Boron aggregate for microgravity combustion experiment as well as preparation method and application of boron aggregate

Abstract

The invention provides a boron aggregate for a microgravity combustion experiment as well as a preparation method and application of the boron aggregate. The agglomerate is formed by agglomerating and dispersing high-purity amorphous boron on ethyl acetate and then drying, and is fixed on the annular structure of the tungsten filament in a spherical shape, the porosity is 48.19 + / -5%, the particle sizes comprise 5 mm and 3 mm, and the surface is coated with a paraffin coating layer with the thickness of 0.12 mm, so that the agglomerate can be effectively prevented from being contacted with air and water vapor to be oxidized during storage, and the service life of the agglomerate is prolonged. And the fixation of the boron aggregate and the tungsten filament structure is ensured. The preparation process of the aggregate comprises the three steps of tungsten filament supporting structure manufacturing, original boron aggregate manufacturing and paraffin surface coating, an obtained boron aggregate sample can be fixed to a gas phase flame burner through annular structures at the two ends, and the aggregate has the outstanding advantages of being stable in storage, rapid in ignition, stable in combustion and the like; the device can effectively meet the application requirements of the space microgravity experiment on sample transportation safety, space positioning accuracy and stable and splashing-free combustion, and provides reference for efficient preparation of boron aggregates in the microgravity combustion experiment.

Description

Technical Field

[0001] This invention relates to the field of space combustion experiment technology, specifically to a boron agglomerate for microgravity combustion experiments, its preparation method, and its application in combustion experiments in a microgravity environment. Background Technology

[0002] Solid propellants hold an irreplaceable position in aerospace, military, and other fields, possessing advantages such as high energy density, small carrying volume, and strong propulsion. They are widely used in the propulsion systems of rockets, missiles, hypersonic vehicles, and explosives. Among various solid fuels, boron is one of the most promising metallic fuel components for solid-fuel rocket engines and ramjet engines. It has extremely high calorific value and volumetric calorific value, releasing enormous energy during combustion to provide stronger thrust for spacecraft and effectively improve their range and payload capacity.

[0003] In practical applications, boron particles are often agglomerated and granulated to improve propellant processing performance, enhance boron combustion efficiency, and promote the release of boron's calorific value. Therefore, boron agglomerates are an important form of boron fuel used in solid-fuel propulsion systems. Currently, researchers have conducted a series of studies on the ignition and combustion characteristics of boron agglomerates under conventional gravity, but their microgravity ignition and combustion characteristics have not yet been explored. Compared to conventional gravity environments, the gravity acting on objects is significantly reduced in microgravity environments, and buoyancy and the resulting natural convection phenomena almost disappear. This results in significant differences in the ignition and combustion characteristics of boron agglomerates compared to conventional gravity, necessitating further exploration using the microgravity environment of space stations. Summary of the Invention

[0004] This invention was made to solve the above-mentioned problems, and its purpose is to provide a boron agglomerate for microgravity combustion experiments, its preparation method and its application.

[0005] The present invention provides a boron agglomerate for microgravity combustion experiments, characterized in that the boron agglomerate is formed by the agglomeration of boron powder particles, has a spherical structure, and is covered with a paraffin protective layer on its outer surface.

[0006] This invention also provides a method for preparing boron agglomerates for microgravity combustion experiments. The method comprises the following steps: S1: A section of tungsten wire is cut and fixed at both ends to the sides of a burner. A ring structure is formed in the middle as the spatial fixing point and outer framework of the boron agglomerate; S2: Boron powder particles and a solvent are mixed in a certain proportion to obtain a boron slurry. The boron slurry is then dripped onto the ring structure to form boron slurry droplets. The tungsten wire and the boron slurry droplets are dried to obtain the original boron agglomerate; S3: The original boron agglomerate is coated with melted paraffin wax. After cooling, a boron agglomerate with a paraffin wax protective layer is obtained.

[0007] The method for preparing boron agglomerates for microgravity combustion experiments provided by the present invention may also have the following characteristics: wherein, in S2, the boron powder particles are amorphous boron with a particle size of 1-3 μm and a purity of 90% or more.

[0008] The method for preparing boron agglomerates for microgravity combustion experiments provided by the present invention may also have the following feature: wherein, in S2, the ratio of boron powder to solvent is 1-3:2.5-4.5 (g / mL).

[0009] The method for preparing boron agglomerates for microgravity combustion experiments provided by the present invention may also have the following feature: wherein, in S2, the solvent is ethyl acetate.

[0010] The method for preparing boron agglomerates for microgravity combustion experiments provided by the present invention may also have the following feature: wherein, in S3, the thickness of the paraffin protective layer is 0.09-0.12 mm.

[0011] The method for preparing boron agglomerates for microgravity combustion experiments provided by the present invention may also have the following feature: wherein, in S3, the boron agglomerates have a porous structure with a porosity of 48.19% ± 5%.

[0012] The method for preparing boron agglomerates for microgravity combustion experiments provided by the present invention may also have the following characteristics: in S3, the particle size of the boron agglomerates is 5 mm, specifically 4.8-5.4 mm, and the mass is 37-49 mg; or, the particle size of the boron agglomerates is 3 mm, specifically 2.6-3.2 mg, and the mass is 18-22 mg.

[0013] The present invention also provides the application of boron agglomerates for combustion experiments in microgravity environments.

[0014] The role and effect of invention

[0015] The boron agglomerate for microgravity combustion experiments, its preparation method, and its application, as disclosed in this invention, have the following beneficial effects:

[0016] (1) The present invention obtains boron agglomerates through a tungsten wire ring support structure. On the one hand, the ring structure can be used to ensure the sphericity of the boron agglomerates, and on the other hand, it can achieve stable fixation of the boron agglomerates in the combustion experiment, thereby ensuring that the boron agglomerates can be accurately ignited by the igniter in the combustion experiment.

[0017] (2) The present invention uses a method of mixing micron-sized boron powder and solvent and then drying to prepare boron agglomerates without introducing additional curing agents and binders. During the preparation process, the volume of boron agglomerates can be adjusted by changing the amount of boron slurry used. The boron agglomerate samples prepared in this way have a single composition and controllable volume, making them safer to transport and meeting the requirements of microgravity combustion experiments.

[0018] (3) The present invention uses ethyl acetate as a solvent to improve the splashing of particles during combustion. The boron agglomerates of the present invention have the characteristics of stable combustion, which greatly reduces the splashing of particles during combustion and can effectively solve the problem of pollution of space environment by splashed particles.

[0019] (4) This invention utilizes paraffin wax to form a protective layer on the surface of boron agglomerates, which isolates the boron agglomerate samples from the external environment during storage, preventing premature oxidation or reaction and improving the safety and stability of the samples. At the same time, this preparation process can achieve precise control of the thickness of the paraffin wax protective layer, which can be controlled between 0.09 mm and 0.12 mm, thereby reducing the interference of the paraffin wax protective layer on combustion experiments while meeting safety requirements. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the boron agglomerates in Embodiment 1 of the present invention;

[0021] Figure 2 This is a flowchart of the method for preparing boron agglomerates for microgravity combustion experiments in Example 1 of the present invention;

[0022] Figure 3 This is a schematic diagram of the steps in the preparation method of boron agglomerates for microgravity combustion experiments in Example 1 of the present invention;

[0023] Figure 4 This is a comparison diagram of the combustion splashing of boron agglomerates prepared using different solvents in Example 2 of the present invention. Detailed Implementation

[0024] To make the technical means, creative features, objectives and effects of this invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the boron aggregates, preparation methods and applications of this invention for microgravity combustion experiments.

[0025] Example 1

[0026] This embodiment provides boron aggregates for microgravity combustion experiments and their preparation method.

[0027] Figure 1 This is a schematic diagram of the structure of the boron agglomerates in Embodiment 1 of the present invention.

[0028] like Figure 1 As shown, the boron agglomerate is formed by the agglomeration of boron powder particles, has a spherical structure, does not contain curing agents or binders, and is covered with a paraffin protective layer.

[0029] Figure 2 This is a flowchart of the method for preparing boron agglomerates for microgravity combustion experiments in Example 1 of the present invention.

[0030] Figure 3 This is a schematic diagram of the steps in the preparation method of boron agglomerates for microgravity combustion experiments in Example 1 of the present invention.

[0031] like Figure 2-3 As shown, the method for preparing boron aggregates for microgravity combustion experiments specifically includes the following steps:

[0032] S1: Cut a section of tungsten wire, fix its two ends to both sides of the burner, and create a ring structure in the middle as a spatial fixing point and outer framework for the boron agglomerates. The specific operation steps are as follows:

[0033] Fabrication steps of the tungsten wire support structure. A tungsten wire support structure was designed to match the requirements of the space station burner. A 0.5mm thick high-purity tungsten wire was prepared, and a 9cm length was cut using metal cutting pliers. A 4mm diameter ring structure was wound around both ends using the 4mm diameter cylindrical clamp of six-segment pliers. This ring structure serves as the contact end between the tungsten wire and the space station burner. Screws were passed through the ring structures at both ends to fix the tungsten wire to the supports on both sides of the burner. Similarly, a 2mm diameter ring structure was wound around the middle of the tungsten wire using the 2mm diameter cylindrical clamp of six-segment pliers, serving as a spatial fixing point and outer frame for the boron aggregates.

[0034] S2: Boron powder particles are mixed with solvent in a certain proportion to obtain a boron slurry. The boron slurry is then dropped onto a ring structure to form boron slurry droplets. The tungsten wire and the boron slurry droplets are dried to obtain the original boron agglomerates. The specific operation steps are as follows:

[0035] Preparation steps for primary boron aggregates: Prepare a 25mL beaker. First, use a pipette to draw 3.5mL of ethyl acetate into the beaker. Then, use an electronic balance to weigh 2g of micron-sized (1-3µm) amorphous boron powder with a purity of over 90%. Pour the boron powder into the beaker containing ethyl acetate and stir thoroughly to obtain a homogeneous boron slurry. Then, use a fine glass rod to drop the boron slurry from the beaker onto the annular structure in the middle of a tungsten filament, which carries the boron slurry. By changing the amount of slurry used, the volume of the boron aggregates can be finely adjusted to form single-drop spherical boron slurry droplets. After preparation, place the boron slurry droplets along with the tungsten filament into a vacuum oven and dry at 70℃ for 6 hours to allow the ethyl acetate to fully evaporate, obtaining the primary boron aggregates.

[0036] S3: The original boron aggregates are coated with heated and melted paraffin wax. After cooling, boron aggregates with a paraffin wax protective layer are obtained. The specific operation steps are as follows:

[0037] Paraffin coating process: The paraffin wax is placed in a beaker and heated to 90°C until completely dissolved. The paraffin wax used is No. 58 fully refined paraffin wax block. The dried, raw boron agglomerates are carefully removed to avoid impact and placed in the liquid paraffin. A layer of condensed white paraffin wax will first form on the surface. After observing the condensed paraffin wax layer recede, the agglomerates are removed, and excess paraffin wax (excluding the coating layer) is carefully scraped off with tweezers to obtain boron agglomerates with a uniform paraffin wax protective layer on the outer surface.

[0038] Specifically, the thickness of the paraffin protective layer is controlled at 0.09-0.12 mm.

[0039] The boron agglomerates prepared in this embodiment have the following physicochemical properties:

[0040] Boron purity: >90%;

[0041] It has a porous structure with a porosity of 48.19 ± 5%.

[0042] Boron aggregate sample shape: spherical;

[0043] Paraffin coating thickness: 0.12mm

[0044] In this embodiment, a thin glass rod is used to drip boron slurry from a beaker onto a ring-shaped structure in the middle of a tungsten filament, which carries the boron slurry. The volume of the boron agglomerates is finely adjusted by changing the amount of slurry used. Using this method, boron agglomerates with particle sizes of 5 mm or 3 mm were obtained in this embodiment.

[0045] Specifically, when the particle size of the boron agglomerates is 5 mm, its specific particle size is 5.1 ± 0.3 mm, and its mass is 43 ± 6 mg. When the particle size of the boron agglomerates is 3 mm, its specific particle size is 2.9 ± 0.3 mg, and its mass is 20 ± 2 mg.

[0046] Example 2

[0047] This embodiment examines the stability and combustion splashing of boron agglomerates by changing the solvent to prepare different boron agglomerates.

[0048] Boron aggregates were prepared using purified water as a solvent, and the remaining operations were the same as in Example 1, serving as a control.

[0049] Ignition and combustion experiments were conducted on boron agglomerate samples prepared with different solvents, and the combustion was recorded using a high-speed camera.

[0050] Figure 4 This is a comparison diagram of the combustion splashing of boron agglomerates prepared using different solvents in Example 2 of the present invention.

[0051] like Figure 4 As shown in the figure, the boron agglomerates prepared in Example 1, using ethyl acetate as a solvent, maintained their stable morphology and produced no splashing during combustion. In contrast, the boron agglomerates prepared using pure water as a solvent on the right experienced micro-explosions during combustion, leading to agglomerate rupture and particle splashing. It is evident that using ethyl acetate as a solvent provides more stable combustion characteristics compared to conventional methods using water as a solvent, making it more suitable for the requirements of microgravity combustion experiments.

[0052] The role and effect of the embodiments

[0053] The boron agglomerate for microgravity combustion experiments, its preparation method, and its application, as disclosed in this invention, have the following beneficial effects:

[0054] (1) The present invention obtains boron agglomerates through a tungsten wire ring support structure. On the one hand, the ring structure can be used to ensure the sphericity of the boron agglomerates, and on the other hand, it can achieve stable fixation of the boron agglomerates in the combustion experiment, thereby ensuring that the boron agglomerates can be accurately ignited by the igniter in the combustion experiment.

[0055] (2) The present invention uses a method of mixing micron-sized boron powder and solvent and then drying to prepare boron agglomerates. No binder or curing agent is introduced during the preparation process to maintain the purity of the components. At the same time, the volume of boron agglomerates can be adjusted by changing the amount of boron slurry used. The boron agglomerate samples prepared in this way have a single component and controllable volume, making them safer to transport and meeting the requirements of microgravity combustion experiments.

[0056] (3) According to the experimental results of Example 2, compared with the boron agglomerates prepared using pure water as solvent, the boron agglomerates prepared using ethyl acetate as solvent improved the splashing of particles during combustion, had stable combustion characteristics, and greatly reduced particle splashing during combustion, which can effectively solve the problem of splashing particles polluting the space environment.

[0057] (4) This invention utilizes paraffin wax to form a protective layer on the surface of boron agglomerates, which isolates the boron agglomerate samples from the external environment during storage, preventing premature oxidation or reaction and improving the safety and stability of the samples. At the same time, this preparation process can achieve precise control of the thickness of the paraffin wax protective layer, which can be controlled between 0.09 mm and 0.12 mm, thereby reducing the interference of the paraffin wax protective layer on combustion experiments while meeting safety requirements.

[0058] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A boron agglomerate for microgravity combustion experiments, characterized in that, The boron agglomerates are formed by the aggregation of boron powder particles, and have a spherical structure with a paraffin protective layer on their outer surface.

2. A method for preparing boron agglomerates for microgravity combustion experiments, used to prepare the boron agglomerates for microgravity combustion experiments as described in claim 1, characterized in that: Specifically, the steps include the following: S1: Cut a section of tungsten wire, fix its two ends to the two sides of the burner, and make a ring structure in the middle as the spatial fixing point and outer frame of the boron agglomerate. S2: The boron powder particles are mixed with a solvent in a certain proportion to obtain a boron slurry. The boron slurry is then dropped onto the annular structure to form boron slurry droplets. The tungsten wire and the boron slurry droplets are dried to obtain the original boron agglomerates. S3: The original boron agglomerates are coated with heated and melted paraffin wax, and after cooling, the boron agglomerates with the paraffin wax protective layer on their outer surface are obtained.

3. The method for preparing boron agglomerates for microgravity combustion experiments according to claim 2, characterized in that: in, In S2, the boron powder particles are amorphous boron with a particle size of 1-3 μm and a purity of over 90%.

4. The method for preparing boron agglomerates for microgravity combustion experiments according to claim 3, characterized in that: in, In S2, the ratio of boron powder to solvent is 1-3:2.5-4.5 (g / mL).

5. The method for preparing boron agglomerates for microgravity combustion experiments according to claim 4, characterized in that: in, In S2, the solvent is ethyl acetate.

6. The method for preparing boron agglomerates for microgravity combustion experiments according to claim 2, characterized in that: in, In S3, the thickness of the paraffin protective layer is 0.09-0.12 mm.

7. The method for preparing boron agglomerates for microgravity combustion experiments according to claim 6, characterized in that: in, In S3, the boron agglomerates have a porous structure with a porosity of 48.19% ± 5%.

8. The method for preparing boron agglomerates for microgravity combustion experiments according to claim 7, characterized in that: in, In step S3, the boron agglomerates have a particle size of 5 mm, specifically 4.8-5.4 mm, and a mass of 37-49 mg, or... The boron agglomerates have a particle size of 3 mm, specifically 2.6-3.2 mg, and a mass of 18-22 mg.

9. The application of the boron agglomerates for microgravity combustion experiments according to claim 1 in combustion experiments in a microgravity environment.

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