A central large-debonded combustion chamber structure

Abstract

The application discloses a middle large-debonding combustion chamber structure, which comprises a shell, an adiabatic layer, a lining layer and a propellant column, the propellant column is firmly bonded with the adiabatic layer through the lining layer, the adiabatic layer is bonded with the head and tail of the shell, and the middle part is not bonded, and the interface between the adiabatic layer and the shell is in a free-debonding state in the unbonded part. The free-debonding of the interface between the adiabatic layer of the cylinder segment and the shell releases the stress of the solid propellant column, solves the problem of the debonding of the interface between the propellant, the lining layer and the adiabatic layer caused by the deformation of the solid propellant column in the solidification cooling and low-temperature severe environment, effectively prevents the damage of the propellant structure, and is favorable for improving the working reliability of the solid rocket engine. Meanwhile, compared with the traditional combustion chamber adopting the free-filling propellant column, the structure process is simpler, the production cycle can be greatly shortened, the cost is lower, and the universality is higher.

Description

Technical Field

[0001] This invention belongs to the technical field of solid rocket engine combustion chamber structure design, specifically relating to a central large debonding combustion chamber structure. Background Technology

[0002] Combustion chamber propellant loading is a crucial component of solid rocket motors, and the integrity of the propellant loading structure directly impacts the engine's thrust performance and reliability. When solid propellant grains undergo cooling and curing in harsh cryogenic environments, the outer surface of the grain shrinks inward due to internal stress. This causes debonding at the propellant / liner / insulation interface, resulting in loading defects. Consequently, this leads to an abnormal increase in the combustion surface area during engine operation, triggering a sudden surge in thrust and pressure.

[0003] Currently, free-loading propellant grains with a protective sleeve are mainly used as a means to prevent loading defects caused by debonding at the propellant / liner / insulation layer interface of solid propellant grains. However, the protective sleeve not only reduces the amount of propellant in the engine but also increases the difficulty of propellant loading design. If the gap between the protective sleeve and the insulation layer is too small, it is not conducive to propellant loading; if it is too large, it will lead to an increase in gas combustion at the gap, which is not conducive to thermal protection and reduces the reliability of the combustion chamber. In addition, free-loading propellant grains need to consider assemblability. When interference with the insulation layer makes loading difficult, manual grinding is required before loading. Compared with wall casting, the combustion chamber production cycle of free-loading propellant grains is longer and the process is more complex. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a centrally located large debonding combustion chamber structure. By freely debonding the insulation layer at the interface between the cylindrical section and the shell, the stress of the solid propellant grain is released. This solves the problem of propellant / liner / insulation layer interface debonding caused by the deformation of the solid propellant grain during solidification cooling and in harsh low-temperature environments. It effectively prevents damage to the propellant loading structure and improves the operational reliability of solid rocket engines. At the same time, compared with traditional combustion chambers using freely loaded propellant grains, this structure has a simpler manufacturing process, can greatly shorten the production cycle, has lower costs, and has higher versatility.

[0005] The specific technical solution of the present invention is as follows:

[0006] A centrally located debonded combustion chamber structure includes a shell, an insulation layer, a liner, and a propellant grain. The propellant grain is firmly bonded to the insulation layer through the liner. The insulation layer is bonded to the head and tail of the shell, but not in the middle. The interface between the insulation layer and the shell is in a free debonded state in the non-bonded part.

[0007] The free debonding state at the interface between the insulation layer and the middle section of the shell has the function of releasing the stress of the propellant, so as to prevent the interface between the propellant and the insulation layer from debonding and causing damage to the propellant loading structure.

[0008] Preferably, the length of the free-detaching portion of the insulation layer accounts for 82% of the total length of the propellant column.

[0009] Preferably, the insulation layer is EPDM rubber.

[0010] Preferably, the lining is made of an adhesive that has excellent adhesion to the insulation material.

[0011] Preferably, the housing is made of high-strength alloy steel.

[0012] Preferably, the head, middle, and tail of the shell are respectively the front end cap, the cylindrical section, and the rear end cap, and each part is welded by vacuum electron beam welding.

[0013] Preferably, the propellant grain is a solid propellant.

[0014] Preferably, the propellant is an end-burning solid propellant, with an inner diameter of φ282mm to φ282mm, a length of 3172mm, and an elongation greater than 40%.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The combustion chamber structure provided by the present invention effectively releases the stress caused by temperature changes in the solid propellant grain through the free debonding of the insulation layer of the cylindrical section and the shell interface, avoids the debonding of the propellant and insulation layer interface, ensures the integrity of the propellant structure, and is conducive to improving the working reliability of solid rocket engine.

[0017] (2) Compared with the traditional combustion chamber with free-loading propellant, the combustion chamber structure provided by the present invention avoids the need to set up a cover sleeve, which not only eliminates the risk caused by unreasonable gap between the cover sleeve and the insulation layer, but also simplifies the production process. At the same time, it avoids the limitation that the combustion chamber with free-loading propellant must have a large opening at one end. The front and rear joints of the combustion chamber shell provided by the present invention can change the opening size according to the actual task requirements, and have high versatility.

[0018] (3) The propellant grain of the present invention is reliably bonded to the heat insulation layer through the liner, and the heat insulation layer is reliably bonded to the head and tail of the shell, which effectively ensures that the propellant grain will not be relatively displaced from the shell during engine transportation, etc.

[0019] (4) The novel combustion chamber structure provided by the present invention has the advantages of simple structure, strong operability and high filling ratio, which is conducive to reducing costs and increasing efficiency. Attached Figure Description

[0020] To more clearly illustrate the technical solutions disclosed in this invention, the accompanying drawings used in some embodiments of this invention will be briefly described below. Obviously, the drawings described below are merely drawings of some embodiments of this invention, and those skilled in the art can obtain other drawings based on these drawings. Furthermore, the drawings described below can be considered schematic diagrams and are not intended to limit the actual dimensions of the products or the actual flow of the methods involved in the embodiments of this invention.

[0021] Figure 1 A front half-sectional view of a central large debonding combustion chamber structure provided in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the debonding position of a central large debonding combustion chamber structure provided in an embodiment of the present invention.

[0023] The attached diagram is labeled as follows: 1. Shell; 2. Insulation layer; 3. Liner; 4. Propellant charge. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] This invention provides a central debonding combustion chamber structure, comprising a shell, an insulation layer, a liner, and a propellant grain. The propellant grain is firmly bonded to the insulation layer through the liner. The insulation layer is bonded to the head and tail of the shell, but not to the middle section. The interface between the insulation layer and the shell is in a free debonding state in the non-bonded portion.

[0026] The free debonding state at the interface between the insulation layer and the middle section of the shell has the function of releasing the stress of the propellant, so as to prevent the interface between the propellant and the insulation layer from debonding and causing damage to the propellant loading structure.

[0027] Preferably, the length of the free-detaching portion of the insulation layer accounts for 82% of the total length of the propellant column.

[0028] Preferably, the insulation layer is EPDM rubber.

[0029] Preferably, the lining is made of an adhesive that has excellent adhesion to the insulation material.

[0030] Preferably, the housing is made of high-strength alloy steel.

[0031] Preferably, the head, middle, and tail of the shell are respectively the front end cap, the cylindrical section, and the rear end cap, and each part is welded by vacuum electron beam welding.

[0032] Preferably, the propellant grain is a solid propellant.

[0033] Preferably, the propellant is an end-burning solid propellant, with an inner diameter of φ282mm to φ282mm, a length of 3172mm, and an elongation greater than 40%.

[0034] Example

[0035] like Figure 1 As shown, an embodiment of the present invention provides a central large debonding combustion chamber structure, including a shell (1), an insulation layer (2), a liner (3), and a propellant grain (4).

[0036] The shell (1) is made of high-strength alloy steel and adopts a front end cap + cylindrical section + rear end cap design, and each section is welded by vacuum electron beam welding; the inner surface of the combustion chamber shell (1) after the above-mentioned forming is sandblasted to roughen the inner surface, so as to improve the bonding performance between the insulation layer (2) and the shell (1); adhesive is uniformly sprayed on the head and tail of the shell (1), that is, the front end cap + part of the cylindrical section connected with the front end cap and the rear end cap + part of the cylindrical section connected with the rear end cap are uniformly sprayed with adhesive; the insulation layer (2) is firmly bonded to the head and tail of the shell (1) by airbag pressurization, and the remaining parts are detached, the specific detachment locations are as follows Figure 2 As shown, the insulation layer (2) is not bonded to the shell (1) from point a to point b, and is in a free detached state. The length from point a to point b is 2600mm, accounting for 82% of the total length of the propellant column (4), so as to release the stress of the propellant column and effectively prevent the destruction of the propellant loading structure.

[0037] The shell (1) with the above-mentioned bonded insulation layer (2) is placed in an oven for curing. The curing conditions are: oven temperature +60℃, and static curing in the oven for 5-7 days. The inner surface of the above-mentioned cured insulation layer (2) is roughened, and then the lining layer (3) (i.e., the adhesive layer) is uniformly coated. Finally, the propellant column (4) is vacuum-cast onto the inner surface of the above-mentioned lining layer (3). The entire assembly is placed in an oven for curing to form a combustion chamber. The curing conditions are: oven temperature +60℃, and static curing in the oven for 5-7 days.

[0038] The insulation layer (2) is made of EPDM rubber. Its complex head and tail surfaces are made by aluminum alloy molds and polytetrafluoroethylene is sprayed on the mold surface. The cylindrical section adopts a variable thickness design method according to the time of exposure to the gas, which can effectively prevent heat from being transferred to the shell (1) and play a role in protecting the shell (1). The propellant (4) is a solid propellant with an end-burning solid propellant with an elongation of more than 40%, which meets the requirements of the axial and radial deformation rates of the propellant.

[0039] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make possible variations and modifications to the technical solutions of the present invention based on the disclosed content without departing from the spirit and scope of the 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 present invention. The protection scope of the present invention is defined by the appended claims.

[0040] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A centrally located large debonded combustion chamber structure, comprising a shell (1), an insulation layer (2), a liner (3), and a propellant charge (4), wherein the propellant charge (4) is firmly bonded to the insulation layer (2) through the liner (3), characterized in that: The insulation layer (2) is bonded to the head and tail of the shell (1), but not to the middle. The interface between the insulation layer (2) and the shell (1) is in a free detached state in the unbonded part. The length of the free detached portion of the insulation layer (2) accounts for 82% of the total length of the drug column (4); The head, middle and tail of the shell (1) are respectively the front end cap, the cylindrical section and the rear end cap, and each part is welded by vacuum electron beam welding. The propellant grain (4) is a solid propellant; The propellant (4) is an end-burning solid propellant with an inner diameter of φ282mm~φ282mm, a length of 3172mm, and an elongation greater than 40%.

2. The central large debonding combustion chamber structure according to claim 1, characterized in that, The free debonding state at the interface between the insulation layer (2) and the middle section of the shell (1) has the function of releasing the stress of the propellant column (4) and preventing the interface between the propellant column (4) and the insulation layer (2) from debonding and causing damage to the propellant loading structure.

3. The central large debonding combustion chamber structure according to claim 1, characterized in that, The insulation layer (2) is EPDM rubber.

4. The central large debonding combustion chamber structure according to claim 1, characterized in that, The lining (3) is made of an adhesive that has excellent adhesion to the insulation layer (2) material.

5. The central large debonding combustion chamber structure according to claim 1, characterized in that, The shell (1) is made of high-strength alloy steel.

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