Flexible array sensor for flame recession monitoring and method of making and using same

Abstract

The present application belongs to the related technical field of solid engine online detection, and discloses a flexible array sensor for combustion surface recession monitoring, a preparation method and application thereof. The flexible array sensor is in a strip shape, and comprises a polymer film substrate, an upper resistance array, a lower resistance array, a single-sided common lead, a single-sided short lead and a single-sided long lead. The upper resistance array and the lower resistance array are arranged on the polymer film substrate in parallel. The single-sided common lead, the single-sided long lead and the single-sided short lead are arranged on the polymer film substrate. The two sides of the upper resistance array are connected to the single-sided common lead and the single-sided long lead respectively, and the two sides of the lower resistance array are connected to the single-sided common lead and the single-sided short lead respectively. In use, the single-sided common lead, the single-sided long lead and the single-sided short lead are connected to a resistance measurement module respectively. The present application realizes real-time monitoring of the combustion surface position according to resistance change.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid engine online detection, and more particularly to a flexible array sensor for monitoring of burning surface recession and a preparation method and application thereof. BACKGROUND

[0002] A solid rocket engine is mainly used as a main power device in the fields of missile weapons, launch vehicles and other aerospace fields, and is composed of a grain, a shell, a nozzle and an ignition device. During the combustion process of the propellant, the burning surface of the grain recedes along the radial direction of the engine shell. Monitoring of the burning surface recession, adiabatic ablation, throat ablation, grain deformation and other situations occurring during the operation of the solid engine is of great significance for upgrading and replacing the solid engine and improving its safety and reliability.

[0003] When the engine is working, the propellant combustion chamber must withstand high temperature and high pressure, and the online monitoring equipment needs to be electrostatically shielded. These complex environments or complex design requirements pose great challenges to the research and development of the online monitoring system of the solid engine. Therefore, it is urgent to carry out research on online monitoring technology suitable for the high temperature, high pressure and other complex environments of the solid engine.

[0004] The development of sensors is the key to real-time monitoring technology of solid engines. At present, many scholars have researched on monitoring sensors for stress, strain, temperature, humidity and aging conditions of solid engines. In view of the special monitoring requirements of solid engines, such as miniaturization and wirelessness, various sensors such as ceramic thick film stress sensors, interface bonded stress sensors, polymer optical fiber oxygen sensors and embedded wireless dual-mode sensors have been used for multi-parameter real-time monitoring of solid engines. However, the application of flexible electronic technology in real-time monitoring of solid engines is still blank.

[0005] The extensible flexible electronics can be seamlessly attached to the surface of complex engine structural components to achieve complete conformity, which can effectively monitor the temperature, pressure, strain and other information of the surface of complex engine structural components. At the same time, its ultra-soft and ultra-thin characteristics can provide a better solution for obtaining strain, temperature and other parameters of complex structures without affecting the original structure, especially in the field of aerospace structures. The application of flexible electronics in real-time monitoring of solid engines has great potential, which provides support for better promoting the development of solid power technology and related detection technology. SUMMARY

[0006] In view of the above defects or improvement needs of the prior art, the present application provides a flexible array sensor for monitoring the recession of a burning surface, a preparation method and application thereof. The flexible array sensor is arranged radially along the cross section of a propellant grain. When the propellant grain burns, the recession of the burning surface causes the resistor to burn out, which changes the feedback resistance of the flexible array sensor, and the real-time monitoring of the position of the burning surface is realized according to the change of the resistance.

[0007] To achieve the above object, according to one aspect of the present application, a flexible array sensor for monitoring the recession of a burning surface is provided. The flexible array sensor is in a strip shape, which comprises a polymer film substrate, an upper resistor array, a lower resistor array, a single-sided common lead, a single-sided long lead and a single-sided short lead. The upper resistor array and the lower resistor array are arranged on the polymer film substrate in parallel. The single-sided common lead, the single-sided long lead and the single-sided short lead are arranged on the polymer film substrate. The two sides of the upper resistor array are connected to the single-sided common lead and the single-sided long lead, respectively. The two sides of the lower resistor array are connected to the single-sided common lead and the single-sided short lead, respectively. In use, the single-sided common lead, the single-sided long lead and the single-sided short lead are connected to a resistance measurement module.

[0008] Further, the single-sided common lead is arranged on one side of the polymer film substrate, the single-sided long lead is arranged on the other side of the polymer film substrate, and the single-sided short lead is arranged adjacent to the single-sided long lead and between the single-sided common lead and the single-sided long lead.

[0009] Further, the polymer film substrate is in a strip shape, which is selected from a polyimide film.

[0010] Further, the upper resistor array comprises a plurality of long resistor devices, which are identical. The plurality of long resistor devices are arranged in a linear array between the single-sided common lead and the single-sided long lead, and the two ends of each long resistor device are connected to the single-sided common lead and the single-sided long lead, respectively. The plurality of long resistor devices are connected in parallel to form the upper resistor array.

[0011] Further, the lower resistor array comprises a plurality of short resistor devices, which are identical. The plurality of short resistor devices are arranged in a linear array between the single-sided common lead and the single-sided short lead, and the two ends of each short resistor device are connected to the single-sided common lead and the single-sided short lead, respectively. The plurality of short resistor devices are connected in parallel to form the lower resistor array.

[0012] Further, the single-sided common lead, the single-sided long lead and the single-sided short lead are silver paste wires with lead terminals at the bottom ends, and the lead terminals of the single-sided common lead, the single-sided long lead and the single-sided short lead are arranged side by side, facilitating the connection of the leads to the resistance measurement module.

[0013] The application further provides a preparation method of the flexible array sensor for combustion surface recession monitoring, which is used for preparing the flexible array sensor for combustion surface recession monitoring as described above, and comprises the following steps: firstly, attaching a resistor device mask to the surface of a polymer film and brushing carbon nanotube ink on the mask; then, tearing off the mask after the ink is dried and solidified, and then drying the carbon nanotube resistor device using a hot plate; then, printing high-viscosity conductive paste to the surface of the polymer film by silk screen printing to form the single-sided common lead, the single-sided long lead and the single-sided short lead with lead terminals; and then, drying the leads using a hot plate, thereby completing the preparation of the flexible array sensor.

[0014] The application further provides a solid rocket engine, which comprises a grain, a plurality of flexible array sensors as described above, a resistance measurement module and a microprocessor, wherein the resistance measurement module is connected to the microprocessor, the single-sided common lead, the single-sided long lead and the single-sided short lead of the flexible array sensor are respectively connected to the resistance measurement module, the plurality of flexible array sensors are respectively attached to the end faces of the grain and are uniformly arranged in a scattered manner around the central axis of the grain, the resistance detection module is used for detecting the resistance values of the corresponding flexible array sensors and transmitting the detected resistance values to the microprocessor, and the microprocessor is used for calculating the lengths of the corresponding flexible array sensors burned according to the received resistance values, obtaining the relationship between the resistance values of the flexible array sensors and the recession distances of the grain combustion surface, fitting the positions of the grain combustion surface according to the lengths of the plurality of flexible array sensors burned, and thus realizing the real-time monitoring of the combustion surface recession.

[0015] Further, the grain is provided with a through grain inner hole, the flexible array sensor is arranged radially along the end face of the grain, the upper resistance array is arranged adjacent to the grain inner hole, and the lower resistance array is arranged adjacent to the outer circumference of the grain.

[0016] Further, during the online monitoring, the grain is burned from the grain inner hole outward, the flexible array sensor is burned with the grain during the burning process, the detected resistance values change constantly, the length of the flexible array sensor burned is calculated according to the resistance values, and then the position of the grain combustion surface is obtained.

[0017] Overall, compared with the prior art, the flexible array sensor for combustion surface recession monitoring and the preparation method and application thereof provided by the application mainly have the following beneficial effects:

[0018] 1. The upper and lower resistance arrays are arranged side by side, the sensor comprises three leads, one lead is shared by the two resistance arrays, and the three leads are connected with a resistance measurement module, the two resistance arrays do not interfere with each other, and the number of leads used is reduced. In addition, the number of series resistors of the resistance array is adjusted to adjust the sensitivity of the detection value.

[0019] 2. The flexible array sensor is used to detect the position of the burning surface by detecting the change of the resistance in the combustion process, the sensor is conformally attached to the end surface of the propellant grain, so that the feedback signal is more accurate, and the problem that the traditional temperature control sensor is burned out due to high temperature and cannot monitor the extreme environment of high temperature and high pressure is solved.

[0020] 3. With the help of multiple flexible array sensors, long-distance burning surface position monitoring can be achieved.

[0021] 4. The flexible array sensor has small volume, simple preparation process and easy-to-obtain material, which greatly saves the preparation cost. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a use schematic diagram of the flexible array sensor for burning surface recession monitoring provided by the present application;

[0023] Figure 2 is a partial schematic diagram of a solid rocket engine provided by the present application;

[0024] Figure 3 (a) and (b) in are resistance value change curve diagrams in the working process of the flexible array sensor provided by the present application.

[0025] In all the drawings, the same reference signs are used to represent the same elements or structures, wherein: 1-polymer film substrate, 2-upper resistance array, 3-long resistance device, 4-single-sided long lead, 5-lower resistance array, 6-short resistance device, 7-single-sided short lead, 8-single-sided common lead, 9-propellant grain, 10-bore of the propellant grain. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0027] Please refer to Figure 1 and Figure 2The application provides a flexible array sensor for flame front movement monitoring, which is in a strip shape and comprises a polymer film substrate 1, an upper resistance array 2, a lower resistance array 5, a single-sided common lead 8, a single-sided short lead 7 and a single-sided long lead 4. The upper resistance array 2 and the lower resistance array 5 are arranged on the polymer film substrate 1 in parallel. The single-sided common lead 8 is arranged on one side of the polymer film substrate 1, the single-sided long lead 4 is arranged on the polymer film substrate 1, and the single-sided short lead 7 is arranged on the polymer film substrate 1, adjacent to the single-sided long lead 4 and between the single-sided common lead and the single-sided long lead 4. The two sides of the upper resistance array 2 are connected to the single-sided common lead 8 and the single-sided long lead 4 respectively, and the two sides of the lower resistance array 5 are connected to the single-sided common lead 8 and the single-sided short lead 7 respectively. The upper resistance array 2 and the lower resistance array 5 are arranged at opposite ends of the polymer film substrate 1 and do not interfere with each other. In use, the single-sided common lead 8, the single-sided long lead 4 and the single-sided short lead 7 are connected to a resistance measurement module.

[0028] The polymer film substrate 1 is in a strip shape and is made of a polyimide film. The polyimide film has good insulation performance and is easy to burn, and is a commonly used substrate for flexible sensors.

[0029] The upper resistance array 2 comprises a plurality of long resistance devices 3. The long resistance devices 3 have the same size to ensure theoretical consistency of resistance. The long resistance devices 3 are arranged in a linear array between the single-sided common lead 8 and the single-sided long lead 4, and the two ends of each long resistance device 3 are connected to the single-sided common lead 8 and the single-sided long lead 4 respectively. The long resistance devices 3 are connected in parallel to form the upper resistance array 2.

[0030] The lower resistance array 5 comprises a plurality of short resistance devices 6. The short resistance devices 6 have the same size to ensure theoretical consistency of resistance. The short resistance devices 6 are arranged in a linear array between the single-sided common lead 8 and the single-sided short lead 7, and the two ends of each short resistance device 6 are connected to the single-sided common lead 8 and the single-sided short lead 7 respectively. The short resistance devices 6 are connected in parallel to form the lower resistance array 5.

[0031] The length of the long resistance device 3 is slightly longer than the length of the short resistance device 6, and the length of the single-sided long lead 4 is greater than the length of the single-sided short lead 7. The long resistance device 3 and the short resistance device 6 are both made of carbon nanotubes. The long resistance device 3 and the short resistance device 6 with uniform length and uniform width are prepared by mask brushing, so as to ensure consistency of resistance in the upper resistance array and the lower resistance array 5.

[0032] The single-sided common lead 8, the single-sided long lead 4 and the single-sided short lead 7 are silver paste wires with lead terminals at the bottom ends, and the lead terminals of the single-sided common lead 8, the single-sided long lead 4 and the single-sided short lead 7 are arranged side by side to facilitate the connection of the lead to the resistance measuring module, and the lead terminal lead-out wires are connected to the resistance measuring module.

[0033] In one embodiment, the polymer film substrate 1 is a polyimide film with a thickness of 0.1 mm, which has excellent radiation resistance and electrical insulation, and can be burned in a high-temperature combustion environment, thereby affecting the resistance value change of the resistance sensor.

[0034] According to the measurement length, the overall size of the flexible array sensor is 5mmx100mm, the upper resistance array 2 and the lower resistance array 5 each contain 18 resistance devices, the long resistance device 3 has a width of 0.4mm and a length of 3mm, which is slightly larger than the distance between the single-sided common lead 8 and the single-sided long lead 4, which is 2.6mm, and the array spacing is 2.5mm; the short resistance device 6 has a width of 0.4mm and a length of 2mm, which is slightly larger than the distance between the single-sided common lead 8 and the single-sided short lead 7, which is 1.6mm, and the array spacing is 2.5mm; the spacing between the upper resistance array 2 and the lower resistance array 5 is 5mm.

[0035] The single-sided long lead 4, the single-sided short lead 7 and the single-sided common lead 8 each have a width of 0.5mm, and the size of the terminal lead terminal at the end is 3mmx1mm; the lead for connecting the resistance measuring module is led out by the corresponding terminal lead terminal of the single-sided long lead 4, the single-sided short lead 7 and the single-sided common lead 8, and during measurement, the single-sided long lead 4 and the single-sided common lead 8 form a loop, and the single-sided short lead 7 and the single-sided common lead 8 form a loop, respectively detecting the resistance value change of the upper and lower resistance arrays 5.

[0036] The present application also provides a preparation method of the flexible array sensor for monitoring the burning surface recession as described above, which mainly comprises the following steps:

[0037] Step one, preparation of resistance device: cut the mask, attach the resistance device mask to the surface of the polymer film, and then brush the carbon nanotube ink on the mask.

[0038] In this embodiment, the mask plate is designed and the mask is cut, and the mask is attached to the surface of the polyimide film, and then the carbon nanotube solution with a concentration of 0.014mg / mL is prepared by ultrasonic dispersion of the carbon nanotube in the dispersant, and the prepared carbon nanotube solution is brushed on the flexible substrate with the mask attached using a soft brush.

[0039] Step two, sintering of resistance device: after the ink is slightly dried and solidified, the mask is removed, and then the carbon nanotube resistance device is dried using a hot plate.

[0040] In this embodiment, the flexible substrate coated with carbon nanotubes is left for 40 minutes, and after the ink is slightly dried and shaped, the mask is removed, and then heated to 80℃ using a hot plate for 30 minutes to completely dry the carbon nanotubes, forming a carbon nanotube resistor device.

[0041] Step three, preparation of conductive wires: high-viscosity conductive paste is printed onto the surface of the polymer film by screen printing technology to form conductive wires with lead terminals.

[0042] In this embodiment, a screen printing plate is prepared, the printing plate is aligned with the carbon nanotube resistor device, and low-temperature silver paste with a viscosity of 10000 cps is printed onto the flexible substrate by screen printing technology to form silver paste wires with lead terminals.

[0043] Step four, sintering of conductive wires: the conductive wires are dried using a hot plate to complete the preparation of the flexible array sensor.

[0044] In this embodiment, the hot plate is heated to 140℃ and sintered for 20 minutes to solidify the silver paste on the flexible substrate, forming three conductive leads, and completing the preparation of the resistive sensor.

[0045] The present application also provides a solid motor, which comprises a propellant grain 9, a plurality of flexible array sensors as described above, a resistance measurement module, and a microprocessor, wherein the resistance measurement module is connected to the microprocessor. The single-sided common lead 8, the single-sided long lead 4, and the single-sided short lead 7 of the flexible array sensor are respectively connected to the resistance measurement module. A plurality of flexible array sensors are respectively attached to the end face of the propellant grain 9 and are uniformly arranged in a scattered manner around the central axis of the propellant grain 9. It can be understood that in other embodiments, in addition to arranging a plurality of flexible array sensors on the end face of the propellant grain 9, a plurality of flexible array sensors can also be arranged on the cross section of the propellant grain 9 perpendicular to the length direction of the propellant grain 9 to test the burning surface recession at different lengths of the propellant grain 9 in real time.

[0046] The propellant grain 9 is provided with a through propellant inner hole 10, the flexible array sensor is arranged radially along the end face of the propellant grain 9, the upper resistance array 2 is arranged adjacent to the propellant inner hole 10, and the lower resistance array 5 is arranged adjacent to the outer circumference of the propellant grain 9. The resistance detection module is used to detect the resistance value of the corresponding flexible array sensor and transmit the detected resistance value to the microprocessor. The microprocessor is used to calculate the length of the corresponding flexible array sensor that is burning according to the received resistance value, and obtain the relationship between the resistance value of the flexible array sensor and the burning surface recession distance of the propellant grain, and then fit the position of the burning surface of the propellant grain according to the lengths of a plurality of flexible array sensors that are burning, thereby realizing real-time monitoring of the burning surface recession.

[0047] Referring to Figure 3 In the online monitoring, the propellant 9 is burned from the propellant inner hole 10 to the outside, and the resistor is burned with the propellant in the burning process, the resistance value obtained by detection is constantly changed, the length of the sensor burning can be calculated according to the resistance value, the relationship curve surface of the resistance value of the resistance type sensor and the burning surface retreat distance is established, the position of the propellant burning surface can be fitted through the length measured by multiple resistance type sensors, and the real-time monitoring of the burning surface retreat is realized.

[0048] Those skilled in the art can easily understand that the above description is only a preferred embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A flexible array sensor for flame recession monitoring, characterized in that: the flexible array sensor is in a strip shape, comprising a polymer film substrate, an upper resistor array, a lower resistor array, a single-sided common lead, a single-sided long lead and a single-sided short lead, the upper resistor array and the lower resistor array are arranged on the polymer film substrate in parallel, the single-sided common lead, the single-sided long lead and the single-sided short lead are arranged on the polymer film substrate, the two sides of the upper resistor array are connected to the single-sided common lead and the single-sided long lead respectively, and the two sides of the lower resistor array are connected to the single-sided common lead and the single-sided short lead respectively; in use, the single-sided common lead, the single-sided long lead and the single-sided short lead are connected to a resistor measurement module respectively. The single-sided common lead is arranged on one side of the polymer film substrate, the single-sided long lead is arranged on the other side of the polymer film substrate, and the single-sided short lead is arranged adjacent to the single-sided long lead and between the single-sided common lead and the single-sided long lead.

2. The flexible array sensor for flame recession monitoring of claim 1, wherein: The polymer film substrate is in a strip shape and is made of polyimide film.

3. The flexible array sensor for flame recession monitoring of claim 1, wherein: The upper resistor array comprises a plurality of long resistor devices, the lower resistor array comprises a plurality of short resistor devices, the plurality of long resistor devices are the same, the plurality of long resistor devices are arranged in a linear array between the single-sided common lead and the single-sided long lead, and the two ends of the long resistor device are connected to the single-sided common lead and the single-sided long lead respectively, and the plurality of long resistor devices are connected in parallel to form the upper resistor array; the plurality of short resistor devices are connected in parallel to form the lower resistor array.

4. The flexible array sensor for flame recession monitoring of claim 1, wherein: The plurality of short resistor devices are the same, the plurality of short resistor devices are arranged in a linear array between the single-sided common lead and the single-sided short lead, and the two ends of the short resistor device are connected to the single-sided common lead and the single-sided short lead respectively.

5. The flexible array sensor for flame recession monitoring of claim 4, wherein: The single-sided common lead, the single-sided long lead and the single-sided short lead are silver paste wires with lead terminals at the bottom, and the lead terminals of the single-sided common lead, the single-sided long lead and the single-sided short lead are arranged in parallel to facilitate lead connection to the resistor measurement module.

6. A flexible array sensor for flame front recession monitoring according to any one of claims 1-4, wherein: The preparation method is used for preparing the flexible array sensor for flame recession monitoring according to any one of claims 1-6, comprising the following steps: first, attaching a resistor device mask to the surface of the polymer film and brushing carbon nanotube ink on the mask; then, after the ink is dried and solidified, the mask is removed, and then the carbon nanotube resistor device is dried using a hot plate; then, the conductive paste is printed to the surface of the polymer film by screen printing to form the single-sided common lead, the single-sided long lead and the single-sided short lead with lead terminals; then, the leads are dried using a hot plate, and the preparation of the flexible array sensor is completed.

7. A method of fabricating a flexible array sensor for flame front recession monitoring, the method comprising: providing a substrate; providing a plurality of sensing elements; and providing a plurality of interconnects, wherein the plurality of sensing elements and the plurality of interconnects are provided on the substrate. ​ 8. A solid motor characterized by: The solid engine comprises a propellant grain, a plurality of flexible array sensors according to any one of claims 1-6, a resistance measurement module and a microprocessor, the resistance measurement module being connected to the microprocessor; the single-side common lead, the single-side long lead and the single-side short lead of the flexible array sensor being connected to the resistance measurement module respectively; a plurality of the flexible array sensors are respectively attached to the end face of the propellant grain and are uniformly arranged in a scattered manner around the central axis of the propellant grain; the resistance measurement module is used for detecting the resistance value of the corresponding flexible array sensor and transmitting the detected resistance value to the microprocessor; the microprocessor is used for calculating the length of the combustion of the corresponding flexible array sensor according to the received resistance value and obtaining the relationship between the resistance value of the flexible array sensor and the retreat distance of the propellant grain combustion surface, and then fitting the position of the propellant grain combustion surface according to the lengths of combustion of a plurality of flexible array sensors, so as to realize real-time monitoring of the retreat of the combustion surface.

9. The solid motor of claim 8, wherein: The propellant grain is provided with a through propellant grain inner hole, the flexible array sensor is arranged radially along the end face of the propellant grain, the upper resistance array is arranged adjacent to the propellant grain inner hole, and the lower resistance array is arranged adjacent to the outer circumference of the propellant grain.

10. The solid motor of claim 9, wherein: In online monitoring, the propellant grain is burned outwardly from the propellant grain inner hole, the flexible array sensor is burned out with the propellant grain during the combustion process, the detected resistance value is constantly changed, the length of the combustion of the flexible array sensor is calculated according to the resistance value, and then the position of the propellant grain combustion surface is obtained.

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