Flexible sacrificial capacitive sensor with real-time position feedback of the burning surface and method of manufacturing
By using a flexible sacrificial capacitor sensor with a distributed capacitor array on the propellant grain to monitor the burner position in real time, the problem of insufficient accuracy in measuring the internal ballistic curve of solid rocket motors is solved, achieving high-precision burner position feedback, which is suitable for high-temperature and high-pressure environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- THE GENERAL DESIGNING INST OF HUBEI SPACE TECH ACAD
- Filing Date
- 2023-02-22
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies cannot achieve real-time quantitative measurement of the internal ballistic curve of solid rocket engines, resulting in insufficient design accuracy.
A flexible sacrificial capacitance sensor with real-time combustion surface position feedback was designed. By distributing multiple capacitor arrays on the propellant grain, the position of the combustion surface is monitored in real time by utilizing changes in capacitance values. Combined with a capacitance detection module, a loop is formed to achieve real-time quantitative measurement of the combustion surface position.
It improves the accuracy of internal ballistic prediction in solid rocket engines, enables real-time monitoring of the burning surface position, and features small sensor size, simple manufacturing process, low cost, and suitability for high temperature and high pressure environments.
Smart Images
Figure CN116291971B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of fuel online monitoring technology, and in particular to a flexible sacrificial capacitive sensor for real-time fuel surface position feedback and its fabrication method. Background Technology
[0002] The internal trajectory of a solid rocket motor is a crucial performance indicator. Due to the unique operating mechanism of solid rocket motors, the internal trajectory curve cannot generally be directly controlled during the design process. Instead, the desired internal trajectory must be achieved through the design of the propellant grain shape and material.
[0003] In a typical propellant design process, designers first provide a preliminary design based on the desired internal trajectory, then simulate and predict the engine's internal trajectory, and repeatedly adjust the propellant design based on the predicted results until the predicted results closely approximate the desired internal trajectory. However, the spatial distribution of various propellant burning rate influencing factors during engine operation cannot be completely uniform, and the actual propellant burning rate at different locations within the engine will inevitably differ.
[0004] Real-time quantitative measurement of the propellant charge burning surface position can effectively improve the prediction accuracy of the internal trajectory of the engine, which has great practical significance and value for engine design. Summary of the Invention
[0005] This application provides a flexible sacrificial capacitive sensor with real-time combustion surface position feedback and its preparation method, enabling real-time quantitative measurement of the combustion surface position of the propellant grain.
[0006] In a first aspect, a flexible sacrificial capacitive sensor for real-time position feedback of a burning surface is provided, comprising:
[0007] Substrate;
[0008] A flexible capacitive sensor, wherein the flexible capacitive sensor is disposed on the substrate;
[0009] An encapsulation coating is applied to the surface of the flexible capacitive sensor.
[0010] Furthermore, the flexible capacitive sensor also has lead terminals for connecting wires to form a circuit between the flexible capacitive sensor and the capacitance detection module.
[0011] In some embodiments, the flexible capacitive sensor includes several capacitor arrays spaced apart along the length of the flexible capacitive sensor, and each capacitor array has two lead terminals for connecting wires so that the capacitor array and the capacitance detection module form an independent circuit.
[0012] In some embodiments, the capacitor array includes two parallel leads and a plurality of interdigital electrode devices located between the two leads, wherein one end of a portion of the interdigital electrode devices is connected to one of the leads and one end of another portion of the interdigital electrode devices is connected to the other lead, and the interdigital electrode devices on the leads are interspersed with the interdigital electrode devices on the other leads along the extension direction of the leads.
[0013] Each of the leads has a lead terminal at its end for connecting to a wire.
[0014] In some embodiments, of the two leads of the capacitor array, one is a common lead and the other is an independent lead, and the common lead of each capacitor array is the same lead;
[0015] And / or, the interdigitated electrode device is manufactured using silver paste, copper paste, or a mixed plasma formed of silver paste and copper paste;
[0016] And / or, the leads are manufactured using silver paste, copper paste, or a mixture of silver paste and copper paste;
[0017] And / or, the spacing between two adjacent interdigitated electrode devices is 200 μm;
[0018] And / or, the spacing between two adjacent capacitor arrays is 5 mm;
[0019] And / or, there are two capacitor arrays with different widths, one capacitor array having a distance of 2.6 mm between the two leads and a length of 2.5 mm for the interdigitated electrode, and the other capacitor array having a distance of 1.6 mm between the two leads and a length of 1.5 mm for the interdigitated electrode.
[0020] In some embodiments, the widths of the capacitor arrays are different, and the capacitor arrays are arranged sequentially according to their widths along the length of the flexible capacitive sensor.
[0021] In some embodiments, the encapsulation coating is a gel electrolyte;
[0022] And / or, the substrate is made of polyimide film, PET or PP;
[0023] And / or, the length * width of the lead terminal is 3mm * 1mm;
[0024] And / or, the flexible capacitive sensor has a length * width of 100mm * 5mm.
[0025] Secondly, a method for fabricating a flexible sacrificial capacitive sensor with real-time position feedback of the burning surface as described above is provided, comprising:
[0026] Printing flexible capacitive sensors on a substrate;
[0027] A flexible sacrificial capacitive sensor is obtained by encapsulating it with a coating.
[0028] In some embodiments, printing a flexible capacitive sensor on a substrate includes the following steps:
[0029] The conductive paste is printed onto a substrate and then heated and sintered to solidify the conductive paste on the substrate, forming a flexible capacitive sensor.
[0030] In some embodiments, the viscosity of the conductive paste is 8000–12000 cps, and the heating and sintering includes a heating time of 20–50 min and a heating temperature of 100–140 °C.
[0031] In some embodiments, encapsulation is performed on the flexible capacitive sensor to form an encapsulation coating, including the following steps:
[0032] A gel electrolyte is applied to a flexible capacitive sensor, and after drying, an encapsulation coating is formed.
[0033] The beneficial effects of the technical solution provided in this application include:
[0034] When the flexible sacrificial capacitive sensor provided in this application is used for online monitoring of solid rocket motors, multiple flexible sacrificial capacitive sensors can be uniformly attached to the end face of the propellant in a circumferential array. The length direction of the flexible sacrificial capacitive sensor is consistent with the radius direction of the propellant. The end of the flexible sacrificial capacitive sensor is close to the inner hole of the propellant, and the lead end is close to the side of the propellant. Each flexible sacrificial capacitive sensor has a wire leading out from the lead end to connect to the capacitance detection module. The propellant starts to burn outward from the inner hole of the propellant. During the combustion process, the flexible capacitive sensor is burned along with the propellant. The detected capacitance value changes continuously. The length of the sensor burning can be calculated based on the capacitance value. A surface relationship between the capacitance resistance of the flexible capacitive sensor and the burning surface retreat distance can be established. The position of the burning surface of the propellant can be fitted by the length measured by multiple flexible sacrificial capacitive sensors, realizing real-time monitoring of the burning surface retreat. Attached Figure Description
[0035] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0036] Figure 1A schematic diagram of the structure of a flexible sacrificial capacitive sensor for real-time position feedback of the burning surface provided in an embodiment of this application;
[0037] Figure 2 This is a schematic diagram of the structure of the flexible capacitive sensor provided in the embodiments of this application;
[0038] Figure 3 This is a schematic diagram of the installation of the flexible sacrificial capacitive sensor for real-time position feedback of the combustion surface provided in the embodiments of this application.
[0039] In the figure: 1. Substrate; 2. Flexible capacitive sensor; 20. Capacitor array; 200. Interdigitated electrode device; 201. Common lead; 202. Individual lead; 203. Lead terminal; 3. Encapsulation coating; 4. Capacitance detection module; 5. Wire; 6. Propellant cartridge; 60. Propellant cartridge inner hole. Detailed Implementation
[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0041] See Figure 1 , Figure 2 and Figure 3 As shown, this application embodiment provides a flexible sacrificial capacitive sensor with real-time position feedback of the burning surface, which includes a substrate 1, a flexible capacitive sensor 2 and an encapsulation coating 3. The flexible capacitive sensor 2 is disposed on the substrate 1, and the encapsulation coating 3 is encapsulated on the surface of the flexible capacitive sensor 2. The flexible capacitive sensor 2 also has lead terminals 203, which are used to connect wires 5 so that the flexible capacitive sensor 2 and the capacitance detection module 4 form a circuit.
[0042] When the flexible sacrificial capacitive sensor provided in this application is used for online monitoring of solid rocket motors, multiple flexible sacrificial capacitive sensors can be uniformly attached to the end face of the propellant charge 6 in a circumferential array. The length direction of the flexible sacrificial capacitive sensor is consistent with the radius direction of the propellant charge 6. The end of the flexible sacrificial capacitive sensor is close to the inner hole 60 of the propellant charge, and the lead end is close to the side of the propellant charge. Each flexible sacrificial capacitive sensor has a wire leading out from the lead end to connect to the capacitance detection module 4. The propellant charge 6 starts to burn outward from the inner hole 60 of the propellant charge. During the combustion process, the flexible capacitive sensor 2 is burned along with the propellant charge, and the detected capacitance value changes continuously. The length of the sensor burning can be calculated based on the capacitance value, and a surface relationship between the capacitance resistance of the flexible capacitive sensor and the distance of the burning surface retreat can be established. The position of the burning surface of the propellant charge can be fitted by the length measured by multiple flexible sacrificial capacitive sensors, realizing real-time monitoring of the burning surface retreat.
[0043] The aforementioned encapsulation coating 3 can be made of gel electrolyte, which can effectively improve the stability of ion movement.
[0044] Substrate 1 is a polymer film, which can be made of polyimide film, PET or PP, or film-type insulating materials. Polyimide film has good radiation resistance and electrical insulation, and can be burned in a high-temperature combustion environment, thereby affecting the capacitance and resistance changes of the sensor.
[0045] The length and width dimensions of the aforementioned lead terminal 203 can be designed according to actual needs. For example, as an example, the length and width are 3mm and 1mm.
[0046] The width and length dimensions of the aforementioned flexible capacitive sensor 2 can be designed according to actual needs. For example, as an example, the length and width are 100mm and 5mm.
[0047] The flexible capacitive sensor 2 may include a capacitor array 20, which is elongated. The flexible capacitive sensor 2 has two leads, which are the two leads of the capacitor array 20.
[0048] The flexible capacitive sensor 2 may also include multiple capacitor arrays 20 spaced apart along the length of the flexible capacitive sensor 2. In this case, the flexible capacitive sensor 2 has at least three leads, and each capacitor array 20 has two lead terminals 203 for connecting wires 5, so that the capacitor array 20 and the capacitance detection module 4 form an independent circuit and the capacitor arrays 20 do not interfere with each other.
[0049] Specifically, see Figure 2As shown, the capacitor array 20 includes two parallel leads and a plurality of interdigital electrode devices 200 located between the two leads. The interdigital electrode devices 200 are distributed in parallel at intervals. The spacing between two adjacent interdigital electrode devices 200 can be determined according to actual measurement needs, for example, the spacing between two adjacent interdigital electrode devices 200 is 200 μm. The interdigital electrode devices 200 can be manufactured using silver paste, copper paste, or a mixed plasma. The mixed plasma is, for example, formed by silver paste and copper paste. The interdigital electrode devices 200 are prepared by screen printing, and their... The length and width are uniform to ensure consistent capacitance and reactance in the capacitor array. The leads can also be made of silver paste, copper paste, or mixed plasma. For example, the mixed plasma is formed by silver paste and copper paste. One end of a portion of the interdigitated electrode devices 200 is connected to one of the leads, and one end of another portion of the interdigitated electrode devices 200 is connected to another lead. Along the extension direction of the leads, the interdigitated electrode devices 200 on the leads are distributed crosswise with the interdigitated electrode devices 200 on the other leads. Each lead has a lead terminal 203 at its end for connecting a wire 5.
[0050] The spacing between two adjacent capacitor arrays 20 can be determined according to actual measurement needs, for example, the spacing between two adjacent capacitor arrays 20 is 5mm.
[0051] See Figure 2 As shown, under the same length, if the flexible capacitive sensor 2 uses a single capacitor array 20, there will be too many capacitors connected in parallel, and the change in the detected capacitance may not be obvious. If three or more capacitor arrays 20 are used, there will be too many end leads and the size occupied may not meet the requirements of small size design.
[0052] Therefore, in order to achieve both high performance and reduced fabrication difficulty, the sensor size needs to be reduced. (See [reference needed]) Figure 2 As shown, of the two leads of capacitor array 20, one is a common lead 201 and the other is an independent lead 202, and the common lead 201 of each capacitor array 20 is the same lead.
[0053] To ensure that the independent lead 202 runs in a straight line with a shorter length, facilitating wiring, further reducing fabrication difficulty, and decreasing the sensor size, see [reference needed]. Figure 2 As shown, each capacitor array 20 has a different width, and along the length of the flexible capacitor sensor 2, each capacitor array 20 is arranged in order of its width.
[0054] As a preferred option, see Figure 2As shown, there are two capacitor arrays 20 with different widths. The distance between the two leads of one capacitor array 20 is 2.6 mm, and the length of the interdigital electrode device 200 is 2.5 mm. The distance between the two leads of the other capacitor array 20 is 1.6 mm, and the length of the interdigital electrode device 200 is 1.5 mm.
[0055] This application also provides a method for fabricating the above-mentioned flexible sacrificial capacitive sensor with real-time position feedback of the burning surface, which includes the following steps:
[0056] 101: Print flexible capacitive sensor 2 on substrate 1.
[0057] 102: Encapsulation is performed on the flexible capacitive sensor 2 to form an encapsulation coating 3, thereby obtaining a flexible sacrificial capacitive sensor.
[0058] In step 101, the flexible capacitive sensor 2 is encapsulated, which specifically includes the following steps: preparing a screen printing plate, printing a low-temperature conductive paste, such as silver paste, copper paste or mixed paste, onto the substrate 1 using screen printing technology, and heating and sintering it to solidify the conductive paste on the substrate 1 to form the flexible capacitive sensor 2.
[0059] The viscosity of the conductive paste can be selected according to the actual preparation needs. For example, the viscosity of the conductive paste is 8000-12000 cps. The heating and sintering includes heating time and heating temperature. The specific data can be selected according to the actual preparation needs. For example, the heating time is 20-50 min and the heating temperature is 100-140℃.
[0060] In step 101, the flexible capacitive sensor 2 is encapsulated to form an encapsulation coating 3, which includes the following steps:
[0061] A gel electrolyte is applied to the flexible capacitive sensor 2, and after drying, an encapsulation coating 3 is formed.
[0062] As can be seen, the flexible sacrificial capacitive sensor provided in this application detects the position of the burning surface by detecting changes in capacitance during combustion. The sensor is conformally attached to the end face of the propellant column, making the feedback signal more accurate and solving the problem that traditional temperature control sensors cannot monitor extreme environments of high temperature and high pressure due to high temperature burnout.
[0063] This application utilizes multiple capacitor arrays to achieve long-distance monitoring of the burning surface position.
[0064] The sensor in this application is small in size, has a simple manufacturing process, and uses readily available materials, which greatly reduces manufacturing costs.
[0065] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.
[0066] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0067] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A flexible sacrificial capacitive sensor for real-time position feedback of a burning surface, characterized in that, It includes: Substrate (1); A flexible capacitive sensor (2) is disposed on the substrate (1); Encapsulation coating (3), the encapsulation coating (3) is encapsulated on the surface of the flexible capacitive sensor (2); The flexible capacitive sensor (2) includes multiple capacitor arrays (20) spaced apart along the length of the flexible capacitive sensor (2), and each capacitor array (20) has two lead terminals (203) for connecting wires (5) so that the capacitor array (20) and the capacitance detection module (4) form an independent circuit. The capacitor array (20) includes two parallel leads and a plurality of interdigital electrode devices (200) located between the two leads. One end of a portion of the interdigital electrode devices (200) is connected to one of the leads, and one end of another portion of the interdigital electrode devices (200) is connected to the other lead. Along the extension direction of the leads, the interdigital electrode devices (200) on the leads are intersected with the interdigital electrode devices (200) on the other leads. Each of the leads has a lead terminal (203) at its end for connecting a wire (5). Of the two leads of the capacitor array (20), one is a common lead (201) and the other is an independent lead (202), and the common lead (201) of each capacitor array (20) is the same lead; Each of the capacitor arrays (20) has a different width, and along the length direction of the flexible capacitive sensor (2), each of the capacitor arrays (20) is arranged in sequence according to its width.
2. The flexible sacrificial capacitive sensor with real-time position feedback of the combustion surface as described in claim 1, characterized in that: The interdigitated electrode device (200) is manufactured using silver paste, copper paste, or a mixture of silver paste and copper paste. And / or, the leads are manufactured using silver paste, copper paste, or a mixture of silver paste and copper paste; And / or, the spacing between two adjacent interdigitated electrode devices (200) is 200 μm; And / or, the spacing between two adjacent capacitor arrays (20) is 5 mm; And / or, there are two capacitor arrays (20) with different widths, one of which has a distance of 2.6 mm between the two leads and a length of 2.5 mm for the interdigitated electrode device (200), and the other has a distance of 1.6 mm between the two leads and a length of 1.5 mm for the interdigitated electrode device (200).
3. The flexible sacrificial capacitive sensor with real-time position feedback of the combustion surface as described in claim 1, characterized in that: The encapsulation coating (3) uses a gel electrolyte; And / or, the substrate (1) is made of polyimide film, PET or PP; And / or, the length * width of the lead terminal (203) is 3mm * 1mm; And / or, the length*width of the flexible capacitive sensor (2) is 100mm*5mm.
4. A method for fabricating a flexible sacrificial capacitive sensor with real-time position feedback of the combustion surface as described in claim 1, characterized in that, It includes: A flexible capacitive sensor (2) is printed on a substrate (1); A flexible sacrificial capacitor sensor is obtained by encapsulating the flexible capacitive sensor (2) to form an encapsulation coating (3).
5. The preparation method according to claim 4, characterized in that, The flexible capacitive sensor (2) is printed on the substrate (1) by the following steps: The conductive paste is printed onto the substrate (1) and heated and sintered to solidify the conductive paste on the substrate (1) to form a flexible capacitive sensor (2).
6. The preparation method according to claim 5, characterized in that: The viscosity of the conductive paste is 8000~12000cps, and the heating and sintering process includes a heating time of 20~50min and a heating temperature of 100~140℃.
7. The preparation method according to claim 4, characterized in that, Encapsulation is performed on the flexible capacitive sensor (2) to form an encapsulation coating (3), including the following steps: A gel electrolyte is applied to the flexible capacitive sensor (2), and after drying, an encapsulation coating (3) is formed.