Engine test device, blade release device and release method

Abstract

The invention relates to an engine testing device, a blade releasing device and a blade releasing method. The blade releasing device comprises a clamping assembly, a driving assembly and a driving assembly, the clamping assembly comprises a fixed part and a sliding part, and the fixed part and the sliding part provide a clamping space on the inner side in the circumferential direction and are used for clamping a blade; the triggering assembly comprises a shape memory spring and a heating piece, one side of the shape memory spring is connected with the heating piece, and the other side of the shape memory spring abuts against the sliding part, so that the sliding part is tightly pressed on the fixed part; when the heating piece works, the size of the shape memory spring is changed, and the sliding part is driven to be away from the fixed part so as to release the blade. The blades are accurately released at the target rotating speed.

Description

Technical Field

[0001] The technical field of the present invention relates to an engine test device, a blade release device and a release method. Background Art

[0002] When a blade undergoes a fly-off, the fly-off blade will impact the engine casing, causing a primary damage to the casing. At the same time, the remaining blades will rub against the casing, and during the rubbing process, the casing will suffer secondary damage. In addition, under specific circumstances, the rubbing load will cause coupled vibrations of the casing and other structures, resulting in harmful consequences to the engine. In the above process, airworthiness regulations require that the engine casing must have the ability to contain, and it is not allowed to have a situation where the casing is penetrated. At the same time, it is necessary to avoid harmful consequences caused by rubbing. Therefore, during the engine design stage, it is necessary to study the containment ability of the casing and the overall response of the engine during the rubbing process through containment tests and rubbing tests.

[0003] How to accurately release the blade at the target speed is the key to the success of the containment test and the rubbing test. Currently, the commonly used detachment methods are prefabricated cracks, explosive fly-off and local heating.

[0004] The fly-off method of prefabricating cracks mainly prefabricates cracks with a certain depth at the blade root. As the blade speed increases, the centrifugal force gradually increases. When the stress level at the remaining material of the blade root is higher than the material ultimate strength, the blade undergoes a fly-off. Due to uncertain factors such as machining errors, material property deviations, and notch sensitivity, there is a large error between the actual fly-off speed of the blade and the target speed, which affects the test results.

[0005] The method of explosive fly-off detonates a detonator pre-installed at the blade root by wire or wireless means after filling explosives at the blade root, breaking the remaining material at the blade root to trigger the fly-off of the blade. This method is somewhat dangerous during the filling process of the explosives, and the fire and smoke generated by the explosion will also affect the high-speed camera recording during the test process.

[0006] The principle of the local heating method is to maintain a certain time at a predetermined speed and use a heating rod or heating sheet to reduce the ultimate strength of the clamping material below the stress it receives, causing the blade to fly off. This method requires a relatively high heating temperature, and materials with low temperature sensitivity such as composite materials do not have the characteristic of significantly changing the material ultimate tensile strength with a significant increase in temperature, so it does not have wide applicability. Summary of the Invention

[0007] The object of the present invention is to provide a blade release device.

[0008] Another object of the present invention is to provide an engine test device.

[0009] Another object of the present invention is to provide a method for releasing a blade.

[0010] A blade release device according to an aspect of the present invention includes: a clamping assembly including a fixed part and a sliding part, the fixed part and the sliding part providing a clamping space on the inner circumferential side for clamping the blade; a triggering assembly including a shape memory spring and a heating element, one side of the shape memory spring is connected to the heating element, and the other side abuts against the sliding part to press the sliding part against the fixed part; wherein, when the heating element works, the size of the shape memory spring changes, driving the sliding part away from the fixed part to release the blade.

[0011] The technical solution of the present application realizes the movement of the sliding part by heating the shape memory spring. When the moving distance is greater than the size of the clamped part of the blade, the blade flies off. When the shape memory spring is in the heated state, the deformation process is rapid and the fly-off trigger time is short, enabling precise release at the target rotational speed. Moreover, during the heating process, by slowing down the deformation process, it can be observed that the size of the shape memory spring changes gradually, the blade moves outward gradually, and after the blade flies off, it can better maintain the flight attitude of the blade, and can simulate the situation of the blade flying off and rubbing against the casing under the real engine working environment, making the test result more accurate. At the same time, this process has high safety, does not generate factors such as dust and strong light that affect high-speed photography, and can better observe the test results. There is no limitation on the material of the flying-off blade, and the applicable range is wide.

[0012] In one or more embodiments of the blade release device, the blade release device includes a first state and a second state: in the first state, the heating element does not work, the length of the shape memory spring is a first length, the sliding part abuts against the fixed part, providing the clamping space for generating a clamping force on the blade; in the second state, the heating element works, the length of the shape memory spring is a second length, the sliding part moves away from the fixed part, releasing the clamping space to eliminate the clamping force; wherein, the second length is less than the first length.

[0013] In one or more embodiments of the blade release device, the triggering assembly further includes a bolt, the bolt includes a cylindrical section, one side of the shape memory spring is fixedly sleeved on the cylindrical section; an installation hole is opened inside the bolt, the heating element is embedded in the installation hole; a heating groove is opened on the cylindrical section, and the heating groove communicates with the installation hole to transfer the heat of the heating element to the shape memory spring.

[0014] In one or more embodiments of the blade release device described above, the mounting hole is a stepped hole, including a first hole, a second hole, and a third hole. The second hole is a threaded hole. The first hole, the second hole, and the third hole are connected in sequence, and their diameters decrease in sequence. The heating element includes a holding section, a mounting section, and a heating section. The holding section is located in the first hole. The mounting section is provided with a threaded structure to cooperate with the second hole to fix the heating element in the mounting hole. The heating section is located in the third hole, and the heating groove communicates with the third hole.

[0015] In one or more embodiments of the blade release device described above, the blade release device further includes a support. The support includes a threaded hole, and the bolt includes a threaded section. The threaded hole cooperates with the threaded section to fix the trigger assembly to the support.

[0016] In one or more embodiments of the blade release device described above, the support and the fixed part are respectively located on the circumferential two sides of the sliding part. The sliding part includes a first concave part and a second concave part. The first concave part is located radially outside the second concave part. The support includes a first convex part, and the first convex part is located radially outside the threaded hole. The first convex part cooperates with the first concave part. The fixed part includes a second convex part, and the second convex part cooperates with the second concave part. The radially outer wall surface of the second convex part constitutes the radially bottom wall surface of the clamping space.

[0017] In one or more embodiments of the blade release device described above, a plurality of arc-shaped protrusions are provided on the radial wall surfaces of the first concave part and the second concave part, so that the contacts with the first convex part and the second convex part are point contacts.

[0018] In one or more embodiments of the blade release device described above, the blade release device further includes a turntable, and the support, the fixed part and the turntable are integrally formed.

[0019] According to an engine test device of another aspect of the present invention, it includes a casing, a blade, and the blade release device described in any one of the above. The blade release device is located radially inside the casing, and the blade is clamped by the sliding part and the fixed part of the clamping assembly of the blade release device.

[0020] In one or more embodiments of the engine test device described above, the blade includes a tenon head, and the clamping space provided by the sliding part and the fixed part includes a tenon groove. The tenon head cooperates with the tenon groove to fix the blade by the clamping assembly.

[0021] A method for releasing a blade according to another aspect of the present invention includes: a sliding clamping portion and a fixed clamping portion cooperate to provide a clamping space for fixedly clamping the blade; a shape memory spring presses the sliding clamping portion against the fixed clamping portion; a heating element heats the shape memory spring, causing the shape memory spring to contract and the sliding clamping portion to move away from the fixed clamping portion; and the blade disengages from the clamping space. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other features, properties, and advantages of the present invention will become more apparent from the following description in conjunction with the drawings and embodiments, in which like reference numerals always denote like features. It should be noted that these drawings are only examples and are not drawn to scale, and should not be construed as limiting the actual scope of protection required by the present invention, where:

[0023] Figure 1A is a schematic structural view of a first state of a blade release device according to an embodiment.

[0024] Figure 1B is a schematic structural view of a second state of a blade release device according to an embodiment.

[0025] Figure 2A is a schematic structural view of a trigger assembly according to an embodiment from one perspective.

[0026] Figure 2B is a schematic structural view of a trigger assembly according to an embodiment from another perspective.

[0027] Figure 2C is a schematic structural view of a heating element according to an embodiment.

[0028] Figure 3 is a schematic structural view of a support and a fixed portion according to an embodiment.

[0029] Figure 4A is a schematic structural view of a sliding portion according to an embodiment from one perspective.

[0030] Figure 4B is a schematic structural view of a sliding portion according to an embodiment from another perspective.

[0031] Figure 5 is a schematic structural view of a shape memory spring according to an embodiment.

[0032] Figure 6 is a schematic structural view of an engine test device according to an embodiment.

[0033] Figure 7 is a schematic flowchart of a method for releasing a blade according to an embodiment.

[0034] Reference Numerals:

[0035] 100 - Blade release device;

[0036] 200 - Blade;

[0037] 10 - Clamping assembly;

[0038] 11 - Fixed part;

[0039] 111 - Second convex part;

[0040] 12 - Sliding part;

[0041] 121 - Tightening hole, 122 - First concave part, 123 - Second concave part, 124 - Arc-shaped protrusion;

[0042] 13 - Clamping space;

[0043] 20 - Trigger assembly;

[0044] 21 - Shape memory spring;

[0045] 22 - Heating element;

[0046] 221 - Holding section, 222 - Mounting section, 223 - Heating section;

[0047] 23 - Bolt;

[0048] 231 - Cylindrical section, 232 - Heating groove, 233 - Threaded section;

[0049] 24 - Mounting hole;

[0050] 241 - First hole, 242 - Second hole, 243 - Third hole;

[0051] 25 - Heating wire;

[0052] 30 - Support;

[0053] 31 - Threaded hole, 32 - First convex part;

[0054] 40 - Turntable, 41 - Rotating shaft;

[0055] 50 - Conductive slip ring;

[0056] 51 - Moving ring, 52 - Stationary ring;

[0057] 300 - Engine test device;

[0058] 60 - Tenon, 61 - Mortise;

[0059] 70 - Casing;

[0060] 400 - Fixed blade;

[0061] 80 - Fixed tenon groove, 81 - Tenon head for fixing the blade. Detailed implementation mode

[0062] Now, various embodiments of the present invention will be described in detail. Examples of these embodiments are shown in the accompanying drawings and described as follows. Although the present invention will be described in combination with exemplary embodiments, it should be understood that this specification is not intended to limit the present invention to those exemplary embodiments. On the contrary, the present invention is intended to cover not only these exemplary embodiments, but also various alternative forms, modifications, equivalent forms and other embodiments that can be included within the spirit and scope of the present invention as defined by the appended claims.

[0063] In the following description, the orientation or positional relationship indicated by terms such as "axial", "circumferential", "radial", "inner", "outer" or other orientation terms is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. The directional terms "axial", "circumferential" and "radial" are based on the engine.

[0064] At the same time, specific words are used in this application to describe the embodiments of this application. For example, "an embodiment" and / or "one embodiment" mean a certain feature, structure or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this application can be appropriately combined.

[0065] Flowcharts are used in this application to illustrate the operations performed by the systems according to the embodiments of this application. It should be understood that the operations before or below do not necessarily need to be executed precisely in sequence. Other operations can also be added to these processes, or one or several steps of operations can be removed from these processes.

[0066] Refer to Figures 1A to 2C As shown, in one embodiment, the specific structure of the blade release device 100 may include a clamping assembly 10 and a triggering assembly 20.

[0067] The clamping assembly 10 includes a fixed part 11 and a sliding part 12. The fixed part 11 and the sliding part 12 provide a clamping space 13 on the circumferential inner side for clamping the blade 200. The meaning of the "fixed part 11" here refers to a structure that provides clamping force but cannot move, and the relative meaning of the "sliding part 12" is a structure that provides clamping force but can move relative to the fixed part 11.

[0068] The triggering component 20 includes a shape memory spring 21 and a heating element 22. One side of the shape memory spring 21 is connected to the heating element 22, and the other side is abutted against the sliding part 12, pressing the sliding part 12 against the fixed part 11. Here, the "shape memory spring 21" means that the spring is made of a shape memory alloy. The shape memory alloy material can recover large deformations, have a large output force, and can perform repeated telescoping with sensitive response. The length of the spring changes when heated and returns to its original length when cooled. The shape memory alloy is preferably a nickel-titanium alloy, but this is not limiting, and any shape memory alloy with a large output force and large recoverable deformation can be used. Here, the "heating element 22" means a component that can generate heat and transfer the heat to the shape memory spring 21.

[0069] Among them, when the heating element 22 works, the size of the shape memory spring 21 changes, driving the sliding part 12 away from the fixed part 11. That is, when the shape memory spring 21 is heated, its size changes, the magnitude of the force applied to the sliding part 12 changes, and the sliding part 12 moves away from the fixed part 11 to release the blade 200.

[0070] The beneficial effects of adopting the above embodiment are as follows: By setting a shape memory spring, heating the spring realizes the movement of the sliding part. When the moving distance is greater than the size of the clamped part of the blade, the blade flies off. When the shape memory spring is in the heated state, the deformation process is rapid, and the fly-off triggering time is short, enabling precise release at the target rotational speed. Moreover, during the heating process, by slowing down the deformation process, it can be observed that the size of the shape memory spring changes gradually, the blade moves outward gradually, and after the blade flies off, it can better maintain the flying attitude of the blade, and can simulate the situation of the blade flying off and rubbing against the casing under the working environment of a real engine, making the test results more accurate. At the same time, this process has high safety, does not generate factors such as dust and strong light that affect high-speed photography, and can better observe the test results. There is no limit to the material of the flying-off blade, and the applicable range is wide.

[0071] In one embodiment, as Figure 5 shown, before assembly, the following treatment is performed on the shape memory spring 21: At high temperature, the length of the shape memory spring 21 is La, and it is cooled to room temperature while maintaining this state. The shape memory spring 21 is stretched to Lb, causing a certain amount of plastic deformation. In the states of length La and Lb, the shape memory spring 21 can both provide spring force. When the shape memory spring 21 is heated, the plastic deformation in the Lb state will be eliminated, and the shape memory spring 21 can be shortened to the length La.

[0072] Refer to Figures 2A to 2CAs shown, in one embodiment, the specific structure of the trigger assembly 20 may further include a bolt 23. The bolt 23 includes a cylindrical section 231, and one side of the shape memory spring 21 is fixedly sleeved on the cylindrical section. An installation hole 24 is formed inside the bolt 23, and the heating element 22 is embedded in the installation hole 24. A heating groove 232 is formed in the cylindrical section 231, and the heating groove 232 communicates with the installation hole 24 so that the heat of the heating element 22 is transferred to the shape memory spring 21. Specifically, the shape memory spring 21 with a length of Lb is sleeved on the cylindrical section 231 of the bolt 23, and one side of the shape memory spring 21 is connected and fixed to the cylindrical section 231 by spot welding, and the heating element 21 is installed in the installation hole 24. Such a structure is simple, convenient for assembly, and can ensure the effective heating of the shape memory spring by the heating element.

[0073] Continue to refer to Figures 2A to 2C As shown, in one embodiment, the specific structure of the trigger assembly 20 may also be that the installation hole 24 is a stepped hole, including a first hole 241, a second hole 242, and a third hole 243. The second hole 242 is a threaded hole, and the first hole 241, the second hole 242, and the third hole 243 are connected in sequence, and their diameters decrease in sequence. The heating element 22 includes a holding section 221, an installation section 222, and a heating section 223. The holding section 221 is located in the first hole 241. The meaning of the "holding section 221" refers to the position where the hand of a tool or a technician contacts the heating element 22 and applies force to install the heating element 22 into the installation hole 24. In one embodiment, as Figure 2B shown, the first hole 241 is an internal hexagonal hole, the holding section 221 is a hexagonal head, and the size of the hexagonal head is smaller than that of the internal hexagonal hole, and there is a gap between the two, which is convenient for a screwdriver to operate and screw the heating element 22 into the installation hole 24 through the hexagonal head. The installation section 222 is provided with a threaded structure to cooperate with the second hole 242 to fix the heating element 22 in the installation hole 24. The heating section 223 is located in the third hole 243, and the heating groove 232 communicates with the third hole 243. Such a structure is simple, convenient for assembly, cleverly combines the heating element and the shape memory spring into an integral component, and can ensure the effective heating of the shape memory spring.

[0074] Refer to Figures 2A to 3 As shown, in one embodiment, the specific structure of the blade release device 100 may further include a support 30. The support 30 includes a threaded hole 31, and the bolt 23 includes a threaded section 233. The threaded hole 31 cooperates with the threaded section 233 to fix the trigger assembly 20 to the support 30. In this way, the fixation of the trigger assembly is realized, and the structure is simple and easy to disassemble and assemble. In one embodiment, as Figure 4A 、 Figure 4B Combined with Figure 6As shown, the support 30 includes a plurality of threaded holes 31, the blade release device 100 includes a plurality of trigger components 20, the sliding part 12 includes a plurality of pressing holes 121, the threaded sections 233 of the bolts 23 of the plurality of trigger components 20 are respectively and correspondingly fixed to the plurality of threaded holes 31, and the shape memory springs 21 of the plurality of trigger components 20 enable the sliding part 12 to have sufficient pressing force to press tightly against the fixed part 11 through the pressing holes 121.

[0075] Reference Figures 1A to 4B As shown, in one embodiment, the specific structure of the trigger component 20 may be that the support 30 and the fixed part 11 are respectively located on the circumferential two sides of the sliding part 12. The sliding part 12 includes a first concave part 122 and a second concave part 123, and the first concave part 122 is located radially outside the second concave part 123; the support 30 includes a first convex part 32, the first convex part 32 is located radially outside the threaded hole 31, and the first convex part 32 cooperates with the first concave part 122; the fixed part 11 includes a second convex part 111, and the second convex part 111 cooperates with the second concave part 123; the radially outer wall surface of the second convex part 111 constitutes the radial bottom wall surface of the clamping space 13. Such a setting can ensure that in the test during the speed increase state, the sliding part 12 is subjected to the thrust of the shape memory spring 21, and the first convex part and the first concave part, and the second convex part and the second concave part are in contact at the same time, so that the blade can be subjected to a more stable clamping force and fixed in the clamping space. At the same time, it can also play a certain guiding role when the sliding part moves away from the fixed part.

[0076] Reference Figure 1A 、 Figure 1B 、 Figure 4A 、 Figure 4B As shown, in one embodiment, the specific structure of the sliding part 12 may be that the radial wall surfaces of the first concave part 122 and the second concave part 123 are provided with a plurality of arc-shaped protrusions 124, so that the contact with the first convex part 32 and the second convex part 111 is point contact. Under the action of centrifugal force, the point contact can reduce the frictional resistance of the contact surface when the shape memory spring 21 contracts due to heat and the sliding part 12 slides away from the fixed part 11, enabling the blade release device 100 to respond more quickly and realizing the precise release of the blade at the target speed.

[0077] Reference Figure 6As shown, in one embodiment, the specific structure of the blade release device 100 may further include a turntable 40. The support 30, the fixing part 11 and the turntable 40 are integrally formed. The blade release device 100 further includes a rotating shaft 41 and a conductive slip ring 50. The turntable 40 rotates around the rotating shaft 41. The conductive slip ring 50 includes a moving ring 51 and a static ring 52. The moving ring 51 is sleeved on the rotating shaft 41, and the static ring 52 is sleeved on the moving ring 51. The trigger assembly 20 includes a heating wire 25. One side of the heating wire 25 is connected to the heating element 22, and the other side of the heating wire 25 is led out through the gap between the moving ring 51 and the static ring 52. The heating wire 25 is fixed on the surfaces of the turntable 40 and the rotating shaft 41 by means of glue or pressing to prevent the heating wire from breaking during rotation.

[0078] Reference Figures 1A to 6 As shown, in one embodiment, the specific structure of the blade release device 100 may include a first state 1001 and a second state 1002: In the first state 1001, the heating element 22 does not work, the length of the shape memory spring 21 is the first length, the sliding part 12 abuts against the fixing part 11, providing a clamping space 13 for generating a clamping force on the blade 200. In the second state 1002, the heating element 22 works, the length of the shape memory spring 21 is the second length, the sliding part 12 moves away from the fixing part 11, releasing the clamping space 13 to eliminate the clamping force. Among them, the second length is less than the first length.

[0079] Specifically, the trigger assembly 20, the sliding part 12 and the blade 200 are installed on the turntable 40, and the bolt 23 is tightened into the threaded hole 31 of the support 30. At this time, the shape memory spring 21 presses the sliding part 12 through the top hole 121. The sliding part 12 cooperates with the fixing part 11 under the action of the spring force to fix the blade 200 in the clamping space 13. In this state, the length Lg of the shape memory spring 21 is less than Lb and greater than La.

[0080] After assembly, start the motor to drive the rotating shaft 41 to drive the turntable 40 to gradually increase the speed. During the speed increase process, the sliding part 12 and the turntable 40 are fixed by the cooperation of the first convex part and the first concave part, and the cooperation of the second convex part and the second concave part. The sliding part 12 is subjected to the extrusion of the shape memory spring 21 to offset the circumferential force of the blade 5 on the sliding part 12 under the action of the centrifugal load, preventing the blade 200 from coming out. This state is the first state 1001.

[0081] After reaching the predetermined test speed, the heating wire 25 heats the heating element 22 through the conductive slip ring 50, and the heat is transferred to the shape memory spring 21 through heat conduction. After reaching a certain temperature (usually about 400 °C), the length of the shape memory spring 21 gradually shortens. At this time, it is impossible to maintain the continuous pressing of the sliding part 12, and the sliding part 12 gradually moves away from the fixed part 11. At the same time, the blade 200 moves radially outward, and this state is the second state 1002;

[0082] In one embodiment, as Figure 1A shown, the blade 200 includes a tenon 60. The clamping space 13 provided by the sliding part 12 and the fixed part 11 includes a mortise 61. The tenon 60 cooperates with the mortise 61 to fix the blade 200 by the clamping assembly 10. When the radial outer distance L1 between the sliding part 12 and the fixed part 11 is greater than the maximum width L0 of the tenon 50, the blade 200 flies off.

[0083] Refer to Figures 1A to 6 shown. In one embodiment, the engine test device 300 includes a casing 70, a blade 200, and the blade release device 100 as described above. The blade release device 100 is located radially inside the casing 300, and the blade 200 is clamped by the sliding part 12 and the fixed part 11 of the clamping assembly 10 of the blade release device 100. In one embodiment, the engine test device 300 further includes a fixed blade 400. On the radial opposite side of the clamping space 13, the turntable 40 is provided with a fixed mortise 80, and the fixed mortise 80 cooperates with the tenon 81 of the fixed blade to fixedly install the fixed blade 400. The beneficial effect of such a setting is that it can achieve the precise release of the blade at the target speed, has no limitation on the blade material, has a wide application range, and can clearly observe the test results, and the test safety is high.

[0084] Refer to Figure 7 shown. In one embodiment, the specific steps of the blade release method may include: the sliding clamping part and the fixed clamping part cooperate to provide a clamping space to fixedly clamp the blade; the shape memory spring presses the sliding clamping part against the fixed clamping part; the heating element heats the shape memory spring, the shape memory spring shrinks, and the sliding clamping part moves away from the fixed clamping part; the blade disengages from the clamping space. By using the method of this embodiment, the precise release of the flying-off blade can be achieved at the target speed, and the test results can be clearly observed.

[0085] Although the present invention is disclosed above with preferred embodiments, it is not used to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A blade release device, characterized in that, it comprises: a clamping assembly including a fixed part and a sliding part, the fixed part and the sliding part providing a clamping space on the inner circumferential side for clamping the blade; a triggering assembly including a shape memory spring and a heating element, one side of the shape memory spring is connected to the heating element, and the other side abuts against the sliding part, pressing the sliding part against the fixed part; wherein, when the heating element works, the size of the shape memory spring changes, driving the sliding part away from the fixed part to release the blade.

2. The blade release device according to claim 1, characterized in that, the blade release device includes a first state and a second state: In the first state, the heating element does not work, the length of the shape memory spring is a first length, the sliding part abuts against the fixed part, providing the clamping space for generating a clamping force on the blade; In the second state, the heating element works, the length of the shape memory spring is a second length, the sliding part moves away from the fixed part, releasing the clamping space to eliminate the clamping force; wherein, the second length is less than the first length.

3. The blade release device according to claim 1, characterized in that, the triggering assembly further includes a bolt, the bolt includes a cylindrical section, one side of the shape memory spring is fixedly sleeved on the cylindrical section; an installation hole is opened inside the bolt, the heating element is embedded in the installation hole; a heating groove is opened on the cylindrical section, and the heating groove communicates with the installation hole so that the heat of the heating element is transmitted to the shape memory spring.

4. The blade release device according to claim 3, characterized in that, the installation hole is a stepped hole, including a first hole, a second hole and a third hole, the second hole is a threaded hole, the first hole, the second hole and the third hole are connected in sequence, and their diameters decrease in sequence; the heating element includes a holding section, an installation section and a heating section, the holding section is located in the first hole, the installation section is provided with a threaded structure to cooperate with the second hole to fix the heating element in the installation hole, the heating section is located in the third hole, and the heating groove communicates with the third hole.

5. The blade release device according to claim 3, characterized in that, the blade release device further includes a support, the support includes a threaded hole, the bolt includes a threaded section, and the threaded hole cooperates with the threaded section to fix the triggering assembly to the support.

6. The blade release device according to claim 5, characterized in that, the support and the fixed part are respectively located on the circumferential two sides of the sliding part; the sliding part includes a first concave part and a second concave part, the first concave part is located radially outside the second concave part; the support includes a first convex part, the first convex part is located radially outside the threaded hole, and the first convex part cooperates with the first concave part; the fixed part includes a second convex part, and the second convex part cooperates with the second concave part; the radially outer wall surface of the second convex part constitutes the radially bottom wall surface of the clamping space.

7. The blade release device according to claim 6, characterized in that, The radial wall surfaces of the first concave portion and the second concave portion are provided with a plurality of arc-shaped protrusions, so that the contacts with the first convex portion and the second convex portion are point contacts.

8. The blade release device according to claim 5, wherein, the blade release device further includes a turntable, and the support, the fixing portion and the turntable are integrally formed.

9. An engine test device, wherein, it includes a casing, a blade and the blade release device according to any one of claims 1-8. The blade release device is located radially inside the casing, and the blade is clamped by the sliding portion and the fixing portion of the clamping assembly of the blade release device.

10. The engine test device according to claim 9, wherein, the blade includes a tenon head, and the clamping space provided by the sliding portion and the fixing portion includes a tenon groove. The tenon head is engaged with the tenon groove to fix the blade by the clamping assembly.

11. A blade release method, wherein, it includes: The sliding clamping portion and the fixed clamping portion cooperate to provide a clamping space to fixedly clamp the blade; The shape memory spring presses the sliding clamping portion against the fixed clamping portion; The heating element heats the shape memory spring, the shape memory spring contracts, and the sliding clamping portion moves away from the fixed clamping portion; The blade disengages from the clamping space.

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