Device and method for measuring axial force of casing gas

Abstract

The present invention provides a device for measuring the gas axial force of a casing, which is used to measure the gas axial force borne by a pair of butt-jointed casing mounting edges. In the measuring frame, the first end is used to connect with a casing mounting edge, and the bridging portion is configured to connect the first end and the second end across the casing mounting edge. In the measuring element, each follower arm is rotatably arranged at the second end through the bottom, and the head is used to abut against the other casing mounting edge, whereby, under the action of the gas axial force, the follower arm follows the pair of casing mounting edges and unfolds with each other, the connecting arm connects the waist of the follower arm, and provides a strain portion for generating tensile strain as the follower arms unfold with each other, and the measuring circuit includes a strain sensor arranged on the connecting arm. The present invention also provides a method for measuring the gas axial force of a casing. The above-mentioned measuring device can reliably measure the gas axial force of a casing.

Description

Technical Field

[0001] The invention relates to a measuring device and a measuring method for the casing gas axial force of an aeroengine or a gas turbine. Background Art

[0002] In order to ensure the stable and reliable operation of aircraft engines, it is necessary to measure and monitor the gas axial force on each casing mounting edge, and obtain accurate test data to improve the overall design capability of the engine. At present, the measurement of gas axial force in China is mainly converted into strain measurement at special positions through a certain structural form. For example, the measurement of axial force at the bearing position of an aircraft engine is generally completed by designing a specific force measuring ring auxiliary device. There is no mature and reliable method for measuring the axial force on the mounting edge of the aircraft engine casing in China, mainly because the measurement area is small, the vibration strain is large, the axial stiffness of the casing is large, and the operating temperature is high, making the measurement difficult and the error is large. The existing clamping measurement structure generally measures compressive strain, which is easily affected by the buckling effect, thereby affecting the reliability of the measurement.

[0003] Therefore, it is necessary to provide a measuring device that can reliably measure the axial force of casing gas. Summary of the invention

[0004] The object of the present invention is to provide a device for measuring the axial force of casing gas, which can reliably measure the axial force of casing gas.

[0005] The present invention provides a device for measuring the gas axial force of a casing, which is used to measure the gas axial force borne by a pair of casing mounting edges that are butted against each other. The measuring device comprises a measuring frame, a measuring element and a measuring circuit, wherein the measuring frame comprises a first end, a second end and a bridging portion, the first end is used to be connected to one of the pair of casing mounting edges, the bridging portion is configured to cross the pair of casing mounting edges to connect the first end and the second end, the measuring element comprises a pair of follower arms and a connecting arm, each follower arm comprises a bottom, a waist and a head, each follower arm is rotatably arranged at the second end of the measuring frame through the bottom, the head is used to abut against the other of the pair of casing mounting edges, whereby, under the action of the gas axial force, the pair of follower arms follow the pair of casing mounting edges and expand with each other, the connecting arm connects the waist of the pair of follower arms, and provides a strain portion, which is used to generate tensile strain as the pair of follower arms expand with each other, and the measuring circuit comprises a strain sensor arranged on the connecting arm.

[0006] In one embodiment, the casing assembly where the pair of casing mounting edges are located has a central axis and a radial direction; the measuring device has a symmetry plane passing through the central axis and extending in the radial direction, and the pair of follower arms are symmetrically arranged relative to the symmetry plane.

[0007] In one embodiment, the casing assembly where the pair of casing mounting edges are located has a radial direction; the first end of the measuring frame has a first convex wall protruding radially inward, and the first fastener penetrates the first convex wall and the pair of casing mounting edges.

[0008] In one embodiment, the connecting arm and the pair of follower arms are integrated.

[0009] In one embodiment, the connecting arm and the pair of follower arms are made of a plate material, and the strain portion is formed by a thinned area of ​​the plate material.

[0010] In one embodiment, the connecting arm includes two thick plate portions and a thin plate portion, wherein the two thick plate portions are respectively connected to the waists of the pair of follower arms, and the thin plate portion is thinned relative to the thick plate portion and is connected between the two thick plate portions.

[0011] In one embodiment, the bottoms of the pair of follower arms are detachably disposed at the second end portion.

[0012] In one embodiment, the casing assembly where the pair of casing mounting edges are located has a central axis; the rotation axes of the bottoms of the pair of follower arms are parallel to each other and perpendicular to the central axis.

[0013] In one embodiment, the second end of the measuring frame has a second convex wall protruding radially inward, and the second convex wall has a mounting flange extending axially toward the first end; a second fastener passes through the bottom of each follower arm and is fastened to the mounting flange, whereby the follower arm is rotatably mounted on the second end of the measuring frame, and the second fastener provides sufficient clamping force on the bottom of the follower arm to prevent the follower arm from sliding relative to the second fastener during the measurement process.

[0014] In one embodiment, a waist-shaped hole is provided at the bottom of each follower arm for the second fastener to pass through.

[0015] The present invention also provides a method for measuring the axial force of casing gas, which adopts the aforementioned measuring device, including: fixing the first end of the measuring frame of the measuring device on one side of the pair of casing mounting edges, so that the heads of a pair of follower arms of the measuring element of the measuring device are against the lower edge of the other side of the pair of casing mounting edges; adjusting the contact tightness between the heads of the pair of follower arms and the lower edge, so that when the casing mounting edge is subjected to the axial force of gas, the movement of the lower edge causes the pair of follower arms to unfold each other, thereby generating tensile strain in the strain portion of the connecting arm of the measuring element; and obtaining the temperature and strain of the connecting arm to obtain the stretching amount of the strain portion at this time, and reversely calculating the axial force of gas borne by the pair of casing mounting edges.

[0016] In one embodiment, the axial deformation Δd of the lower edge is first calculated according to formula (1):

[0017]

[0018] Wherein, Δs is the stretching amount of the strain portion, c is the straight length of the follower arm when subjected to the axial force of the gas, h is the straight distance between the bottom and the waist of the follower arm when subjected to the axial force of the gas, d1 is the axial length of the follower arm before subjected to the axial force of the gas, d2 is the axial length of the follower arm when subjected to the axial force of the gas, Δd=d2-d1;

[0019] Then, the gas axial force is inversely calculated according to the axial deformation Δd of the lower edge.

[0020] The above-mentioned measuring device for the axial force of the gas in the casing can convert the axial deformation of the mounting edge of the casing into the tensile deformation of the strain part of the connecting arm, which can directly avoid the adverse influence of the buckling effect, thereby improving the reliability of measuring the axial force of the gas in the casing. In addition, the bridge part of the measuring frame of the above-mentioned measuring device crosses the butted mounting edge of the casing, and the follower arm contacts the mounting edge of the casing, making full use of the limited measuring space, ensuring stable contact, reducing the influence of vibration, and improving the measuring accuracy.

[0021] The above-mentioned method for measuring the axial force of the casing gas adopts the above-mentioned measuring device, which is simple to calibrate and has a small error. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which:

[0023] Figure 1 is a perspective view showing an exemplary measuring device according to the present invention.

[0024] Figure 2 It is a cross-sectional view showing that the measuring device is installed on a pair of casing mounting edges.

[0025] Figure 3 is a cross-sectional view showing an exemplary measurement stand.

[0026] Figure 4 is a side view showing the measuring device installed on a pair of casing mounting edges.

[0027] Figure 5 is a perspective view showing an exemplary measurement assembly.

[0028] Figure 6 is a plan view showing an exemplary measurement assembly.

[0029] Figure 7 is a schematic diagram showing the arrangement of strain sensors.

[0030] Figure 8 is another schematic diagram showing the arrangement of strain sensors.

[0031] Fig. 9 It is a schematic diagram showing the change of the measuring component compared with the initial state when it is subjected to the axial force of the gas.

[0032] Fig.10 FIG. 4 is a flowchart exemplarily showing the operation of measuring the gas axial force using a measuring device. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with specific implementation methods and accompanying drawings. More details are elaborated in the following description to facilitate a full understanding of the present invention. However, the present invention can obviously be implemented in a variety of other ways different from this description. Those skilled in the art can make similar generalizations and deductions based on actual application situations without violating the connotation of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific implementation method.

[0034] For example, a first feature described later in the specification as being formed above or on a second feature may include an embodiment in which the first feature and the second feature are formed by direct connection, and may also include an embodiment in which an additional feature is formed between the first feature and the second feature, so that the first feature and the second feature may not be directly connected. Further, when a first element is described as being connected or combined with a second element, the description includes an embodiment in which the first element and the second element are directly connected or combined with each other, and also includes an embodiment in which one or more other intervening elements are added to indirectly connect or combine the first element and the second element.

[0035] Figure 1 The three-dimensional structure of the measuring device 10 for the axial force of the casing gas is shown as an example. Figure 2 As shown, the measuring device 10 can measure the gas axial force borne by a pair of butted casing mounting edges 91, 92. It should be understood that the drawings are only for illustration and are not drawn in proportion, and should not be used to limit the actual protection scope of the present invention.

[0036] The pair of casing mounting edges 91 , 92 measured by the measuring device 10 are included in a casing assembly 90 . The casing assembly 90 includes a pair of casings 901 , 902 butted against each other by the pair of casing mounting edges 91 , 92 . Figure 2 In the embodiment, the casing mounting edge 91 is on the casing 901 ( Figure 2 The end of the barrel of the left side of the casing ( Figure 2The flange edge protruding outwards at the right end of the middle, and the casing mounting edge 92 is on the casing 902 ( Figure 2 The end of the barrel of the right receiver ( Figure 2 The casing assembly 90 includes a flange edge or mounting edge protruding outwardly at the left end (in the middle), and a pair of casing mounting edges 91 and 92 can be fastened and docked by mounting bolts passing through the two when in use. The interior of the casing 901 or 902 is used to support or contain the fluid machinery. The casing assembly 90 where the pair of casing mounting edges 91 and 92 are located has a central axis (not shown). The casing assembly 90 also has a radial direction R0, a circumferential direction C0, and an axial direction X0 defined by the central axis. The direction indication is shown in some drawings for ease of description and understanding.

[0037] For ease of description, spatial relational terms such as "left", "right", etc. may be used herein to describe the relationship between an element or feature shown in the drawings and other elements or features. It should be understood that these spatial relational terms are intended to include other directions of elements or components in use or operation in addition to the directions depicted in the drawings. For example, if the components in the drawings are flipped, the direction of the element described as being "left" of other elements or features will be changed to "right" of the other elements or features, and therefore, the spatial relational descriptors used herein should be interpreted accordingly.

[0038] The measuring device 10 comprises a measuring frame 1 . Figure 3 The structure of the measuring frame 1 is shown as an example. The measuring frame 1 includes a first end 11, a second end 12 and a bridge portion 13. Figure 2 and Figure 4 The first end portion 11 can be connected to one of the pair of casing mounting edges 91 and 92 ( Figure 2 In the embodiment, the left side casing mounting edge 91 is connected, and the bridging portion 13 is configured to connect the first end portion 11 and the second end portion 12 across the pair of casing mounting edges 91 and 92.

[0039] The measuring device 10 further comprises a measuring element 2 . Figure 5 and Figure 6 An exemplary configuration of the measuring element 2 is shown by way of example. Figure 1 and Figure 2 The measuring element 2 includes a pair of follower arms 4 (which may be referred to as follower arms 4a and follower arms 4b when described separately) and a connecting arm 5. Each follower arm 4 includes a bottom 41, a waist 42 and a head 43. Each follower arm 4 is rotatably disposed on the second end 12 of the measuring frame 1 through the bottom 41, and the head 43 is used to abut against the other of the pair of casing mounting edges 91 and 92 ( Figure 2The connecting arm 5 is connected to the waist 42 of the pair of follower arms 4, that is, the connecting arm 5 is connected between the waist 42 of the follower arm 4a and the waist 42 of the follower arm 4b. In addition, the connecting arm 5 provides a strain portion 50 for generating tensile strain as the pair of follower arms 4 are spread apart from each other.

[0040] like Figure 7 and Figure 8 As shown, the measuring device 10 further comprises a measuring circuit 3 , which comprises strain sensors 31 , 32 , 33 , 34 arranged on the connecting arm 5 .

[0041] The above-mentioned measuring device 10 converts the axial deformation of the casing mounting edges 91, 92, especially the casing mounting edge 92, caused by the axial force of the gas into the sliding of the head 43 of the follower arm 4 in contact therewith. The lateral sliding of the head 43 causes each follower arm 4 to rotate through the bottom 41, and then a pair of follower arms 4 are unfolded from each other. At this time, the axial deformation of the casing mounting edge 92 is converted into the tensile deformation of the connecting arm 5 through the lateral sliding of the head 43. Compared with the compressive deformation, which is easy to become unstable, the tensile deformation can directly avoid the buckling effect, making the measurement process more stable. Moreover, in the above-mentioned measuring device 10, the bridge portion 13 of the measuring frame 1 spans the butted casing mounting edges 91, 92, has good stability, and the follower arm 4 is in contact with the casing mounting edge 92, making full use of the limited measuring space to facilitate sliding, while ensuring stable contact, reducing the influence of vibration, and improving the measurement accuracy.

[0042] In the above-mentioned measuring device 10, the measuring frame 1 and the measuring element 2 are designed to be separated, so that in actual measurement, the corresponding measuring element 2 can be designed according to the specific form of the casing mounting edges 91 and 92, thereby improving the versatility of the measurement.

[0043] In the illustrated embodiment, the first end portion 11 of the measuring frame 1 may have a first convex wall 110 protruding inwardly along the radial direction R0, and the first fastener 81 may penetrate the first convex wall 110 and the pair of casing mounting edges 91, 92. For example, the first convex wall 110 is provided with a bolt mounting hole 111, and the first fastener 81 may be a mounting bolt. The mounting bolt as the first fastener 81 may sequentially pass through the bolt mounting hole 111 of the first convex wall 110 and the docking bolt connection hole of the pair of casing mounting edges 91, 92 and then be fastened by a nut 810. When this connection method is adopted, the first fastener 81 may directly use the mounting bolts used for docking the casing mounting edges. If the original mounting bolts are not long enough, they may be replaced with lengthened mounting bolts of the same specification to adapt to the thickness of the first convex wall 110. The first fastener 81 not only connects the aforementioned pair of casing mounting edges 91 , 92 , but also connects the first end 11 of the measuring frame 1 to the casing mounting edge 91 , so that the measuring device 10 can be installed without changing the original structure of the casing assembly 90 or the casing mounting edge 91 .

[0044] See also Figure 1 and Figure 4 The first convex wall 110 may be provided with two bolt mounting holes 111 corresponding to the distribution of the butt bolt connection holes of the casing mounting edges 91 and 92, and the two mounting bolts of the first fastener 81 may respectively pass through the two bolt mounting holes 111 to connect the measuring frame 1 to the casing mounting edges 91 and 92. In this way, the measuring frame 1 may have better stability.

[0045] The number of casing mounting edges of aircraft engines is large and of various forms. In addition, there are a large number of attached structures such as pipelines or sensors around them, so that the remaining space is small. Therefore, the space available for arranging the measuring device is small, and the versatility of existing measuring devices is relatively weak. The measuring device 10 of the aforementioned structure is small and flexible. The first fastener 81 is used to connect the first end 11 of the measuring frame 1 and the casing mounting edges 91 and 92, which can also make the measuring device 10 more versatile and easy to assemble and disassemble. In addition, the structure of the engine is complex, and the aforementioned structure can also make the measuring device 10 avoid changing the original structure of the engine.

[0046] Generally, the positions available for measurement are mainly the mounting edge of the casing and the outer surface of the casing (barrel). Among them, the flange of the mounting edge of the casing is short and the mounting bolts are densely distributed, so the area available for measurement is very cramped. In addition, the axial stiffness of the casing is large and unevenly distributed in the circumferential direction. Therefore, the deformation of the outer surface of the casing caused by the axial force of the gas is small and irregular, and the ideal measurement area of ​​the outer surface of the casing is also quite limited. In other words, the effective area available for measurement is small. Fixing the measuring device 10 on the mounting edge 91 of the casing provides a suitable measurement position, which makes it easy to obtain accurate measurement data and is also simple to calibrate.

[0047] It is understood that specific words are used herein to describe the embodiments of the present invention, such as "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic associated with at least one embodiment of the present invention. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" mentioned twice or more in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present invention may be appropriately combined. In addition, the use of words such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above words have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0048] In the illustrated embodiment, the bottom 41 of the follower arm 4 is detachably disposed at the second end 12, for example, Figure 1 and Figure 5 As shown, the measuring device 10 is connected to the second end 12 of the measuring frame 1 by a second fastener 82 such as an axle bolt. This can facilitate the installation of the measuring device 10.

[0049] In the illustrated embodiment, the second end portion 12 of the measuring frame 1 may have a second convex wall 120 protruding inwardly along the radial direction R0, and the second convex wall 120 may have a mounting flange 121 extending along the axial direction X0 toward the first end portion 11. Figures 1 to 3 The second convex wall 120 has a certain thickness along the axial direction X0 and has a notch 122 opening toward the first end 11, and the lower groove wall of the notch 122 can constitute the mounting flange 121. The second fastener 82 can pass through the bottom 41 of each follower arm 4 and be fastened to the mounting flange 121, thereby, the follower arm 4 can be rotatably mounted on the second end 12 of the measuring frame 1, and the second fastener 82 can provide sufficient pressing force on the bottom 41 of the follower arm 4 to prevent the follower arm 4 from sliding relative to the second fastener 82 during the measurement process. Figures 1 to 3 as well as Figure 5The second fastener 82 may be, for example, an axle bolt, which may pass through the through hole of the bottom 41 of the follower arm 4 and be fastened to the threaded hole 123 of the mounting flange 121. The tightening degree of the axle bolt (as an example of the second fastener 82) in the threaded hole 123 may be adjusted to provide a pressing force to the bottom 41 of the follower arm 4, so that the follower arm 4 will follow the mounting edges 91, 92 of the casing without any unwanted sliding. The second fastener 82 such as an axle bolt used to connect the measuring element 2 and the measuring frame 1 may provide a pre-tightening effect for the measurement, avoid the measurement error caused by the initial gap, and make the overall measuring device 10 more stable. In another embodiment, the follower arm 4 may be integrally provided with a mounting rod having a threaded section for fastening, so that the mounting rod may pass through the through hole of the mounting flange 121, and then the threaded section of the mounting rod may be fastened by a nut, thereby making the follower arm 4 rotatably arranged at the second end 12.

[0050] In the illustrated embodiment, the perforation of the bottom 41 of the follower arm 4 may be a waist-shaped hole 411, that is, the bottom 41 of the follower arm 4 may be provided with a waist-shaped hole 411 for the second fastener 82 to pass through. In this way, the position of the bottom 41 of the follower arm 4 at the second end 12 is adjustable, so the extension length of the follower arm 4 is adjustable, so that it is convenient to adjust during installation so that the head 43 of the follower arm 4 abuts against the casing mounting edges 91 and 92, and can also adapt to various casing mounting edges of the engine, which can better enhance the applicability. In other words, the bottom 41 of the follower arm 4 adopts a waist hole design, and the spacing between the follower arm 4 and the casing mounting edge 92 can be adjusted to adapt to casing mounting edges 91 and 92 of different thicknesses. It can be understood that the contact pre-tightening of the head 43 of the follower arm 4 and the lower edge of the casing mounting edge 92 can be achieved synchronously with the fastening of the first end 11 of the measuring frame 1 to the casing mounting edge 91 through a pre-design. However, in comparison, the contact preload force is adjusted by adjusting the extension length of the follower arm 4 through the second fastener 82, and the structure and operation are simpler.

[0051] In the illustrated embodiment, the measuring device 10 may have a symmetry plane, which passes through the central axis of the aforementioned casing assembly 90 and extends along the radial direction R0, that is, a meridian plane of the casing assembly 90 that includes both the radial direction R0 and the axial direction X0, that is, Figure 2 The pair of follower arms 4 can be symmetrically arranged relative to the symmetry plane. In this way, the lateral sliding of the two follower arms 4 during the measurement process can be substantially the same, which is conducive to converting the accurate value of the gas axial force. In the illustrated embodiment, the rotation axes of the bottoms 41 of the pair of follower arms 4 are parallel to each other and perpendicular to the central axis of the casing assembly 90. Figure 2 In the embodiment, the rotation axes of the bottoms 41 of the two follower arms 4 extend vertically. In this way, it is easier to convert the gas axial force.

[0052] In the illustrated embodiment, the connecting arm 5 and the pair of follower arms 4 may be integrated. Preferably, the connecting arm 5 and the pair of follower arms 4 may be made of a plate, and the strain portion 50 may be formed by the thinned area of ​​the plate. In this case, the connecting arm 5 and the pair of follower arms 4 may constitute a measuring sheet as a whole, and the head 43 of the follower arm 4 may be flat. In the illustrated embodiment, the head 43 of the follower arm 4 may be in a semi-cylindrical form, that is, the measuring element 2 may adopt a double-head cylindrical design. In this way, the head 43 of the follower arm 4 may form a line contact with the mounting edges 91 and 92 of the casing, which may facilitate sliding, while ensuring stable contact and reducing the influence of vibration. The thickness of the rest of the connecting arm 5 and the follower arm 4 may be much greater than the thickness of the strain portion 50. Similarly, the thickness of the measuring frame 1 may also be much greater than the thickness of the strain portion 50. In this way, the rest of the connecting arm 5, the follower arm 4, and the measuring frame 1 may be set as a rigid body relative to the strain portion 50. The advantage of this arrangement is that, since the rigidity of the remaining parts of the measuring element except the strain portion 50 and the measuring frame 1 is large enough and rigidly fixed to the casing mounting edge 91, it can be considered that the strain of the strain portion 50 basically reflects the axial strain of the casing mounting edge 92, thereby accurately measuring the axial force of the gas through a simple structure. It can be understood that in another embodiment, the connecting arm 5 and the aforementioned pair of follower arms 4 can also be separately arranged and then connected together through a connection means such as high-strength bonding.

[0053] In the illustrated embodiment, the connecting arm 5 may include two thick plate portions 51 (which may be referred to as thick plate portion 51a and thick plate portion 51b when described separately) and a thin plate portion 52. The two thick plate portions 51 are respectively connected to the waist portions 42 of the pair of follower arms 4, such as Figure 6 The thin plate portion 52 is thinner than the thick plate portion 51 and is connected between two sections of the thick plate portion 51. Preferably, the thickness of the thin plate portion 52 can be less than 1 / 3 of the thickness of the thick plate portion 51, so that the stiffness of the thick plate portion 51 relative to the thin plate portion 52 can be ensured to be sufficiently large.

[0054] Figure 7 An exemplary distribution of strain sensors 31, 32, 33, 34 in the measuring circuit 3 is shown from the side of the axial direction X0, and Figure 8 This exemplary distribution is shown from the radial outside. Figure 7 and Figure 8In the illustrated embodiment, strain sensors 31 and 32 are arranged on both sides (in the figure, radially outward and radially inward) of the thin plate portion 52 (as an example of the strain portion 50) of the connecting arm 5, and strain sensors 33 and 34 are arranged on both sides (in the figure, radially outward and radially inward) of the thick plate portion 51 of the connecting arm 5, and the four strain sensors 31, 32, 33, and 34 form a full-bridge circuit. For example, by attaching four strain gauges to the corresponding areas of the connecting arm 5, a full bridge can be formed very conveniently, and the full-bridge form enables the measuring device 10 to have the function of temperature self-compensation. It can be understood that the measuring circuit 3 can also replace other circuit structures.

[0055] The operating temperature of aircraft engine casings is generally high. On the one hand, the strain caused by temperature is large, which greatly exceeds the strain caused by the axial force of the gas. Taking the connection and installation edge of the combustion chamber casing and the high-pressure turbine as an example, the regional temperature exceeds 600°C, causing 8000 to 9800 microstrains. On the other hand, the measurement error of the sensor will also be amplified at high temperatures. For example, at 600°C, the thermal output error of the high-temperature strain gauge is 20 to 100 microstrains, and the measurement error of the temperature sensor thermocouple is 0.25% to 1%. In a preferred embodiment, the measuring frame 1 and the measuring element 2 of the measuring device 10 can use the same material and / or process as the casing assembly 90, which can ensure that when the temperature of the casing assembly 90 changes, the entire measuring device 10 and the casing assembly 90 expand or contract evenly, reducing the impact of thermal strain.

[0056] Aircraft engine casings are subject to a variety of excitation loads during operation, such as rotor imbalance, incomplete combustion, etc. The dynamic strains caused by these excitations affect the measurement of gas axial force, and the causes of dynamic strain triggering are complex and irregular.

[0057] The deformation or strain of the casing mounting edge caused by the axial force of the gas is generally small. The existing clamping measurement structure generally measures compressive strain, which requires detailed simulation calculation and design to avoid buckling. In addition, the compressive measurement position is often short and thick, which is not conducive to the selection and arrangement of strain sensors, affecting their range and accuracy.

[0058] The measuring device is compact and simple in structure, easy to load and unload, easy to calibrate, and has high measurement accuracy. The measuring device converts the measurement method of the clamping structure from compressive strain to tensile strain through ingenious design, which can directly avoid the adverse effects of the buckling effect. Moreover, the measuring device can quantitatively amplify the initial strain to improve the measurement accuracy. In addition, the measuring device can reduce the influence of temperature and vibration, and can be applied to the casing installation edge with high working temperature and complex vibration environment. At the same time, the adjustable distance and detachable measuring element make the measuring device have strong versatility, and can be used for the measurement of the casing installation edge at different positions of the engine.

[0059] Fig. 9The deformation coordination diagram of the measuring element 2 subjected to the gas axial force when measuring with the illustrated measuring device 10 is shown as an example, wherein the dotted line represents the schematic geometric configuration of the measuring element 2 before being subjected to the gas axial force, and the solid line represents the schematic geometric configuration of the measuring element 2 when subjected to the gas axial force. It can be understood that Fig. 9 The model of each component is simplified. The follower arm 4 and the connecting arm 5 are simplified to a straight line respectively. The bottom 41, waist 42 and head 43 of the follower arm 4 are simplified to a point respectively. The bottom 41 can be considered as the rotation center of the follower arm 4, the waist 42 can be considered as the connection position between the follower arm 4 and the connecting arm 5, and the head 43 can be considered as the contact position of the follower arm 4 contacting the casing mounting edge 92. When the casing assembly 90 (or, the casing mounting edges 91, 92) is subjected to the axial force of the gas, the measuring device 10 can convert the axial deformation of the casing mounting edge 92 into the sliding of the head 43 of the follower arm 4 of the measuring element 2. The bottom 41 of the follower arm 4 can, for example, rotate around the second fastener 82, and then convert it into the tensile deformation of the strain portion 50 of the connecting arm 5 at the waist 42 of the follower arm 4. Since the stiffness of the measuring frame 1 and other parts of the measuring element 2 is large enough and is consistent with Figure 2 The casing mounting edge 91 on the left side is rigidly fixed, so it can be considered that the deformation Δs of the strain portion 50 can directly reflect the Figure 2 The axial deformation Δd of the casing mounting edge 92 on the right side.

[0060] See also Fig. 9 , we can get the following relationship:

[0061] Δs=s2-s1

[0062] Δd=d2-d1

[0063]

[0064] Among them, Δs is the stretching amount of the strain portion 50 (or, the connecting arm), s2 is the length of the connecting arm 5 when subjected to the axial force of the gas, and s1 is the length of the connecting arm 5 before subjected to the axial force of the gas (or, called the initial length); Δb is the change in the distance between the heads 43 of a pair of follower arms 4, b2 is the distance between the heads 43 of a pair of follower arms 4 when subjected to the axial force of the gas, and b1 is the distance between the heads 43 of a pair of follower arms 4 before subjected to the axial force of the gas (or, called the initial distance); c is the straight-line length of the follower arm 4 when subjected to the axial force of the gas, h is the straight-line distance between the bottom 41 and the waist 42 of the follower arm 4 when subjected to the axial force of the gas, d1 is the axial length of the follower arm 4 before subjected to the axial force of the gas, and d2 is the axial length of the follower arm 4 when subjected to the axial force of the gas, and Δd=d2-d1.

[0065] According to the above relationship, the inventors obtained formula (1):

[0066]

[0067] Therefore, the axial deformation Δd of the casing mounting edge 92 can be calculated according to the deformation Δs of the strain portion 50. The axial deformation Δd can reflect the magnitude of the axial force of the gas.

[0068] It can also be understood that although the above formula (1) is calculated on the basis that the entire measuring device 10 is symmetrical, when measuring the qualitative change trend of the gas axial force, the formula (1) can still be used to reversely calculate the magnitude of the gas axial force.

[0069] As mentioned earlier, Fig. 9 The model of each component is simplified in the figure. Taking the follower arm 4 as an example, the straight length of the follower arm 4 refers to the distance between its bottom 41 and its head 43.

[0070] The present invention also provides a method for measuring the axial force of casing gas. The measuring method can be used Figures 1 to 8 The measuring device 10 shown. The measuring method may include the following steps:

[0071] Step S1: On one side of a pair of casing mounting edges 91, 92 ( Figure 2 The first end 11 of the measuring frame 1 of the measuring device 10 is fixed so that the head 43 of the pair of follower arms 4 of the measuring element 2 is on the other side ( Figure 2 middle, right side) against the other side ( Figure 2 In the middle, the lower edge of the casing mounting edge 92).

[0072] The lower edge of the casing mounting edge 92 is also the portion of the outer surface of the casing 902 where the casing is located. The strain is the largest here and is easy to measure.

[0073] Step S2: Adjust the contact tightness between the head 43 of the pair of follower arms 4 and the lower edge, so that when the casing mounting edge 92 is subjected to the axial force of the gas, the movement of the lower edge causes the pair of follower arms 4 to spread out from each other, thereby generating tensile strain in the strain portion 50 of the connecting arm 5 of the measuring element 2.

[0074] For example, the installation position of the bottom 41 of the follower arm 4 is adjusted through the waist-shaped hole 411, thereby adjusting the contact tightness between the head 43 of the follower arm 4 and the lower edge. In one embodiment, certain lubrication measures can be taken to facilitate the sliding of the head 43 of the follower arm 4.

[0075] Step S3: by acquiring the temperature and strain of the connecting arm 5 , the stretching amount Δs of the strain portion 50 at this time is obtained, and the gas axial force borne by the pair of casing mounting edges 91 , 92 is inversely calculated.

[0076] In step S3, the axial deformation Δd of the lower edge may be calculated according to equation (1) first; and then the axial force of the gas may be inversely calculated according to the axial deformation Δd of the lower edge.

[0077] Fig.10 The exemplary steps of the method for measuring the axial force of casing gas are shown as examples. The first fastener 81 is a mounting bolt, and the second fastener 82 is an axis bolt. Fig.10 The process shown in generally includes the following steps:

[0078] (1) Estimate the approximate strain range, and then determine the size of the connecting arm 5 of the measuring element 2 (for example, in the form of a measuring sheet) based on the available measurement area of ​​the casing mounting edge and the specifications of the strain sensor, and then determine the remaining dimensions of the measuring element 2 and the size of the second fastener 82 (for example, in the form of an axle bolt). Design the measuring frame 1 based on the characteristics of the measuring element 2, the casing mounting edges 91, 92 and the second fastener 82. To ensure the accuracy of strain measurement, the main structure of the measuring frame 1 and the measuring element 2 (including the follower arm 4 and the connecting arm 5 except the strain portion 50) must be designed to ensure sufficient rigidity. Preferably, a simulation algorithm is used to perform the above structural optimization design, such as Fig.10 shown.

[0079] (2) The measuring frame 1 is mounted on one side through the first fastener 81. Figure 2 The measuring frame 1 is mounted on the casing mounting edge 91 on the left side (in the middle), and is tightened according to the designed torque to ensure that the connection stiffness between the measuring frame 1 and the casing assembly 90 is large enough.

[0080] (3) Place the measuring element 2 on the measuring frame 1 and insert the second fastener 82. Figure 2 According to the distribution of the mounting bolts of the casing mounting edge 92 on the right side (in the middle), the appropriate distance is adjusted so that the head 43 of the follower arm 4 of the measuring element 2 is fully fitted with the lower edge of the outer surface of the casing mounting edge 92 on the right side.

[0081] (4) By adjusting the second fastener 82, a certain preload force is applied to the measuring element 2 to avoid the measurement error caused by the initial gap, so as to stabilize the entire measuring device 10 and ensure that the preload forces of the second fasteners 82 corresponding to the two follower arms 4 are consistent as much as possible.

[0082] (5) When the casing assembly 90 is subjected to the axial force of the gas, the measuring device 10 converts the deformation of the lower edge of the casing mounting edge into the sliding of the head 43 of the follower arm 4 of the measuring element 2 through line contact, and the bottom 41 of the follower arm 4 rotates around the second fastener 82, which is then converted into the tensile deformation of the thinned area (i.e., the strain portion 50) of the connecting arm 5 of the measuring element 2. Since the rigidity of the measuring frame 1 and the measuring element 2 is large enough and they are rigidly fixed to the casing mounting edge 91 on the left side, it can be considered that the deformation amount Δs of the strain portion 50 directly reflects the deformation amount Δd of the lower edge of the casing mounting edge 92 on the right side.

[0083] The deformation can be amplified to meet the measurement accuracy requirements through appropriate geometric design, for example, by adjusting the position of the waist 42 of the follower arm 4 of the measuring element 2 and the size of the thinned area constituting the strain portion 50 .

[0084] (6) Paste four strain gauges at the marked position of measuring element 2 to form a full bridge to achieve the effect of temperature self-compensation, such as Figure 7 and Figure 8 shown.

[0085] (7) After calibrating the measuring device 10, the relationship between the temperature T, the strain ε, and the gas axial force F is obtained, that is, a fitting formula or a graph of F=f(ε,T) is obtained through calibration. The calibrated measuring device 10 can be used to measure the casing gas axial force of the aircraft engine.

[0086] In one embodiment, during actual calibration or measurement, multiple groups of measuring devices 10 may be evenly arranged on the casing mounting edges 91 and 92 along the circumferential direction C0, and the arithmetic mean of their strains may be used for calculation. This may improve the reliability of the measuring device 10, obtain more stable results, and reduce the influence of random factors such as structural vibration.

[0087] In general, the measuring device is small, simple and easy to process, and does not require changing the original structure of the measured casing. The measuring device is easy to install and disassemble, and does not require additional procedures. Moreover, the measuring device and method allow the measuring area to be set on the mounting edge of the casing, which is easy to calibrate.

[0088] The measuring frame of the measuring device spans the mounting edge of the butted casing and several bolts for butting, and has good stability. The measuring element adopts a double-head cylindrical design to make line contact with the mounting edge of the casing, which can maximize the use of limited measuring space to facilitate sliding, while ensuring stable contact and reducing the impact of vibration.

[0089] The above-mentioned measuring device converts the deformation of the lower edge of the casing mounting edge caused by the axial force of the gas into the sliding of the head of the follower arm through line contact, and then converts it into the tensile deformation of the waist connecting arm, which can directly avoid the buckling effect. In a preferred embodiment, the waist position of the connecting arm and the size of the connecting arm can be adjusted through reasonable geometric design, and the deformation of the lower edge of the casing mounting edge can be reflected in the deformation of the connecting arm in an amplified form, thereby meeting the measurement accuracy requirements.

[0090] Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may 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 according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A device for measuring the gas axial force of a casing, used to measure the gas axial force borne by a pair of butt-jointed casing mounting edges, characterized in that: include: The measuring frame comprises a first end, a second end and a bridge portion, wherein the first end is used to be connected to the pair of casing mounting edges, and the bridge portion is configured to connect the first end and the second end across the pair of casing mounting edges; Measuring elements, including: A pair of follower arms, each follower arm comprising a bottom, a waist and a head, each follower arm is rotatably arranged at the second end of the measuring frame through the bottom, and the head is used to abut against a side of the pair of casing mounting edges opposite to the first end, whereby, under the action of the gas axial force, the pair of follower arms follow the pair of casing mounting edges and spread out from each other; and a connecting arm connecting waist portions of the pair of follower arms and providing a strain portion for generating a tensile strain as the pair of follower arms are extended from each other; and The measuring circuit comprises a strain sensor arranged on the strain portion of the connecting arm.

2. The measuring device according to claim 1, characterized in that The casing assembly where the pair of casing mounting edges are located has a central axis and a radial direction; The measuring device has a symmetry plane passing through the central axis and extending in the radial direction, and the pair of follower arms are symmetrically arranged relative to the symmetry plane.

3. The measuring device according to claim 1, characterized in that The casing assembly where the pair of casing mounting edges are located has a radial direction; The first end of the measuring frame has a first convex wall protruding radially inward, and the first fastener penetrates the first convex wall and the pair of casing mounting edges.

4. The measuring device according to claim 1, characterized in that The connecting arm and the pair of follower arms are integrated.

5. The measuring device according to claim 4, characterized in that The connecting arm and the pair of follower arms are made of a plate, and the strain portion is formed by a thinned area of ​​the plate.

6. The measuring device according to claim 1, characterized in that The connecting arm comprises: Two thick plate portions, respectively connected to the waists of the pair of follower arms; and The thin plate portion is thinner than the thick plate portion and is connected between two sections of the thick plate portion.

7. The measuring device according to claim 1, characterized in that The bottoms of the pair of follower arms are detachably disposed at the second end portion.

8. The measuring device according to claim 2, characterized in that The casing assembly where the pair of casing mounting edges are located has a central axis; The rotation axes of the bottoms of the pair of follower arms are parallel to each other and perpendicular to the central axis.

9. The measuring device according to claim 2, characterized in that The second end of the measuring frame has a second convex wall protruding radially inward, and the second convex wall has a mounting flange extending axially toward the first end; The second fastener passes through the bottom of each follower arm and is fastened to the mounting flange, whereby the follower arm is rotatably mounted on the second end of the measuring frame, and the second fastener provides sufficient clamping force on the bottom of the follower arm to prevent the follower arm from sliding relative to the second fastener during the measurement process.

10. The measuring device according to claim 9, characterized in that A waist-shaped hole is arranged at the bottom of each follower arm for the second fastener to pass through.

11. A method for measuring the axial force of casing gas, using the measuring device as claimed in any one of claims 1 to 10, characterized in that: include: Fixing the first end of the measuring frame of the measuring device on one side of the pair of casing mounting edges, so that the heads of a pair of follower arms of the measuring element of the measuring device abut against the lower edge of the other side of the pair of casing mounting edges; Adjusting the contact tightness between the head of the pair of follower arms and the lower edge, so that when the mounting edge of the casing is subjected to the axial force of the gas, the movement of the lower edge causes the pair of follower arms to spread apart from each other, thereby generating tensile strain in the strain portion of the connecting arm of the measuring element; By acquiring the temperature and strain of the connecting arm, the stretching amount of the strain portion at this time is obtained, and the gas axial force borne by the pair of casing mounting edges is reversely calculated.

12. The measuring method according to claim 11, characterized in that: First, the axial deformation Δd of the lower edge is calculated according to formula (1): Wherein, Δs is the stretching amount of the strain portion, c is the straight length of the follower arm when subjected to the axial force of the gas, h is the straight distance between the bottom and the waist of the follower arm when subjected to the axial force of the gas, d1 is the axial length of the follower arm before subjected to the axial force of the gas, d2 is the axial length of the follower arm when subjected to the axial force of the gas, Δd=d2-d1; Then, the gas axial force is inversely calculated according to the axial deformation Δd of the lower edge.

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