Solid propellant combustion condensed phase product collecting device and testing method

Abstract

The invention discloses a solid propellant combustion condensed phase product collecting device and a testing method. The solid propellant combustion condensed phase product collecting device comprises a collecting pipe and at least two collecting cylinders, and at least two collecting barrels are mounted at the end part of the collecting pipe in a sleeving manner to form a multi-stage collecting area. Furthermore, the device can be used for researching and testing the thermal increment of products with different particle sizes of the combustion condensed phase of the solid propellant and the impact of a heat insulation material. The collecting device disclosed by the invention is simple and easy to manufacture, not only can distinguish the distribution of the particle size of the condensed phase particles along with space, but also can research the impact force, thermal increment and erosion and ablation capabilities of the condensed phase particles with different particle sizes by additionally arranging a strain gauge, a temperature measuring device or a heat insulating layer at the bottom of the collecting area and combining with the particle size distribution obtained by collecting condensed phase products.

Description

Technical Field

[0001] The present invention relates to the field of solid rocket engines and solid propellant combustion, and more particularly to a device for collecting condensed phase products of solid propellant combustion and a testing method. Background Art

[0002] With the widespread use of aluminum-containing solid propellants in solid rocket engines in recent years, problems such as combustion instability caused by the flow of condensed-phase alumina particles in the propellant combustion products and ablation anomalies caused by erosion of the insulation layer have become increasingly prominent. Therefore, the study of condensed-phase particles has become a key topic.

[0003] The particle size of condensed-phase particles is not uniform. Immediately after detaching from the propellant's combustion surface, they are small, often only a few hundred nanometers to a few microns. As the gas flows, the condensed-phase particles aggregate, collide, and fuse, gradually increasing in size. As the vehicle maneuvers and experiences overload, this aggregation phenomenon intensifies, resulting in particles with even larger diameters. Particles of different sizes cause varying levels of gas flow disturbance, heat gain, and erosion damage, so when studying condensed-phase particles, it's crucial to understand the particle size distribution of the object under study.

[0004] The condensed-phase particle collection devices currently used can only simply realize the condensed-phase particle collection function, and it is difficult to distinguish the particle size distribution characteristics with space during the flow of condensed-phase particles. Summary of the Invention

[0005] In view of the defects or shortcomings of the prior art, the present invention provides a device for collecting solid propellant combustion condensed phase products.

[0006] To this end, the solid propellant combustion condensed phase product collection device provided by the present invention includes a collection pipe and at least two collection cylinders;

[0007] The collecting pipe is open at both axial ends, one of which is a feed end and the other is a discharge end, wherein the discharge port is divided into at least two discharge ports by at least one circular partition, one of the at least two discharge ports is a circular discharge port located at the center of the discharge port, and the remaining discharge ports are annular, and the remaining discharge ports are arranged around the circular discharge port and are distributed radially in sequence; the circular partition is fixedly connected to the collecting pipe via a support beam;

[0008] Therefore, the collection tube is open at one end and closed at the other end;

[0009] A collecting cylinder is installed at each discharge port of the collecting tube, and each collecting cylinder is installed in sequence. Gaps are left between the side walls and bottoms of adjacent collecting cylinders to form a collecting area. At the same time, the outermost collecting cylinder is fixedly connected to the collecting tube, and the inner collecting cylinder is fixedly connected to the circular partition.

[0010] Optionally, each collection zone is provided with a collection liquid, and the distance between the liquid surface of the collection liquid in each collection zone and the feeding end of the collection tube is equal. The collection liquid is water or other liquid that does not react with the condensed phase particles.

[0011] Optionally, a thermocouple is installed at the bottom of each collection zone, and a heat transfer plate is arranged on the thermocouple.

[0012] Optionally, the circular partition plate is provided with an internal thread, the end of the discharge end of the collection tube is provided with an internal thread, and the end of the open end of the collection cylinder is provided with an external thread. The circular partition plate and the corresponding collection cylinder are connected through the threads, and the collection tube and the corresponding collection cylinder are connected through the threads. A sealing gasket is arranged at each threaded connection.

[0013] Optionally, the discharge end of the collection tube is divided into three discharge ports by two circular partition plates.

[0014] The application also provides a testing device for condensed phase products of solid propellant combustion, which comprises a combustion chamber, an inverted conical converging cylinder, a gas passage tube and a nozzle assembly. The feeding port of the inverted conical converging cylinder is connected with the discharge port of the combustion chamber. The gas passage tube is provided with an axial feeding port, a radial discharge port and an axial discharge port. The axial feeding port of the gas passage tube is connected with the discharge port of the inverted conical converging cylinder, the radial discharge port is connected with the nozzle assembly, and the axial discharge port is connected with the feeding end of the collection tube in the collection device.

[0015] The application also provides a testing method for condensed phase products of solid propellant combustion. The particle size distribution of the condensed phase products of solid propellant combustion is tested by using the above device. During the testing, each collection zone is provided with a collection liquid, and the distance between the liquid surface of the collection liquid in each collection zone and the feeding end of the collection tube is equal. Another testing method for condensed phase products of solid propellant combustion is to test the heat increment of each particle size product of the condensed phase products of solid propellant combustion by using the above device. During the testing, a thermocouple is installed at the bottom of each collection zone, and a heat transfer plate is arranged on the thermocouple.

[0016] The device of the application can also be used for testing the ablation rate of thermal insulation materials. The corresponding method uses the above device to test the ablation rate of thermal insulation materials under the impact condition of each particle size product of the condensed phase products of solid propellant combustion. During the testing, a thermal insulation material is installed at the bottom of each collection zone.

[0017] The testing device of the application is simple and easy to manufacture, and the related testing method is simple and easy to implement. The device of the application can be used for fine research on the spatial distribution of the particle size of the condensed phase products of solid propellant combustion. By installing a temperature measuring device or a thermal insulation layer at the bottom of each collection zone and combining the collection of the condensed phase products, the heat increment and the erosion and ablation ability of condensed phase particles of different particle sizes can be studied. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Figure of the solid rocket engine experimental system of the present application.

[0019] Figure 2 Sectional view of the condensed phase product collection device of the present application.

[0020] Figure 3 Schematic diagram of the structure design of the discharge end of the collection pipe of the present application. DETAILED DESCRIPTION

[0021] Unless otherwise defined, scientific and technical terms used in this text are understood according to the knowledge of the ordinary skilled person in the relevant field.

[0022] The embodiments of the present application are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0023] In the description of the present application, it should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0024] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0025] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For the ordinary skilled person in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Example 1:

[0028] The present invention provides a solid propellant combustion condensed phase product collection device suitable for existing solid rocket engine experimental systems. Figure 1 The solid rocket engine experimental system shown includes a combustion chamber 1, an inverted conical convergent tube 2, a gas passage 3 and a nozzle assembly 4, wherein the gas passage is provided with an axial feed port, a radial discharge port and an axial discharge port, the feed port of the inverted conical convergent tube is connected to the discharge port of the combustion chamber, the axial feed port of the gas passage is connected to the discharge port of the inverted conical convergent tube, the radial discharge port is connected to the nozzle assembly, and the axial discharge port is connected to the solid propellant combustion condensed phase product collection device of the present invention.

[0029] See also Figure 2 As shown, the solid propellant combustion condensed phase product collection device of the present invention includes a collection pipe 501 and at least two collection cylinders (502, 503, 504) installed at the end of the collection pipe;

[0030] Specifically, both axial ends of the collecting tube are open, one of which is the feed end (connected to the axial discharge port of the gas pipe when in use), and the other is the discharge end, wherein the discharge port is divided into at least two discharge ports by at least one circular partition 505, one of the at least two discharge ports is a circular discharge port located at the center of the discharge port, and the remaining discharge ports are annular, and the remaining discharge ports are arranged around the circular discharge port and distributed in sequence along the radial direction; the circular partition is fixedly connected to the collecting tube by a support beam 506; in the specific scheme, the corresponding number of discharge ports can be selected and designed according to the combustion characteristics of the solid propellant, Figure 2 The device shown has two or three discharge ports, and correspondingly, from the inside to the outside, a first collection barrel 502, a second collection barrel 503 and a third collection barrel 504 are installed in sequence;

[0031] A collecting cylinder is installed at each discharge port of the collecting tube, which is specifically connected to the open end of the collecting cylinder, so that each collecting cylinder is installed in sequence, and gaps are left on the side walls and bottoms of adjacent collecting cylinders to form a collecting area. At the same time, the outermost collecting cylinder is fixedly connected to the collecting tube, and the inner collecting cylinder is fixedly connected to the circular partition. Figure 2 In the device shown, the outermost collecting cylinder is threadedly connected to the collecting pipe, the inner collecting cylinder is threadedly connected to the corresponding circular partition, and a silicone sealing gasket is provided at each threaded connection.

[0032] In operation, the solid propellant combustion chamber produces high-temperature and high-pressure gas and molten alumina particles; the condensed-phase particle flow converges to a designed concentration through the converging section, during which the condensed-phase particles collide, fuse, and separate; the gas molecules with small molecular weight are discharged through the gas pipe and the nozzle, while the condensed-phase particles vertically downward into the condensed-phase product collection device under the action of their own inertia, and then the particles of different sizes enter the corresponding collection cylinders through the collection pipe.

[0033] In specific solutions, the size of the collection pipe and each collection zone can be designed according to research needs, Figure 2 The device shown in the drawing has a collection pipe 501 with an internal axial length of 120 mm and an inner diameter of 65 mm;

[0034] The first collection cylinder 502 has an inner diameter of 20 mm and an internal axial size of 20 mm;

[0035] The second collection cylinder 503 has an inner diameter of 40 mm and an internal axial size of 30 mm, and the radial gap size between the inner wall of the second collection cylinder 503 and the outer wall of the first collection cylinder 502 is 9 mm, and the axial gap size is 10 mm;

[0036] The third collection cylinder 504 has an inner diameter of 60 mm and an internal axial size of 40 mm, and the radial gap size between the inner wall of the third collection cylinder 504 and the outer wall of the second collection cylinder 503 is 9 mm, and the axial gap size is 10 mm.

[0037] The device of this embodiment is used to collect products of different particle sizes, and water is used as the collection liquid, and the distance between the liquid surface of each collection zone and the inlet of the collection pipe 501 is 100 mm.

[0038] Example 2:

[0039] The difference between this example and Example 1 is that the internal axial length of the collection pipe 501 is 100 mm, and the distance between the liquid surface of each collection zone and the inlet of the collection pipe 501 is 80 mm.

[0040] Example 3:

[0041] The difference between this example and Example 1 is that the internal axial length of the collection pipe 501 is 80 mm, and the distance between the liquid surface of each collection zone and the inlet of the collection pipe 501 is 60 mm.

[0042] The condensed-phase products of three-component composite propellants containing 17% aluminum were collected by the devices of Examples 1-3, the grain diameter was 200 mm, the height was 10 mm, the ignition pressure was 6 MPa, and the combustion time was 5 s.

[0043] Table 1 shows the average particle size obtained by the collection device of each example, where d 43 represents the volume average diameter of the particles.

[0044] Table 1 Average particle size d of each region of the particles in the embodiment 43 distributed

[0045] Test Example Primary collection zone Secondary collection zone Tertiary collection zone Example 1 373.606 120.461 3.347 Example 2 164.013 73.619 2.041 Example 3 140.593 58.372 1.224

[0046] The results in Table 1 show significant differences in the average particle diameters across different collection zones. Particle diameters increase as they approach the center, and decrease as they do so. There is a clear correlation between particle diameter and the spatial distribution of the collection zone. Furthermore, as the collection device lengthens, the average particle diameter increases, indicating that agglomeration formation significantly influences the degree of particle aggregation.

[0047] Furthermore, the device of the present invention can be used to measure the heat gain of propellant condensed phase products of varying particle sizes. Specifically, a temperature measuring device can be installed at the bottom of the corresponding collection tube during testing. Furthermore, the device of the present invention can also be used to measure the ablation rate of thermal insulation materials used in solid rocket engines, such as EPDM-based composite insulation materials, which are made from an EPDM matrix supplemented with functional ingredients such as aramid fiber, carbon fiber, and silica.

[0048] Example 4:

[0049] A thermocouple was affixed to the bottom of each collecting tube in Example 1, and a heat transfer plate graphite plate was installed on the thermocouple to test the temperature change, i.e., the heat increment, under the same combustion conditions as in Example 1 and different particle size impact conditions (no collecting liquid was installed in each collecting area during the test). The results were: the collection area in the first collecting tube increased in temperature by 33°C (i.e., the heat increment was 33°C), the collection area in the second collecting tube increased in temperature by 17°C, and the collection area in the third collecting tube increased in temperature by 5°C.

[0050] Example 5:

[0051] An insulation layer (EPDM insulation material) was attached to the bottom of each collection tube in Example 1 to test the insulation's ablation rate under the same combustion conditions as in Example 1, with varying particle sizes impacting the material. The results showed an ablation rate of 1.7 mm / s for the insulation layer at the bottom of the first collection tube, 0.8 mm / s for the insulation layer at the bottom of the second collection tube, and 0.2 mm / s for the insulation layer at the bottom of the third collection tube. During this test, the insulation layer thickness was directly measured before and after the test. The ablation rate was calculated by dividing the difference in thickness before and after the test by the propellant combustion duration.

[0052] The above description is only a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any slight modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A device for collecting solid propellant combustion condensed phase products, characterized in that: It comprises a collecting tube (501) and at least two collecting cylinders (502, 503, 504); The collecting pipe is open at both axial ends, one of which is a feed end and the other is a discharge end, wherein the discharge port is divided into at least two discharge ports by at least one circular partition (505), one of the at least two discharge ports is a circular discharge port located at the center of the discharge port, and the remaining discharge ports are annular, and the remaining discharge ports are arranged around the circular discharge port and are distributed in sequence along the radial direction; the circular partition is fixedly connected to the collecting pipe via a support beam (506); Therefore, the collection tube is open at one end and closed at the other end; A collecting cylinder is installed at each discharge port of the collecting tube, and each collecting cylinder is installed in sequence. Gaps are left between the side walls and bottoms of adjacent collecting cylinders to form a collecting area. At the same time, the outermost collecting cylinder is fixedly connected to the collecting tube, and the inner collecting cylinder is fixedly connected to the circular partition.

2. The solid propellant combustion condensed phase product collection device according to claim 1, characterized in that: Each collecting area is filled with a collecting liquid, and the distance between the collecting liquid level in each collecting area and the feed end of the collecting tube is equal. The collecting liquid is water or other liquid that does not react with the condensed phase particles.

3. The solid propellant combustion condensed phase product collection device according to claim 1, characterized in that: A thermocouple is installed at the bottom of each collection area, and a heat transfer plate is provided on the thermocouple.

4. The solid propellant combustion condensed phase product collection device according to claim 1, 2 or 3, characterized in that: The circular partition is provided with an internal thread, the discharge end of the collection tube is provided with an internal thread, the open end of the collection barrel is provided with an external thread, the circular partition is connected to the corresponding collection barrel through threads, and the collection tube is connected to the corresponding collection barrel through threads; and each threaded connection is provided with a sealing gasket.

5. The solid propellant combustion condensed phase product collection device according to claim 1, 2 or 3, characterized in that: The discharge end of the collecting pipe is divided into three discharge ports by two circular partitions.

6. A solid propellant combustion condensed phase product testing device, comprising a combustion chamber (1), an inverted conical convergent cylinder (2), a gas passage (3) and a nozzle assembly (4), wherein the feed port of the inverted conical convergent cylinder is connected to the discharge port of the combustion chamber, characterized in that: The gas conduit is provided with an axial feed port, a radial discharge port and an axial discharge port. The axial feed port of the gas conduit is connected to the discharge port of the inverted conical convergent cylinder, the radial discharge port is connected to the nozzle assembly, and the axial discharge port is connected to the feed end of the collecting pipe in the collecting device according to claim 1.

7. A method for testing condensed phase products of solid propellant combustion, characterized in that: The device described in claim 6 is used to test the particle size distribution of the condensed phase products of solid propellant combustion. During the test, each collection area is filled with collection liquid, and the distance between the collection liquid level in each collection area and the feed end of the collection tube is equal.

8. A method for testing condensed phase products of solid propellant combustion, characterized in that: The device described in claim 6 is used to test the heat increment of various particle size products of the solid propellant combustion condensed phase product. During the test, a thermocouple is installed at the bottom of each collection area, and a heat transfer plate is provided on the thermocouple.

9. A method for testing the ablation rate of thermal insulation materials, characterized in that: The device described in claim 6 is used to test the ablation rate of the insulation material under the impact conditions of products of various particle sizes of the solid propellant combustion condensed phase products. During the test, insulation material is installed at the bottom of each collection area.

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