Hybrid rocket fuel combustion method and combustion device

Abstract

The present invention provides a hybrid rocket fuel combustion method that includes supplying a hydrogen peroxide solution into a combustion chamber provided with a solid fuel, wherein the concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, and the combustion method includes at least one of: (i) supplying oxygen and the hydrogen peroxide solution into the combustion chamber; and (ii) heating the hydrogen peroxide solution prior to being supplied into the combustion chamber.

Description

[Technical field]

[0001] The present invention relates to a method and apparatus for burning hybrid rocket fuel, and more particularly to a method and apparatus for burning hybrid rocket fuel using hydrogen peroxide and oxygen together with solid fuel. [Background technology]

[0002] In recent years, there has been an increase in the development of ultra-small satellites weighing less than 100 kg. These ultra-small satellites can be launched using the piggyback method.

[0003] Known satellite orbits include, for example, low Earth orbit (LEO), geostationary orbit (GSO), and sun-synchronous orbit (SSO).

[0004] The piggyback method allows a spacecraft, such as a microsatellite, to be carried together with the main satellite, for example up to a geostationary transfer orbit (GTO).

[0005] Since the geostationary transfer orbit (GTO) is the closest orbit to deep space, it can be released from the Earth's gravity and depart for deep space with only an acceleration of 700 m / s. For example, if the timing is chosen carefully, it can reach Venus with an acceleration of 1.06 km / s, and Mars with an acceleration of 1.15 km / s. In addition, from the orbit of the Gateway, a manned lunar outpost being considered as part of the international space exploration plan, it will be possible to transition to a Mars flyby orbit with an acceleration of 0.7 km / s. With an acceleration capability of 0.7 to 1.2 km / s, it would be possible to easily transfer from a geostationary transfer orbit (GTO) to a flyby orbit to the Moon, Mars, or Venus. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] 2014 Space Transportation Symposium STCP-2014-044, Takeshi Sakuma et al., "Development of a propulsion system for microsatellites using 60wt% hydrogen peroxide and its on-orbit demonstration" [Non-Patent Document 2] Proceedings of the 2020 Annual Conference of the Japan Society of Mechanical Engineers [September 13-16, 2020, Nagoya], Hiroaki Takada et al., "Ignition characteristics of a CAMUI-type hybrid rocket using 60wt% hydrogen peroxide solution" Summary of the Invention [Problem to be solved by the invention]

[0007] In order to adopt the piggyback method for spacecraft such as microsatellites and space probes, it is desirable to use propellants that are safe, particularly those with extremely low explosiveness and toxicity, and that are easy to transport, store, and obtain. From this perspective, the development of hybrid rockets that use solid fuels such as plastics that have no risk of explosion is being considered.

[0008] Hybrid rockets can use low-toxicity propellants called "green propellants" along with solid fuels such as plastics. Examples of green propellants that can be used include HAN (HydroxylAmmonium Nitrate), ADN (Ammonium DiNitramide), and HNF (Hydrazinium Nitro Formate) propellants. Although development of green propellants is progressing in various countries, they are subject to export and import restrictions because they can be used for military purposes, and there are issues with their availability.

[0009] Nitric acid, fuming nitric acid, and dinitrogen tetroxide can also be used as propellants, but they require special safety management, making it difficult to inexpensively build small spacecraft using them. Nitrous oxide can also be used as a propellant, but once it exceeds its critical temperature of 36.7°C, its density drops rapidly and there is a risk that the container will burst.

[0010] Therefore, as a low-toxicity propellant, "hydrogen peroxide water" (i.e. hydrogen peroxide (H 2 O 2 ) has been investigated (for example, Non-Patent Documents 1 and 2).

[0011] When hydrogen peroxide is used at a concentration of 65 wt% or more, it is able to evaporate all water (both the water contained in the hydrogen peroxide and the water produced by its own decomposition) through the heat generated by its own decomposition. The oxygen produced by the decomposition of hydrogen peroxide can promote the combustion of solid fuel and propel a spacecraft. However, when hydrogen peroxide is used at a concentration of 65 wt% or more, the decomposition of hydrogen peroxide proceeds in a chain reaction and at an accelerated rate, which can cause self-decomposition in the tank, increasing the internal pressure of the tank and leading to an accident.

[0012] On the other hand, when the concentration of hydrogen peroxide water is less than 65 wt%, the accelerated decomposition of hydrogen peroxide, which is a problem at concentrations of 65 wt% or more, can be suppressed due to the heat balance relationship in which the latent heat of vaporization is greater than the heat of decomposition.

[0013] However, when using hydrogen peroxide water as a propellant at a concentration of less than 65 wt%, it is necessary to spray the hydrogen peroxide water with an injector or atomizer (e.g., Non-Patent Document 1), and further increase the decomposition efficiency using a platinum (Pt) catalyst or the like before burning the solid fuel (e.g., Non-Patent Document 2).

[0014] Here, if we consider the combustion of such solid fuels as being divided into "flame or flame that generates thrust, especially actual combustion accompanied by flame holding" and "ignition to create the spark that leads to actual combustion," it was found that when hydrogen peroxide is used at a low concentration of less than 65 wt%, for example, when it is decomposed using a catalyst before being supplied, it is difficult to obtain a large flow rate because the processing capacity of the catalyst is small (for example, Non-Patent Document 2), and it does not reach "actual combustion" if it is supplied without passing through a catalyst.

[0015] Thus, the inventors of the present application realized that there were still problems to be overcome in the combustion of hybrid rocket fuel using low-concentration hydrogen peroxide water, and found it necessary to take measures to address these problems. Specifically, the inventors of the present application discovered the following problems:

[0016] When hydrogen peroxide is used as a propellant for a hybrid rocket at a concentration of less than 65 wt%, combustion occurs when it is decomposed by a catalyst. However, the supply flow rate is limited by the decomposition capacity of the catalyst, leaving room for further improvement.

[0017] The present invention has been made in view of the above problems. That is, the main object of the present invention is to provide an improved method and apparatus for burning hybrid rocket fuel, in particular, to provide an improved method and apparatus for burning hybrid rocket fuel that uses a propellant that is excellent in safety, transportability, storability, availability, etc., and that leads to "main combustion" that is accompanied by flame or flame release, especially flame holding, etc. [Means for solving the problem]

[0018] The inventors of the present application attempted to solve the above problems by taking a new approach, rather than simply extending the conventional technology, and as a result, they came up with the invention of a method and device for burning hybrid rocket fuel, which achieves the above-mentioned main object.

[0019] As mentioned above, when the concentration of hydrogen peroxide is 65% by weight or more, it is prone to self-decomposition, and the decomposition progresses in a chain reaction and accelerated manner. Therefore, if self-decomposition begins inside the tank, the internal pressure of the tank may rise and cause it to explode, which creates problems in safety, transportability, storage, etc., and it was found that it is difficult to use it in a hybrid rocket.

[0020] In addition, when the concentration of hydrogen peroxide is less than 65% by weight, the proportion of water is high, so the latent heat of vaporization becomes greater than the heat of decomposition, and the accelerated decomposition of hydrogen peroxide as described above can be suppressed, resulting in excellent safety, transportability, storage properties, etc. Also, it is quite easy to obtain. For example, when low-concentration (specifically, less than 65% by weight) hydrogen peroxide is used as a propellant (specifically, an oxidizer) in a polyethylene-fueled hybrid rocket, the flame temperature exceeds 2200 K and the main component of the combustion gas is water (H 2 Since the molecular weight of the material is 18, the specific impulse is theoretically high, exceeding 290 seconds in a vacuum (see Figure 16). In addition, the possibility of eroding the nozzle is low. Therefore, low-concentration (specifically, less than 65% by weight) aqueous hydrogen peroxide has excellent theoretical performance as well as safety, transportability, storability, and availability.

[0021] However, hydrogen peroxide solution with less than 65% by weight is more than 35% by weight water, and the inventors' research has revealed that it is extremely difficult to remove the water in the system or combustion chamber to concentrate the hydrogen peroxide and use it as an oxidizer when used in hybrid fuel, making combustion, especially flame stability, difficult.The inventors' research has also revealed that hydrogen peroxide solution with less than 65% by weight does not reach "main combustion" if it is supplied without passing it through a catalyst.

[0022] Therefore, the inventors of the present application investigated maintaining flame stability by assisting the combustion of hybrid rocket fuel by supplying a small amount of oxygen along with a low concentration (specifically, less than 65% by weight) of hydrogen peroxide water into the combustion chamber, basically without using a catalyst and without directly increasing the concentration of hydrogen peroxide in the system or combustion chamber.

[0023] Surprisingly, it was found that a small amount of oxygen assisting the combustion can heat the hydrogen peroxide above its boiling point, promoting its vaporization and thus maintaining the flame of the hybrid rocket fuel. It was also found that because only a small amount of such assist oxygen is required, it can be installed on spacecraft and the like cheaply and safely.

[0024] Based on this knowledge, the inventors of the present application discovered that by preferably simultaneously supplying both oxygen and hydrogen peroxide to the combustion chamber containing the solid fuel of a hybrid rocket, the flame of the hybrid rocket fuel can be significantly maintained, and thus completed the present invention.

[0025] Furthermore, the inventors have discovered that the flame of the hybrid rocket fuel can be maintained by heating the hydrogen peroxide solution before supplying it to the combustion chamber.

[0026] The present invention provides a method for burning hybrid rocket fuel, which includes supplying hydrogen peroxide to a combustion chamber containing solid fuel, wherein the concentration of hydrogen peroxide in the hydrogen peroxide is less than 65% by weight, and which includes at least one of: (i) supplying oxygen and the hydrogen peroxide to the combustion chamber; and (ii) heating the hydrogen peroxide before supplying it to the combustion chamber. Furthermore, the present invention provides a hybrid rocket fuel combustion device comprising a combustion chamber for containing solid fuel, a line for supplying oxygen, and a line for supplying hydrogen peroxide solution, the line for supplying oxygen and the line for supplying hydrogen peroxide solution being connected to the combustion chamber, and the concentration of hydrogen peroxide in the hydrogen peroxide solution being less than 65% by weight. Effect of the Invention

[0027] The present invention provides an improved method and apparatus for burning hybrid rocket fuel. Note that the effects described herein are merely exemplary and not limiting, and additional effects may be provided. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic diagram showing a combustion device according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a schematic diagram showing a combustion device according to a second embodiment of the present disclosure. [Diagram 3] FIG. 3 is a schematic diagram showing a combustion device according to a third embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic diagram showing a combustion device according to a fourth embodiment of the present disclosure. [Diagram 5] FIG. 5 is a schematic diagram showing a combustion device according to a fifth embodiment of the present disclosure. [Figure 6] FIG. 6 is a set of photographs showing the combustion experiment in Example 1 ((A) before ignition, (B) ignition, (C) combustion (flame holding), (D) supply stop, and (E) a comparison between ignition (left) and actual combustion (flame holding) (right)). [Figure 7] FIG. 7 is a graph showing the history of flow rate and pressure in the combustion experiment in Example 1. [Figure 8] FIG. 8 is a graph showing the history of flow rate and pressure in the combustion experiment in Example 2. [Figure 9]FIG. 9 is a graph showing the history of flow rate and pressure in the combustion experiment in Example 3. [Figure 10] FIG. 10 is a graph showing the history of flow rate and pressure in the combustion experiment in Example 4. [Figure 11] FIG. 11 is a graph showing the history of flow rate and pressure in the combustion experiment in Example 7. [Figure 12] FIG. 12 is a graph showing the temperature history of the hydrogen peroxide solution near the supply port in the combustion experiment in Example 7. [Figure 13] FIG. 13 is a graph showing the history of the flow rate and pressure in the combustion experiment in Comparative Example 1. [Figure 14] FIG. 14 is a graph showing the history of flow rate and pressure in the combustion experiment in Comparative Example 2. [Figure 15] FIG. 15 is a graph showing the history of flow rate and pressure in the combustion experiment in Comparative Example 3. [Figure 16] FIG. 16 is a graph showing the specific impulse (s) and flame temperature (K) for a low-concentration (60 wt%) hydrogen peroxide solution (combustion chamber pressure 2 MPa, nozzle opening ratio 100). [Figure 17] FIG. 17 shows a schematic diagram of a cascaded multistage impinging-jet (CAMUI (CAscaded MUltistage Impinging-jet) type) solid fuel. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The present invention relates to a "method of burning hybrid rocket fuel" and a "device for burning hybrid rocket fuel."

[0030] (Aspect 1) In one aspect, the present invention is characterized in that the concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, and oxygen, preferably a small amount of oxygen (hereinafter sometimes referred to as "assist oxygen") is supplied to the combustion chamber of the hybrid rocket fuel together with such hydrogen peroxide solution.

[0031] Before describing in detail the hybrid rocket fuel combustion method of the present disclosure, the hybrid rocket fuel combustion device of the present disclosure will be briefly described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the basic concept of the present invention, and each element shown in the figure is merely shown as a schematic example for understanding the present invention, and other configurations may be added as necessary.

[0032] For example, as shown in FIG. 1, a hybrid rocket fuel combustion device (10) of the present disclosure includes a combustion chamber (2) for accommodating solid fuel (1), a line (3) for supplying oxygen (hereinafter also referred to as the “oxygen supply line”), and a line (5) for supplying hydrogen peroxide (hereinafter also referred to as the “hydrogen peroxide supply line”). An oxygen supply line (3) and a hydrogen peroxide supply line (5) may be connected to the combustion chamber (2). Here, the oxygen supply line (3) may be connected to an oxygen supply source (4) (e.g., an oxygen tank, a liquid oxygen storage tank, etc.), and the hydrogen peroxide supply line (5) may be connected to a hydrogen peroxide supply source (6) (e.g., a hydrogen peroxide storage tank, etc.). In the hybrid rocket fuel combustion device (10) of the present disclosure, the concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, and preferably 60% or less.

[0033] In the hybrid rocket fuel combustion device (10) disclosed herein, even though the concentration of the hydrogen peroxide solution is low (specifically, less than 65%), by supplying oxygen together with such low concentration hydrogen peroxide solution, preferably by supplying assist oxygen in an amount of at least 10% by weight, and preferably at least 25% by weight, relative to the hydrogen peroxide solution, the combustion of the solid fuel (1) can be promoted, and the combustibility of the hybrid rocket fuel can be further improved by maintaining the flame.

[0034] The hybrid rocket fuel combustion method disclosed herein may use a combustion device such as that shown in FIG. 1, and includes supplying oxygen and aqueous hydrogen peroxide to a combustion chamber (2) containing a solid fuel (1), preferably in parallel, and particularly preferably simultaneously, and is characterized in that the concentration of hydrogen peroxide in the aqueous hydrogen peroxide is less than 65% by weight.

[0035] (Aspect 2) In another aspect, the present invention is characterized in that the hydrogen peroxide concentration in the hydrogen peroxide solution is less than 65% by weight, and such hydrogen peroxide solution is supplied to the combustion chamber of the hybrid rocket fuel in a heated state, preferably heated to 100°C or higher.

[0036] Before describing in detail the hybrid rocket fuel combustion method of the present disclosure, the hybrid rocket fuel combustion device of the present disclosure will be briefly described with reference to Fig. 5. Fig. 5 is a schematic diagram showing the basic concept of the present invention, and each element shown in the figure is merely shown as a schematic example for understanding the present invention, and other configurations may be added as necessary.

[0037] For example, as shown in FIG. 5, a hybrid rocket fuel combustion device (50) of the present disclosure includes a combustion chamber (52) for accommodating solid fuel (51), a line (55) for supplying hydrogen peroxide (hereinafter sometimes referred to as the "hydrogen peroxide supply line"), and a heating means (58) for heating the hydrogen peroxide. Here, the hydrogen peroxide supply line (55) may be connected to a hydrogen peroxide supply source (56) (e.g., a hydrogen peroxide storage tank, etc.). In the hybrid rocket fuel combustion device (50) of the present disclosure, the concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, and preferably 60% or less.

[0038] In the hybrid rocket fuel combustion device (50) of the present disclosure, even though the concentration of hydrogen peroxide solution is low (specifically, less than 65%), by supplying such low concentration hydrogen peroxide solution in a heated state to the combustion chamber (52), it is possible to promote the combustion of the solid fuel (51), and by maintaining flame stability, it is possible to further improve the combustibility of the hybrid rocket fuel.

[0039] The hybrid rocket fuel combustion method of the present disclosure may use a combustion device such as that shown in FIG. 5, and is characterized in that it includes supplying heated hydrogen peroxide water to a combustion chamber (52) containing solid fuel (51), and the hydrogen peroxide concentration in the hydrogen peroxide water is less than 65% by weight.

[0040] The terms used in the hybrid rocket fuel combustion method and combustion device disclosed herein will be explained in detail below.

[0041] The terms used in the hybrid rocket fuel combustion method and combustion device disclosed herein will be explained in detail below.

[0042] (definition) In this disclosure, the term "rocket" refers broadly to a jet propulsion device that propels forward by the reaction of a substance such as a combustion product gas ejected backward without the aid of oxygen from the atmosphere, and narrowly to a chemical rocket that uses combustion as an energy source to generate thrust.

[0043] In this disclosure, the term "hybrid rocket" refers to a rocket that uses a combination of at least two different propellants, preferably a "solid fuel" and a liquid or gaseous "oxidizer." In this disclosure, the term "hybrid rocket" more specifically refers to a rocket that burns by supplying a liquid or gaseous oxidizer to a combustion chamber containing solid fuel, and then propels itself by ejecting the resulting gas.

[0044] In this disclosure, the term "hybrid rocket fuel" refers to a fuel that includes at least two different types of propellants in different phases in combination. There is no particular restriction on the type of propellants that are combined. The hybrid rocket fuel preferably includes a solid fuel and a liquid or gaseous oxidizer in combination. In this disclosure, the hybrid rocket fuel may refer to two or more propellants collectively, or may refer to only one of the propellants. For example, the solid fuel and the oxidizer may be collectively referred to as hybrid rocket fuel. Alternatively, the hybrid rocket fuel or simply the fuel may refer to only the solid fuel, or may refer to only the oxidizer.

[0045] In this disclosure, "combustion" refers to the chemical reaction of the fuel contained in the hybrid rocket, particularly the oxidation reaction. Specifically, it refers to the chemical reaction between the solid fuel and the oxidizer, more specifically, the oxidation reaction of the solid fuel by the oxidizer. By using a combination of the solid fuel and the oxidizer, particularly a liquid oxidizer, a larger acceleration can be obtained in a short time.

[0046] In the present disclosure, the term "solid fuel" refers to a fuel that is solid at least at room temperature (25°C), and may be made from, for example, plastic (e.g., polymer plastic material). More specifically, the term refers to a solid fuel made from at least one selected from the group consisting of polyethylene-based, polyester-based, polyurethane-based, polyacrylonitrile-based, and acrylic-based plastics or resins. Of these, it is preferable to use a solid fuel made from a polyethylene-based or acrylic-based plastic or resin. Of these, it is particularly preferable to use a solid fuel made from an ethylene-based plastic (high-density polyethylene (HDPE)) or an acrylic-based polymethyl methacrylate (PMMA).

[0047] There is no particular restriction on the shape of the solid fuel, but from the viewpoint of combustion efficiency and high thrust, it is preferable to use a cascaded multistage impinging-jet (CAMUI) type solid fuel (see FIG. 17). The CAMUI solid fuel shown in FIG. 17 is as follows: fuel It may have a block 61 , a spacer 62 , and a port 63 .

[0048] The CAMUI solid fuel is composed of multiple cylindrical fuel blocks with a short axial length. Each fuel block may have two combustion ports at axially symmetrical positions. Multiple such fuel blocks may be arranged in a vertical row to form a fuel grain used for one combustion. A cylindrical spacer made of fuel may be provided between the fuel blocks of each row to form a gap between the fuel blocks. Combustion gas can flow downstream by passing through the ports and fuel blocks of each row in sequence. The ports of adjacent fuel blocks may be shifted by 90° from each other, and the jet of combustion gas flowing out of the port collides with the downstream fuel, causing combustion in the stagnation region.

[0049] In the CAMUI type solid fuel, the main combustion surfaces are the front end surface (collision surface), the rear end surface (surface facing the collision surface) of the fuel block, and the inner wall of the port, and in addition, the inner wall of the spacer can also be burned.

[0050] In the present disclosure, the term "oxidizer" refers to a liquid or gaseous substance or composition that can cause an oxidation reaction by chemical reaction with a solid fuel and can burn the solid fuel. In the present invention, it is preferable to use a liquid oxidizer as the oxidizer. For example, hydrogen peroxide solution can be used.

[0051] In this disclosure, "hydrogen peroxide" refers to hydrogen peroxide (H 2 O 2 ) in water.

[0052] In this disclosure, the "concentration" of "hydrogen peroxide solution" means the ratio of the weight of hydrogen peroxide to the total weight of hydrogen peroxide solution, expressed as a percentage (%) (unit: % by weight). Alternatively, it means the ratio of the mass of hydrogen peroxide to the total mass of hydrogen peroxide solution, expressed as a percentage (%) (unit: % by mass). % by weight and % by mass basically indicate the same value, and in this disclosure, these terms can be used interchangeably.

[0053] In the present disclosure, the concentration of the aqueous hydrogen peroxide is, for example, less than 65% by weight or mass, and preferably 60% or less.

[0054] In this disclosure, with regard to the concentration of hydrogen peroxide, since the exothermic decomposition of hydrogen peroxide occurs at a concentration of 65% by weight, for ease of explanation, concentrations below 65% by weight are referred to as "low concentration" and concentrations of 65% by weight or more are referred to as "high concentration."

[0055] There is no particular lower limit to the concentration of the aqueous hydrogen peroxide solution, and it is greater than 0% by weight, for example, 20% by weight or more, and preferably 50% by weight or more.

[0056] As a propellant that may be contained in the hybrid rocket fuel, for example, at least one selected from the group consisting of nitric acid, fuming nitric acid, dinitrogen tetroxide, nitrous oxide, ammonium perchlorate, ammonium nitrate, nitroglycerin, nitrocellulose, and green propellants (for example, HAN (HydroxylAmmonium Nitrate)-based, ADN (Ammonium DiNitramide)-based, and HNF (Hydrazinium Nitro Formate)-based propellants) may be used.

[0057] In this disclosure, "combustion device" refers to a device or system capable of combusting the fuels described above.

[0058] In the present disclosure, the combustion device includes at least a "combustion chamber for accommodating solid fuel," a "line for supplying oxygen," and a "line for supplying hydrogen peroxide solution."

[0059] In this disclosure, a "combustion chamber" refers to a housing capable of containing a fuel, such as the solid fuel described above, and in which the fuel can be burned. In this disclosure, a combustion chamber is also referred to as a "motor case," and a "motor case" with fuel may be referred to as a "rocket motor" or a "motor assembly" or simply a "motor."

[0060] The combustion chamber preferably has a cylindrical shape. There are no particular limitations on the shape and dimensions of the combustion chamber, nor on the material from which the combustion chamber is made.

[0061] The combustion chamber may be optionally provided with, for example, a valve, a filter, a nozzle (such as a melting nozzle or a graphite nozzle), an injector and / or an atomizer.

[0062] In this disclosure, the term "line for supplying oxygen" (or oxygen supply line) refers to a line for supplying oxygen (which may be "gas" or "liquid") from an oxygen supply source (e.g., an oxygen tank or a storage tank for liquid oxygen, etc.) into a combustion chamber. There are no particular limitations on the shape and dimensions of the oxygen supply line, and there are no particular limitations on the material from which the oxygen supply line is made.

[0063] In this disclosure, a "line for supplying hydrogen peroxide" (or hydrogen peroxide supply line) means a line for supplying hydrogen peroxide from a hydrogen peroxide supply source (e.g., a hydrogen peroxide storage tank, etc.) to a combustion chamber. There are no particular limitations on the shape and dimensions of the hydrogen peroxide supply line, and there are no particular limitations on the material from which the hydrogen peroxide supply line is made.

[0064] The oxygen supply line and the hydrogen peroxide supply line may be connected directly or indirectly to the combustion chamber. The oxygen supply line and the hydrogen peroxide supply line may be connected to the combustion chamber independently (see FIG. 2), or may be connected so that they are mixed on the way (see FIG. 3).

[0065] The oxygen supply line and the hydrogen peroxide supply line may be optionally provided with, for example, a filter, an orifice, a valve (e.g., a needle valve, a ball valve, a check valve), a nozzle, a meter (e.g., a flow meter), a sensor (e.g., a temperature sensor, a pressure sensor), a regulator, an injector, and / or an atomizer.

[0066] In the present disclosure, the term "heating means" refers to a device capable of heating hydrogen peroxide solution, etc. The heating means is not particularly limited as long as it can heat hydrogen peroxide solution, and examples of the heating means include a heat exchanger, a heater, etc.

[0067] (Combustion method) (Aspect 1) In one embodiment, the hybrid rocket fuel combustion method of the present disclosure (hereinafter sometimes referred to as the "first combustion method of the present disclosure") comprises supplying oxygen and hydrogen peroxide to a combustion chamber containing a solid fuel. The first combustion method of the present disclosure is characterized in that the hydrogen peroxide concentration in the hydrogen peroxide solution is less than 65% by weight or mass, in other words, that a low-concentration hydrogen peroxide solution is used. Previous research has shown that low-concentration hydrogen peroxide can be used as an oxidizer for solid fuel in hybrid rockets. However, if solid fuel combustion is divided into "flames or flames that generate thrust, especially actual combustion accompanied by flame holding" and "ignition to create the spark that leads to actual combustion," the problem is that low-concentration hydrogen peroxide will burn if it is decomposed with a catalyst before being supplied, but if it is sprayed as is without passing it through a catalyst, it will not reach "actual combustion" accompanied by flame holding. The inventors of the present application considered that it would be difficult to vaporize hydrogen peroxide in a combustion chamber with low-concentration hydrogen peroxide, and therefore considered supplementary supply of oxygen (which may be gas or liquid) to the combustion chamber together with low-concentration hydrogen peroxide. In other words, they considered providing oxygen as an "assist" for the combustion of solid fuel by hydrogen peroxide. Supplying oxygen into the combustion chamber increases the temperature inside the chamber upon ignition, and the heat generated by this increases the vaporization of hydrogen peroxide (boiling point: 62.8°C (21mmHg), 80°C (46mmHg), 151.4°C (760mmHg)), which is expected to decompose the hydrogen peroxide contained in the hydrogen peroxide water and ultimately increase the partial pressure of oxygen in the combustion chamber. Therefore, the first combustion method of the present disclosure is characterized in that "oxygen" is supplied to a combustion chamber equipped with a solid fuel together with low-concentration hydrogen peroxide solution. By supplying oxygen to the combustion chamber along with low-concentration hydrogen peroxide, it is possible to achieve not only ignition, but also main combustion accompanied by flame and flame release, and in particular flame holding, as well as the sustainment of main combustion. In particular, it is possible to burn solid fuel using low-concentration hydrogen peroxide without using a catalyst as in the past.

[0068] In this disclosure, "flame" refers to the light and / or heat released during combustion (hereinafter sometimes referred to as "combustion flame").

[0069] In this disclosure, "flame-off" means that the combustion flame is blown out of the combustion chamber.

[0070] In the present disclosure, "flame holding" means that the combustion flame is maintained for at least 5 seconds, preferably 10 seconds or more. In other words, the combustion continues for at least 5 seconds, preferably 10 seconds or more.

[0071] In the first combustion method of the present disclosure, oxygen and hydrogen peroxide solution may be supplied to the combustion chamber in parallel. In the present disclosure, "parallel supply" means that oxygen and hydrogen peroxide are supplied from separate sources. It is preferable to supply oxygen and hydrogen peroxide simultaneously.

[0072] By supplying oxygen and hydrogen peroxide to the combustion chamber in parallel, preferably by supplying oxygen and hydrogen peroxide simultaneously, it becomes possible to sustain the combustion, particularly to hold the flame, even when a low concentration of hydrogen peroxide is used. Also, the amount of oxygen supplied can be further reduced.

[0073] In the first combustion method of the present disclosure, hydrogen peroxide solution may be supplied while oxygen is present in the combustion chamber. In other words, hydrogen peroxide solution may be supplied to a combustion chamber charged with oxygen, preferably while continuing the supply of oxygen. Alternatively, after oxygen is supplied to the combustion chamber, hydrogen peroxide solution may be supplied, preferably while continuing the supply of oxygen. In this way, flame stability is possible even when a low concentration of hydrogen peroxide solution is used. Also, the amount of oxygen supplied can be further reduced.

[0074] In the first combustion method of the present disclosure, oxygen and hydrogen peroxide solution can be supplied to the combustion chamber from separate lines.

[0075] For example, as shown diagrammatically in FIG. 1, oxygen can be supplied to the combustion chamber (2) from an oxygen source (4) via line (3). Hydrogen peroxide can be supplied to the combustion chamber (2) from a hydrogen peroxide supply source (6) via a line (5).

[0076] There is no particular restriction on the flow rate of oxygen that can be supplied from the oxygen source (4) via line (3) to the combustion chamber (2). When the purity of the oxygen is 99.9% or more, the flow rate is preferably 5% or more and 90% or less, for example, 10% or more and 80% or less, 10% or more and 50% or less, 20% or more and 40% or less, or 20% or more and 35% or less, by weight, of the total flow rate of the oxygen and the hydrogen peroxide solution.

[0077] There is no particular limitation on the flow rate of hydrogen peroxide that can be supplied from hydrogen peroxide source (6) via line (5) to combustion chamber (2). When the concentration of hydrogen peroxide is less than 65% by weight, the flow rate is preferably 10% or more and 95% or less, for example, 20% or more and 90% or less, 50% or more and 90% or less, 60% or more and 80% or less, or 65% or more and 80% or less, by weight based on the total flow rate of oxygen and hydrogen peroxide.

[0078] The oxygen may be supplied as a gas or a liquid, but from the standpoint of handling, storage and cost, it is preferable to supply the oxygen to the combustion chamber as a gas.

[0079] The concentration of hydrogen peroxide in the hydrogen peroxide solution is low, i.e., less than 65% by weight, and preferably 60% or less. Even with such a low concentration of hydrogen peroxide solution, combustion of the hybrid rocket fuel, particularly flame stabilization, is possible without using a catalyst, by supplying oxygen to the combustion chamber. Flame stabilization of the hybrid rocket fuel is possible by supplying low concentration hydrogen peroxide solution, preferably while oxygen is present, more preferably while continuing the supply of oxygen, to the combustion chamber in which oxygen has been charged, preferably while continuing the supply of oxygen, or by supplying low concentration hydrogen peroxide solution to the combustion chamber, preferably while continuing the supply of oxygen, after oxygen has been supplied to the combustion chamber.

[0080] There is no particular restriction on the order in which oxygen and hydrogen peroxide are supplied, so long as oxygen is supplied so that both oxygen and hydrogen peroxide are present or coexist in the combustion chamber. In the first combustion method of the present disclosure, it is preferable to supply oxygen and hydrogen peroxide simultaneously. By supplying oxygen and hydrogen peroxide simultaneously, the flame of the hybrid rocket fuel can be better maintained.

[0081] In a first combustion method of the present disclosure, oxygen can assist the combustion of hybrid rocket fuels, and more specifically, the combustion of solid fuels. In this disclosure, "assisting combustion" means to assist in the combustion of a hybrid rocket fuel (e.g., a fuel using a combination of a solid fuel and a liquid or gaseous oxidizer) during the combustion of the hybrid rocket fuel. More specifically, when hydrogen peroxide is used as the oxidizer, it means promoting the vaporization of hydrogen peroxide contained in hydrogen peroxide or its decomposition into oxygen. By supplying oxygen, a larger amount of hydrogen peroxide can be vaporized from the hydrogen peroxide solution, and the solid fuel can be burned more efficiently to maintain the flame.

[0082] The ratio of oxygen to the hydrogen peroxide solution is not particularly limited, and is equal to or less than the weight (100% or less), for example, 10% to 90%, preferably 10% to 70%, more preferably 10% to 50%, even more preferably 20% to 50%, and even more preferably 25% to 50%. Flame stability can be maintained with a smaller amount of oxygen than the hydrogen peroxide solution. The amount of oxygen supplied may be in excess of the amount of hydrogen peroxide solution (may exceed 100%).

[0083] Surprisingly, in the present invention, the supply of oxygen can assist combustion without using a catalyst, so the supplied hydrogen peroxide solution does not need to be subjected to a catalyst. For example, in the conventional method described in Non-Patent Document 2, ignition is performed by catalytically decomposing hydrogen peroxide using an atomizer and a catalyst (specifically, a platinum (Pt) catalyst) (however, no progress to full combustion has been observed). However, in the method disclosed herein, it is possible to progress to full combustion after ignition without using a catalyst. Note that the method disclosed herein does not exclude the use of an atomizer or a catalyst.

[0084] In the first combustion method of the present disclosure, it is particularly preferable to start the supply of oxygen to the combustion chamber, and after ignition, continue to supply oxygen to the combustion chamber while supplying hydrogen peroxide solution to the combustion chamber, thereby maintaining combustion of the solid fuel and flame stability. By supplying oxygen to the combustion chamber in advance and igniting it, the temperature of the combustion chamber is raised, and then by supplying hydrogen peroxide water while supplying oxygen to the combustion chamber, more hydrogen peroxide can be vaporized, and the solid fuel can be burned more efficiently to maintain flame stability. In other words, flame stability can be maintained with a smaller amount of oxygen.

[0085] (Aspect 2) In another embodiment, the hybrid rocket fuel combustion method of the present disclosure (hereinafter, sometimes referred to as the "second combustion method of the present disclosure") comprises supplying heated hydrogen peroxide solution to a combustion chamber containing a solid fuel. In other words, the second combustion method of the present disclosure comprises supplying high-temperature hydrogen peroxide solution to a combustion chamber containing a solid fuel. The second combustion method of the present disclosure is characterized in that the concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight or mass, in other words, that a low-concentration hydrogen peroxide solution is used.

[0086] The inventors of the present application considered that it would be difficult to vaporize hydrogen peroxide in a combustion chamber with low concentration hydrogen peroxide water, and investigated supplying low concentration hydrogen peroxide water in a heated state to the combustion chamber. By supplying high-temperature hydrogen peroxide to the combustion chamber, the energy required to vaporize the hydrogen peroxide in the combustion chamber is reduced, and it is expected that combustion will be promoted.

[0087] Therefore, the second combustion method of the present disclosure is characterized in that hydrogen peroxide solution is supplied in a heated state to a combustion chamber containing a solid fuel. By supplying hydrogen peroxide solution in a heated state to the combustion chamber, it is possible to achieve the main combustion accompanied by flame, flame release, and particularly flame holding, as well as the continuation of the main combustion. In particular, it is possible to burn the solid fuel using low-concentration hydrogen peroxide solution without using a catalyst as in the past.

[0088] In the second combustion method, the temperature of the hydrogen peroxide solution supplied to the combustion chamber may be preferably 100° C. or higher, more preferably 120° C. or higher, and even more preferably 130° C. or higher. By increasing the temperature of the hydrogen peroxide solution, it becomes easier to sustain the combustion, particularly to hold the flame.

[0089] The location where the hydrogen peroxide solution is heated is not particularly limited. For example, the hydrogen peroxide solution may be heated in the hydrogen peroxide supply source (56) or in the hydrogen peroxide solution supply line (55). When the hydrogen peroxide solution supply line (55) is heated, the hydrogen peroxide solution may be heated at any location in the hydrogen peroxide solution supply line (55), for example, near the hydrogen peroxide solution supply source (56) or near the combustion chamber (52).

[0090] The heating means for heating the hydrogen peroxide solution is not particularly limited, and a heat exchanger, a heater, or the like can be used.

[0091] The first and second combustion methods of the present disclosure may be combined. For example, in the first combustion method of the present disclosure, hydrogen peroxide may be heated and supplied to the combustion chamber. That is, high-temperature hydrogen peroxide and oxygen may be supplied to the combustion chamber. By combining the first and second combustion methods of the present disclosure, it becomes easier to sustain the combustion, particularly to maintain the flame.

[0092] (Combustion equipment) (Aspect 1) A combustion device for hybrid rocket fuel according to one embodiment of the present disclosure (hereinafter, sometimes referred to as "first combustion device according to the present disclosure") includes a combustion chamber for accommodating solid fuel, a line for supplying oxygen, and a line for supplying hydrogen peroxide. The line for supplying oxygen and the line for supplying hydrogen peroxide may be connected to the combustion chamber. The concentration of hydrogen peroxide in the hydrogen peroxide is less than 65% by weight. In other words, a low concentration of hydrogen peroxide can be used.

[0093] For example, as shown in FIG. 1, a combustion device (10) of the present disclosure includes a combustion chamber (2) for accommodating a solid fuel (1), a line for supplying oxygen (or an oxygen supply line) (3), and a line for supplying hydrogen peroxide (or a hydrogen peroxide supply line) (5). The oxygen supply line (3) and the hydrogen peroxide supply line (5) may be connected to the combustion chamber (2). The oxygen supply line (3) and the hydrogen peroxide supply line (5) may be directly connected to the combustion chamber (2), for example, as shown in Figures 1 and 2. Alternatively, as shown in Figure 3, the oxygen supply line (3) and the hydrogen peroxide supply line (5) may be combined and then indirectly connected to the combustion chamber (2) via a mixed flow line. The oxygen supply line (3) may be connected to an oxygen source (4) (eg, an oxygen tank or a storage tank of liquid oxygen, etc.). The hydrogen peroxide supply line (5) may be connected to a hydrogen peroxide supply source (6) (e.g., a hydrogen peroxide storage tank, etc.). The first combustion device of the present disclosure may further include ignition means (7), which will be described in detail below.

[0094] The first combustion device of the present disclosure is characterized in that the hydrogen peroxide concentration in the hydrogen peroxide solution is less than 65% by weight or mass, in other words, a low-concentration hydrogen peroxide solution can be used.

[0095] In the first combustion device of the present disclosure, low-concentration hydrogen peroxide solution and oxygen can be supplied to the combustion chamber (2) via the hydrogen peroxide solution supply line (5) and the oxygen supply line (3), respectively. Only a small amount of oxygen can be supplied to the combustion chamber (2) via the oxygen supply line (3). In other words, oxygen can contribute to the combustion of the solid fuel (1) in the combustion chamber (2) as "assist oxygen," and can achieve flame stabilization, particularly during the combustion of the solid fuel (1).

[0096] In the first combustion device of the present disclosure, the oxygen supply line and the hydrogen peroxide supply line may be directly connected to the combustion chamber. Alternatively, the oxygen supply line and the hydrogen peroxide supply line may be combined with each other and indirectly connected to the combustion chamber.

[0097] In this disclosure, the oxygen supply line and the hydrogen peroxide supply line being “directly” connected to the combustion chamber means that, for example, as shown in FIG. 1, the oxygen supply line (3) and the hydrogen peroxide supply line (5) can be independently connected to the combustion chamber (2) without being connected to each other.

[0098] For example, as shown in Fig. 2, the oxygen supply line (23) and the hydrogen peroxide solution supply line (25) may be connected separately to the combustion chamber (22). With such a configuration, the flow rates of oxygen and hydrogen peroxide solution can be more appropriately adjusted. In particular, the flow rate of oxygen relative to the hydrogen peroxide solution can be more appropriately adjusted. This allows for more appropriate control of combustion, more appropriate control of flame stabilization during combustion, and ultimately allows flame stabilization to be maintained for a longer period of time.

[0099] In the present disclosure, the oxygen supply line and the hydrogen peroxide supply line are combined with each other and connected to the combustion chamber “indirectly” means, for example, as shown in FIG. 3, that the oxygen supply line (33) and the hydrogen peroxide supply line (35) are connected with each other and have a mixing point (P 1 ) via the mixed line (L 1 ) to the combustion chamber (32).

[0100] In addition, other lines such as a purge line (102) may be connected as shown in FIG.

[0101] In the first combustion device of the present disclosure, since it is equipped with an oxygen supply line and a hydrogen peroxide supply line, the amounts of oxygen and hydrogen peroxide can be more appropriately controlled.

[0102] In the first combustion device of the present disclosure, a smaller amount of oxygen (assist oxygen) can be supplied to the hydrogen peroxide solution. More specifically, oxygen can be supplied to the hydrogen peroxide solution at a ratio of, for example, 10% to 50%, preferably 25% to 50%, by weight. By supplying oxygen to the combustion chamber at such a ratio, the solid fuel combustion and flame holding can be more appropriately maintained.

[0103] In the first combustion device and combustion method of the present disclosure, from the viewpoint of maintaining flame stability, the amount of oxygen supplied may be increased as the concentration of the hydrogen peroxide solution is reduced, thereby making it possible to more appropriately maintain the combustion of the solid fuel and the flame stability.

[0104] (Aspect 2) In another aspect, a combustion device for a hybrid rocket fuel of the present disclosure (hereinafter sometimes referred to as the "second combustion device of the present disclosure") includes a combustion chamber for containing solid fuel, a line for supplying hydrogen peroxide solution, and a heating means for heating the hydrogen peroxide solution.

[0105] The location of the heating means is not particularly limited, and may be disposed, for example, inside or outside the hydrogen peroxide source (56), or may be disposed midway through the hydrogen peroxide supply line (55). When disposed midway through the hydrogen peroxide supply line (55), the heating means may be disposed anywhere in the hydrogen peroxide supply line (55), for example, near the hydrogen peroxide supply source (56) of the hydrogen peroxide supply line (55) or near the combustion chamber (52).

[0106] The heating means includes, for example, a heat exchanger, a heater, and the like.

[0107] The combustion device and the combustion method of the present disclosure will be described in detail below with reference to several embodiments.

[0108] (First embodiment) 1 shows a combustion device 10 for hybrid rocket fuel according to a first embodiment of the present disclosure. The combustion device 10 corresponds to a first combustion device of the present disclosure. The combustion device 10 includes a combustion chamber 2 for accommodating a solid fuel 1, a line 3 for supplying oxygen (oxygen supply line or simply line), and a line 5 for supplying hydrogen peroxide solution (hydrogen peroxide solution supply line or simply line). The line 3 and the line 5 can be connected to the combustion chamber 2 independently of each other.

[0109] Lines 3 and 5 may be joined together if necessary and connected to the combustion chamber 2 as a mixed flow line (see Figures 3 and 4).

[0110] Lines 3 and 5 may each independently be coupled with a filter, an orifice, a valve (e.g., a needle valve, a ball valve, a check valve), a nozzle, a meter (e.g., a flow meter), a sensor (e.g., a temperature sensor, a pressure sensor), a regulator, an injector, and / or an atomizer, etc., as necessary.

[0111] An oxygen supply source 4 may be connected to the line 3. There are no particular limitations on the oxygen supply source 4 as long as it can supply gaseous or liquid oxygen. For example, an oxygen tank or a liquid oxygen storage tank may be used as the oxygen supply source 4. The oxygen supply source 4 may be provided with a regulator (not shown) for adjusting the flow rate.

[0112] A hydrogen peroxide supply source 6 may be connected to the line 5. There are no particular limitations on the hydrogen peroxide supply source 6 as long as it can supply liquid hydrogen peroxide. For example, a storage tank for hydrogen peroxide can be used as the hydrogen peroxide supply source 6.

[0113] The combustion chamber 2 ("rocket motor", "motor assembly" or "motor") containing the solid fuel 1 may be equipped with injectors, atomizers, catalysts, nozzles, jackets (e.g., water-cooled jackets), etc. as needed to further improve combustion efficiency.

[0114] The solid fuel 1 may be wrapped in, for example, a heat insulating material and placed inside the combustion chamber 2. As the heat insulating material, for example, glass fiber reinforced plastic (GFRP) or the like can be used.

[0115] As the solid fuel 1, from the viewpoint of combustion characteristics and high thrust, for example, fuel grains of a cascade array multi-stage impinging jet (CAMUI) type shown in FIG. 17 may be used.

[0116] An ignition means 7 may be connected to the motor (hereinafter, sometimes referred to as an "ignition apparatus" or an "ignition device"). There are no particular limitations on the ignition means 7 as long as it can burn at least oxygen by ignition. Examples of ignition by the ignition means 7 include arc ignition, laser ignition, solid explosive ignition, electric plasma ignition, gas torch ignition, and / or heating ignition. There are no particular limitations on the timing of ignition.

[0117] In the combustion device 10, oxygen and hydrogen peroxide can be supplied to the combustion chamber 2 independently from the oxygen supply source 4 and the hydrogen peroxide supply source 6. This allows the flow rates of oxygen and hydrogen peroxide to be appropriately adjusted. In particular, a small amount of oxygen (or assist oxygen) can be supplied to the combustion chamber 2. In the combustion device 10, both oxygen and hydrogen peroxide can be supplied to the combustion chamber 2. More preferably, oxygen and hydrogen peroxide can be supplied to the combustion chamber 2 simultaneously.

[0118] For example, oxygen and hydrogen peroxide solution can be supplied in parallel from the oxygen supply source 4 and the hydrogen peroxide solution supply source 6 to the combustion chamber 2. Alternatively, hydrogen peroxide solution may be supplied to the combustion chamber 2 charged with oxygen, preferably while supplying oxygen, or hydrogen peroxide solution may be supplied from the hydrogen peroxide solution supply source 6 to the combustion chamber 2, preferably while supplying oxygen, after oxygen is supplied from the oxygen supply source 4 to the combustion chamber 2. More specifically, the supply of oxygen from the oxygen supply source 4 to the combustion chamber 2 is started, and after ignition by the ignition means 7, hydrogen peroxide solution can be supplied from the hydrogen peroxide solution supply source 6 to the combustion chamber 2 while oxygen is continuously supplied from the oxygen supply source 4 to the combustion chamber 2.

[0119] In the combustion device 10, the concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight or mass, and preferably 60% or less.

[0120] Second embodiment Fig. 2 shows a combustion device 20 for hybrid rocket fuel according to a second embodiment of the present disclosure. The combustion device 20 is a more specific example of the combustion device 10 shown in Fig. 1. The combustion device 20 corresponds to the first combustion device of the present disclosure. For example, the combustion device 20 includes a valve V 1 ,V 2 , regulator R 1 ,R 2 1. Except for the provision of the pressure feed tank 28 and the pressure feed line 29, the combustion device 10 may be configured in the same manner as the combustion device 10 shown in FIG. Solid fuel 21, combustion chamber 22, oxygen supply line 23, oxygen supply source 24, hydrogen peroxide supply line 25, hydrogen peroxide supply source 26, and ignition means 27 shown in Figure 2 correspond to solid fuel 1, combustion chamber 2, oxygen supply line 3, oxygen supply source 4, hydrogen peroxide supply line 5, hydrogen peroxide supply source 6, and ignition means 7 shown in Figure 1, respectively.

[0121] In the combustion device 20 shown in FIG. 2, for example, an oxygen tank capable of supplying gaseous oxygen can be used as the oxygen supply source 24. The oxygen supply source 24 is provided with a regulator R 1 may be connected to regulate the flow rate of oxygen leaving the oxygen source 24. Oxygen source 24 and regulator R 1 The oxygen supply line 23 that can be connected to the valve V 1 may be connected to the combustion chamber 22 via Valve V 1 may be connected to a controller (not shown) as needed to better regulate the flow rate of oxygen through the oxygen supply line 23.

[0122] In the combustion device 20 shown in FIG. 2, a hydrogen peroxide supply line 25 that may be provided between a hydrogen peroxide supply source 26 and the combustion chamber 22 is provided with a valve V 2 may be arranged. Valve V 2 may be connected to a controller (not shown) as necessary, to more appropriately regulate the flow rate of hydrogen peroxide passing through the hydrogen peroxide supply line 25.

[0123] A pressure tank 28 capable of supplying pressure gas such as nitrogen may be connected to the hydrogen peroxide solution supply source 26 via a pressure line 29. As the pressure tank 28, for example, a nitrogen tank capable of supplying gaseous nitrogen may be used. Nitrogen gas is preferable because it is inexpensive. Other inert gases such as helium and argon may also be used. The pressure tank 28 is equipped with a regulator R 2 may be connected to the pressure tank 28, thereby more appropriately adjusting the flow rate of the gas flowing out of the pressure tank 28, and therefore the flow rate of the hydrogen peroxide solution flowing out from the hydrogen peroxide solution supply source 26 via the line 25.

[0124] In the combustion device 20 shown in FIG. 1 and V 2 By providing this, the ratio of oxygen to hydrogen peroxide solution can be adjusted to, for example, 10% or more and 50% or less, preferably 25% or more and 50% or less, on a weight basis, and an assist amount of oxygen can be more appropriately supplied to the combustion chamber.

[0125] Third embodiment Fig. 3 shows a combustion device 30 for hybrid rocket fuel according to a third embodiment of the present disclosure. The combustion device 30 is, for example, a modified version of the combustion device 20 shown in Fig. 2. The combustion device 30 corresponds to the first combustion device of the present disclosure. Specifically, the combustion device 30 is arranged at a mixing point P 1 and mixed flow line L 1 The combustion device 20 shown in FIG. 2 can be configured in the same manner as the combustion device 20 shown in FIG. 2 except for the provision of the mixed flow line L1 may be a part of the oxygen supply line 33 or a part of the hydrogen peroxide solution supply line 35. Mixed current point P 1 and mixed flow line L 1 By providing the nozzle, the hydrogen peroxide solution can be sprayed more efficiently. As shown in FIG. 3, there is a solid fuel 31, a combustion chamber 32, an oxygen supply line 33, an oxygen supply source 34, a hydrogen peroxide supply line 35, a hydrogen peroxide supply source 36, an ignition means 37, a pressure tank 38, a pressure line 39, and a valve (V 3 ,V 4 ), regulator (R 3 ,R 4 ) respectively represent the solid fuel 21, the combustion chamber 22, the oxygen supply line 23, the oxygen supply source 24, the hydrogen peroxide water supply line 25, the hydrogen peroxide water supply source 26, the ignition means 27, the pressure tank 28, the pressure line 29, and the valve (V 1 ,V 2 ), regulator (R 1 ,R 2 )

[0126] The combustion device 30 shown in FIG. 3 has a mixing point P 1 and mixed flow line L 1 By providing the mixed flow line L, oxygen and hydrogen peroxide solution mixed in an appropriate ratio can be simultaneously supplied to the combustion chamber 32. 1 An injector, an atomizer and / or a catalyst can be connected to the fuel cell as necessary.

[0127] In addition, the oxygen supply line 33 and the hydrogen peroxide supply line 35 are mixed at a point P 1 Other members such as an adapter and a manifold may be provided separately.

[0128] (Fourth embodiment) Fig. 4 shows a combustion device 40 for hybrid rocket fuel according to a fourth embodiment of the present disclosure. The combustion device 40 is, for example, a modified version of the combustion device 30 shown in Fig. 3. The combustion device 40 corresponds to the first combustion device of the present disclosure. Specifically, the combustion device 40 includes a purge tank 101, a purge line 102, a mixed flow point P 3 , mixed flow line L 3 , Valve V 7 and regulator R 7 The combustion device 30 shown in FIG. 3 can be configured in the same manner as the combustion device 30 shown in FIG. 3 except for the provision of the mixed flow line L 3 may be a part of the oxygen supply line 43 or a part of the hydrogen peroxide solution supply line 45. As shown in FIG. 4, there is a solid fuel 41, a combustion chamber 42, an oxygen supply line 43, an oxygen supply source 44, a hydrogen peroxide supply line 45, a hydrogen peroxide supply source 46, an ignition means 47, a pressure tank 48, a pressure supply line 49, and a valve (V 5 ,V 6 ), regulator (R 5 ,R 6 ), mixed current point P 2 , mixed flow line L 2 3, respectively, a solid fuel 31, a combustion chamber 32, an oxygen supply line 33, an oxygen supply source 34, a hydrogen peroxide solution supply line 35, a hydrogen peroxide solution supply source 36, an ignition means 37, a pressure tank 38, a pressure line 39, and a valve (V 3 ,V 4 ), regulator (R 3 ,R 4 ), mixed current point P 1 , mixed flow line L 1 Corresponds to.

[0129] The combustion device 40 is provided with a purge tank 101, a purge line 102, and a mixed flow point P 3 , mixed flow line L 3 , Valve V 7 and regulator R 7 This allows, for example, purging of the combustion chamber 42 after combustion has ended. Purging of the combustion chamber 42 is preferably performed before and / or after the start of the combustion cycle.

[0130] For example, a nitrogen tank capable of supplying gaseous nitrogen can be used as the purge tank 101. Nitrogen gas is preferable because it is inexpensive. Other inert gases, such as helium and argon, may also be used. The purge tank 101 is equipped with a regulator R 7 may be connected to the purge tank 101, so that the flow rate of the purge gas flowing out of the purge tank 101 can be more appropriately adjusted. Valve V 7 may be connected to a controller (not shown) as needed to better regulate the flow rate of purge gas passing through the purge line 102.

[0131] A mixing point P of the oxygen supply line 43 and the purge line 102 3 Other components such as an adapter or manifold may be provided separately. 3 The mixed flow line L 2 It may also be provided in.

[0132] In the above embodiments, each component may be used in appropriate combination as needed, and other components (e.g., valves, filters, orifices, nozzles, meters, sensors, actuators, regulators, injectors and / or atomizers, etc.) may be added as needed.

[0133] Fifth embodiment 5 shows a combustion device 50 for hybrid rocket fuel according to a fifth embodiment of the present disclosure. The combustion device 50 corresponds to the second combustion device of the present disclosure. The combustion device 50 includes a combustion chamber 52 for accommodating a solid fuel 51, a line 55 for supplying hydrogen peroxide solution (hydrogen peroxide solution supply line or simply line), and a heating means 58 for heating the hydrogen peroxide solution. The line 55 is connected to the combustion chamber 52.

[0134] Line 55 may be the same as line 5 of combustion system 10 shown in FIG.

[0135] The heating means 58 may be located anywhere in the line 55. Preferably, the heating means 58 is located near the feed to the combustion chamber 52.

[0136] Solid fuel 51, combustion chamber 52, hydrogen peroxide supply line 55, hydrogen peroxide supply source 56, and ignition means 57 shown in Figure 5 correspond to solid fuel 1, combustion chamber 2, hydrogen peroxide supply line 5, hydrogen peroxide supply source 6, and ignition means 7 shown in Figure 1, respectively. EXAMPLES

[0137] Example 1 Preparation of the combustion device The combustion apparatus was assembled as shown in FIG. Solid fuel: A tandem multistage impinging-jet (CAMUI) type solid fuel (see Figure 17) made of polymethyl methacrylate (PMMA) and a spacer (8 mm) made of polymethyl methacrylate (PMMA) were used (Figure 6(A)). Combustion chamber: To visualize the inside, a motor case made of polymethyl methacrylate (PMMA) was used (a graphite nozzle was installed at the bottom (nozzle diameter: 4 mm)). Ignition means: Nichrome wire (heating element) connected to DC power supply (24V) Oxygen source: Oxygen tank Oxygen supply line: Stainless steel tubing (1 / 4 inch Swagelok® tubing) Hydrogen peroxide supply source: Storage tank of 60% hydrogen peroxide (pressurized with nitrogen) Hydrogen peroxide supply line: Stainless steel tubing (1 / 4 inch Swagelok® tubing) Injector: Top of motor case

[0138] Combustion Cycle Combustion cycle and combustion results are shown. 6 The photograph and combustion history are shown in Figure 7. (A-1) A voltage of 24 V was applied to the nichrome wire and the nichrome wire was heated for 8 seconds. (A-2) Gaseous oxygen was supplied at a flow rate of 1.5 g / s. (B) Ignition lasted for 2 seconds (C) While continuing to supply gaseous oxygen, hydrogen peroxide was supplied at a flow rate of 4.5 g / s for 5 seconds (weight ratio of oxygen:hydrogen peroxide=20:80). (D) The supply of oxygen and hydrogen peroxide was stopped.

[0139] Fig. 6(A) shows the "before ignition" state, Fig. 6(B) shows the "ignition" state, Fig. 6(C) shows the "flame holding" state, and Fig. 6(D) shows the "supply stop" state. Fig. 6(E) compares the state of the flame at ignition (left) and at flame holding (right).

[0140] FIG. 7 shows the history of the combustion experiment carried out in Example 1. The supply of gaseous oxygen to the combustion chamber was started (flow rate: 1.5 g / s) and ignited (heated) for 2 seconds. After that, while supplying gaseous oxygen to the combustion chamber, hydrogen peroxide solution was supplied to the combustion chamber (flow rate: 4.5 g / s) (weight ratio of oxygen:hydrogen peroxide solution = 20:80) (molar ratio of oxygen:hydrogen peroxide = 30:70). The simultaneous supply of gaseous oxygen and hydrogen peroxide solution led to main combustion, and the flame was maintained for at least 5 seconds (see Figure 6 (C)). The combustion chamber pressure rose to a maximum of just under 0.6 MPa.

[0141] Example 2 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 1.5 g / s) and ignited for 2 seconds, after which, while supplying gaseous oxygen to the combustion chamber, hydrogen peroxide solution was supplied at a flow rate of 3 g / s (weight ratio of oxygen:hydrogen peroxide solution=33:66) (molar ratio of oxygen:hydrogen peroxide=50:50), and a combustion experiment was carried out in the same manner as in Example 1. The combustion chamber pressure rose to a maximum of just under 0.5 MPa. The history of the combustion experiment is shown in Figure 8. In Example 2, the combustion progressed to the main combustion state by simultaneously supplying gaseous oxygen and hydrogen peroxide solution, and the flame could be maintained for at least 5 seconds.

[0142] Example 3 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 1.5 g / s) and ignited for 2 seconds. After that, while supplying gaseous oxygen to the combustion chamber, hydrogen peroxide solution was supplied for 2 seconds, after which the supply of gaseous oxygen was stopped, and then only hydrogen peroxide solution was supplied at a flow rate of 2.5 g / s for 4 seconds. A combustion experiment was performed in the same manner as in Example 1, except that the supply of gaseous oxygen to the combustion chamber was started (flow rate: 1.5 g / s) and ignited for 2 seconds. The history of the combustion experiment is shown in Figure 9. In Example 3, the simultaneous supply of gaseous oxygen and hydrogen peroxide solution led to the transition to main combustion, and the flame was able to be maintained for at least 2 seconds. However, the flame was extinguished immediately after the supply of gaseous oxygen was stopped.

[0143] Example 4 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 2.0 g / s), and ignited for 3 seconds. After that, the hydrogen peroxide solution was supplied at a flow rate of 2.5 to 3.5 g / s (weight ratio of oxygen:hydrogen peroxide solution=40:60) (molar ratio of oxygen:hydrogen peroxide=60:40) while the gaseous oxygen was supplied to the combustion chamber. A combustion experiment was carried out in the same manner as in Example 1. The combustion chamber pressure rose to a maximum of 0.68 MPa. The history of the combustion experiment is shown in Figure 10. In Example 4, the combustion progressed to the main combustion state by simultaneously supplying gaseous oxygen and hydrogen peroxide solution, and the flame could be maintained for at least 15 seconds.

[0144] Example 5 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 2.0 g / s) and ignited for 3 seconds, after which the hydrogen peroxide solution was supplied to the combustion chamber at a flow rate of 0.5 g / s (weight ratio of oxygen:hydrogen peroxide solution=80:20) (molar ratio of oxygen:hydrogen peroxide=90:10), and a combustion experiment was carried out in the same manner as in Example 1. The combustion chamber pressure rose to a maximum of 0.51 MPa. In Example 5, the combustion transitioned to the main combustion state by simultaneously supplying gaseous oxygen and hydrogen peroxide solution, and the flame could be maintained for at least 15 seconds.

[0145] Example 6 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 2.0 g / s) and ignited for 3 seconds. After that, the hydrogen peroxide solution was supplied to the combustion chamber at a flow rate of 0.3 g / s (weight ratio of oxygen:hydrogen peroxide solution=87:13) (molar ratio of oxygen:hydrogen peroxide=95:5), while the gaseous oxygen was supplied to the combustion chamber. A combustion experiment was carried out in the same manner as in Example 1. The combustion chamber pressure rose to a maximum of 0.54 MPa. In Example 6, the combustion transitioned to the main combustion state by simultaneously supplying gaseous oxygen and hydrogen peroxide solution, and the flame could be maintained for at least 15 seconds.

[0146] Example 7 The combustion apparatus was assembled as shown in FIG. Solid fuel: A CAMUI (CAscaded MUltistage Impinging-jet) type solid fuel (see Figure 17) made of polymethyl methacrylate (PMMA) and a spacer (8 mm) made of polymethyl methacrylate (PMMA) were used. Combustion chamber: To visualize the inside, a motor case made of polymethyl methacrylate (PMMA) was used (a graphite nozzle was installed at the bottom (nozzle diameter: 4 mm)). Ignition means: Nichrome wire (heating element) connected to DC power supply (24V) Hydrogen peroxide supply source: Storage tank of 60% hydrogen peroxide (pressurized with nitrogen) Hydrogen peroxide supply line: Stainless steel tubing (1 / 4 inch Swagelok® tubing) Heating means: Heat exchanger (150℃) Injector: Top of motor case

[0147] Combustion Cycle The combustion cycle and combustion results are shown in the combustion histories in Figures 11 and 12. (A) A voltage of 24 V was applied to the nichrome wire, and the nichrome wire was heated for 8 seconds. (B) Hydrogen peroxide was supplied at a flow rate of 1.2 to 2.3 g / s. (C) Ignition lasted for 2 seconds (D) Hydrogen peroxide was supplied for 50 seconds. (E) The supply of hydrogen peroxide was stopped.

[0148] 11 and 12 show the history of the combustion experiment carried out in Example 7. The supply of heated hydrogen peroxide to the combustion chamber was started (flow rate: 1.2-2.3g / s), and after ignition (heating) for 2 seconds, the supply of heated hydrogen peroxide to the combustion chamber continued, and the combustion chamber transitioned to main combustion, and the flame was able to be maintained for at least 50 seconds. The temperature of the hydrogen peroxide near the supply port to the combustion chamber was over 120°C. The combustion chamber pressure rose to a maximum of just under 0.2 MPa.

[0149] Comparative Example 1 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 2g / s), and ignition was continued for 2 seconds. Then, the supply of gaseous oxygen to the combustion chamber was stopped, and only hydrogen peroxide solution was supplied to the combustion chamber (flow rate: 8g / s). The flame immediately disappeared. The history of the combustion experiment is shown in Figure 13.

[0150] Comparative Example 2 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 2.8g / s), and ignition was confirmed after 2 seconds of ignition. When only gaseous oxygen was supplied to the combustion chamber for 3 seconds (flow rate: 2.8g / s), ignition was confirmed. The combustion chamber pressure generally only rose to 0.4MPa. The history of the combustion experiment is shown in Figure 14.

[0151] Comparative Example 3 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 2g / s), and ignition was continued for 2 seconds. Then, the supply of gaseous oxygen to the combustion chamber was stopped, and only hydrogen peroxide solution was supplied to the combustion chamber (flow rate: 3g / s). The flame immediately disappeared. The history of the combustion experiment is shown in Figure 15.

[0152] Comparative Example 4 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 2g / s), and ignited for 3 seconds. Then the supply of gaseous oxygen to the combustion chamber was stopped, and only hydrogen peroxide solution was supplied to the combustion chamber (flow rate: 5.1g / s). The flame was immediately extinguished. The combustion chamber pressure generally only rose to 0.2MPa.

[0153] Comparative Example 5 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 2g / s), and after ignition for 3 seconds, the supply of gaseous oxygen to the combustion chamber was stopped and only hydrogen peroxide solution was supplied to the combustion chamber (flow rate: 3.1g / s). The flame was immediately extinguished. The combustion chamber pressure generally only rose to 0.2MPa.

[0154] Comparative Example 6 The supply of gaseous oxygen to the combustion chamber was started (flow rate: 2 g / s), and after ignition for 3 seconds, the supply of gaseous oxygen to the combustion chamber was stopped, and only hydrogen peroxide solution was supplied to the combustion chamber (flow rate: 10.5 g / s). The flame was immediately extinguished. In Comparative Example 6, the combustion chamber pressure was increased to 0.6 MPa using a melting nozzle, but the flame could not be maintained.

[0155] From the results of Examples 1 to 6, it was possible to obtain improved combustibility by simultaneously supplying oxygen and hydrogen peroxide solution from the oxygen supply line and hydrogen peroxide solution supply line, respectively, to the combustion chamber. In particular, it was possible to maintain flame stability.

[0156] In contrast, in Comparative Example 1 and Comparative Examples 3 to 6, in which only hydrogen peroxide water was supplied, the flame was immediately extinguished when hydrogen peroxide was supplied, and the flame could not be maintained. In Comparative Example 2, in which only gaseous oxygen was supplied, ignition was confirmed, and the combustion chamber pressure in a combustion experiment conducted using only gaseous oxygen was obtained.

[0157] From the above, it is demonstrated that the presence of oxygen together with low concentration hydrogen peroxide assists combustion. It is believed that by continuing to supply oxygen to the combustion chamber, the hydrogen peroxide solution receives heat from the flame produced by the combustion (ignition) of the oxygen, and the hydrogen peroxide in the solution is heated to its boiling point (e.g. 122°C) and vaporized. As a result, the volume and pressure in the combustion chamber increase, and the hydrogen peroxide is decomposed into oxygen, further assisting the combustion, which is believed to have further promoted it.

[0158] In the case of simultaneous supply of oxygen and hydrogen peroxide, as the hydrogen peroxide flows through the CAMUI fuel together with the oxygen combustion gas, the water evaporates and the temperature rises to the boiling point of hydrogen peroxide (e.g. 122°C), causing the hydrogen peroxide to vaporize. This is thought to increase the volume due to the change in state from liquid to gas, which in turn increases the combustion chamber pressure. It is thought that oxygen is generated at the timing of vaporization, and that combustion occurs, not only at the top surface of the CAMUI fuel, but also downstream from the second stage onwards, causing flames (Figures 6(C) and (E)). In addition, in Comparative Example 1 and Comparative Examples 3 to 6, in which only hydrogen peroxide water was supplied, the supply of heat from gaseous oxygen was stopped, so it was difficult to obtain this amount of heat from the heat of oxygen ignition, and it is believed that flame stabilization could not be maintained.

[0159] Furthermore, from the results of Examples 1 to 6 above, it was found that even when a low concentration of hydrogen peroxide solution is used, it is possible to supply hydrogen peroxide solution at a large flow rate without passing it through a catalyst, and even in such a case, the combustion of the hybrid rocket fuel, particularly flame stability, can be maintained. [Industrial Applicability]

[0160] The combustion method and combustion apparatus disclosed herein use low-concentration (less than 65% by weight) hydrogen peroxide solution as a propellant, making it safe, easy to transport, store, and obtain, and since it has improved combustibility when oxygen is supplied, it can be used in the kick motors of hybrid rockets, etc. The disclosed combustion methods and apparatus provide innovative orbital transfer capabilities. For example, the combustion method and combustion device of the present disclosure can provide an acceleration capacity of 0.7 to 1.2 km / s, making it possible to transfer from a geostationary transfer orbit (GTO) to a flyby orbit to, for example, the Moon, Mars, or Venus. The present disclosure includes the following aspects. [1] 1. A method for combusting hybrid rocket fuel, comprising: supplying aqueous hydrogen peroxide to a combustion chamber containing a solid fuel, The concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, (i) supplying oxygen and the hydrogen peroxide solution to the combustion chamber and causing combustion; and (ii) heating and vaporizing the hydrogen peroxide solution before supplying it to the combustion chamber. Hybrid rocket fuel combustion method. [2] (i) A method for burning a hybrid rocket fuel as described in [1] above, comprising supplying oxygen and the hydrogen peroxide solution to the combustion chamber. [3] The combustion method according to [2] above, wherein the oxygen and the hydrogen peroxide solution are supplied to the combustion chamber in parallel. [4] The combustion method according to the above [2] or [3], wherein the hydrogen peroxide solution is supplied to the combustion chamber containing the oxygen. [5] The combustion method according to any one of the above [2] to [4], wherein the oxygen is supplied to the combustion chamber, and then the hydrogen peroxide solution is supplied. [6] The combustion method according to any one of the above [2] to [5], wherein the oxygen and the hydrogen peroxide solution are supplied to the combustion chamber from independent lines. [7] The combustion method according to any one of the above [2] to [6], wherein the oxygen is supplied to the combustion chamber as a gas. [8] The combustion method according to any one of the above [2] to [7], wherein the ratio of the oxygen to the hydrogen peroxide solution is 10% or more and 50% or less by weight. [9] The combustion method according to any one of the above items [2] to [8], further comprising starting the supply of oxygen to the combustion chamber, and after ignition, supplying the hydrogen peroxide solution to the combustion chamber while supplying oxygen to the combustion chamber, thereby maintaining combustion of the solid fuel and flame stability.

[10] (ii) A method for burning a hybrid rocket fuel as described in [1] above, comprising heating the hydrogen peroxide solution before supplying it to the combustion chamber.

[11] The method for burning hybrid rocket fuel described in

[10] above, wherein the hydrogen peroxide solution is heated to 100°C or higher and vaporized, and then supplied to the combustion chamber.

[12] The combustion method according to any one of the above [1] to

[11] , wherein the concentration of the hydrogen peroxide in the hydrogen peroxide solution is 60% or less by weight.

[13] The combustion method according to any one of the above [1] to

[12] , wherein the supplied hydrogen peroxide solution is not subjected to a catalyst.

[14] a combustion chamber for accommodating a solid fuel, a line for supplying oxygen, and a line for supplying hydrogen peroxide solution, the line for supplying oxygen and the line for supplying hydrogen peroxide solution being connected to the combustion chamber; A hybrid rocket fuel combustion device that maintains combustion and flame holding of the solid fuel by supplying the oxygen to the hydrogen peroxide solution in a ratio of 10% or more and 50% or less by weight.

[15] The combustion device according to

[15] above, wherein the line for supplying oxygen and the line for supplying hydrogen peroxide solution are combined with each other and connected to the combustion chamber.

[16] The combustion device according to

[15] above, wherein the line for supplying oxygen and the line for supplying hydrogen peroxide solution are each separately connected to the combustion chamber.

[17] The combustion device according to any one of the above

[14] to

[16] , wherein the concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight. [Explanation of symbols]

[0161] 1,21,31,41,51 solid fuel 2,22,32,42,52 Combustion chamber 3,23,33,43 Lines / Oxygen Supply Lines 4,24,34,44 Oxygen Source 5,25,35,45,55 Line / Hydrogen peroxide supply line 6,26,36,46,56 Hydrogen peroxide supply source 7,27,37,47,57 Ignition means 10,20,30,40,50 Combustion equipment 28, 38, 48 Pressure tank 29, 39, 49 Pressure lines 101 Purge tank 102 Purge Line R 1 ,R 2 ,R 3 ,R 4 ,R 5 ,R 6 ,R 7 Regulator V 1 ,V 2 ,V 3 ,V 4 ,V 5 ,V 6 ,V 7 valve P 1 ,P 2 ,P 3 Mixed current point L 1 .L 2 .L 3 Mixed flow line

Claims

1. A method for burning hybrid rocket fuel, comprising supplying aqueous hydrogen peroxide to a combustion chamber containing a solid fuel, The concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, (i) supplying oxygen and the hydrogen peroxide solution to the combustion chamber and causing combustion; A method for burning hybrid rocket fuel, comprising supplying the oxygen and the hydrogen peroxide solution to the combustion chamber in parallel.

2. The combustion method according to claim 1 , further comprising the step of supplying the hydrogen peroxide solution to the combustion chamber containing the oxygen.

3. A method for combusting hybrid rocket fuel, comprising supplying aqueous hydrogen peroxide to a combustion chamber containing a solid fuel, The concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, (i) supplying oxygen and the hydrogen peroxide solution to the combustion chamber and causing combustion; A method for burning hybrid rocket fuel, comprising: supplying the oxygen to the combustion chamber and then supplying the hydrogen peroxide solution.

4. A method for burning hybrid rocket fuel, comprising supplying aqueous hydrogen peroxide to a combustion chamber containing a solid fuel, The concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, (i) supplying oxygen and the hydrogen peroxide solution to the combustion chamber and causing combustion; A method for burning hybrid rocket fuel, wherein the oxygen and the hydrogen peroxide solution are supplied to the combustion chamber from independent lines.

5. A method for burning hybrid rocket fuel, comprising supplying aqueous hydrogen peroxide to a combustion chamber containing a solid fuel, The concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, (i) supplying oxygen and the hydrogen peroxide solution to the combustion chamber and causing combustion; A method for burning hybrid rocket fuel, comprising: starting the supply of oxygen to the combustion chamber; and, after ignition, supplying the hydrogen peroxide solution to the combustion chamber while continuing to supply the oxygen to the combustion chamber, thereby maintaining combustion and flame holding of the solid fuel.

6. A method for combusting hybrid rocket fuel, comprising supplying aqueous hydrogen peroxide to a combustion chamber containing a solid fuel, The concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight, (i) supplying oxygen and the hydrogen peroxide solution to the combustion chamber and causing combustion; A method for burning hybrid rocket fuel, wherein the supplied hydrogen peroxide solution is not subjected to a catalyst.

7. 7. The method of claim 1, 3, 4, 5 or 6, wherein the oxygen is supplied to the combustion chamber as a gas.

8. 7. The combustion method according to claim 1, 3, 4, 5 or 6, wherein the ratio of said oxygen to said hydrogen peroxide solution is 10% or more and 50% or less by weight.

9. 7. The combustion method according to claim 1, 3, 4, 5 or 6, wherein the concentration of the hydrogen peroxide in the hydrogen peroxide solution is 60% or less by weight.

10. a combustion chamber for accommodating a solid fuel, a line for supplying oxygen, and a line for supplying hydrogen peroxide solution, the line for supplying oxygen and the line for supplying hydrogen peroxide solution being connected to the combustion chamber; A hybrid rocket fuel combustion device that maintains combustion and flame stability of the solid fuel by supplying the oxygen to the hydrogen peroxide solution in a ratio of 10% to 50% by weight.

11. 11. The combustion device according to claim 10, wherein the line for supplying oxygen and the line for supplying hydrogen peroxide solution are combined with each other and connected to the combustion chamber.

12. 11. The combustion device according to claim 10, wherein the line for supplying oxygen and the line for supplying hydrogen peroxide solution are each separately connected to the combustion chamber.

13. The combustion device according to any one of claims 10 to 12, wherein the concentration of hydrogen peroxide in the hydrogen peroxide solution is less than 65% by weight.

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