Fan blade gas-heat deicing system with flexible air pipe and flexible air pipe fixing and dismounting method of fan blade gas-heat deicing system

Abstract

The invention discloses a fan blade gas heat deicing system with a flexible air pipe and a flexible air pipe fixing and dismounting method thereof.The fan blade gas heat deicing system comprises a heater, an air blower and an air guide pipe, the air guide pipe is formed by connecting a hard air pipe and the flexible air pipe, an air inlet of the heater is connected with an air outlet of the air blower, and an air outlet of the heater is communicated with an air inlet of the hard air pipe; an air outlet of the hard air pipe is communicated with an air inlet of the soft air pipe; the flexible air pipe is arranged in the blade front edge cavity, and a plurality of air guide holes are formed in the side, facing the windward side of the blade, of the flexible air pipe. Hooks are installed on the longitudinal axis of a blade web in a front edge cavity of the blade at intervals, a plurality of fixing ropes corresponding to the hooks are arranged on the side, facing the leeside of the blade, of the flexible air pipe, and the flexible air pipe is fixed to the blade web in the mode that the fixing ropes are sleeved with openings of the hooks. The air guide pipe can extend to the blade tip, the deicing effect of the blade tip is enhanced, a new hot air backflow channel can be constructed in the blade blocked by the blade tip, and the air heat deicing effect is achieved.

Description

Technical Field

[0001] The invention relates to deicing of blades of a wind turbine generator set, and in particular to a wind turbine blade air-heat deicing system with a flexible air duct and a method for fixing and disassembling the flexible air duct. Background Art

[0002] At present, wind turbines located in mountainous areas in the north and south are faced with the problem of being unable to generate electricity in winter due to ice on the blades: since there is no effective means to remove the ice from the blades, they can only wait for the weather to warm up and the ice to melt naturally, resulting in huge losses in power generation. The ice also has a serious impact on the safety, service life, and maintenance costs of the units, causing safety hazards to surrounding people, livestock, and equipment, and impacting the stable operation of the power grid, exacerbating the contradiction between electricity consumption and power generation during the ice period.

[0003] Gas-heat deicing is a relatively mature method for deicing blades of wind turbines. It can be used for both the modification of existing wind turbines and the installation of new wind turbines. It has a long service life, is easy to maintain, will not attract lightning, and has a certain anti-icing ability. The principle of gas-heat deicing is: the inside of the blade is a closed cavity, and a blower and a heater are installed in the blade cavity. The heater heats the cold air in the blade, and then the blower sends the heated hot air out, which circulates along the designed air duct in the blade. The hot air heats the inner surface of the blade, and the heat is transferred from the inner surface of the blade to the outer surface of the blade. When the temperature of the outer surface of the blade exceeds zero degrees, the anti-icing and deicing effect can be achieved. When designing specifically, such as Figure 1 , Figure 2 As shown, the heater 1 and the blower 2 are installed in the manhole baffle at the root 14 of the blade. The air outlet of the heater 1 sends the hot air to a place about one-third of the blade length away from the blade root through the air duct 3. Because the space of the blade leading edge cavity 7 is too narrow to construct the air duct 3, a baffle 4 is installed here so that the hot air flowing out of the air duct 3 is blocked by the baffle 4 and cannot flow back. It can only move from the blade leading edge cavity 7 to the direction of the blade tip 5, and then flow back through the process holes set at the blade tip 5 through the web cavity 6 and the blade trailing edge cavity 11 into the air inlet of the blower 2 to form a hot air circulation channel.

[0004] After the blades are frozen, the ice changes the shape of the blades, destroys the original lifting body structure of the blades, and sharply reduces the wind-catching ability of the blades. In addition, the ice also increases the weight of the blades and increases the wind resistance, making it difficult for the blades to reach the theoretical speed, causing the wind turbine's power generation capacity to drop sharply or even shut down. The part that has the greatest impact on the lifting body structure is the leading edge 10 of the blade facing the wind, because the closer the ice is to the blade tip, the greater the moment of inertia, and the greater the impact on the blade. Therefore, the de-icing must first remove the ice from the leading edge 10 of the blade, and the closer the leading edge 10 of the blade is to the blade tip 5, the more priority it needs to be given to de-icing. In order to achieve a better gas-heat deicing effect and reduce the self-consumption of electricity, it is necessary to consider that the heat of the heater 1 should be used preferentially in the blade leading edge cavity 7 near the blade tip 5 during design. To this end, the gas-heat deicing system uses the air duct 3 to send hot air to the blade tip 5 along the blade belly 9 of the blade leading edge cavity 7. However: first, because the closer the blade leading edge cavity 7 is to the blade tip 5, the smaller the cross-sectional area is, when constructing on the existing fan blades, the workers often cannot move forward to the place where the blade is one-third of the blade length away from the blade root (at the baffle 4), so the air duct 3 can only be arranged here; second, the hot air comes out of the heater 1 to the blade tip 5, and the further forward the heat is, the smaller the heat will be. The less, the lower the temperature, the worse the deicing effect, which is exactly the opposite of the actual need; thirdly, the blade tips of some blades are blocked, and the hot air cannot flow from the blade tip process hole to the blade trailing edge cavity 11 and the web cavity 6 between the two webs, that is, a hot air circulation channel cannot be formed, and the hot air cannot circulate, resulting in the heat of the heater 1 cannot be delivered, and the deicing function fails. The current method of repairing blades with blocked blade tips is to open a skylight at the blade tip 5, use a drilling machine to forcibly punch holes to form a hot air circulation channel, and then seal the skylight. This is not only time-consuming and labor-intensive, but also the blade factory and the owner are worried that the blade will be damaged due to the immature skylight technology. Summary of the invention

[0005] One of the technical problems to be solved by the present invention is that, in view of the deficiency that the air duct in the existing air thermal deicing system for fan blades cannot deliver hot air to a position close to the blade tip, the present invention provides a fan blade air thermal deicing system with a soft air duct, which can extend the air duct to the blade tip and enhance the deicing effect at the blade tip, and a method for fixing and disassembling the soft air duct.

[0006] The second technical problem to be solved by the present invention is that, for blades with blocked blade tips, the present invention provides a fan blade air thermal deicing system with a soft air duct and a method for fixing and disassembling the soft air duct, which can form a new hot air flow circulation channel in the leading edge cavity of the blade to solve the problem of interruption of the hot air flow circulation channel for air thermal deicing after the blade tip is blocked.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A fan blade air heating deicing system with a flexible air duct comprises a heater and a blower, wherein the air inlet of the heater is connected to the air outlet of the blower, the air outlet of the heater is communicated with the air inlet of the air guide duct, and the hot air blown out of the air outlet of the air guide duct is communicated with the air inlet of the blower through a hot air return channel, and the structural features thereof are:

[0009] The front end of the air guide duct is a hard air duct, and the rear end of the air guide duct is a soft air duct. The air inlet of the hard air duct is connected to the air outlet of the heater, and the air outlet of the hard air duct is connected to the air inlet of the soft air duct.

[0010] The inner cavity of the blade is divided into a blade leading edge cavity facing the windward side of the blade and a blade trailing edge cavity facing the leeward side of the blade by the blade web, the soft air duct is arranged in the blade leading edge cavity and extends to near the blade tip, and the soft air duct is provided with a plurality of air guide holes on the side facing the windward side of the blade;

[0011] A hook is installed at a certain distance on the longitudinal axis of the blade web in the blade leading edge cavity, and a plurality of fixing ropes are arranged on the side of the flexible air duct facing the leeward side of the blade corresponding to the hook. The flexible air duct is fixed to the blade web by inserting the fixing rope into the opening of the hook.

[0012] Preferably, a soft air duct telescopic structure is arranged at the interface between the soft air duct and the hard air duct, and the soft air duct telescopic structure includes a fixed end and a movable end arranged in sequence along the length direction of the blade, and the distance between the fixed end and the movable end is equal to the opening depth of the hook, and the fixed end is detachably connected to the movable end.

[0013] Preferably, the opening of the hook faces the blade tip, the fixing rope is installed parallel to the cross section of the soft air duct, and the fixed end is arranged closer to the blade root than the movable end.

[0014] Preferably, the opening depth of the hook is 15-60 mm.

[0015] Preferably, the curvature of the fixing rope is 25°-40°, and the length of the fixing rope is greater than the corresponding arc length of the outer wall of the flexible air duct.

[0016] Preferably, three groups of the flexible air duct telescopic structures are arranged around the flexible air duct.

[0017] Preferably, one or more auxiliary fixing ropes are arranged in front and behind the fixing rope respectively, the auxiliary fixing ropes are arranged parallel to the fixing rope, and the spacing between each two in the sequence composed of the auxiliary fixing ropes and the fixing ropes is smaller than the opening depth of the hook.

[0018] Preferably, the spacing between the hooks on the blade web is 1500mm-2500mm.

[0019] Preferably, the size and density of the air guide holes on the flexible air duct are considered according to the heat required for deicing at that position. Generally, the closer the air guide holes on the flexible air duct are to the blade tips, the larger the caliber and density are.

[0020] Preferably, the cross-sectional area of ​​the flexible air duct becomes smaller as it approaches the blade tip, so as to maintain sufficient wind pressure to push the hot air flow toward the blade tip.

[0021] Preferably, the rigid air duct is installed on the blade web, and a baffle is installed between the blade web and the blade leading edge, and the air outlet of the rigid air duct passes through the baffle.

[0022] Preferably, when the blade tip is blocked, a plurality of hot air reflow holes are provided on the baffle plate to form a new hot air reflow channel between the blade web and the blade leading edge.

[0023] Preferably, the connection between the soft air duct and the hard air duct is fixed by a clamp.

[0024] Preferably, the soft air duct is an air distribution duct.

[0025] Based on the same inventive concept, the present invention also provides a method for fixing a soft air duct of the fan blade air-heat deicing system, which comprises the following steps:

[0026] 1) When the corresponding blade is in the horizontal or downward position, turn on the blower and blow the soft air duct straight, so that the soft air duct is close to the blade belly, and the fixing rope on the soft air duct is close to the hook on the blade belly;

[0027] 2) Release the moving end of the flexible air duct telescopic structure, so that the flexible air duct is extended under the action of wind force, and each fixing rope on the flexible air duct just reaches the opening of the corresponding hook on the blade web;

[0028] 3) Retract the movable end of the flexible air duct telescopic structure so that each fixing rope on the flexible air duct is inserted into the opening of the corresponding hook on the blade web, thereby completing the fixing of the flexible air duct.

[0029] Based on the same inventive concept, the present invention also provides a method for disassembling the soft air duct of the fan blade air-heat deicing system, which comprises the following steps:

[0030] 1) When the corresponding blades are in the horizontal or downward position, turn on the blower to straighten the flexible air duct;

[0031] 2) Release the moving end of the flexible air duct telescopic structure, so that the flexible air duct is extended under the action of wind force, and each fixing rope on the flexible air duct is just disengaged from the opening of the corresponding hook on the blade web;

[0032] 3) Turn off the blower, open the fixing clamp between the soft air duct and the hard air duct, rotate the soft air duct 90° to 180°, and then tighten the clamp to fix the soft air duct;

[0033] 4) Turn on the blower again and blow the flexible air duct straight, so that the fixing rope on the flexible air duct is away from the hook on the blade web, and the flexible air duct is away from the blade web;

[0034] 5) Turn off the blower again and slowly retract the soft air duct. After the soft air duct is fully retracted, open the clamp between the soft air duct and the hard air duct and remove the soft air duct.

[0035] Principle of the design method of the present invention:

[0036] 1) With the help of the contraction and extension characteristics of the soft air duct, the soft air duct can be extended to the tip of the blade when the wind is input, so that the hot air is automatically sent to the tip of the blade;

[0037] 2) Open air guide holes on the soft air duct as needed (the closer the air guide holes are to the blade tip, the larger the diameter and density of the air guide holes are), and control the heat distribution along the soft air duct during heating through the air guide holes, so as to heat the leading edge of the blade as needed, that is, the total heat distribution is performed according to the heat required for de-icing the leading edge of the blade;

[0038] 3) Send the most heat to the blade tip (the closer to the blade tip, the larger the diameter and density of the air guide holes on the soft air duct), and give priority to removing ice from the blade tip;

[0039] 4) Because there is always air loss along the way in the soft air duct, in order to maintain sufficient wind pressure and push the hot air flow to the blade tip, the cross-sectional area of ​​the soft air duct becomes smaller as it gets closer to the blade tip;

[0040] 5) For blades with blocked blade tips, the hot air blown out of the soft air duct can flow back to the root of the blade through the blade leading edge cavity outside the soft air duct and the hot air return hole on the baffle, and then be sucked in by the blower, blown into the heater, and after reheating, blown to the blade tip through the air guide pipe to form a new stable circulation air duct. Figure 3 .

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1) The present invention adds a soft air duct design at the outlet of the last section of the hard air duct, and uses hot air to extend it to the tip of the blade, which not only extends the transportation channel of wind resources and solves the construction problem of extending the air guide duct in the blade, but also enables the hot air to reach the tip of the blade first, ensuring the deicing effect of the tip of the blade, so that the hot air resources can be accurately allocated to the deicing position of the blade;

[0043] 2) The soft air duct of the present invention is provided with an air guide hole at a position toward the leading edge of the blade, so as to guide the hot air to blow directly toward the leading edge of the blade, which not only improves the heat utilization efficiency, but also improves the deicing speed and deicing capacity of the leading edge of the blade;

[0044] 3) The diameter and number of the air guide holes on the flexible air duct of the present invention are designed along its length according to the heat required for deicing the leading edge of the blades at different positions. The closer to the blade tip, the higher the priority level (the larger the diameter and density of the air guide holes are at the blade tip), so that the total heat of the deicing system is scientifically distributed, and the blade tip position that needs deicing the most is given priority to ensure that the heat is sufficient. Not only is the deicing effect good, but the heat utilization efficiency is also greatly improved, and the total power of the heater and the overall self-consumption of the deicing system are reduced;

[0045] 4) The cross-sectional area of ​​the soft air duct of the present invention is smaller as it approaches the blade tip, so that although there are air guide holes along the soft air duct and there is always air loss, it can still maintain sufficient wind pressure to push the hot air flow to the blade tip;

[0046] 5) In the case that the hot air return duct required for normal deicing cannot be formed by the blade tip being blocked, the present invention reconstructs a new hot air circulation duct by constructing a hot air return duct in the leading edge cavity of the blade outside the soft air duct, thereby solving the problem that the blade tip is blocked and the gas-heat deicing cannot be achieved. Moreover, the newly constructed hot air circulation duct enables the hot air to return from the outlet of the soft air duct close to the blade tip. The closer to the blade tip, the higher the temperature and the more heat. This fully complies with the principle that the closer to the blade tip, the higher the priority level of deicing heat distribution, and the better the deicing effect.

[0047] 6) In the case that the blade tip is blocked and a normal de-icing hot air return duct cannot be formed, the present invention newly constructs a hot air return duct in the leading edge cavity of the blade outside the soft air duct by opening a hot air return hole on the baffle. The total cross-sectional area of ​​the hot air return hole can be made as large as possible to reduce the hot air return wind resistance and improve the de-icing performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0049] Figure 1 This is a schematic diagram of the installation structure of the existing wind turbine blade internal gas thermal deicing system.

[0050] Figure 2 Schematic diagram of the blade ice coverage state.

[0051] Figure 3 It is a schematic diagram of the structure of the present invention.

[0052] Figure 4 This is a schematic diagram of the connection between soft air duct and hard air duct.

[0053] Figure 5 This is a schematic diagram of the length of the soft air duct when the blade tip is not blocked.

[0054] Figure 6 This is a diagram showing the distribution of air guide holes on the flexible air duct.

[0055] Figure 7 Schematic diagram of the hook structure installed on the blade belly.

[0056] Figure 8 Schematic diagram of the hook installation position on the blade belly.

[0057] Fig. 9 This is the structural diagram of the fixed rope installation on the flexible air duct (relative to the cross section of the flexible air duct).

[0058] Fig.10 This is a schematic diagram of the installation position of the fixing rope on the flexible air duct.

[0059] Fig.11 This is a schematic diagram of the arrangement of the flexible air duct telescopic structure surrounding the flexible air duct.

[0060] Fig.12 This is a state diagram of the mobile end of the flexible air duct telescopic structure.

[0061] Fig.13 This is a diagram showing the fixed connection status of the movable end and the fixed end of the flexible air duct telescopic structure.

[0062] Fig.14 This is a schematic diagram of the location of the auxiliary fixing rope on the flexible air duct.

[0063] Fig.15 It is a schematic diagram of the structure of the present invention when the blade tip is blocked.

[0064] Fig.16 Schematic diagram of the length of the soft air duct when the blade tip is blocked.

[0065] Fig.17 This is a front view structural diagram of the baffle.

[0066] Fig.18 This is a diagram of the temperature changes of each blade after the de-icing system is turned on for half an hour.

[0067] Fig.19 This is a diagram of the temperature changes of each blade after the de-icing system is turned on for two hours.

[0068] In the figure: 1. heater; 2. blower; 3. air guide duct; 4. baffle; 5. blade tip; 6. web cavity; 7. blade leading edge cavity; 8. blade tip blockage; 9. blade web; 10. blade leading edge; 11. blade trailing edge cavity; 12. clamp; 13. hot air return channel; 14. blade root; 15. hook; 16. fixing rope; 17. flexible air duct telescopic structure; 18. auxiliary fixing rope; 31. hard air duct; 32. flexible air duct; 41. hot air return hole; 42. hard air duct perforation; 171. fixed end; 172. mobile end; 311. hard air duct air outlet; 321. air guide hole; 322. flexible air duct air inlet. DETAILED DESCRIPTION

[0069] The present invention is further described below in conjunction with specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0070] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0071] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] See also Figure 3-Figure 6 The first embodiment of the air-heat deicing system for fan blades of the present invention comprises a heater 1 and a blower 2 installed in a manhole baffle at the root 14 of the blade, the air inlet of the heater 1 is connected to the air outlet of the blower 2, the air outlet of the heater 1 is connected to the air inlet of the air duct 3, the air outlet of the air duct 3 points to the direction of the blade tip 5, and the hot air sent out by the air duct 3 blows toward the blade tip and then enters the air inlet of the blower 2 through the hot air reflux channel 13.

[0073] The front end of the air duct 3 adopts a conventional hard air duct 31, and the rear end of the air duct 3 adopts a soft air duct 32. The air inlet of the hard air duct 31 is connected with the air outlet of the heater 1, and the air outlet of the hard air duct 31 is connected with the air inlet of the soft air duct 32, and the soft air duct 32 is arranged in the blade leading edge cavity 7 and extends to near the blade tip 5. The soft air duct 32 is provided with a plurality of air guide holes 321 at the position facing the blade leading edge 10 (that is, the side of the blade facing the windward side of the blade), so that the hot air is blown toward the blade leading edge 10 and the blade tip 5, and then enters the web cavity 6 and the blade trailing edge cavity 11 through the process hole of the blade tip 5, and finally flows into the air inlet of the blower 2 located at the blade root 14 to form a hot air circulation channel.

[0074] The hard air duct 31 is installed on the blade web 9 , and a baffle 4 is installed between the blade web 9 and the blade leading edge 10 , and an air outlet of the hard air duct 31 passes through the baffle 4 .

[0075] like Figure 7 - Fig.14 As shown, hooks 15 are installed at intervals along the length direction of the blade at the middle position of the blade web 9 in the blade leading edge cavity 7, and the opening of the hook 15 faces the blade tip 5. A plurality of fixing ropes 16 are designed at the contact position with the blade web 9 on the soft air duct 32, and each fixing rope 16 is installed parallel to the cross section of the soft air duct 32, and the interval between adjacent fixing ropes 16 is equal to the interval between adjacent hooks 15. The soft air duct 32 is fixed to the blade web 9 by inserting the fixing rope 16 into the opening of the hook 15.

[0076] At the interface between the soft air duct 32 and the hard air duct 31, three groups of soft air duct telescopic structures 17 are arranged around the soft air duct 32. The soft air duct telescopic structure 17 includes a fixed end 171 and a movable end 172 arranged along the longitudinal axis of the blade web 9, and the distance between the fixed end 171 and the movable end 172 is equal to the opening depth of the hook 15, and the fixed end 171 and the movable end 172 are detachably connected. In this embodiment, the opening depth of the hook 15 is 30 mm.

[0077] When the first embodiment of the fan blade air-heat deicing system of the present invention is implemented:

[0078] 1. The baffle 4 is installed in the blade leading edge cavity 7, or the outlet of the last section of the hard air duct 31 is fixed with a clamp 12 to fix the soft air duct 32, such as the air distribution duct, see Figure 4 ;

[0079] 2. The length of the soft air duct S2 is based on the distance S from the outlet of the last section of the hard air duct to the blade tip, minus the blade length S1 that the soft air duct 32 cannot pass because the cross-sectional area of ​​the blade leading edge cavity 7 is smaller as it approaches the blade tip 5, that is, the length of the soft air duct S2 = S-S1, see Figure 5 ;

[0080] 3. The soft air duct 32 is provided with air guide holes 321 at the position toward the leading edge 10 of the blade as required. The size and density of the air guide holes 321 are considered according to the heat required for deicing the leading edge 10 of the corresponding blade. The overall principle is that the closer to the blade tip 5, the higher the priority level, that is, the closer to the blade tip 5, the larger the diameter and density of the air guide holes 321. Figure 6 ;

[0081] 4. The cross-sectional area of ​​the soft air duct 32 becomes smaller as it gets closer to the blade tip, so as to maintain sufficient wind pressure to push the hot air flow toward the blade tip 5.

[0082] 5. Design of hook 15: Figure 7 The material is made of soft materials such as plastic, so that the hook 15 and the blade web 9 can deform synchronously without damage; the material strength of the hook 15 must ensure that it will not break during long-term use; the total thickness H of the hook 15 needs to be controlled within 10mm to ensure that it will not cause excessive deformation of the soft air duct 32 during use, thereby increasing wind resistance; the opening depth L of the hook 15 is the same as the telescopic length of the soft air duct telescopic structure 17, which is 30mm.

[0083] 6. The hook 15 can be fixed in a variety of ways: for example, double-sided tape can be pasted on the fixing surface of the hook 15 and the hook 15 can be pasted to a predetermined position on the blade web 9 through the double-sided tape, or the hook 15 can be integrally formed with the blade web 9 when the blade web 9 is manufactured.

[0084] 7. The first hook 15 is fixed at the middle of the blade web 9. The opening of the hook 15 is 2m away from the outlet of the hard air duct 31. A hook 15 is fixed every 2m. Figure 8 ;

[0085] 8. The fixing rope 16 on the soft air duct 32 is fixed parallel to the cross section of the soft air duct 32 and installed on the outer wall of the soft air duct 32 on the back of the air guide hole 321. The arc is 30° and the length is slightly longer than the arc length of the outer wall of the corresponding soft air duct 32, so as to facilitate the insertion of the hook 15. Fig. 9 ;

[0086] 9. The first fixing rope 16 is located on the soft air duct 32 at a position 2m+1cm from the interface between the soft air duct 32 and the hard air duct 31 to the blade tip. One is installed every 2m. Fig.10 ;

[0087] 10. Design of the flexible air duct telescopic structure 17: At the position where the flexible air duct 32 is inserted into the hard air duct 31, three sets of flexible air duct telescopic structures 17 are arranged around the flexible air duct 32, see Fig.11Each set of flexible air duct telescopic structures 17 includes a fixed end 171 and a movable end 172 arranged 30 mm apart along the length direction of the blade, and the distance between the fixed end 171 and the movable end 172 is equal to the opening depth of the hook 15, and the fixed end 171 and the movable end 172 are detachably connected. When the flexible air duct 32 needs to be extended, the movable end 172 is loosened, and the flexible air duct 32 is retracted. Fig.12 When the soft air duct 32 needs to be shortened, the fixed end 171 and the movable end 172 are tied together and fixed, see Fig.13 ;

[0088] 11. In order to eliminate process errors and improve the success rate of inserting the fixing rope 16, one or more auxiliary fixing ropes 18 are added in front and behind each fixing rope 16. The auxiliary fixing ropes 18 are arranged parallel to the fixing ropes 16. The spacing between the auxiliary fixing ropes 18 and the fixing ropes 16 is less than the opening depth of the hook 15, which is 25 mm. Fig.14 .

[0089] The specific fixing method of the soft air duct 32 in the first embodiment of the fan blade air heating deicing system of the present invention is:

[0090] 1. When the corresponding blade is in a horizontal or downward position, turn on the blower 2 to blow the soft air duct 32 straight. Because the soft air duct 32 is provided with an air guide hole 321 on the side facing the leading edge of the blade, the reaction force of the air guide will make the soft air duct 32 close to the blade web 9, and the fixing rope 16 on the soft air duct 32 and the hook 15 on the blade web 9 will be close to each other;

[0091] 2. Release the movable end 172 of the flexible air duct telescopic structure 17, so that the flexible air duct 32 is extended under the action of wind force, and each fixing rope 16 on the flexible air duct 32 just reaches the opening of the corresponding hook 15 on the blade web 9;

[0092] 3. Retract the movable end 172 of the flexible air duct telescopic structure 17, and insert each fixing rope 16 on the flexible air duct 32 into the opening of the corresponding hook 15 on the blade web 9, and prevent it from coming out, thus completing the fixing of the flexible air duct 32.

[0093] When the soft air duct 32 in the first embodiment of the air-heat deicing system for fan blades of the present invention needs to be repaired or replaced, the old soft air duct 32 can be taken out. The specific method is as follows:

[0094] 1. Turn on the blower 2 when the corresponding blade is in the horizontal or downward position to blow the flexible air duct 32 straight;

[0095] 2. Release the movable end 172 of the flexible air duct telescopic structure 17, so that the flexible air duct 32 is extended under the action of wind force, and each fixing rope 16 on the flexible air duct 32 is just disengaged from the opening of the corresponding hook 15 on the blade web 9;

[0096] 3. Turn off the blower 2, open the fixing hoop 12 between the flexible air duct 32 and the rigid air duct 31, rotate the flexible air duct 32 by 90° to 180°, and then lock the hoop 12 to fix the flexible air duct 32.

[0097] 4. Open the blower 2 again to straighten the flexible air duct 32. At this time, due to the air guiding function of the air guiding holes 321, the fixing rope 16 on the flexible air duct 32 will move away from the hook 15 on the blade web 9, and at the same time, the flexible air duct 32 will also deflect to one side and move away from the blade web 9.

[0098] 5. Turn off the blower 2 again, slowly retract the flexible air duct 32. After the flexible air duct 32 is completely retracted, open the hoop 12 between the flexible air duct 32 and the rigid air duct 31, and then the flexible air duct 32 can be removed.

[0099] Please refer to Figure 15-17 , the second embodiment of the air thermal de-icing system for the fan blade of the present invention is generally the same as the first embodiment. The difference is that the tip of the fan blade is blocked by 8, and a plurality of hot air return holes 41 are opened on the baffle 4. After the hot air in the flexible air duct 32 is blown out, it is blocked by the tip block 8 and cannot reach the web cavity 6 and the blade trailing edge cavity 11. It can only return through the new hot air return channel 13 formed by the hot air return holes 41 on the outer periphery of the flexible air duct 32 in the blade leading edge cavity 7 and enter the air inlet of the blower 2 located at the blade root 14 to form a new hot air circulation channel.

[0100] Due to the tip block 8, considering the cross-sectional area of the hot air return channel 13, the length S2' of the flexible air duct is referenced by the distance S from the outlet of the last rigid air duct to the tip of the blade, subtracting the blade length S1 that the flexible air duct 32 cannot pass through because the cross-sectional area of the blade leading edge cavity 7 is smaller closer to the tip block 8, and the length S1' of the flexible air duct that needs to be shortened to ensure the cross-sectional area of the hot air return channel 13, so that the cross-sectional area of the blade leading edge cavity at the outlet of the flexible air duct = the cross-sectional area of the flexible air duct + the cross-sectional area of the newly formed hot air return channel 13, and the length of the flexible air duct S2' = S - S1 - S1', as shown in Fig.16 ; A plurality of hot air return holes 41 (such as Fig.17 ) are opened on the baffle 4 to form a new hot air return channel 13 (refer to the right arrow shown in Figure 3 ) on the outer periphery of the air duct 3 in the blade leading edge cavity 7 between the blade web 9 and the blade leading edge 10.

[0101] Through the use of drones and infrared cameras to record the external temperature changes of the first blade equipped with a flexible air duct (cloth air duct) and the second and third blades without the flexible air duct (cloth air duct), the experimental results shown in Fig.18 and Fig.19 are obtained. Among them, Fig.18 is the temperature change state diagram of each blade half an hour after the de-icing system is turned on, Fig.19This is a diagram of the temperature changes of each blade after the de-icing system is turned on for two hours.

[0102] Depend on Fig.18 It can be seen that more heat is concentrated at the outlet of the hard air duct of the second and third blades, and because the first blade is installed with a soft air duct (air duct), part of the heat that should have been concentrated at the outlet of the hard air duct is transported to the middle and tip of the blade, and because the soft air duct (air duct) is provided with an air guide hole 321 toward the leading edge 10 of the blade, the heat is mainly used to heat the leading edge 10 of the blade. Therefore, the temperature after the outlet of the hard air duct of the first blade rises quickly, which is significantly higher than the temperature at the corresponding position on the second and third blades, and the distribution is more uniform. Since the second blade is fixed in an upward direction and is exposed to a larger area of ​​sunlight, its temperature is higher than that of the third blade.

[0103] Depend on Fig.19 It can be seen that as the de-icing system is turned on for an increased time, the outer surface temperatures of the three blades all rise, but the temperature distribution of the first blade is more balanced than that of the second and third blades, with smaller fluctuations. The peak temperature of the first blade is 35.6°C, the trough temperature is 31.0°C, and the temperature difference is 4.6°C; the peak temperature of the second blade is 39.7°C, the trough temperature is 31.8°C, and the temperature difference is 7.9°C; the peak temperature of the third blade is 41.2°C, the trough temperature is 26.6°C, and the temperature difference is 14.6°C. It can be seen that after the first blade is installed with the air distribution duct, the temperature difference is the smallest and the heat distribution is the most uniform, which is conducive to further improving the energy efficiency ratio of the de-icing system.

[0104] The above is only a specific implementation scheme of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the art can make many possible changes and modifications to the technical scheme of the present invention by using the technical content disclosed above without departing from the scope of the technical scheme of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical scheme of the present invention should fall within the protection scope of the technical scheme of the present invention.

Claims

1. A fan blade air heating deicing system with a flexible air duct, comprising a heater and a blower, wherein the air inlet of the heater is connected to the air outlet of the blower, the air outlet of the heater is connected to the air inlet of the air duct, and the hot air blown out of the air outlet of the air duct is connected to the air inlet of the blower through a hot air return channel, characterized in that: The front end of the air guide duct adopts a hard air duct, and the rear end of the air guide duct adopts a soft air duct, the air inlet of the hard air duct is connected to the air outlet of the heater, and the air outlet of the hard air duct is connected to the air inlet of the soft air duct; The inner cavity of the blade is divided into a blade leading edge cavity facing the windward side of the blade and a blade trailing edge cavity facing the leeward side of the blade by the blade web, the soft air duct is arranged in the blade leading edge cavity and extends to near the blade tip, and the soft air duct is provided with a plurality of air guide holes on the side facing the windward side of the blade; A hook is installed at a certain distance on the longitudinal axis of the blade web in the blade leading edge cavity, and a plurality of fixing ropes are arranged on the side of the flexible air duct facing the leeward side of the blade corresponding to the hook. The flexible air duct is fixed to the blade web by inserting the fixing rope into the opening of the hook.

2. The fan blade air heating deicing system with a flexible air duct according to claim 1 is characterized in that: A flexible air duct telescopic structure is arranged at the interface between the flexible air duct and the rigid air duct, and the flexible air duct telescopic structure includes a fixed end and a movable end arranged in sequence along the length direction of the blade, and the distance between the fixed end and the movable end is equal to the opening depth of the hook, and the fixed end is detachably connected to the movable end.

3. The fan blade air heating deicing system with a flexible air duct according to claim 2 is characterized in that: The opening of the hook faces the blade tip, the fixing rope is installed parallel to the cross section of the soft air duct, and the fixing end is arranged closer to the blade root than the moving end.

4. The fan blade air heating deicing system with a flexible air duct according to claim 2, characterized in that: The opening depth of the hook is 15-60 mm.

5. The fan blade air heating deicing system with a flexible air duct according to claim 3 is characterized in that: The curvature of the fixing rope is 25°-40°, and the length of the fixing rope is greater than the corresponding arc length of the outer wall of the soft air duct.

6. The fan blade air heating deicing system with a flexible air duct according to claim 2, characterized in that: Three groups of the flexible air duct telescopic structures are arranged around the flexible air duct.

7. The fan blade air heating deicing system with a flexible air duct according to claim 2, characterized in that: One or more auxiliary fixing ropes are arranged in front and behind the fixing rope respectively. The auxiliary fixing ropes are arranged parallel to the fixing rope. The spacing between the auxiliary fixing ropes and the fixing ropes in the sequence is smaller than the opening depth of the hook.

8. The fan blade air heating deicing system with a flexible air duct according to claim 2, characterized in that: The spacing between the hooks on the blade web is 1500mm-2500mm.

9. A method for fixing a flexible air duct of a fan blade air-heat deicing system as claimed in any one of claims 1 to 8, characterized in that The following steps are involved: 1) When the corresponding blade is in the horizontal or downward position, turn on the blower and blow the soft air duct straight, so that the soft air duct is close to the blade belly, and the fixing rope on the soft air duct is close to the hook on the blade belly; 2) Release the moving end of the flexible air duct telescopic structure, so that the flexible air duct is extended under the action of wind force, and each fixing rope on the flexible air duct just reaches the opening of the corresponding hook on the blade web; 3) Retract the movable end of the flexible air duct telescopic structure so that each fixing rope on the flexible air duct is inserted into the opening of the corresponding hook on the blade web, thereby completing the fixing of the flexible air duct.

10. A method for disassembling the soft air duct of the fan blade air-heat deicing system according to any one of claims 1 to 8, characterized in that The following steps are involved: 1) When the corresponding blades are in the horizontal or downward position, turn on the blower to straighten the flexible air duct; 2) Release the moving end of the flexible air duct telescopic structure, so that the flexible air duct is extended under the action of wind force, and each fixing rope on the flexible air duct is just disengaged from the opening of the corresponding hook on the blade web; 3) Turn off the blower, open the fixing clamp between the soft air duct and the hard air duct, rotate the soft air duct 90° to 180°, and then tighten the clamp to fix the soft air duct; 4) Turn on the blower again and blow the flexible air duct straight, so that the fixing rope on the flexible air duct is away from the hook on the blade web, and the flexible air duct is away from the blade web; 5) Turn off the blower again and slowly retract the soft air duct. After the soft air duct is fully retracted, open the clamp between the soft air duct and the hard air duct and remove the soft air duct.

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