Dynamic measurement system and method for ablative interface of thermal insulation layer of solid rocket engine

Abstract

According to the dynamic measurement system and method for the ablation interface of the heat insulation layer of the solid rocket engine, the position of the ablation surface is obtained by measuring the resistance of two resistance wires which are provided with insulation skins and are embedded in the heat insulation layer side by side, and conversion is carried out. When the resistance wires are fused due to ablation, the fused resistance wire metal is communicated with the two resistance wires side by side on the same side of the ablation surface, so that two loops are generated in circuits on the two sides of the ablation position, and a resistance value is obtained for the first time. The resistance and the length of the resistance wire are in a linear relationship, and the accurate ablation position can be deduced according to the continuous decrease of the resistance in the ablation process. Double rows of resistance wires are embedded in an engine heat insulation layer in an orthogonal latticed layered mode, and multiple layers of resistance wire grids are evenly arranged on the heat insulation layer in the thickness direction. In the thermal insulation layer ablation process, the local part of the resistance wire grid is fused due to ablation, a two-dimensional-three-dimensional thermal insulation layer ablation result is obtained from an acquired resistance database by using a resistance-ablation surface reconstruction method, the dynamic ablation process of the thermal insulation layer can be further reconstructed, and test measurement is completed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aerospace thermal protection ablation test, and particularly relates to a solid rocket engine insulation layer ablation interface dynamic measurement system and method based on mesh resistance wire ablation monitoring, which is used for testing the dynamic ablation process of the insulation layer of a solid rocket engine during operation, feeding back the real-time ablation degree of the overall insulation structure, and effectively monitoring the asymmetric local ablation process of the insulation layer under overload conditions. BACKGROUND

[0002] During the operation of a solid rocket engine, the insulation layer is used to isolate the internal high-temperature and high-pressure gas environment, preventing the gas from damaging the engine metal / non-metal shell and causing flight failure problems such as shell failure and burn-through. The insulation layer is in a harsh environment of high temperature (3500K), high pressure (up to 10MPa), and multi-phase gas (aluminum particle liquid phase, solid phase) ablation and erosion during engine operation. The gas will have chemical ablation and mechanical erosion effects on the insulation layer, causing it to gradually thin. Global dynamic ablation monitoring technology of the insulation layer is a key technology that affects the accurate assessment of the safety of the thermal structure of the engine.

[0003] The traditional insulation layer ablation measurement method is to disassemble the engine after the engine test, measure the remaining thickness of the insulation layer at key positions, and then deduce the ablation thickness. This method does not have real-time testing capability and cannot establish a real-time and complete evaluation system for the dynamic ablation process of the insulation layer. The limitations of the post-measurement method restrict the development of fine forward design of the insulation layer. The dynamic ablation measurement method based on local points can only accurately measure the ablation process at a single position, but it is difficult to measure the global dynamic ablation of the insulation layer. Accurate measurement of the global dynamic ablation process of the insulation layer, especially under normal operation and overload conditions, is of great engineering significance and practical value for obtaining the dynamic ablation rate of the insulation layer, optimizing the insulation design scheme, and selecting reliable insulation materials. SUMMARY

[0004] (I) Technical problem to be solved

[0005] The present application proposes a solid rocket engine insulation layer ablation interface dynamic measurement system and method to solve the technical problem of how to accurately obtain the global dynamic ablation interface process of the engine insulation layer, improve the limitations and non-real-time nature of post-ablation measurement, and break through the technical problem of being unable to measure asymmetric ablation under engine overload conditions.

[0006] (II) Technical solution

[0007] In order to solve the above technical problems, the application provides a solid rocket engine heat insulation layer ablation interface dynamic measurement system, which comprises an orthogonal grid layered pre-embedded double-row resistance wire and a wire.

[0008] Further, the orthogonal grid layered pre-embedded double-row resistance wire comprises a circumferentially arranged double-row resistance wire and an axially arranged double-row resistance wire, which are uniformly arranged in all positions in the heat insulation layer in the circumferential direction and the axial direction respectively, forming an orthogonal grid structure; when ablation of the heat insulation layer occurs, the resistance wire at any position is exposed, and the ablation information is reflected through an electrical signal.

[0009] Further, the two resistance wires with insulating sheaths in the orthogonal grid layered pre-embedded double-row resistance wire are arranged side by side; when ablation does not occur, the two resistance wires are not connected and are connected to the external data acquisition system through the wires at the tail ends respectively; when ablation occurs, the melted resistance wire generates a metal resistance wire melting metal oxide cap at the melting end, so that the two resistance wires are connected and a loop signal is generated; at this time, the ablation information can be obtained by measuring the resistance; further ablation causes the resistance wire to be shortened and the resistance to be smaller, and the resistance signal is continuously obtained.

[0010] Further, in the single-layer heat insulation layer, a plurality of groups of double-row resistance wires are arranged in the heat insulation layer in an orthogonal grid layered manner.

[0011] Further, the circumferentially arranged single group of double-row resistance wires starts from a quadrant position of the engine, circumferentially surrounds the heat insulation layer for one turn, is embedded in the heat insulation layer along the surface layer with the same thickness, and ends at a position directly below the quadrant, and the front and rear ends of the resistance wire are connected to the external data acquisition system through two wires respectively.

[0012] Further, the axially arranged single group of double-row resistance wires starts from the heat insulation layer in the front head of the engine, is embedded in the heat insulation layer along the surface layer with the same thickness, and ends at the heat insulation layer in the rear head of the engine, and the front and rear ends of the resistance wire are connected to the external data acquisition system through two wires respectively.

[0013] Further, the heat insulation layer is layered and pasted according to the number of embedded resistance wires, so as to ensure uniform installation of the resistance wire in the thickness direction of the heat insulation layer; when the heat insulation layer and the resistance wire are laid, a layer of heat insulation layer with the same thickness is laid first, the orthogonal resistance wire is laid on the heat insulation layer, then a second layer of heat insulation layer is laid, and the two layers of heat insulation layer are fused and closely attached through an oven, and so on, one layer of heat insulation layer, one layer of resistance wire, and a plurality of layers of transversely arranged double-row resistance wires and longitudinally arranged double-row resistance wires and layered pasted heat insulation layers are laid.

[0014] Furthermore, this invention proposes a dynamic measurement method for the ablation interface of a solid rocket engine insulation layer. Using the aforementioned dynamic measurement system for the ablation interface of a solid rocket engine insulation layer, the method includes the following steps: Orthogonal grid-shaped layered pre-embedded double-row resistance wires and conductors are pre-embedded within the insulation layer using a layered patch method; the conductors are connected to an external data acquisition system. At the start of the test, the engine operates, and the data acquisition system records test data in real time. During ground testing, the engine does not experience overload, and the insulation layer ablates uniformly at each axial section. When the insulation layer ablates to the resistance wires, the resistance changes, and test data is recorded. During flight testing, the engine undergoes a stop-motion maneuver, causing overload on the combustion chamber gases, resulting in localized asymmetric ablation of the insulation layer. The ablation of the insulation layer in the overload direction is severe, the resistance wires are exposed earlier, and the resistance changes; test data is recorded. After the test, the measurement data is used to obtain the global dynamic measurement results of the ablation interface through a resistance-ablation surface reconstruction method.

[0015] Furthermore, the solution process of the resistance-ablation surface reconstruction method is as follows: when the resistor receives a signal, the resistance changes from infinity to a finite value. The resistance signal is assigned to the resistance matrix arranged in a regular pattern. The resistance matrix is ​​converted into a remaining length matrix according to the arrangement of the wire length matrix. Then, the remaining length matrix is ​​mapped onto the interface matrix after meshing. The 0-1 interface is obtained through the LevelSet method, which is the position of the ablation surface.

[0016] Furthermore, the resistance-ablation surface reconstruction method specifically includes the following steps:

[0017] (1) Establish a cylindrical coordinate system

[0018] A cylindrical coordinate system is set for the insulation layer to represent its position information: X(r, θ, z);

[0019] (2) Define the resistance state

[0020] The resistance wire was not burned out: the parallel resistor could not be burned out to form a single-sided connection, and no circuit was formed, so the initial resistance was infinite.

[0021] Resistance wire ablation: Calculation of resistance wire ablation location, resistance R0 of a single resistance wire, and resistance R after ablation. b Length L0, length L after burning b The resistance of a resistance wire is directly proportional to its length. The residual ratio k = L is defined as follows: b / L0=R b / 2R0; Remaining length L b =k·L0,L b The location is the edge of the ablated surface;

[0022] (3) Constructing the resistance matrix

[0023] Radial direction: Front end cap side: A = [R] q1 R q2 R q3 …R qn ],

[0024] Rear end cap side: B = [R] h1 R h2 R h3 …R hn ];

[0025] Circumferential direction: Second quadrant side: C = [R] Ⅱ1 R Ⅱ2 R Ⅱ3 …R Ⅱn ],

[0026] Four-quadrant side: D = [R] Ⅳ1 R Ⅳ2 R Ⅳ3 …R Ⅳn ];

[0027] Where n is the number of resistors at the corresponding location; R has two states:

[0028]

[0029] Combine the four arrays into a single-layer resistance matrix:

[0030]

[0031] The resistance matrices for the remaining layers are obtained using this method: R1, R2, R3…R n ;

[0032] (4) Construct the matrix of remaining resistance wire length

[0033] Based on the conversion factor k, the remaining length matrix L is obtained:

[0034]

[0035] Matrix L represents the remaining length of a single-layer resistance wire after melting.

[0036] The remaining length matrix results for the remaining layers are obtained using this method: L1, L2, L3…L n ;

[0037] (5) Mapping of the remaining length matrix to cylindrical coordinates

[0038] The remaining length matrix data is converted into a cylindrical coordinate system, where the r-coordinate corresponds to different layer numbers, and the θ and z-coordinates correspond to the single-layer remaining length matrix L; a mapping relationship between the cylindrical coordinate system and the remaining length matrix is ​​constructed, X = {E}{L1, L2, L3…L n}, where E is the mapping matrix; based on this, the adiabatic layer results in cylindrical coordinates are obtained;

[0039] (6) Reconstruction of ablation interface based on level set method

[0040] The X-dimensional matrix is ​​meshed, with r, θ, and z divided into several mesh elements. Each mesh element has an L value. A Q matrix is ​​defined, and for each mesh element, a value is assigned based on a judgment in cylindrical coordinates. The Q value is assigned using the following judgment:

[0041]

[0042] After traversing each grid cell, the insulation layer interface is reconstructed using the LevelSet algorithm. The interface between 0 and 1 in cylindrical coordinates is the boundary of the insulation layer.

[0043] (III) Beneficial Effects

[0044] This invention proposes a dynamic measurement system and method for the ablation interface of a solid rocket motor insulation layer. The system measures the resistance of two parallel insulated resistance wires embedded in the insulation layer to determine the location of the ablation surface. When a resistance wire melts due to ablation, the molten metal connects the two parallel resistance wires on the same side of the ablation surface, creating two circuits on either side of the ablation location and obtaining the resistance value for the first time. The resistance is linearly related to the length of the resistance wire; the precise location of the ablation can be inferred from the decreasing resistance during the ablation process. Double rows of resistance wires are embedded in the engine insulation layer in an orthogonal grid pattern, with a grid size of approximately 200mm × 200mm. Four to five layers of the resistance wire grid are evenly distributed across the insulation layer thickness. During the ablation process, the resistance wire grid partially melts due to ablation. The collected resistance database is used to obtain two-dimensional to three-dimensional ablation results using a resistance-ablation surface reconstruction method, enabling further reconstruction of the dynamic ablation process of the insulation layer and completion of experimental measurements.

[0045] This invention obtains the dynamic ablation rate and process of the engine's global insulation layer by using a grid-like double-row resistance line pre-embedded in the insulation layer and a resistance-ablation surface reconstruction method. This improves upon the limitations and non-real-time nature of post-ablation measurements, overcomes the problem of not being able to measure asymmetric ablation under engine overload conditions, and establishes a method for reconstructing the ablation surface corresponding to the resistance database. This invention has the advantages of simple principle, low measurement cost, and high measurement accuracy, and has good application prospects for global real-time measurement and forward thermal protection design of solid rocket engine insulation layers.

[0046] Compared with existing methods for measuring insulation layers, the present invention has the following advantages:

[0047] 1. The dynamic measurement system and method for the ablation interface of the solid rocket motor insulation layer based on resistance wire melting monitoring proposed in this invention can accurately capture the position of the ablation surface in real time, and has the characteristics of accuracy, global coverage and effectiveness.

[0048] 2. The resistance wire used in this invention is characterized by being readily available, low in cost, and simple in principle.

[0049] 3. This invention proposes an orthogonal grid-like layered arrangement method. It can measure the global ablation process of the insulation layer. The resistance lines based on the grid arrangement can detect the ablation status at each location through ablation, thus providing a global perspective.

[0050] 4. The layered patch insulation layer arrangement method proposed in this invention can effectively reduce the resistance wire arrangement method, while not affecting the normal installation and laying of the insulation layer.

[0051] 5. The resistance-ablation surface reconstruction method proposed in this invention can reconstruct the ablation interface and obtain accurate interface data.

[0052] 6. The measurement system and method proposed in this invention can not only measure conventional ablation, but also perform real-time global measurement of asymmetric ablation caused by abnormal overload conditions. Attached Figure Description

[0053] Figure 1 This is a schematic diagram illustrating the composition and working principle of the dynamic measurement system for the ablation interface of the solid rocket motor insulation layer according to the present invention.

[0054] Figure 2 This is a diagram illustrating the ablation measurement process of parallel resistance lines in this invention.

[0055] Figure 3 This is a schematic diagram of the multi-layer resistor layering method for pre-embedding double-row resistor wires in an orthogonal grid pattern in this invention;

[0056] Figure 4 This is a schematic diagram of the solution process of the resistance-ablation surface reconstruction method in this invention.

[0057] In the diagram: 1-Engine housing; 2-Insulation layer; 3-Circumferentially arranged double-row resistance wires; 4-Axially arranged double-row resistance wires; 5-Resistance wires; 6-Insulation sheath; 7-Wires; 8-Resistance wire fused metal oxide cap; 9-Horizontally arranged double-row resistance wires; 10-Vertically arranged double-row resistance wires; 11-Layered adhesive insulation layer. Detailed Implementation

[0058] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0059] This embodiment proposes a dynamic measurement system for the ablation interface of the insulation layer in a solid rocket motor, the composition of which and its working principle are as follows: Figure 1 As shown, it mainly includes orthogonal grid-like layered pre-embedded double-row resistor wires and conductors 7.

[0060] An orthogonal grid-like layered pre-embedded double-row resistance wire is embedded in the insulation layer 2 of the engine casing 1 of the engine under test, for use in dynamic testing of the ablation interface within the insulation layer 2.

[0061] The orthogonal grid-like layered embedded double-row resistance wires include circumferentially arranged double-row resistance wires 3 and axially arranged double-row resistance wires 4, which are uniformly distributed circumferentially and axially throughout all positions within the insulation layer 2, forming an orthogonal grid structure. When the insulation layer 2 is ablated, the resistance wires at any position are exposed, and the ablation information can be reflected through electrical signals.

[0062] The double-row resistance wire is the main measuring device. By measuring the resistance of two parallel resistance wires 5 with insulating sheaths 6, the location of the ablation surface can be calculated. When resistance wire 5 melts due to ablation, the molten resistance wire connects the two parallel resistance wires on the same side of the ablation surface through the melting metal oxide cap 8, creating a circuit and obtaining the resistance value for the first time. The resistance value is linearly related to the length of the resistance wire; based on the resistance value, the accurate location of the ablation within that set of parallel resistance wires can be calculated.

[0063] The ablation measurement process of adjacent parallel resistance lines in each direction in the circumferentially arranged double-row resistance lines 3 and the axially arranged double-row resistance lines 4 is as follows: Figure 2 As shown, wire 7 is a conductive element connecting the resistance wire 5 to the data acquisition system, used to transmit electrical signals. Wire 7 is embedded between the engine housing 1 and the insulation layer 2 to prevent combustion gas erosion. Two resistance wires 5 with insulating sheaths 6 are placed side-by-side. When erosion has not occurred, the two resistance wires 5 are not connected and are connected to the external data acquisition system via wires 7 at their respective ends. When erosion occurs, the molten resistance wire 5 will generate a metallic resistance wire cap 8 at the molten end, connecting the two resistance wires 5 and generating a loop signal. At this point, erosion information can be obtained by measuring the resistance. Further erosion causes the resistance wire 5 to shorten, reducing the resistance and allowing for continuous acquisition of resistance signals.

[0064] Within the single-layer insulation layer 2, multiple sets of double-row resistance wires are arranged in an orthogonal grid pattern. The resistance wires 5 are arranged in an orthogonal grid pattern, with 200mm x 200mm crosses. Four to five layers of resistance wire grids are evenly distributed across the thickness of the insulation layer 2. Since the insulation layer 2 is a closed-loop barrel structure, the orthogonal grid is arranged circumferentially and axially. The circumferentially arranged single-set double-row resistance wires begin at the first quadrant (directly below) of the engine, circle the insulation layer 2, are embedded along the surface of the insulation layer 2 with equal thickness, and terminate directly below the first quadrant. The front and rear ends of the resistance wires 5 are connected to an external data acquisition system via two wires 7. The axially arranged single-set double-row resistance wires begin within the insulation layer 2 of the engine's front end cap, are embedded along the surface of the insulation layer 2 with equal thickness, and terminate at the insulation layer 2 of the engine's rear end cap. The front and rear ends of the resistance wires 5 are connected to an external data acquisition system via two wires 7. Meanwhile, considering the technical difficulty of embedding the resistance wires, a layered patch-type insulation layer arrangement method was adopted. The insulation layer 2 is layered according to the number of embedded resistance wire layers to ensure that the resistance wires 5 are uniformly installed in the thickness direction of the insulation layer.

[0065] The method of laying out multi-layer resistors with orthogonal grid-like layered pre-embedded double-row resistor wires is as follows: Figure 3 As shown. When laying the insulation layer 2 and the resistance wire 5, first lay a layer of insulation layer 2 of equal thickness, then lay the orthogonal resistance wire on the insulation layer 2, then lay the second layer of insulation layer 2, and heat it in an oven to melt and tightly bond the two layers of insulation layer 2 together. This process is repeated, with one layer of insulation layer 2, one layer of resistance wire 5, multiple layers of horizontally arranged double-row resistance wire 9 and vertically arranged double-row resistance wire 10, and a layered adhesive insulation layer 11.

[0066] The experimental procedure for dynamic ablation measurement of the insulation layer is as follows: During engine manufacturing and assembly, orthogonal grid-shaped layered pre-embedded double-row resistance wires and conductors 7 are embedded in the insulation layer 2 using a layered patch method. Conductors 7 are connected to the data acquisition system, and the measurement power is turned on. At the start of the test, the engine operates, and the data acquisition system records test data in real time. During ground testing, the engine does not experience overload, and the insulation layer ablates uniformly across all axial sections. When the insulation layer ablates to the resistance wires, the resistance changes, and test data is recorded. During flight testing, the engine undergoes pitch and yaw maneuvers, causing overload on the combustion chamber gases. This leads to localized asymmetric ablation of the insulation layer, with severe ablation in the overload direction, resulting in earlier exposure of the resistance wires and changes in resistance. Test data is recorded. After the test, the measurement data is used to obtain the global dynamic measurement results of the ablation interface through a resistance-ablation surface reconstruction method.

[0067] The solution process of the resistance-ablation surface reconstruction method is as follows: Figure 4As shown. When the resistor receives a signal, the resistance changes from infinity to a finite value. The resistance signal is assigned to the resistor matrix R arranged in a regular pattern. The resistor matrix R is converted into the remaining length matrix L according to the arrangement of the wire length matrix. Then, the remaining length matrix L is mapped onto the interface matrix after the mesh is divided. The 0-1 interface is obtained through the LevelSet method, which is the position of the ablation surface.

[0068] The resistance-ablation surface reconstruction method specifically includes the following steps:

[0069] (1) Establish a cylindrical coordinate system

[0070] A cylindrical coordinate system is set for the insulation layer to represent its position information: X(r, θ, z).

[0071] (2) Define the resistance state

[0072] a) The resistance wire was not burned out: the parallel resistor could not be burned out to form a single-sided connection, and no circuit was formed, so the initial resistance was infinite.

[0073] b) Resistance wire ablation: Calculation of the ablation location of the resistance wire, resistance R0 of a single resistance wire, and resistance R after ablation. b Length L0, length L after burning b The resistance of a resistance wire is directly proportional to its length. The residual ratio k = L is defined as follows: b / L0=R b / 2R0. Remaining length L b =k·L0, where L b The location is the edge of the ablation surface.

[0074] (3) Constructing the resistance matrix

[0075] Radial direction: Front end cap side: A = [R] q1 R q2 R q3 …R qn ],

[0076] Rear end cap side: B = [R] h1 R h2 R h3 …R hn ].

[0077] Circumferential direction: Second quadrant side: C = [R] Ⅱ1 R Ⅱ2 R Ⅱ3 …R Ⅱn ],

[0078] Four-quadrant side: D = [R] Ⅳ1 R Ⅳ2 R Ⅳ3 …R Ⅳn ].

[0079] Where n is the number of resistors at the corresponding location; R has two states:

[0080]

[0081] Combine the four arrays into a single-layer resistance matrix:

[0082]

[0083] The resistance matrices for the remaining layers are obtained using this method: R1, R2, R3…R n .

[0084] (4) Construct the matrix of remaining resistance wire length

[0085] Based on the conversion factor k, the remaining length matrix L is obtained:

[0086]

[0087] Matrix L represents the remaining length of a single-layer resistance wire after melting.

[0088] The remaining length matrix results for the remaining layers are obtained using this method: L1, L2, L3…L n .

[0089] (5) Mapping of the remaining length matrix to cylindrical coordinates

[0090] The remaining length matrix data is converted into a cylindrical coordinate system, where the r-coordinate corresponds to different layer numbers, and the θ and z-coordinates correspond to the single-layer remaining length matrix L. A mapping relationship between the cylindrical coordinate system and the remaining length matrix is ​​constructed: X = {E}{L1, L2, L3…L} n}, where E is the mapping matrix. Based on this, the adiabatic layer results in cylindrical coordinates are obtained.

[0091] (6) Reconstruction of ablation interface based on the level set method

[0092] The X-dimensional matrix is ​​meshed, with r, θ, and z divided into several mesh elements. Each mesh element has an L value. A Q matrix is ​​defined, and for each mesh element, a value is assigned based on a judgment in cylindrical coordinates. The Q value is assigned using the following judgment:

[0093]

[0094] After traversing each grid cell, the insulation layer interface is reconstructed using the LevelSet algorithm. The interface between 0 and 1 in cylindrical coordinates is the boundary of the insulation layer.

[0095] The design features of this invention are as follows:

[0096] 1. This invention establishes a complete dynamic measurement system for the ablation interface of the thermal insulation layer of a solid rocket engine, including resistance lines, a layered grid arrangement method, and a resistance-ablation surface reconstruction method. The measurement scheme can provide effective and accurate data for the ablation of the engine thermal insulation layer under normal operation and overload conditions.

[0097] 2. This invention calculates the location data of the ablation surface by measuring the resistance of two insulating resistance wires. When a resistance wire melts due to ablation, the molten metal connects the two parallel resistance wires on the same side of the ablation surface, creating a circuit and obtaining the resistance value for the first time. The resistance is linearly related to the length of the resistance wires; based on the resistance value, the accurate location of the ablation on the set of parallel resistance wires can be calculated.

[0098] 3. This invention transmits electrical signals to the data acquisition system by connecting the resistance wire with a conductor. The conductor is embedded between the engine housing and the insulation layer to prevent combustion gas erosion.

[0099] 4. This invention uses multiple sets of double-row resistance wires arranged in an orthogonal grid pattern within the insulation layer to measure global ablation characteristics. Within each single layer, the resistance wires intersect at 200mm x 200mm intervals to form an orthogonal grid pattern. Four to five layers of resistance wire grids are uniformly arranged across the thickness of the insulation layer.

[0100] 5. By arranging resistance wires along the circumference and axial direction within the insulation layer, this invention can accurately measure the ablation of the insulation layer under normal working conditions and overload working conditions, and can accurately capture the asymmetric ablation characteristics of the insulation layer under overload conditions.

[0101] 6. By setting a layered patch-type insulation layer arrangement method, the present invention can reduce the difficulty of installing resistance wires while ensuring uniform arrangement in the thickness direction.

[0102] 7. The resistance-ablation surface reconstruction method proposed in this invention can reconstruct the ablation interface after obtaining the resistance array through matrix transformation, finite difference, mesh generation and LevelSet method to obtain accurate interface data.

[0103] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A dynamic measurement system for the ablation interface of the insulation layer of a solid rocket motor, characterized in that, The dynamic measurement system for the ablation interface of the solid rocket engine insulation layer includes orthogonal grid-shaped layered pre-embedded double-row resistance wires and conductors. The orthogonal grid-shaped layered pre-embedded double-row resistance wires are pre-embedded in the insulation layer of the engine casing of the engine under test for dynamic testing of the ablation interface within the insulation layer. The conductors are embedded between the engine casing and the insulation layer and are conductive elements connecting the resistance wires and the data acquisition system for transmitting electrical signals.

2. The dynamic measurement system for the ablation interface of the insulation layer of a solid rocket motor as described in claim 1, characterized in that, The orthogonal grid-like layered pre-embedded double-row resistance wires include circumferentially arranged double-row resistance wires and axially arranged double-row resistance wires, which are uniformly arranged in all positions within the insulation layer in the circumferential and axial directions, respectively, forming an orthogonal grid-like structure; when the insulation layer is ablated, the resistance wire at any position is exposed and the ablation information is reflected through electrical signals.

3. The dynamic measurement system for the ablation interface of the insulation layer of a solid rocket motor as described in claim 1, characterized in that, In the orthogonal grid-like layered pre-embedded double-row resistance wire, two resistance wires with insulating sheaths are placed side by side. When ablation does not occur, the two resistance wires are not connected and are connected to the external data acquisition system through the wires at their tail ends. When ablation occurs, the molten resistance wires generate a metal resistance wire at the molten end that melts the metal oxide cap, connecting the two resistance wires and generating a loop signal. At this time, ablation information can be obtained by measuring the resistance. Further ablation causes the resistance wires to shorten and the resistance to decrease, allowing for continuous acquisition of resistance signals.

4. The dynamic measurement system for the ablation interface of the insulation layer of a solid rocket motor as described in claim 1, characterized in that, Within a single-layer insulation layer, multiple sets of double-row resistance wires are arranged in an orthogonal grid pattern.

5. The dynamic measurement system for the ablation interface of the insulation layer of a solid rocket motor as described in claim 4, characterized in that, The single-group double-row resistor wires arranged circumferentially start at the first quadrant of the engine, circle the insulation layer, are embedded in the insulation layer of equal thickness, and end directly below the first quadrant. The two ends of the resistor wires are connected to the external data acquisition system through two wires.

6. The dynamic measurement system for the ablation interface of the insulation layer of a solid rocket motor as described in claim 4, characterized in that, The axially arranged single-group double-row resistance wires start inside the insulation layer of the engine front end cap, are embedded along the surface of the insulation layer of equal thickness, and end in the insulation layer of the engine rear end cap. The front and rear ends of the resistance wires are connected to the external data acquisition system through two wires respectively.

7. The dynamic measurement system for the ablation interface of the insulation layer of a solid rocket motor as described in claim 4, characterized in that, The insulation layer is laid in layers according to the number of embedded resistance wires to ensure that the resistance wires are installed evenly in the thickness direction of the insulation layer. When laying the insulation layer and resistance wires, first lay a layer of insulation layer of equal thickness, then lay the orthogonal resistance wires on the insulation layer, then lay the second layer of insulation layer, and heat the two layers of insulation layer by heating in an oven to melt and tightly bond them together. This process is repeated, with one layer of insulation layer, one layer of resistance wire, and multiple layers of horizontally arranged double-row resistance wires, vertically arranged double-row resistance wires, and layered adhesive insulation layers laid.

8. A method for dynamically measuring the ablation interface of the insulation layer in a solid rocket motor, characterized in that, The dynamic measurement system for the ablation interface of the solid rocket engine insulation layer according to any one of claims 1 to 7 includes the following steps: pre-embedding orthogonal grid-shaped layered double-row resistance wires and conductors in the insulation layer using a layered patching method, and connecting the conductors to an external data acquisition system; at the start of the test, the engine operates, and the data acquisition system records test data in real time; when the engine is tested on the ground, no overload occurs, and the insulation layer ablates uniformly at each axial section; when the insulation layer ablates to the resistance wires, the resistance changes, and test data is recorded; when the engine is tested in flight, the engine operates, causing an overload on the combustion chamber gas, resulting in localized asymmetric growth of insulation layer ablation, with severe ablation in the overload direction, early exposure of the resistance wires, and a change in resistance, and test data is recorded. After the experiment, the measurement data were used to obtain the dynamic measurement results of the global ablation interface through the resistance-ablation surface reconstruction method.

9. The method for dynamic measurement of the ablation interface of the insulation layer of a solid rocket motor as described in claim 8, characterized in that, The solution process of the resistance-ablation surface reconstruction method is as follows: when the resistor receives a signal, the resistance changes from infinity to a finite value. The resistance signal is assigned to the resistance matrix arranged in a regular pattern. The resistance matrix is ​​converted into the remaining length matrix according to the arrangement of the wire length matrix. Then, the remaining length matrix is ​​mapped onto the interface matrix after the mesh is divided. The 0-1 interface is obtained through the Level Set method, which is the position of the ablation surface.

10. The method for dynamic measurement of the ablation interface of the insulation layer of a solid rocket motor as described in claim 9, characterized in that, The resistance-ablation surface reconstruction method specifically includes the following steps: (1) Establish a cylindrical coordinate system A cylindrical coordinate system is set for the insulation layer to represent its position information: X(r, θ, z); (2) Define the resistance state The resistance wire was not burned out: the parallel resistor could not be burned out to form a single-sided connection, and no circuit was formed, so the initial resistance was infinite. Resistance wire ablation: Calculation of resistance wire ablation location, resistance R0 of a single resistance wire, and resistance R after ablation. b Length L0, length L after burning b The resistance of a resistance wire is directly proportional to its length. The residual ratio k = L is defined as follows: b / L0=R b / 2R0; Remaining length L b =k·L0,L b The location is the edge of the ablated surface; (3) Constructing the resistance matrix Radial direction: Front end cap side: A = [R] q1 R q2 R q3 …R qn ], Rear end cap side: B = [R] h1 R h2 R h3 …R hn ]; Circumferential direction: Second quadrant side: C = [R] Ⅱ1 R Ⅱ2 R Ⅱ3 …R Ⅱn ], Four-quadrant side: D = [R] Ⅳ1 R Ⅳ2 R Ⅳ3 …R Ⅳn ]; Where n is the number of resistors at the corresponding location; R has two states: Combine the four arrays into a single-layer resistance matrix: The resistance matrices for the remaining layers are obtained using this method: R1, R2, R3…R n ; (4) Construct the matrix of remaining resistance wire length Based on the conversion factor k, the remaining length matrix L is obtained: Matrix L represents the remaining length of a single-layer resistance wire after melting. The remaining length matrix results for the remaining layers are obtained using this method: L1, L2, L3…L n ; (5) Mapping of the remaining length matrix to cylindrical coordinates The remaining length matrix data is converted into a cylindrical coordinate system, where the r-coordinate corresponds to different layer numbers, and the θ and z-coordinates correspond to the single-layer remaining length matrix L; a mapping relationship between the cylindrical coordinate system and the remaining length matrix is ​​constructed, X = {E}{L1, L2, L3…L n }, where E is the mapping matrix; based on this, the adiabatic layer results in cylindrical coordinates are obtained; (6) Reconstruction of ablation interface based on level set method The X-dimensional matrix is ​​meshed, with r, θ, and z divided into several mesh elements. Each mesh element has an L value. A Q matrix is ​​defined, and for each mesh element, a value is assigned based on a judgment in cylindrical coordinates. The Q value is assigned using the following judgment: After traversing each grid cell, the insulation layer interface is reconstructed using the LevelSet algorithm. The interface between 0 and 1 in cylindrical coordinates is the boundary of the insulation layer.

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