Structure and method for enhancing propellant coating interface reliability

Abstract

The application discloses a structure and method for enhancing the reliability of propellant coating interface, the structure comprising a charge grain, a side coating layer and an end coating layer, wherein, a stress release groove is arranged in the side coating layer at the closed end of the grain; and a coating liquid is arranged in the stress release groove. The method comprises the following steps: step S1: winding and coating the charge grain according to the process requirements, and solidifying; step S2: flattening the end face of the grain; step S3: retaining the side coating layer, and inwardly digging a groove in the grain to process a stress release groove; step S4: filling the stress release groove with the coating liquid, and solidifying; and step S5: pasting the end coating layer to the end face of the coating liquid after the solidification in step S4, and pressurizing and solidifying. The structure prepared by the method can increase the difficulty of the contact between high-temperature gas and the internal charge, can guarantee the working performance of the charge even in the case of environmental change, and greatly improves the coating reliability.

Description

Technical Field

[0001] This invention relates to the field of propellant coating technology, and more specifically to a structure and method for enhancing the reliability of propellant coating interfaces. Background Technology

[0002] The statements in this section provide only background information relevant to the disclosure of this application and may not constitute prior art.

[0003] Columnar solid propellant charge structures typically employ side and end-face coverings to achieve single-end-face combustion of the charge.

[0004] The propellant grain side coating adopts a winding coating process. The propellant is fixed on the tooling, and a CNC lathe is used to control the lathe speed, pitch and other parameters to wind and coat the epoxy resin coating agent and composite base tape on the side of the propellant grain. After the coating agent cures, further processing is carried out to prevent the side of the propellant from burning.

[0005] The end face of the propellant column is covered by a flame-retardant coating sheet. The flame-retardant coating material, nitrocellulose lacquer cloth or EPDM, is pre-processed into a thin circular sheet and then pasted onto the end face of the propellant column.

[0006] Therefore, the propellant grain, side coating, and end coating are three different materials. Due to the influence of ambient temperature changes under different environments, the strain scale of these three materials varies, which can easily cause the bonding interface to separate. When assembled into the engine, the interface separation can easily cause ignition because it cannot be flame-retardant, affecting the performance of the propellant in the engine.

[0007] Therefore, the method of covering the explosive charge needs to be improved. Summary of the Invention

[0008] The purpose of this invention is to address the problem that current coating methods affect performance by providing a structure and method that enhances the reliability of the propellant coating interface, solves the problem of reduced flame retardancy due to interface separation caused by changes in ambient temperature, and ensures that the propellant charge maintains single-end-face combustion during use, thereby improving the engine's environmental adaptability.

[0009] The technical solution of the present invention is as follows:

[0010] A method for enhancing the reliability of propellant coating interfaces includes the following steps:

[0011] Step S1: Wrap the propellant column with the sides according to the process requirements and allow it to cure;

[0012] Step S2: Smooth the end face of the propellant column;

[0013] Step S3: Retain the side coating layer, and cut a groove inwards from the propellant grain to create a stress relief groove;

[0014] Step S4: Fill the stress relief tank with coating liquid and allow it to cure;

[0015] Step S5: Apply the end coating layer to the end face of the coating liquid after the curing in step S4, and then apply pressure to cure.

[0016] By utilizing the stable connection between the coating fluid in the stress relief tank and the side coating layer, the propellant charge, and the end coating layer, a buffer is provided for the thermal expansion and contraction of the side and end coating layers of the propellant charge. Even if the side and end coating layers separate due to environmental factors, the coating fluid in the stress relief tank can still seal the interface. Furthermore, it extends the path for external high-temperature gas to enter the propellant and contact the solid end of the propellant charge, increasing the difficulty for the high-temperature gas to ignite the internal propellant charge and effectively preventing propellant fire.

[0017] According to a preferred embodiment, the depth of the stress relief groove is 0.3mm-3mm. The depth of the stress relief groove needs to create an angle between the propellant and the side coating layer, extending the path for external air to enter the propellant and contact the propellant; the minimum depth is 0.3mm. If the depth of the stress relief groove is too large, it will not be conducive to the solidification of the coating liquid and will not guarantee sufficient propellant quantity; the maximum depth of the stress relief groove is 3mm.

[0018] According to a preferred embodiment, the coating liquid is a mixture of acetone and nitrocellulose lacquer.

[0019] According to a preferred embodiment, the ratio of acetone to nitrocellulose lacquer in the coating solution is 1:2 to 1:6, and the mixture needs to be stirred at room temperature for 30 minutes after mixing. When the ratio of acetone to nitrocellulose lacquer is too small, the nitrocellulose lacquer has poor fluidity, affecting the coating and filling effect; when the ratio of acetone to nitrocellulose lacquer is too large, acetone will evaporate and generate bubbles, thus affecting the filling effect. Therefore, a ratio of acetone to nitrocellulose lacquer of 1:2 to 1:6 is the optimal ratio.

[0020] According to a preferred embodiment, in step S4, the curing time is 15 minutes.

[0021] According to a preferred embodiment, in step S5, the pressure for curing is 50N to 100N, and the curing time is at least 4 hours.

[0022] In another aspect, the present invention provides a structure for enhancing the reliability of the propellant side-coating and end-coating interfaces, comprising a propellant grain, a side-coating layer, and an end-coating layer.

[0023] It also includes a stress relief groove, which is disposed at one end of the propellant column sealed within the side coating layer;

[0024] The stress relief tank is filled with a coating liquid.

[0025] According to a preferred embodiment, the depth of the stress relief groove is 0.3mm-3mm.

[0026] According to a preferred embodiment, the side of the stress relief groove that contacts the propellant and the side that contacts the side coating are configured with uneven end faces. For example, they are wavy or serrated, further extending the path for external high-temperature gas to enter the propellant.

[0027] According to a preferred embodiment, the coating liquid is a mixture of acetone and nitrocellulose lacquer.

[0028] Compared with existing technologies, the advantages of this invention are:

[0029] 1. A structure and method for enhancing the reliability of propellant coating interfaces, which, by means of the buffer of stress relief grooves, increases the difficulty of forming interfaces between the propellant side coating and end coating. Even if an interface is formed, the coating liquid filled in the stress relief grooves can block external high-temperature gases, extend the path of high-temperature gases from the end face into the propellant interior, increase the difficulty of solid end arcing, and enhance the reliability of the propellant side coating and end coating interfaces. Attached Figure Description

[0030] Figure 1 A schematic diagram of existing propellant coating;

[0031] Figure 2 This is a schematic diagram of the improved propellant coating in this application.

[0032] Reference numerals: 100-charged propellant column, 200-side coating, 300-end coating, 400-stress relief groove. Detailed Implementation

[0033] It should be noted that 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.

[0034] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0035] Example 1

[0036] A method for enhancing the reliability of propellant coating interfaces includes the following steps:

[0037] Step S1: Wrap the propellant column 100 around its sides according to the process requirements and allow it to cure;

[0038] Step S2: Smooth the end face of the medicine column;

[0039] Step S3: Retain the side coating layer 200, and cut a groove inward from the explosive charge to create a stress relief groove 400;

[0040] Step S4: Fill the stress relief tank 400 with coating liquid and allow it to cure;

[0041] Step S5: Apply the end coating layer 300 to the end face of the coating liquid after the curing in step S4, and cure under pressure.

[0042] By utilizing the stable connection between the coating liquid in the stress relief tank 400 and the side coating layer 200, the charge, and the end coating layer 300, a buffer is provided for the thermal expansion and contraction of the side coating layer 200 and the end coating layer 300 of the charge. Even if the side coating layer 200 and the end coating layer 300 separate due to environmental factors, the coating liquid in the stress relief tank 400 can still seal the interface. Furthermore, it extends the path for external high-temperature gas to enter and contact the charge at the solid end, increasing the difficulty for the high-temperature gas to contact the charge and ignite the internal charge, thus preventing the charge from igniting.

[0043] According to a preferred embodiment, the depth of the stress relief groove 400 is 0.3mm-3mm. The depth of the stress relief groove 400 needs to create an angle between the propellant and the side coating layer 200, extending the path for external air to enter the propellant and contact the propellant; the minimum depth is 0.3mm. If the depth of the stress relief groove 400 is too large, it will hinder the solidification of the coating fluid and reduce the amount of propellant filling the propellant. Therefore, the maximum depth of the stress relief groove 400 is 3mm.

[0044] According to a preferred embodiment, the coating liquid is a mixture of acetone and nitrocellulose lacquer.

[0045] According to a preferred embodiment, the ratio of acetone to nitrocellulose lacquer in the coating solution is 1:2, and the solution is stirred at room temperature for 30 minutes.

[0046] According to a preferred embodiment, in step S4, the curing time is 15 minutes.

[0047] According to a preferred embodiment, in step S5, the pressure for curing is 50N to 100N, and the curing time is at least 4 hours.

[0048] Example 2

[0049] Existing propellant coating methods such as Figure 1 As shown.

[0050] The present invention provides a structure for enhancing the reliability of the propellant coating interface, as follows: Figure 2 As shown, it includes a propellant charge 100, a side coating layer 200, and an end coating layer 300.

[0051] It also includes a stress relief groove 400, which is disposed at one end of the propellant column inside the side covering layer 200;

[0052] The stress relief tank 400 is filled with a coating liquid.

[0053] According to a preferred embodiment, the depth of the stress relief groove 400 is 0.3mm-3mm.

[0054] According to a preferred embodiment, the side of the stress relief groove 400 that contacts the propellant is configured as an uneven end face to enhance the contact strength between the stress relief groove 400 and the propellant. For example, it can be serrated or wavy.

[0055] According to a preferred embodiment, the side of the stress relief groove 400 that contacts the inner side of the side covering layer 200 is configured as an uneven end face. For example, it can be serrated or wavy, which further extends the path for high-temperature gas to enter the interior and contact the explosive charge during external operation, thus more reliably preventing explosive flashover.

[0056] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A method for enhancing the reliability of propellant coating interfaces, characterized in that, Includes the following steps: Step S1: Wrap the propellant column (100) around its sides according to the process requirements and allow it to cure; Step S2: Smooth the end face of the medicine column; Step S3: Retain the side coating layer (200), and cut a groove inward from the propellant grain to create a stress relief groove (400); Step S4: Fill the stress relief tank (400) with coating liquid and allow it to cure; Step S5: Apply the end coating layer to the end face of the coating liquid after the curing in step S4, and then apply pressure to cure.

2. The method for enhancing the reliability of the propellant coating interface according to claim 1, characterized in that, The depth of the stress relief groove (400) is 0.3mm-3mm.

3. The method for enhancing the reliability of the propellant coating interface according to claim 1, characterized in that, The coating liquid is a mixture of acetone and nitrocellulose lacquer.

4. The method for enhancing the reliability of the propellant coating interface according to claim 1, characterized in that, In step S4, the curing time is 15 minutes.

5. The method for enhancing the reliability of the propellant coating interface according to claim 1, characterized in that, In step S5, the pressure for curing is 50N to 100N, and the curing time is at least 4 hours.

6. A structure for enhancing the reliability of the propellant coating interface, characterized in that, It includes a propellant charge (100), a side coating (200), and an end coating (300). It also includes a stress relief groove (400), which is disposed at one end of the propellant column within the side covering layer (200); The stress relief tank (400) is filled with a coating liquid.

7. The structure for enhancing the reliability of the propellant coating interface according to claim 6, characterized in that, The depth of the stress relief groove (400) is 0.3mm-3mm.

8. The structure for enhancing the reliability of the propellant coating interface according to claim 6, characterized in that, The side of the stress relief groove (400) that contacts the charge and / or the side that contacts the inside of the side covering layer (200) is provided as an uneven end face.

9. The structure for enhancing the reliability of the propellant coating interface according to claim 6, characterized in that, The coating liquid is a mixture of acetone and nitrocellulose lacquer.

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