Wind turbine blade fatigue life prediction apparatus and method

Abstract

The present application relates to the technical field of wind turbines, and in particular to a wind turbine blade fatigue life prediction apparatus, comprising a mounting frame, cylinders I, a mounting cylinder I, connecting rods, a wind turbine generator set, etc. A plurality of cylinders I are fixedly connected to the lower part of the mounting frame; the telescopic ends of all the cylinders I are jointly fixedly connected to the mounting cylinder I; a plurality of connecting rods are fixedly connected in the mounting cylinder I in annular fashion at equal intervals; all the connecting rods are jointly connected to the wind turbine generator set; and the wind turbine generator set is externally connected to a current monitor. In the present invention, an external sandblasting device can be controlled to spray sand into a mounting cylinder II through sandblasting pipes, and then the sand is blown to wind turbine blades by means of a fan, simulating sand-laden wind condition, monitoring the power generation stability and efficiency of the wind turbine blades under the sand-laden wind condition; and an external water pump can spray water into the mounting cylinder II through water spraying pipes, and then the water is blown to the wind turbine blades by means of the fan, simulating rainy and windy conditions, monitoring the power generation stability and efficiency of the wind turbine blades under the rainy and windy conditions.

Description

A wind turbine blade fatigue life prediction device and method TECHNICAL FIELD

[0001] The present application relates to the technical field of wind turbine, in particular to a wind turbine blade fatigue life prediction device and method. BACKGROUND

[0002] Chinese patent CN115493830A proposes a wind turbine blade fatigue life prediction method and device, which predicts the fatigue life test of the wind turbine blade through the cumulative damage method; however, it can only predict the fatigue life of the wind turbine blade under mild natural wind, and fails to fully consider and simulate the influence of adverse weather conditions such as sandstorm wind, rain and wind on the fatigue life of the blade, which makes its prediction function relatively single and has certain limitations. SUMMARY

[0003] In order to overcome the shortcomings that the current fatigue life test of the wind turbine blade fails to fully consider and simulate the influence of adverse weather conditions such as sandstorm wind, rain and wind on the fatigue life of the blade, which makes its prediction function relatively single and has certain limitations, the present application provides a wind turbine blade fatigue life prediction device and method.

[0004] Technical scheme: a wind turbine blade fatigue life prediction device, comprising a mounting frame, a plurality of air cylinders I, a mounting cylinder I, a connecting rod and a wind turbine generator; a plurality of air cylinders I are fixedly connected at the lower part of the mounting frame; the extension ends of all the air cylinders I are fixedly connected with the mounting cylinder I; a plurality of connecting rods are fixedly connected in the mounting cylinder I; the wind turbine generator is connected with all the connecting rods, and the wind turbine generator is connected with a current monitor; further comprising a mounting plate, a conical flow guide plate, a mounting cylinder II, a fan, a sand injection pipe and a water injection pipe; the mounting plate is fixedly connected in the mounting cylinder I; the mounting plate is in contact with the lower side of the wind turbine generator; the conical flow guide plate is fixedly connected on the mounting plate; the wind turbine generator penetrates through the conical flow guide plate; the mounting cylinder II is fixedly connected at the upper part of the mounting frame; the fan is fixedly connected at the upper part of the mounting cylinder II; a plurality of sand injection pipes are connected in a ring shape at equal intervals on the mounting cylinder II; a plurality of water injection pipes are connected in a ring shape at equal intervals on the mounting cylinder II, and the water injection pipes are located below the sand injection pipes.

[0005] Further, the lower part of the mounting cylinder I is conical.

[0006] Further, it further comprises a gas injection pipe; a plurality of gas injection pipes are connected in a ring shape at equal intervals on the mounting cylinder II, and the gas injection pipes are located below the water injection pipes.

[0007] Further, it further comprises a mounting frame, an air cylinder II and a blocking ring; a plurality of mounting frames are fixedly connected on the inner side of the mounting cylinder II; one air cylinder II is fixedly connected in each mounting frame; the extension ends of all the air cylinders II are fixedly connected with the blocking ring; the blocking ring is slidingly connected with the mounting cylinder II.

[0008] Further, the blocking ring cross section is in the shape of an inverted circular truncated cone.

[0009] Further, the blocking ring cross section is in the shape of an inverted circular truncated cone.

[0010] Further, the upper surface of the blocking plate is inclined downward.

[0011] Further, the blocking ring cross section is in the shape of an inverted circular truncated cone.

[0012] Further, the upper surface of the blocking plate is inclined downward.

[0013] A method for using a wind turbine blade fatigue life prediction device, comprising the following steps:

[0014] Step one, install the fan blade: install the blade on the fan generator set;

[0015] Step two, simulate wind test: start the fan, the fan generates wind to blow to the fan blade, the fan blade rotates, and then drives the fan generator set to work and generate electricity;

[0016] Step three, damage degree test: after the fan blade is blown by wind for a certain time, the friction coefficient detector is used to test the friction coefficient of the fan blade and record the data;

[0017] Step four, predict fatigue life: repeat steps two and three, record the friction coefficient of the fan blade after being blown by wind at different speeds, based on these friction coefficient data, calculate the damage degree of the blade under different wind speeds, and finally predict the fatigue life of the fan blade through the damage function.

[0018] The present application has the following advantages: 1. The present application can control the external sand blasting equipment to spray sand dust into the installation cylinder II through the sand blasting pipe, and then the sand dust is blown to the fan blade by the fan, thereby simulating the sand dust wind, monitoring the power generation stability and efficiency of the fan blade under the sand dust wind; the external water pump can also be used to spray water into the installation cylinder II through the water spraying pipe, and then the water is blown to the fan blade by the fan, thereby simulating the rain and wind, monitoring the power generation stability and efficiency of the fan blade under the rain and wind.

[0019] 2、The present application predicts the fatigue life of the fan blade through the cumulative calculation of the damage of the blade under different wind speeds and the damage function; specifically, after the fan blade is blown by wind for a certain period of time, the fan is stopped, then the two cylinders I drive the installation cylinder I, connecting rod, fan power generation group, mounting plate and conical guide plate to move downward, so that the upper side of the installation cylinder I is separated from the lower side of the installation cylinder II, the friction coefficient detector is used to test the friction coefficient of the fan blade and record the data, the friction coefficient of the fan blade after being blown by wind at different speeds is recorded, based on these friction coefficient data, the damage degree of the blade under different wind speeds is calculated, and finally the fatigue life of the fan blade is predicted through the damage function, and at the same time, when the sand and rain follow the wind to blow the fan blade, the fatigue life of the fan blade under the adverse weather conditions such as sand wind, rain and wind can also be predicted through the cumulative damage method.

[0020] 3、The present application controls the external air pump to pass cold air into the installation cylinder II, the cold air has a larger density than air and will sink and fall on the conical guide plate and the blocking ring, with the passage of cold air, the cold air will eventually immerse the fan blade, after waiting for a certain period of time, the water remaining on the surface of the fan blade is frozen, then the cylinder II is controlled to drive the blocking ring to move upward, so that the blocking ring is reset, and then the fan is started to test the power generation efficiency of the fan blade in the icing state.

[0021] 4、When the fan power generation group vibrates violently, the fan power generation group will produce displacement, move in the movable hole in the middle of the conical guide plate, stretch or compress the spring, and extrude the annular pressure sensor, the greater the pressure sensed by the annular pressure sensor, the greater the vibration of the fan power generation group, so that the vibration of the fan power generation group is sensed through the annular pressure sensor, and then it is determined whether the fan blade installation correction is accurate or damaged. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is a perspective structural schematic view of the wind turbine blade fatigue life prediction device of the present application;

[0023] Fig. 2 is a combined perspective structural schematic view of the sand blasting pipe, water spraying pipe and air jet pipe of the wind turbine blade fatigue life prediction device of the present application;

[0024] Fig. 3 is a combined perspective structural schematic view of the installation frame, cylinder II and blocking ring of the wind turbine blade fatigue life prediction device of the present application;

[0025] Fig. 4 is a front view of the local structure of the wind turbine blade fatigue life prediction device of the present application;

[0026] Fig. 5 is a combined perspective structural schematic view of the spring and annular pressure sensor of the wind turbine blade fatigue life prediction device of the present application.

[0027] Meaning of reference signs in the figure: 1-mounting frame, 2-cylinder I, 3-mounting cylinder I, 4-connecting rod, 5-fan power generation set, 6-mounting plate, 7-conical guide plate, 8-mounting cylinder II, 9-fan, 10-sand injection pipe, 11-water injection pipe, 12-air injection pipe, 13-mounting frame, 14-cylinder II, 15-retaining ring, 16-fan blade, 21-cylinder III, 22-retaining plate, 23-limiting plate, 31-spring, 32-ring pressure sensor, 33-windproof ring. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application. EMBODIMENT

[0029] A wind turbine blade fatigue life prediction device, as shown in FIGS. 1-5, comprises a mounting frame 1, a cylinder I 2, a mounting cylinder I 3, a connecting rod 4 and a fan power generation set 5; two cylinders I 2 are fixedly connected to the lower part of the mounting frame 1; the extension ends of all the cylinders I 2 are fixedly connected together to form the mounting cylinder I 3; four connecting rods 4 are annularly and equidistantly welded in the mounting cylinder I 3; and all the connecting rods 4 are connected together to form the fan power generation set 5, which is connected with a current monitor.

[0030] It also comprises a mounting plate 6, a conical guide plate 7, a mounting cylinder II 8, a fan 9, a sand injection pipe 10 and a water injection pipe 11; the mounting plate 6 is welded in the mounting cylinder I 3; the mounting plate 6 is in contact with the lower side of the fan power generation set 5 to support the fan power generation set 5; the conical guide plate 7 is welded on the mounting plate 6; the fan power generation set 5 penetrates through the conical guide plate 7; the mounting cylinder II 8 is fixedly connected to the upper part of the mounting frame 1; the fan 9 is fixedly connected to the upper part of the mounting cylinder II 8; four sand injection pipes 10 are annularly and equidistantly connected to the mounting cylinder II 8 to simulate a sand and dust environment; and four water injection pipes 11 are annularly and equidistantly connected to the mounting cylinder II 8 to simulate a rainy environment, wherein the water injection pipes 11 are located below the sand injection pipes 10.

[0031] In order to facilitate the gathering and collection of sand and dust and water, the lower part of the mounting cylinder I 3 is conical.

[0032] First step: in use, the fan 9 is connected to an external power source, the sand spraying pipe 10 is connected to an external sand spraying device, and the water spraying pipe 11 is connected to an external water pump. In the initial state, the installation cylinder I 3 has sufficient space to move relative to the installation cylinder II 8. When the blade is detected, a person works in the space to install the blade on the fan generator set 5. Then, the two cylinders I 2 drive the installation cylinder I 3, the connecting rod 4, the fan generator set 5, the installation plate 6, and the conical guide plate 7 to move upwards, so that the upper side of the installation cylinder I 3 contacts the lower side of the installation cylinder II 8, the space between the installation cylinder I 3 and the installation cylinder II 8 is sealed, and then the fan 9 is started. The fan 9 generates wind to blow towards the fan blade 16, the fan blade 16 rotates, and then drives the fan generator set to work and generate electricity. At the same time, by changing the speed of the wind generated by the fan 9, and by the external current monitor connected to the fan generator set, the current change of the fan generator set during power generation can be monitored. In this way, by observing the change of the current, the power generation stability and efficiency of the fan blade 16 under diversified wind load can be monitored, and it is ensured that the fan blade 16 can still maintain excellent energy conversion ability in the actual variable natural wind environment.

[0033] Second step: the present application can monitor the power generation stability and efficiency of the fan blade 16 under the sand dust wind. During monitoring, the external sand spraying device sprays sand dust into the installation cylinder II 8 through the sand spraying pipe 10, and then the sand dust is blown towards the fan blade 16 by the fan 9, thereby simulating the sand dust wind. The power generation stability and efficiency of the fan blade 16 under the sand dust wind are monitored. After the sand dust wind passes through the fan blade 16, it blows towards the conical guide plate 7, and then is guided by the conical guide plate 7 to pass between the conical guide plate 7 and the installation cylinder I 3, and finally blows out from the lower part of the installation cylinder I 3. The conical guide plate 7 protects the fan generator set 5 from being damaged by sand dust. A collection barrel is placed below the installation cylinder I 3 to collect the blown sand dust, so as to avoid the sand dust from being discharged into the external environment and polluting the environment.

[0034] Third step: the present application can also monitor the power generation stability and efficiency of the fan blade 16 under the rain and wind. During monitoring, the external water pump sprays water into the installation cylinder II 8 through the water spraying pipe 11, and then the water is blown towards the fan blade 16 by the fan 9, thereby simulating the rain and wind scenario. The power generation stability and efficiency of the fan blade 16 under the rain and wind are monitored. After the wind carrying rainwater passes through the fan blade 16, it blows towards the conical guide plate 7, and then is guided by the conical guide plate 7 to pass between the conical guide plate 7 and the installation cylinder I 3, and finally blows out from the lower part of the installation cylinder I 3, and then is collected in the collection barrel below the installation cylinder I 3.

[0035] In addition, the present application can predict the fatigue life of the fan blade 16 by the cumulative damage method: the damage of the blade under different wind speeds is cumulatively calculated, and then the fatigue life of the fan blade 16 is predicted through a damage function; the specific operation is that after the fan blade 16 is blown by wind for a certain time, the fan 9 is stopped, then the two cylinders I2 drive the mounting cylinder I3, the connecting rod 4, the fan power generation group 5, the mounting plate 6 and the conical guide plate 7 to move downward, so that the upper side of the mounting cylinder I3 is separated from the lower side of the mounting cylinder II 8, the friction coefficient detector is used to test the friction coefficient of the fan blade 16 and record the data, the friction coefficient of the fan blade 16 after being blown by wind at different speeds is recorded, based on these friction coefficient data, the damage degree of the blade under different wind speeds is calculated, and finally the fatigue life of the fan blade 16 is predicted through the damage function, and at the same time, when the sand and rain follow the wind to blow the fan blade 16, the cumulative damage method can also be used to predict the fatigue life of the fan blade 16 under the conditions of sand wind, rain and wind and other bad weather conditions. Embodiment

[0036] On the basis of embodiment 1, as shown in Figures 2-5, it also includes a jet pipe 12; four jet pipes 12 are connected at equal intervals on the mounting cylinder II 8, and the jet pipe 12 is located below the water pipe 11.

[0037] It also includes a mounting frame 13, a cylinder II 14 and a blocking ring 15; two mounting frames 13 are welded on the inner side of the mounting cylinder II 8; one cylinder II 14 is respectively fixedly connected in each mounting frame 13; the telescopic ends of all the cylinders II 14 are commonly fixedly connected with the blocking ring 15; the blocking ring 15 is in sliding connection with the mounting cylinder II 8.

[0038] In order to prevent water and sand from accumulating and facilitate air flow, the cross section of the blocking ring 15 is in the shape of an inverted circular truncated cone.

[0039] It also includes a cylinder III 21, a baffle 22 and a limiting plate 23; the cylinder III 21 is fixedly connected to the outer surface of the mounting cylinder II 8; the telescopic end of the cylinder III 21 is fixedly connected with the baffle 22; the limiting plate 23 is welded to the lower side of the baffle 22; the baffle 22 and the limiting plate 23 are in sliding connection with the mounting cylinder II 8.

[0040] In order to prevent water accumulation, the upper surface of the baffle 22 is set to be downwardly inclined.

[0041] In the ice and snow cold day, the fan blade 16 surface will have snow or dew ice, when the fan blade 16 surface icing, the external shape and aerodynamic performance of the blade will change, these changes will lead to the wind energy utilization rate is reduced, in order to accurately assess the impact and optimize the fan blade 16 in cold conditions performance, it is necessary to carry out power generation efficiency test of the fan blade 16 under icing condition; The cylinder II 14 is connected with the external power supply in advance, the jet pipe 12 is communicated with the external air pump, in the third step of embodiment 1, after monitoring the power generation stability and efficiency of the fan blade 16 under the rain and wind, a part of water will be left on the surface of the fan blade 16, at this time, the cylinder II 14 drives the baffle ring 15 to move downward, so that the baffle ring 15 contacts with the lower side of the conical guide plate 7 and the inner wall of the mounting cylinder I 3, the gap between the conical guide plate 7 and the mounting cylinder I 3 is blocked by the baffle ring 15, so as to prevent cold air from flowing out of the gap, then, the external air pump is controlled to pass the cold air into the mounting cylinder II 8 through the jet pipe 12, the cold air has larger density than air, which will sink and fall on the conical guide plate 7 and the baffle ring 15, with the input of cold air, the cold air will eventually immerse the fan blade 16, wait for a certain time, so that the water left on the surface of the fan blade 16 is iced, then, the cylinder II 14 drives the baffle ring 15 to move upward, so that the baffle ring 15 moves upward and resets, then the fan 9 is started, so as to test the power generation efficiency of the fan blade 16 under icing condition; When monitoring the power generation stability and efficiency of the fan blade 16 under the rain and wind or sand dust wind, the wind generated by the fan 9 blows on the baffle ring 15, and then passes through the gap between the conical guide plate 7 and the mounting cylinder II 8, another part blows on the conical guide plate 7, and then passes through the gap between the conical guide plate 7 and the mounting cylinder II 8, the two air flows will converge and disturb, since the intersection is located below the fan blade 16, therefore, it will not affect the power generation stability and life prediction results.

[0042] When the fan group is not working, the blades are in different states, some of which are in a vertical downward state, and some are in a flat state. Since the area of the blade in the vertical state is significantly reduced, the amount of snow accumulated on the blade is relatively small. When the snow melts and then freezes, the surface of the blade in the vertical state has only a small amount of ice, or even no ice. In this case, the amount of ice on each blade of the same fan group is significantly different. This unevenness of the amount of ice directly affects the power generation efficiency of the fan blade 16. In order to accurately evaluate and optimize the fan blade 16, it is particularly important to test the power generation efficiency of the fan blade 16 under this condition. Before the above ice making operation is performed, the control cylinder III 21 drives the baffle 22 and the limiting plate 23 to move towards the center point of the installation cylinder II 8, so that the baffle 22 and the limiting plate 23 are close to the fan power generation group 5. Then, the fan 9 is started, the fan 9 generates wind to blow to the fan blade 16, so that the fan blade 16 slowly rotates. When a certain fan blade 16 abuts against the limiting plate 23, the fan blade 16 cannot rotate at this time. At this time, the baffle 22 above this blade is blocked. Then, the fan 9 is turned off. Water is sprayed on the installation cylinder II 8 through the water spraying pipe 11 by the external water pump. The water falls on the blades that are not blocked by the baffle 22. Then, cold air is introduced to make the surface of the fan blade 16 freeze. After freezing, the amount of ice on each blade is significantly different. Then, the control cylinder III 21 drives the baffle 22 and the limiting plate 23 to move away from the center point of the installation cylinder II 8 and reset. The upper surface of the baffle 22 is inclined to prevent water from accumulating and freezing, which affects the sliding of the baffle 22 on the installation cylinder II 8. Then, the fan 9 is started again to test the power generation efficiency of the fan blade 16 under this condition. Embodiment

[0043] On the basis of embodiment 2, as shown in Figures 4-5, it further includes a spring 31, a ring-shaped pressure sensor 32 and a windproof ring 33. Each connecting rod 4 is connected with a spring 31 between each connecting rod 4 and the fan power generation group 5. The middle part of the conical flow guide plate 7 is provided with a movable hole, and the fan power generation group 5 is located in the movable hole. The ring-shaped pressure sensor 32 is fixedly connected in the movable hole of the middle part of the conical flow guide plate 7. The fan power generation group 5 is located in the ring-shaped pressure sensor 32, and there is a gap between the fan power generation group 5 and the ring-shaped pressure sensor 32. The windproof ring 33 is arranged between the upper part of the fan power generation group 5 and the upper part of the conical flow guide plate 7, and the windproof ring 33 is made of elastic silicone rubber.

[0044] In order to prevent water accumulation, the upper surface of the windproof ring 33 is provided with a hydrophobic layer.

[0045] When the fan blade 16 is installed incorrectly or damaged, the blade will generate a certain centrifugal force during rotation, causing severe axial vibration, which will be transmitted to the fan generator set 5, causing it to vibrate violently; therefore, the vibration intensity of the fan generator set 5 can be tested to monitor whether the fan blade 16 is installed incorrectly or damaged; when the fan generator set 5 vibrates violently, the fan generator set 5 will displace in the movable hole in the middle of the conical guide vane 7, stretch or compress the spring 31, and squeeze the annular pressure sensor 32; the greater the pressure sensed by the annular pressure sensor 32, the greater the vibration of the fan generator set 5; thus, the vibration of the fan generator set 5 is sensed by the annular pressure sensor 32, and it is determined whether the fan blade 16 is installed correctly or damaged; under normal circumstances, the blade rotation will also cause the fan generator set 5 to vibrate slightly, but this normal vibration is different from the vibration caused by centrifugal force, and the normal vibration will not cause the fan generator set 5 to displace.

[0046] A wind ring 33 is arranged between the upper part of the fan generator set 5 and the upper part of the conical guide vane 7; the wind ring 33 is made of elastic silicone rubber, and is used to block water or dust from falling on the annular pressure sensor 32 and the fan generator set 5 through the movable hole in the middle of the conical guide vane 7, affecting the vibration sensing of the fan generator set 5; the wind ring 33 is made of elastic silicone rubber, so that when the fan generator set 5 vibrates, it only stretches and compresses the wind ring 33, that is, the conical guide vane 7 does not limit the vibration of the fan generator set 5 through the wind ring 33.

[0047] A wind turbine blade fatigue life prediction device and method, comprising the following steps:

[0048] Step one, install the fan blade 16: install the blade on the fan generator set 5;

[0049] Step two, simulate wind test: start the fan 9, the fan 9 generates wind to blow to the fan blade 16, the fan blade 16 rotates, and then drives the fan generator set to work and generate electricity;

[0050] Step three, damage degree test: after the fan blade 16 is blown by wind for a certain period of time, the friction coefficient detector is used to test the friction coefficient of the fan blade 16 and record the data;

[0051] Step four, predict fatigue life: repeat steps two and three, record the friction coefficient of the fan blade 16 after being blown by wind at different speeds, calculate the damage degree of the blade under different wind speeds based on these friction coefficient data, and finally predict the fatigue life of the fan blade 16 through the damage function.

[0052] It should be understood that the foregoing embodiments are merely illustrative of the present application and that no limitation of the scope of the present application is intended by the same. Furthermore, it should be appreciated that in the practice of the application, modifications can be made by those skilled in the art without departing from the scope of the application as taught by the foregoing disclosure.

Claims

1. A wind turbine blade fatigue life prediction device, comprising a mounting frame (1), a plurality of air cylinders I (2), a mounting cylinder I (3), a plurality of connecting rods (4) and a wind turbine generator (5); the lower part of the mounting frame (1) is fixedly connected with the plurality of air cylinders I (2); the telescopic ends of all the air cylinders I (2) are fixedly connected with the mounting cylinder I (3); the mounting cylinder I (3) is fixedly connected with the plurality of connecting rods (4) at equal intervals in the annular; all the connecting rods (4) are connected with the wind turbine generator (5) in common, and the wind turbine generator (5) is connected with a current monitor; characterized in that, It also includes the mounting plate (6), the conical guide plate (7), the mounting cylinder II (8), the fan (9), the sand injection pipe (10) and the water injection pipe (11); the mounting cylinder I (3) is fixedly connected with the mounting plate (6); the mounting plate (6) is in contact with the lower side of the fan power generation set (5); the mounting plate (6) is fixedly connected with the conical guide plate (7); the fan power generation set (5) penetrates the conical guide plate (7); the upper part of the mounting frame (1) is fixedly connected with the mounting cylinder II (8); the upper part of the mounting cylinder II (8) is fixedly connected with the fan (9); a plurality of sand injection pipes (10) are connected in a ring shape at equal intervals on the mounting cylinder II (8); a plurality of water injection pipes (11) are connected in a ring shape at equal intervals on the mounting cylinder II (8), and the water injection pipes (11) are located below the sand injection pipes (10).

2. A wind turbine blade fatigue life prediction device according to claim 1, characterised in that, The lower part of the mounting cylinder I (3) is conical.

3. A wind turbine blade fatigue life prediction device according to claim 1, wherein It also includes the air injection pipe (12); a plurality of air injection pipes (12) are connected in a ring shape at equal intervals on the mounting cylinder II (8), and the air injection pipes (12) are located below the water injection pipes (11).

4. A wind turbine blade fatigue life prediction device according to claim 3, characterised in that, It also includes the mounting frame (13), the air cylinder II (14) and the blocking ring (15); a plurality of mounting frames (13) are fixedly connected to the inner side of the mounting cylinder II (8); one air cylinder II (14) is fixedly connected in each mounting frame (13); the telescopic ends of all the air cylinders II (14) are fixedly connected with the blocking ring (15); the blocking ring (15) is in sliding connection with the mounting cylinder II (8).

5. A wind turbine blade fatigue life prediction device according to claim 4, characterised in that, The cross section of the blocking ring (15) is in the shape of an inverted circular truncated cone.

6. A wind turbine blade fatigue life prediction device according to claim 4, characterised in that, It also includes the air cylinder III (21), the baffle (22) and the limiting plate (23); the air cylinder III (21) is fixedly connected to the mounting cylinder II (8); the telescopic end of the air cylinder III (21) is fixedly connected with the baffle (22); the lower side of the baffle (22) is fixedly connected with the limiting plate (23); the baffle (22) and the limiting plate (23) are in sliding connection with the mounting cylinder II (8).

7. A wind turbine blade fatigue life prediction device according to claim 6, characterised in that, The upper surface of the baffle (22) is in the shape of downward inclination.

8. A wind turbine blade fatigue life prediction device according to claim 6, characterised in that, It also includes the spring (31), the ring-shaped pressure sensor (32) and the windproof ring (33); one spring (31) is connected between each connecting rod (4) and the fan power generation set (5); the conical guide plate (7) is provided with a movable hole in the middle part, and the fan power generation set (5) is located in the movable hole; the ring-shaped pressure sensor (32) is fixedly connected in the movable hole in the middle part of the conical guide plate (7); the fan power generation set (5) is located in the ring-shaped pressure sensor (32), and there is a spacing between the fan power generation set (5) and the ring-shaped pressure sensor (32); the windproof ring (33) is provided between the upper part of the fan power generation set (5) and the upper part of the conical guide plate (7), and the windproof ring (33) is made of elastic silicone rubber.

9. A wind turbine blade fatigue life prediction device according to claim 8, characterised in that, The upper surface of the windproof ring (33) is provided with a hydrophobic layer.

10. A method of using a wind turbine blade fatigue life prediction device according to any one of claims 1-9, wherein the method comprises: The method comprises the following steps: Step one, installing the fan blade (16): installing the blade on the fan power generation set (5); Step two, simulating wind test: starting the fan (9), the fan (9) generates wind to blow to the fan blade (16), the fan blade (16) rotates, thereby driving the fan generator set to work and generate electricity; Step three, damage degree test: after the fan blade (16) is blown by wind for a certain period of time, the friction coefficient of the fan blade (16) is tested by a friction coefficient detector, and the data is recorded. Step four, predicting fatigue life: repeating step two and step three, recording the friction coefficient of the fan blade (16) after being blown by different speed wind, based on these friction coefficient data, calculating the damage degree of the blade under different wind speed, and finally predicting the fatigue life of the fan blade (16) through the damage function.

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