensors are wireless sensors.

11. The method according to claim 10, wherein a connectivity range of the one or more sensors is up to 0.1 km or more, up to 0.3 km or more, up to 0.5 km or more, up to 0.7 km or more and/or up to 1 km or more, and/or a transmission frequency of the one or more sensors is in the range of 100 MHz to 1 GHz, 300 MHz to 1 GHz, 400 MHz to 950 MHz, 800 MHz to 950 MHz and/or 868 MHz to 915 MHz.

12. The method according to claim 1, wherein the one or more sensors each comprise a switch unit for switching between an active state in which the respective sensor obtains sensor data and an inactive state in which the respective sensor does not obtain sensor data.

13. A mold arrangement for manufacturing a wind turbine blade, comprising: a lower mold, an upper mold configured for arrangement on the lower mold such that an inner cavity is formed in a closed state of the molds, and a first and a second mandrel configured for arrangement in the inner cavity such that a gap is formed between the first and second mandrels, the gap extending in a vertical direction of the molds pointing, in the closed state, from the lower to the upper mold, and the gap being configured for accommodating a fiber lay-up for molding a shear web of the blade, wherein the first and second mandrels comprise one or more sensors arranged at an outer surface thereof and adjacent the gap.

Description

BRIEF DESCRIPTION

[0080] Some of the embodiments will be descripted in detail, with references to the following Figures, wherein like designations denote like members, wherein:

[0081] FIG. 1 shows a wind turbine according to an embodiment;

[0082] FIG. 2 shows a cross-section view of a mold arrangement for manufacturing a wind turbine blade of the wind turbine of FIG. 1, according to an embodiment;

[0083] FIG. 3 shows a cross-section view of a wind turbine blade manufactured by using the mold arrangement shown in FIG. 2, according to an embodiment;

[0084] FIG. 4 shows a schematic view of a sensor of a mandrel of the mold arrangement shown in FIG. 2 according to an embodiment;

[0085] FIG. 5 shows, in cross-section, a further embodiment of a mandrel of the mold arrangement of FIG. 2;

[0086] FIG. 6 shows, in partial perspective view, a further embodiment of a mandrel of the mold arrangement of FIG. 2; and

[0087] FIG. 7 shows a flowchart illustrating a method for manufacturing the wind turbine blade of the wind turbine of FIG. 1 using the mold of FIG. 2, according to an embodiment.

DETAILED DESCRIPTION

[0088] FIG. 1 shows a wind turbine 1 according to an embodiment. The wind turbine 1 comprises a rotor 2 having one or more blades 3 connected to a hub 4. The hub 4 is connected to a generator (not shown) arranged inside a nacelle 5. During operation of the wind turbine 1, the blades 3 are driven by wind to rotate and the wind's kinetic energy is converted into electrical energy by the generator in the nacelle 5. The nacelle 5 is arranged at the upper end of a tower 6 of the wind turbine 1. The tower 6 is erected on a foundation 7 such as a monopile or concrete foundation. The foundation 7 is connected to and/or driven into the ground or seabed.

[0089] In the following an improved method for manufacturing a wind turbine blade 3 according to an embodiment is described with respect to FIGS. 2 to 7.

[0090] FIG. 2 shows a mold arrangement 8 in cross-section for manufacturing one of the wind turbine blades 3 of FIG. 1. The mold arrangement 8 comprises a lower mold 9 and an upper mold 10. In the closed state of the mold arrangement 8 shown in FIG. 2, the upper mold 10 is arranged on the lower mold 9 such that an inner cavity 11 is formed. The mold arrangement 8 further comprises a first mandrel 12 and a second mandrel 13. The mandrels 12, 13 are arranged inside the cavity 11 formed by the lower and upper molds 9, 10. The mandrels 12, 13 are, hence mold cores.

[0091] In the closed state of the mold arrangement 8, gaps 14, 15, 16 are formed between the lower and upper molds 9, 10 and the first and second mandrels 12, 13 for molding the blade 3. In particular, a first gap 14 is formed between the lower mold 9 and the first and second mandrels 12, 13 for molding a lower shell 17 (FIG. 3) of the blade 3. Further, a second gap 15 is formed between the upper mold 10 and the first and second mandrels 12, 13 for molding an upper shell 18 (FIG. 3) of the blade 3.

[0092] Furthermore, a third gap 16 (FIG. 2) is formed between the first and second mandrels 12, 13 for molding a shear web 19 (FIG. 3) of the blade 3. The third gap 16 is defined by mating outer surfaces 20a and 20b of the first and second mandrels 12, 13, respectively. The third gap 16 extends in a vertical direction V of the molds 9, 10 in the closed state of the molds 9, 10 (i.e., in the closed state of the mold arrangement 8). The vertical direction V is, in particular, pointing during the molding process from the lower mold 9 to the upper mold 10.

[0093] The first and second gaps 14, 15 (FIG. 2) are configured for accommodating a fiber lay-up 21 for molding the lower and upper shells 17, 18 (FIG. 3). Further, the third gap 16 is configured for accommodating a fiber lay-up 22 for molding the shear web 19 (FIG. 3) of the blade 3. Further shown in FIG. 2 are two pre-cast beams 23 arranged in the lower and upper molds 9, 10, respectively. The two pre-cast beams 23 are configured to becomein the manufactured state of the blade 3the spar caps 24 (FIG. 3).

[0094] As illustrated in FIG. 2, the fiber lay-up 21, 22 is infused with resin 25 and the resin 25 is cured for forming a fiber-reinforced resin laminate (i.e., the shells 17, 18, the shear web 19 and the connection of the shear web 19, the spar caps 24 and the shells 17, 18).

[0095] For monitoring the infusion and curing process of the resin 25, the first and second mandrels 12, 13 comprise one or more sensors 26 arranged at the outer surface 20a-20d and adjacent the third gap 16, as shown in the enlarged section in FIG. 2. In the example of FIG. 2, there is one sensor 26 shown which is arranged at the outer surface 20a of the first mandrel 12. The sensor 26 may be accommodated in a recess 27 of the outer surface 20a of the first mandrel 12, as illustrated. The sensor 26 may be fixed, for example by an adhesive, at the surface 20a and/or in the recess 27. Further, the sensor 26 is arranged in a middle portion 28 of the first and second mandrels 12, 13. The middle portion 28 is a middle portion with respect to the vertical direction V of the molds 9, 10.

[0096] In other examples more than one sensor 26 may be arranged at the outer surface 20a-20d and adjacent the third gap 16. Further, instead of or in addition to being arranged at the outer surface 20a, 20c of the first mandrel 12, one or more sensors 26 may also be arranged at the outer surface 20b, 20d of the second mandrel 13. Further, instead of or in addition to being arranged in the middle portion 28, one or more of the sensors 26 may also be arranged outside of the middle portion 28. It is also possible that one or more sensors 26 are arranged, instead of in a recess 27 of the outer surface 20a-20d at a flat (i.e., not recessed) outer surface 20a-20d. Moreover, the one or more sensors 26 may also be fixed to the first and/or second mandrels 12, 13 by other means than an adhesive.

[0097] The one or more sensors 26 are, for example, wireless sensors comprising a radio frequency (RF) transmitter/receiver 29 (e.g., an antenna 29, FIG. 4) for transmitting and receiving radio frequency signals 30. The one or more sensors 26 may transmit obtained sensor data by wireless communication using the antenna 29 to a remote computing device 31 (FIG. 2) having a further RF transmitter/receiver 32 (e.g., a further antenna 32). The one or more sensors 26 may be controlled remotelyfor example by a radio frequency signal 30 of the computing device 31by wireless communication using the antenna 29.

[0098] The one or more sensors 26 are, for example, long range radio frequency sensors with a connectivity range of up to 0.5 km to 1 km. Further, a transmission frequency of the one or more sensors 26 is, for example, in the range of 100 MHz to 1 GHz.

[0099] The one or more sensors 26 comprise, for example, a housing 33 (FIG. 4) and a measurement unit 34 accommodated at least partially in the housing 33. The measurement unit 34 may include one or more printed circuit boards with one or more integrated circuits and the like for measuring sensor data and for controlling the sensor 26. The one or more sensors 26 may also have a battery unit 35 for power supply. The one or more sensors 26 comprise, for example, a switch unit 36 for switching between an active state in which the respective sensor 26 obtains sensor data and an inactive state in which the respective sensor 26 does not obtain sensor data.

[0100] As shown exemplarily in FIG. 5 for the first mandrel 12, each of the first and second mandrels 12, 13 may comprise a core 37 and a foam portion 38 covering the core 37. The core 37 includes, for example, a support structure 39 made from wood and surrounding a cavity 40. The core 37 may also include a carbon layer 41 covering the support structure 39. The one or more sensors 26 are then, for example, arranged at an outer surface 20a of the foam portion 38 or in a recess 27 of the outer surface 20a of the foam portion 38.

[0101] FIG. 6 illustrates exemplarily for the first mandrel 12 a case in which the first and/or second mandrels 12, 13 comprise more than one sensor 26 spaced along the vertical direction V and along a longitudinal direction L of the mandrel 12 (which is also the longitudinal direction L of the molds 9, 10 and of the mold arrangement 8, FIG. 2). FIG. 6 shows as an example three sensors 26 spaced along the vertical direction V at a first longitudinal position L1. Further, there are three sensors 26 spaced along the vertical direction V at each of a second and third longitudinal position L2, L3 (in FIG. 6, only two out of three sensors 26 are visible at each position L2, L3). Hence, the sensors 26 in FIG. 6 are also arranged along the longitudinal direction L.

[0102] FIG. 7 shows a flowchart of the method for manufacturing the wind turbine blade 3 using the described mold arrangement 8 of FIG. 2. It is noted that the embodiments of the mandrels 12, 12, 12, 13 and of the sensors 26, 26, 26 shown in FIGS. 5 and 6 may be used as well for the manufacturing method.

[0103] In a first step S1 of the method, the lower mold 9 is provided (FIG. 2). A vacuum bag (not shown) and the fiber lay-up 21 for forming the lower shell 17 (FIG. 3) is arranged in the lower mold 9. Further, a pre-cast beam 23 is arranged in the lower mold 9.

[0104] In a second step S2 of the method, one or more sensors 26 are arranged and fixed at the outer surface 20a-20d of the first and/or second mandrels 12, 13. This may include creating (e.g., cutting) one or more recesses 27 in the outer surface 20a-20d and arranging the one or more sensors 26 in the one or more recesses 27.

[0105] In a third step S3 of the method, the first and second mandrels 12, 13 including the one or more sensors 26 are each covered with a vacuum bag 42 (FIG. 2).

[0106] In a third step S3 of the method, the first and second mandrels 12, 13 and the fiber lay-up 22 for the shear web 19 are arranged in the lower mold 9. The first and second mandrels 12, 13 are, in particular, arranged in the lower mold 9 such that the gap 16 (third gap 16) is formed between the first and second mandrels 12, 13. The gap 16 is defined by the mating outer surfaces 20a, 20b of the first and second mandrels 12, 13. Further, the fiber lay-up 22 for the shear web 19 is arranged in the gap 16. Since the first and/or second mandrels 12, 13 comprise the one or more sensors 26 at its respective outer surface 20a-20d, by arranging the mandrels 12, 13, the one or more sensors 26 are arranged adjacent the gap 16 and adjacent the fiber lay-up 22 for the shear web 19.

[0107] In a fourth step S4 of the method, the upper mold 10 including the fiber lay-up 21 for molding the upper shell 18 (FIG. 3) and the pre-cast beam 23 for forming the upper spar cap 24 is arranged on top of the lower mold 9 and the first and second mandrels 12, 13.

[0108] In a fifth step S5 of the method, vacuum is applied to a space 43 between the upper and lower molds 9, 10 and the mandrels 12, 13. The space 43 is, in particular, defined by the first, second and third gaps 14, 15, 16.

[0109] In a sixth step S6 of the method, the resin 25 is provided through inlets (not shown) and drawn by the generated vacuum into the space 43, i.e., through the gaps 14, 15, 16. In this manner, the fiber lay-up 21, 22 is infused with resin 25.

[0110] In a seventh step S7 of the method, the resin 25 is cured, for example by applying heat.

[0111] In an eighth step S8 of the method, the infusion and/or curing of the resin 25 is monitored by the one or more sensors 26. In particular, sensor data are obtained by the one or more sensors.

[0112] Step S8 can be performed before step S6 and S7, simultaneously with step S6 and/or S7 and/or after step S6 and S7. For example, before opening the one or more resin inlet channels (not shown) for starting the infusion (step S6), sensor data such as the temperature of the surface 20a-20d of the mandrels 12, 13, of the gap 16 and/or of the fiber lay-up 22 in the gap 16 may be obtained. This allows to start the resin infusion (step S6) only when the respective temperature has an appropriate value. In another example, sensor data of the surface 20a-20d of the mandrels 12, 13, of the gap 16, of the fiber lay-up 22 in the gap 16 and/or of the resin 25 flowing through the gap 16 may be obtained (step S8) during the infusion (step S6) and/or curing (step S7) of the resin 25.

[0113] In step S8, the obtained sensor data may be processed by a computing device 31 (FIG. 2) located remotely with respect to the mold arrangement 8. The sensors 26 are, for example, connected wireless with the computing device 31. The sensor data are, for example, interpreted and interpolated using data analytics models to prepare for visualization. The data may, for example, be processed to derive a spatial distribution of a temperature of the mandrels 12, 13 or of a flow front of the resin 25.

[0114] In step S8, the sensor data and/or processed sensor data may, for example, be displayed on a display unit 44 of the computing device 31. Thus, information about the infusion and curing process in the closed molds 9, 10 can be made available for a worker by the display unit 44. In case that the worker recognizes, for example, that the flow front of the resin 25 is not developing as required, s/he can take measures to alter the infusion process in step S6.

[0115] Thus, with the one or more sensors 26 arranged adjacent the fiber lay-up 22 configured to becomein the cured state of the resin 25the shear web 19, the casting of the shear web 19 can be improved.

[0116] Although the present invention has been disclosed in the form of embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0117] For the sake of clarity, it is to be understood that the use of a or an throughout this application does not exclude a plurality, and comprising does not exclude other steps or elements.