Method for improving combustion rate of end-combustion solid propellant

Abstract

The invention discloses a method for improving the burning rate of an end-combustion solid propellant. The method comprises the following steps: preparing a pure silver mesh belt; cutting the prepared pure silver mesh belt to obtain a rectangular strip-shaped pure silver mesh belt; the rectangular strip-shaped pure silver mesh belt is pretreated; embedding the pretreated rectangular strip-shaped pure silver mesh belt into the end combustion solid propellant in the direction perpendicular to the combustion surface; and after demolding, shearing and removing redundant pure silver mesh belts at the two ends of the end-combustion solid propellant to obtain the end-combustion solid propellant embedded with the pure silver mesh belts so as to improve the combustion speed of the end-combustion solid propellant. According to the method, the pure silver mesh belt is embedded in the end-combustion solid propellant, the area of a rapid heat dissipation path is increased, and heat is transferred from a combusted part to an uncombusted part, so that the combustion surface of the end-combustion solid propellant is enlarged, the combustion speed of the end-combustion solid propellant is increased, and the service life of the end-combustion solid propellant is prolonged. The problems that in an existing technical scheme, the burning speed of an end-burning solid propellant is limited in increasing amplitude, burning is uneven, and a single silver wire is prone to being snapped are solved.

Description

Technical Field

[0001] This invention belongs to the field of solid rocket propulsion technology, and particularly relates to a method for increasing the burning rate of end-burning solid propellants. Background Technology

[0002] With the advancement of modern science and technology, higher demands have been placed on the thrust of solid rocket engines. Among these, end-burning solid propellants, due to their advantages of simple structure, stable thrust, and high reliability, are considered a good propellant loading method and are widely used in gas generators, end-launch engines, and boosters in solid rocket engines. However, their small combustion area and low burning rate result in excessively low thrust, which severely limits their application.

[0003] Simply changing the formulation to increase the burning rate of end-burning solid propellants can negatively impact other ballistic properties, processing performance, and safety performance. In the past, the production of end-burning solid propellants often involved embedding silver wires, which have the best thermal conductivity found in nature, into the propellant. In silver-wire-embedded end-burning solid propellants, the enhancement effect of the silver wire, as a one-dimensional linear conductor, is highly dependent on the integrity and consistency of each individual wire. However, the tensile strength of silver wire is only 120MPa~180MPa, and its high cost limits its application. Furthermore, in monofilament-embedded end-burning solid propellants, the small contact area between the silver wire and the propellant limits the acceleration effect. Therefore, there is an urgent need for a material with a special structure and excellent heat transfer properties to be embedded in end-burning solid propellants to improve their burning rate. Summary of the Invention

[0004] The technical problem solved by the present invention is to overcome the shortcomings of the prior art and provide a method for improving the burning rate of end-burning solid propellants. This method involves embedding a specially designed pure silver mesh belt into the end-burning solid propellant to achieve precise and efficient control of the burning rate of the end-burning solid propellant.

[0005] To address the aforementioned technical problems, this invention discloses a method for increasing the burning rate of end-burning solid propellants, comprising: A pure silver mesh belt was prepared. The prepared pure silver mesh strip is cut to obtain rectangular strips of pure silver mesh strip; Pre-treatment of rectangular strip-shaped pure silver mesh strips; The pretreated rectangular strips of pure silver were embedded into the end-burning solid propellant in a direction perpendicular to the combustion surface. After demolding, the excess pure silver mesh strips at both ends of the end-burning solid propellant are cut off to obtain end-burning solid propellant with embedded pure silver mesh strips.

[0006] In the above-mentioned method for increasing the burning rate of end-burning solid propellants, the pure silver mesh belt is prepared by using pure silver wire with a diameter of 0.1 mm and a hand-weaving method.

[0007] In the above method for increasing the burning rate of end-burning solid propellants, the pure silver mesh belt has a pore size of 200 mesh and a square pore shape.

[0008] In the above method for increasing the burning rate of end-burning solid propellants, the rectangular strip of pure silver mesh has a width of 7 mm and a length of 200 mm.

[0009] In the above-mentioned method for improving the burning rate of end-burning solid propellants, the rectangular strip of pure silver mesh is pretreated by: placing the rectangular strip of pure silver mesh in a 2% sodium bicarbonate solution and soaking it for 2-4 hours; then, removing the rectangular strip of pure silver mesh from the sodium bicarbonate solution and wiping it with pure cotton gauze to clean the residue and remove the rust stains on the surface of the rectangular strip of pure silver mesh, so as to improve the bonding strength between the rectangular strip of pure silver mesh and the end-burning solid propellant.

[0010] In the above-mentioned method for increasing the burning rate of end-burning solid propellants, when the pretreated rectangular strip of pure silver mesh is embedded into the end-burning solid propellant in a direction perpendicular to the burning surface, it is ensured that the embedded rectangular strip of pure silver mesh has an intact structure and is located at the center of the end-burning solid propellant.

[0011] The above-mentioned method for increasing the burning rate of end-burning solid propellants further includes: using underwater acoustic emission to test the static burning rate of the prepared end-burning solid propellant embedded with pure silver mesh; wherein, if the static burning rate does not meet the desired growth rate ratio, the aperture of the pure silver mesh is adjusted until the static burning rate meets the desired growth rate ratio; if the static burning rate meets the desired growth rate ratio, it is determined that the currently prepared end-burning solid propellant embedded with pure silver mesh meets the requirements.

[0012] In the above-mentioned method for increasing the burning rate of end-burning solid propellants, when the static burning rate of the prepared end-burning solid propellant embedded with pure silver mesh belt was tested using the underwater acoustic emission method, the test pressure was 6.86 MPa.

[0013] The present invention has the following advantages: This invention discloses a method for increasing the burning rate of end-burning solid propellants. By embedding pure silver mesh strips into the end-burning solid propellant, the area of ​​the rapid heat dissipation path is increased, and heat is transferred from the burned part to the unburned part, thereby expanding the burning surface of the end-burning solid propellant and increasing its burning rate. This solves the problems of limited increase in burning rate, uneven combustion, and easy breakage of single silver wires in existing technologies. Attached Figure Description

[0014] Figure 1 This is a flowchart of a method for increasing the burning rate of end-burning solid propellants according to an embodiment of the present invention. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed herein will be described in further detail below with reference to the accompanying drawings.

[0016] One of the core ideas of this invention is to overcome the shortcomings of silver-embedded wire end-burning solid propellants and to further pursue higher and more stable and uniform burning rates. A method to improve the burning rate of end-burning solid propellants is proposed, which extends silver from "lines" to "surfaces". Compared with silver wires, silver mesh has a larger specific surface area and a better thermal conductivity structure. Moreover, since there are multiple silver wires at the cross-section, the tensile strength is 3 to 5 times that of a single silver wire.

[0017] Reference Figure 1 In this embodiment, the method for increasing the burning rate of the end-burning solid propellant includes: S1, pure silver mesh belt was prepared.

[0018] In this embodiment, pure silver wire with a diameter of 0.1 mm can be used, and a pure silver mesh belt can be prepared by hand weaving. The prepared pure silver mesh belt has a mesh size of 200 meshes and a square mesh shape.

[0019] S2, the prepared pure silver mesh strip is cut to obtain rectangular strips of pure silver mesh strip.

[0020] In this embodiment, the width of the rectangular strip of pure silver mesh obtained by cutting is 7mm and the length is 200mm.

[0021] S3, pre-treatment of rectangular strip-shaped pure silver mesh belt.

[0022] In this embodiment, the rectangular strip of pure silver mesh is placed in a 2% sodium bicarbonate solution and soaked for 2-4 hours. Then, the rectangular strip of pure silver mesh is removed from the sodium bicarbonate solution and wiped with pure cotton gauze to clean the residue and remove the rust stains on the surface of the rectangular strip of pure silver mesh, ensuring that there is no residue, dirt or oxidized parts on the surface of the rectangular strip of pure silver mesh, so as to improve the bonding strength between the rectangular strip of pure silver mesh and the end-burning solid propellant.

[0023] S4. The pretreated rectangular strip of pure silver mesh is embedded into the end-burning solid propellant in a direction perpendicular to the combustion surface.

[0024] In this embodiment, when the pretreated rectangular strip of pure silver mesh is embedded into the end-burning solid propellant perpendicular to the combustion surface, the embedded rectangular strip of pure silver mesh is structurally intact and positioned at the center of the end-burning solid propellant. The end-burning solid propellant is an HTPB-based composite solid propellant, with the following proportions: HTPB content 6%–7%, aluminum powder content 18%–19%, AP content 65%–66%, and other components such as burning rate modifiers 8%–11%.

[0025] S5. After demolding, the excess pure silver mesh strips at both ends of the end-burning solid propellant are cut off to obtain end-burning solid propellant with embedded pure silver mesh strips.

[0026] In this embodiment, by embedding a pure silver mesh belt into the end-burning solid propellant through the above steps S1~S5, the area of ​​the rapid heat dissipation path can be increased, and heat can be transferred from the burned part to the unburned part, thereby expanding the burning surface of the end-burning solid propellant and thus increasing the burning rate of the end-burning solid propellant.

[0027] S6. Using underwater acoustic emission, the static burning rate of the prepared end-burning solid propellant embedded with a pure silver mesh belt is tested. If the static burning rate does not meet the desired growth rate ratio, the aperture of the pure silver mesh belt is adjusted until the static burning rate meets the desired growth rate ratio. If the static burning rate meets the desired growth rate ratio, the currently prepared end-burning solid propellant embedded with a pure silver mesh belt is determined to meet the requirements. The test pressure for testing the static burning rate of the prepared end-burning solid propellant embedded with a pure silver mesh belt using underwater acoustic emission is 6.86 MPa.

[0028] In this embodiment, the speed-up ratio refers to the burning rate of the end-burning solid propellant with embedded pure silver mesh belt divided by the burning rate of the end-burning solid propellant without embedded pure silver mesh belt (or silver wire) under the same combustion conditions. This can intuitively reflect the speed-up effect of the end-burning solid propellant with embedded pure silver mesh belt.

[0029]

[0030] Table 1. Examples of Static Combustion Growth Rates As shown in Table 1 above, the speed-increasing effect of pure silver mesh belt on end-burning solid propellants is far superior to that of single silver wires with diameters of 0.1 mm and 0.15 mm on end-burning solid propellants.

[0031] In summary, this invention discloses a method for increasing the burning rate of end-burning solid propellants. By embedding pure silver mesh strips into the end-burning solid propellant, the area of ​​the rapid heat dissipation path is increased, and heat is transferred from the burned part to the unburned part, thereby expanding the burning surface of the end-burning solid propellant and increasing its burning rate. This solves the problems of limited increase in burning rate, uneven combustion, and easy breakage of single silver wires in existing technologies.

[0032] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0033] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for increasing the burning rate of an end-burning solid propellant, characterized in that, include: A pure silver mesh belt was prepared. The prepared pure silver mesh strip is cut to obtain rectangular strips of pure silver mesh strip; Pre-treatment of rectangular strip-shaped pure silver mesh strips; The pretreated rectangular strips of pure silver were embedded into the end-burning solid propellant in a direction perpendicular to the combustion surface. After demolding, the excess pure silver mesh strips at both ends of the end-burning solid propellant are cut off to obtain end-burning solid propellant with embedded pure silver mesh strips.

2. The method for increasing the burning rate of end-burning solid propellant according to claim 1, characterized in that, The process of preparing a pure silver mesh belt involves using pure silver wire with a diameter of 0.1 mm and employing a hand-weaving method to prepare the pure silver mesh belt.

3. The method for increasing the burning rate of end-burning solid propellant according to claim 1, characterized in that, The pure silver mesh tape has a 200-mesh aperture and a square aperture shape.

4. The method for increasing the burning rate of end-burning solid propellant according to claim 1, characterized in that, The rectangular strip of pure silver mesh is 7mm wide and 200mm long.

5. The method for increasing the burning rate of end-burning solid propellant according to claim 1, characterized in that, The rectangular strip of pure silver mesh is pretreated by immersing it in a 2% sodium bicarbonate solution for 2-4 hours. Then, the strip is removed from the sodium bicarbonate solution and wiped with pure cotton gauze to remove residue and rust, thereby improving the bonding strength between the strip and the end-burning solid propellant.

6. The method for increasing the burning rate of end-burning solid propellant according to claim 1, characterized in that, When embedding the pretreated rectangular strip of pure silver mesh into the end-burning solid propellant in a direction perpendicular to the combustion surface, ensure that the embedded rectangular strip of pure silver mesh is structurally intact and located at the center of the end-burning solid propellant.

7. The method for increasing the burning rate of end-burning solid propellant according to claim 1, characterized in that, Also includes: The static burning rate of the prepared end-burning solid propellant embedded with pure silver mesh was tested using underwater acoustic emission method. If the static burning rate did not meet the desired growth rate ratio, the aperture of the pure silver mesh was adjusted until the static burning rate met the desired growth rate ratio. If the static burning rate met the desired growth rate ratio, the prepared end-burning solid propellant embedded with pure silver mesh was determined to meet the requirements.

8. The method for increasing the burning rate of end-burning solid propellant according to claim 1, characterized in that, When the static burning rate of the prepared end-burning solid propellant embedded with a pure silver mesh belt was tested using the underwater acoustic emission method, the test pressure was 6.86 MPa.

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