阅读说明：本技术 一种低易损固体火箭发动机壳体结构 (Low-damage solid rocket engine shell structure ) 是由 吴才锦 刘建伟 李娟� 袁清泉 王领 梁生云 于 2020-11-12 设计创作，主要内容包括：本发明提供了一种低易损固体火箭发动机壳体结构,包括壳体、缠绕层和密封塞,所述的壳体上开有若干贯通壳体内外的窗口,所述的密封塞与窗口配合,通过包覆于壳体外的纤维复合材料缠绕层将密封塞封闭在窗口中；当发动机受热且温度超过设定温度,缠绕层损毁,密封塞被壳体内压力推动,窗口打开。本发明无需采用检测和驱动机构即可实现密封塞开启泄压的操作；密封塞开启无金属碎片飞出；壳体上开孔较宽,工艺易于实现,同时降低裂纹扩展风险。(The invention provides a low-damage solid rocket engine shell structure, which comprises a shell, a winding layer and a sealing plug, wherein the shell is provided with a plurality of windows penetrating through the inside and the outside of the shell; when the engine is heated and the temperature exceeds the set temperature, the winding layer is damaged, the sealing plug is pushed by the pressure in the shell, and the window is opened. The operation of opening and pressure relief of the sealing plug can be realized without adopting a detection and driving mechanism; the sealing plug is opened without flying out of metal fragments; the holes on the shell are wide, the process is easy to realize, and meanwhile, the risk of crack propagation is reduced.)

1. A low-damage solid rocket engine shell structure comprises a shell, a winding layer and a sealing plug, and is characterized in that the shell is provided with a plurality of windows penetrating through the inside and the outside of the shell, the sealing plug is matched with the windows, and the sealing plug is sealed in the windows through the winding layer made of fiber composite materials wrapping the shell; when the engine is heated and the temperature exceeds the set temperature, the winding layer is damaged, the sealing plug is pushed by the pressure in the shell, and the window is opened.

2. The low vulnerability solid rocket engine casing structure of claim 1 wherein the casing inner surface is covered with a thermal insulation layer.

3. The low vulnerability solid rocket engine shell structure of claim 1 wherein the sum of the flow areas of all windows on the shell is greater than or equal to ten times the area of the nozzle throat.

4. The low vulnerability solid rocket engine case structure of claim 1 wherein the window is an oblong hole with a long axis parallel to the case axis.

5. The low vulnerability solid rocket engine casing structure of claim 1 wherein the windows are evenly distributed on the casing surface along the circumferential direction, arranged in a ring or rings.

6. The low-vulnerability solid rocket engine shell structure according to claim 1, wherein the windows are arranged in no more than three rings on the shell surface, each ring is evenly distributed with no more than eight windows along the circumferential direction, the windows are long circular holes, two ends of a rectangle with a long side length L are respectively connected with a semicircle with a radius R, and the axial distance between two adjacent rings is more than or equal to (L/2); the radius R is (5/100) - (30/100) of the diameter of the engine shell.

7. The low vulnerability solid rocket motor casing structure of claim 1 wherein the insulating layer and the sealing plug are of the same material or of two different materials, if two different materials, the materials of the insulating layer and the sealing plug are compatible.

8. The low vulnerability solid rocket engine casing structure of claim 1 wherein the sealing plug outer surface radius of curvature is consistent with the engine barrel casing outer surface radius of curvature and the sealing plug inner surface radius of curvature is consistent with the engine barrel casing inner surface radius of curvature.

9. The low vulnerability solid rocket engine case structure of claim 1 wherein the wrapping layer is resin based carbon fiber composite material.

Technical Field

The invention relates to the field of rocket engines, in particular to a shell structure capable of quickly releasing internal pressure when the internal pressure of a rocket engine is increased due to external stimulation or abnormally increased due to unknown reasons.

Background

When the environment temperature exceeds the natural temperature of the propellant due to the conditions of fire and the like in the storage process of the solid rocket engine, the propellant grains in the metal shell can be spontaneously combusted, but the strength of the metal shell of the engine is hardly affected at the moment, so that the pressure in the engine shell rises rapidly, explosion is caused, and the surrounding environment is damaged.

Through the research of novelty, the low-damage shell structure technology has certain research at home and abroad, and corresponding achievements are obtained. US patent 3052091 shows a sealing plug device for closing an open structure on an engine, which sealing plug device is composed externally of two semicircular shells, which are fixed in place by explosive bolts. When the explosion bolt is detonated, the two semicircular shells are separated, the sealing plug is pushed out by the pressure of the combustion chamber of the engine, the opening is exposed, and the pressure of the engine is rapidly reduced. US5166468 describes a technique for reducing the vulnerability of solid rocket engines by mounting a set of thermocouples on the engine and an electronic microcircuit which immediately triggers a pyrotechnic device mounted on the engine structure to open a sealing plug to allow venting if the thermocouples detect a fire around the engine. The technology has two defects, one is that a detection and driving mechanism with larger volume and more complex structure is needed, so that the fault is easy to occur; secondly, the sealing plug and the fixing clamp thereof are mostly made of metal, and potential safety hazards exist.

In addition, there is a composite structure solid rocket engine that relies on winding fibers impregnated with resin or based on resin to reinforce its internal structure. French patent FR2606082 describes a solid rocket engine of the above composite structure, the internal structure of which consists of two semi-circular tubes, on which a layer of fibers is wound circumferentially, the internal structure of which can withstand the longitudinal forces of the engine during operation, the external layer of fibers being subjected to internal pressure. European patent EP0559436 also discloses a composite structure for reducing the vulnerability of solid rocket engines, in which a metal casing is provided with a plurality of narrow slots around which a fibrous reinforcement layer impregnated with a matrix resin is wound. If the engine meets fire, the external fiber reinforced layer of the engine is firstly heated and damaged, if the fire continues to spread to cause the propellant to be natural, the metal shell which can only bear the axial force originally deforms, so that the gas is discharged through the narrow gap, and the internal pressure of the engine is prevented from being overlarge. However, the engine shell is provided with a plurality of narrow grooves by adopting the technology, so that the processing is inconvenient, the manufacturability is poor, and the risk of tearing the shell is high.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a low-vulnerability solid rocket engine shell structure, wherein a window is processed on a metal shell, fibers are wound outside the window, when a fire disaster or high temperature occurs, an external fiber layer is rapidly damaged, high-temperature gas generated by propellant combustion is discharged from the window, the risk of explosion is eliminated, and the low vulnerability of the solid rocket engine is realized.

The technical scheme adopted by the invention for solving the technical problems is as follows: a low-vulnerability solid rocket engine shell structure comprises a shell, a winding layer and a sealing plug.

The shell is provided with a plurality of windows which penetrate through the shell, the sealing plug is matched with the windows, and the sealing plug is sealed in the windows through a fiber composite material winding layer which is coated outside the shell; when the engine is heated and the temperature exceeds the set temperature, the winding layer is damaged, the sealing plug is pushed by the pressure in the shell, and the window is opened.

The inner surface of the shell is covered with a heat insulating layer.

The sum of the flow areas of all the windows on the shell is more than or equal to ten times of the area of the throat of the spray pipe.

The window is a long round hole, and the long axis direction is parallel to the axial direction of the shell.

The windows are uniformly distributed on the surface of the shell along the circumferential direction and are arranged into a ring or a plurality of rings.

The window is formed by not more than three rings on the surface of the shell, not more than eight windows are uniformly distributed on each ring along the circumferential direction, each window is a long round hole, two semicircular ends with the radius of R are respectively connected with two ends of a rectangle with the length of L, and the axial distance between every two adjacent rings is more than or equal to (L/2); the radius R is (5/100) - (30/100) of the diameter of the engine shell.

The heat insulating layer and the sealing plug are made of the same material or two different materials, and if the two different materials are adopted, the materials of the heat insulating layer and the sealing plug are compatible.

The curvature radius of the outer surface of the sealing plug is consistent with that of the outer surface of the engine cylindrical shell, and the curvature radius of the inner surface of the sealing plug is consistent with that of the inner surface of the engine cylindrical shell.

The winding layer is made of resin-based carbon fiber composite materials.

The invention has the beneficial effects that: in a pressure relief test, the fiber winding layer is damaged by external stimulation, and the sealing plug is reliably opened under the action of internal pressure, so that the rapid pressure relief of the engine is realized, and the effect of avoiding disastrous accidents is realized.

According to the invention, the opening is formed in the shell, the metal shell and the fiber layer bear the axial force of the engine shell, and the fiber layer bears the circumferential force generated by the internal pressure of the engine shell, so that a complex structure that the opening and the pressure relief of the sealing plug can be realized only by adopting a detection and driving mechanism is avoided; and the sealing plug is opened without flying out of metal fragments. The wide opening on the shell, the easy realization of the process, and the reduction of the crack propagation risk have the advantages of simple and compact structure, clear principle and high reliability.

The materials adopted by the invention are all made in China, the sources are wide, the manufacturability is good, the processing period is short, the product qualification rate is high, the cost is low, and the consistency is good.

Drawings

FIG. 1 is a cross-sectional view of a metal shell;

FIG. 2 is a cross-sectional view of a low vulnerability housing;

FIG. 3 is an enlarged view of a portion of FIG. 2;

in the figure, 1 is a fiber winding layer, 2 is a metal shell, 3 is a sealing plug, and 4 is a heat insulation layer.

Detailed Description

The present invention will be further described with reference to the following drawings and examples, which include, but are not limited to, the following examples.

The window is processed on the metal shell of the solid rocket engine, the fiber is wound outside the window, when a fire disaster or high temperature occurs, the external fiber layer is rapidly damaged, and high-temperature gas generated by propellant combustion is discharged from the window, so that the risk of explosion is eliminated.

The low-damage shell structure comprises a cylindrical shell with a plurality of windows, a fiber composite material winding layer coated on the shell, a heat insulation layer adhered to the inner surface of the shell, and a sealing plug positioned between the fiber winding layer and the heat insulation layer. Wherein, the long round holes (windows) on the cylindrical shell are uniformly distributed along the circumferential direction or are simultaneously and uniformly distributed along the axial direction and the circumferential direction, and the heat insulating layer and the sealing plug can be made of one material or two materials which are compatible. If the engine is heated accidentally, the outer fiber composite material winding layer is damaged, and the sealing plug is opened to release pressure.

When the engine shell is stimulated by the outside, the fiber composite material on the outer layer of the engine shell is firstly deteriorated or even directly damaged, at the moment, the clamping effect of the fiber winding layer on the sealing plug is weakened or disappears, the sealing plug is extruded under the action of the gas pressure inside the engine, the window is opened, the pressure of the engine is rapidly released, and the occurrence of disaster accidents is avoided.

The radius of curvature of the outer surface of the sealing plug should be consistent with the radius of the outer surface of the cylindrical shell of the engine. If the radii of curvature are not uniform, the wrapped layers of fibers wrapped thereon may be damaged. Similarly, the radius of curvature of the inner surface of the bore seal is preferably also substantially the same as the radius of curvature of the inner surface of the engine tubular housing.

The sealing plug and the heat insulating layer are preferably made of the same material and are integrally formed, so that the sealing effect is good and the process is simple. But the disadvantage is that the quality of the sealing plug is not good enough, when the heat insulating layer is made of soft material, the fiber is wound to the window of the shell and will be sunken, so the sealing plug and the heat insulating layer can also be made of two materials, the sealing plug is made of hard material and is compatible with the heat insulating layer material.

The flow area of all the openings on the shell is more than or equal to ten times of the area of the throat of the spray pipe. The shape of the opening can be any, for example, the opening is long elliptical holes, the long axis of the opening is consistent with the axial direction of the shell, each long elliptical hole can be regarded as consisting of a rectangle (long L) and two semi-elliptical parts opposite to the rectangle (long L), or consisting of a rectangle (long L) and two semi-circles (radius R), and the configuration is favorable for preventing crack propagation. The length L of the rectangle is determined according to the length of the engine shell and the design requirement of the hanging position, and the radius R is determined according to the diameter of the engine shell. At most three groups of transverse holes are formed in the engine, each group preferably comprises at most eight holes distributed along the circumferential direction, the number of the holes in each group is controlled to be 3-6, and the axial distance L1 between two continuous hole groups on the shell is more than or equal to 1/2 of the hole length L; the value of the semicircular radius R is 5/100-30/100 of the diameter of the engine shell, the radius R is too small to facilitate pressure relief, and the structural strength of the shell is greatly reduced when the radius R is too large.

The embodiment of the invention is shown in figure 1, wherein the metal shell opening holes of the low-vulnerability shell structure are in a group, 4 long circular holes are uniformly distributed at the front end of the shell, and the holes are 200mm in length and 20mm in width.

As shown in fig. 2, the low-vulnerability shell structure is composed of a perforated metal shell, a fiber winding layer wound on the outer surface of the shell, a heat insulating layer adhered on the inner surface of the shell, and a sealing plug (not easily found in the figure) between the heat insulating layer and the fiber layer.

Fig. 3 is a partial enlarged view of fig. 2, wherein 1 is a fiber winding layer, 2 is a metal casing, 3 is a sealing plug, 4 is a heat insulating layer, and the sealing plug and the heat insulating layer are integrally formed from one material.

In this example, the outer diameter of the engine combustion chamber housing is 200mm and the diameter of the engine throat is 28 mm.

The shell is evenly distributed with 1 group of long round window holes along the circumferential direction, and four holes are arranged. The length L of the rectangular part of the hole is 200mm, the width 2R is 20mm, and both ends of the hole are in a semicircular structure with the radius R.

The metal structure of the low-vulnerability shell structure can adopt any metal material commonly used in the field; the heat insulating layer is polymer elastomer or rubber, which contains various fiber or powder fillers for enhancing heat resistance; the fiber composite material is a resin-based carbon fiber composite material commonly used in the field. The connection of the missile wing and other components can be further installed on the engine shell, and the connecting piece is a metal piece, so that the installation can be carried out only according to a standard process.

When the invention is implemented, the engine can be poured and charged against the wall, and can also be freely charged. If the free filling charging is adopted, a gap is reserved between the grain coating layer and the heat insulation layer, and the pressure is easier to release when the internal pressure is increased due to external stimulation.

The operation of opening and pressure relief of the sealing plug can be realized without adopting a detection and driving mechanism; the sealing plug is opened without flying out of metal fragments; the holes on the shell are wide, the process is easy to realize, and meanwhile, the risk of crack propagation is reduced.

Taking a metal shell of a certain solid rocket engine as an example, two ends of the shell are provided with large holes, the material is D406A, the diameter is 200mm, and the wall thickness is 1.5 mm; winding fibers are T700; the material of the heat insulating layer is ethylene propylene diene monomer; the sealing plug is made of ethylene propylene diene monomer rubber, is consistent with the heat insulating layer and is integrally formed with the heat insulating layer; the specification and the size of the pressure relief hole of the metal shell are as follows:

the number of the holes is as follows: 8, the number of the cells is 8;

opening length L: 100 mm;

the structure of the two ends of the hole is as follows: r8mm semicircle;

the number of groups: 2;

included angle between holes: 90 degrees;

two sets of hole-to-hole distances L1: 50 mm.

The shell of the low-vulnerability solid rocket engine of the embodiment has the bursting pressure of 22MPa and the critical axial pressure of 170 tons, and the structural strength meets the design requirement; the low-vulnerability requirement of the solid rocket engine is realized through a fast burning test, a slow burning test and a fragment impact test in an non-nuclear ammunition risk assessment test (MIL-STD-2105D).