Hybrid rocket

Abstract

To provide a hybrid rocket capable of improving durability of a nozzle.SOLUTION: A hybrid rocket includes: an airframe which has a storage chamber for storing solid fuel, and a combustion chamber for mixing and burning an oxidizer and fuel gas; an oxidizer supply unit for supplying the oxidizer to the combustion chamber; an ignition device for igniting the solid fuel; and a nozzle for injecting gas generated by mixing and burning the fuel gas and the oxidizer. The nozzle includes a cowl and a spike forming a flow passage for injecting the gas, and the spike is formed of a single member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a hybrid rocket. [Background technology]

[0002] Hybrid rockets are known as thrust generating sources for space transport vehicles and propulsion devices such as thrusters for artificial satellites. Hybrid rockets generally use solid fuel and liquid or gaseous oxidizer as propellants. Because the fuel and oxidizer are in different phases, they do not easily mix and burn, making it easier to manage the propellant than solid and liquid rockets. In particular, hybrid rockets that use polymers as solid fuel are easier to manage during storage and transportation. For example, Patent Document 1 discloses a hybrid rocket in which a fuel gas generation chamber for accommodating solid fuel and a combustion chamber for mixing and burning an oxidizer and fuel gas are integrally formed. The high-temperature and high-pressure gas generated by mixing and burning the fuel gas and the oxidizer in the combustion chamber is ejected from a nozzle to obtain thrust for the hybrid rocket. Patent Document 1 gives an example of a nozzle such as a Laval nozzle. Meanwhile, an aerospike nozzle is also known as a nozzle. Conventional conical nozzles (such as Laval nozzles) are designed assuming a constant ambient pressure. While they have the advantages of being simple in structure and easy to manufacture, they also have the disadvantages of reduced nozzle efficiency in a vacuum, and although they can sometimes be used by extending the skirt of the nozzle, they tend to become larger in length and therefore heavier. Conventional aerospike nozzles consist of two parts (a cowl and a spike), and while they have the advantage of being able to adapt to changes in ambient pressure, they have the disadvantage of being complex in structure and heavy. For example, to apply it to the engines of small satellites, the nozzle needs to be capable of withstanding a vacuum, so an aerospike nozzle is chosen. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-7960 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, the spike that constitutes the conventional aerospike nozzle is composed of two parts (a baffle plate and a plug). For example, the baffle plate is fixed to the plug with a metal screw or the like. In this case, when heat is applied to the spike, the difference in the thermal expansion coefficient of each component may cause the spike to be damaged (cracked, chipped, etc.). Therefore, there is room for further improvement in the durability of the spike (aerospike nozzle).

[0005] Therefore, an object of the present invention is to provide a hybrid rocket that can improve the durability of the nozzle. [Means for solving the problem]

[0006] A hybrid rocket according to one embodiment of the present invention comprises a body having a storage chamber for storing solid fuel and a combustion chamber for mixing and burning an oxidizer and a fuel gas, an oxidizer supply section for supplying the oxidizer to the combustion chamber, an ignition device for igniting the solid fuel, and a nozzle for spraying gas produced by mixing and burning the fuel gas and the oxidizer, the nozzle comprising a cowl and a spike which form a flow path for spraying the gas, and the spike which is formed from a single member. Effect of the Invention

[0007] According to the above aspect, a hybrid rocket capable of improving the durability of the nozzle can be provided. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a cross-sectional view of a hybrid rocket according to an embodiment. [Diagram 2] FIG. [Diagram 3] Cross-sectional view taken along line III-III in FIG. 2 . [Figure 4] FIG. [Diagram 5] VV cross-sectional view of Figure 4. [Figure 6] FIG. 3 is a cross-sectional view including a nozzle of Comparative Example 1. [Figure 7] FIG. 2 is a cross-sectional view including a nozzle according to the first embodiment. [Figure 8] FIG. 4 is an explanatory diagram of the results of a combustion experiment on the nozzle of Comparative Example 1. [Figure 9] FIG. 4 is an explanatory diagram of the results of a combustion experiment of the nozzle of the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the embodiment, a direct injection type gas hybrid rocket using an aerospike nozzle (an example of a nozzle) will be described as an example of a hybrid rocket. For example, the hybrid rocket of this embodiment is used as a thrust generating source for a space transport vehicle and a propulsion device such as a thruster for an artificial satellite.

[0010] In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," do not only mean such arrangements or states strictly, but also include arrangements or states in which there is a relative displacement with an angle or distance to the extent that the same function can be obtained with a tolerance. In the drawings used in the following description, the scale of each component may be appropriately changed to show each component with a recognizable size.

[0011] <Hybrid rocket> FIG. 1 is a cross-sectional view of a hybrid rocket 1 according to an embodiment. As shown in FIG. 1, the hybrid rocket 1 includes a body 2, an oxidizer supply unit 3, an ignition device 4, and a nozzle 5.

[0012] <Aircraft> The airframe 2 is formed with a storage chamber 11 for storing the solid fuel 10, and a combustion chamber 12 for mixing and burning an oxidizer and a fuel gas. For example, the airframe 2 is configured with at least an outer wall, an intermediate layer, and an inner wall laminated in this order in the thickness direction. The outer wall of the airframe 2 is formed of a metal such as aluminum in order to maintain mechanical strength and to withstand the pressure of the combustion chamber 12. The intermediate layer is formed of glass-fiber-reinforced plastics (GFRP), phenolic resin, or a composite material thereof, etc., in order to provide a fuel cartridge capable of insulating against a combustion flame. The inner wall is formed of a polymer compound having heat resistance. Examples of materials for forming the inner wall include polymer materials such as ethylene propylene diene rubber (EPDM rubber).

[0013] The fuselage 2 is formed in a cylindrical shape. Hereinafter, the direction along the central axis CL of the fuselage 2 is also referred to as the "axial direction", the direction perpendicular to the central axis CL of the fuselage 2 is also referred to as the "radial direction", and the direction orbiting the central axis CL of the fuselage 2 is also referred to as the "circumferential direction". FIG. 1 corresponds to a cross-sectional view of the hybrid rocket 1 cut along a plane including the central axis CL of the fuselage 2. In the example shown in the figure, the fuselage 2 includes a bottomed cylindrical main body 20 along the axial direction, and an annular flange portion 21 attached to one axial end of the main body 20.

[0014] The storage chamber 11 and the combustion chamber 12 are formed inside the main body 20. The storage chamber 11 is formed in a bottom side portion (a portion opposite the flange portion 21 in the axial direction) of the inside of the main body 20. The combustion chamber 12 is formed in a portion on the flange portion 21 side of the inside of the main body 20. The storage chamber 11 and the combustion chamber 12 are connected to each other in the axial direction. The combustion chamber 12 is a space surrounded by one end surface (a surface on the flange portion 21 side in the axial direction) of the solid fuel 10 stored in the storage chamber 11, an inner peripheral surface of the portion on the flange portion 21 side of the inside of the main body 20, and the flange portion 21 and the surfaces of the nozzle 5 facing one end surface of the solid fuel 10.

[0015] The solid fuel 10 may be, for example, tetra-ol glycidyl azide polymer (tetra-ol GAP). Hereinafter, the solid fuel 10 used in the present embodiment may be simply referred to as "GAP." The solid fuel 10 is not limited to the above and may be changed according to design specifications.

[0016] The flange portion 21 is formed with an accommodation hole 22 that accommodates the nozzle 5, and an ejection hole 23 that ejects gas generated by mixing and burning the fuel gas and the oxidizer. The accommodation hole 22 is disposed between the combustion chamber 12 and the ejection hole 23 in the axial direction. The accommodation hole 22 opens on the combustion chamber 12 side and also opens on the downstream side in the gas ejection direction V to communicate with the ejection hole 23.

[0017] For example, after placing a thermosetting resin (one example of a heat-resistant agent) such as Bakelite in the housing hole 22 of the flange portion 21, the nozzle 5 is placed in the housing hole 22. In this way, the nozzle 5 can be fixed to the flange portion 21 with the heat-resistant agent placed around the nozzle 5. Note that the manner in which the nozzle 5 is fixed to the flange portion 21 is not limited to the above and can be changed according to design specifications.

[0018] <Oxidizing agent supply unit> The oxidizer supply unit 3 is a part for supplying an oxidizer to the combustion chamber 12. In the example shown in the figure, the oxidizer is supplied to the combustion chamber 12 through a supply pipe (not shown) and a hole 3h (hereinafter also referred to as "oxidizer supply hole 3h") that opens on the inner circumferential surface of the part inside the main body part 20 on the flange part 21 side. For example, a pair of oxidizer supply holes 3h are formed at positions facing each other in the radial direction (depth direction of the paper in FIG. 1). The oxidizer supply hole 3h is circular when viewed from the radial direction (depth direction of the paper in FIG. 1). FIG. 1 shows one of the pair of oxidizer supply holes 3h. The oxidizer supply hole 3h communicates with a part of the combustion chamber 12 near the nozzle 5. The mode (number, arrangement, shape, etc.) of the oxidizer supply hole 3h is not limited to the above and can be changed according to design specifications.

[0019] For example, the oxidizer supply hole 3h may be disposed at a position offset from the position shown in Fig. 1 (a position shifted in the vertical direction on the paper surface from the position shown in Fig. 1). For example, the oxidizer supply unit 3 may be configured to impart a swirling flow to the oxidizer supplied to the combustion chamber 12. For example, the configuration of the oxidizer supply unit 3 (the presence or absence of a mechanism for imparting a swirling flow, etc.) is not limited to the above and can be changed according to design specifications.

[0020] Examples of oxidizing agents include nitrous oxide (N 2 It is preferable to use a liquid oxidizer having a high vapor pressure, such as ethyl alcohol (NO). In this case, it is not necessary to provide a pressurizing device such as a pressurized tank, which makes it easier to miniaturize the hybrid rocket 1. The oxidizer is not limited to the above and can be changed according to the design specifications.

[0021] <Ignition device> The ignition device 4 is a device for igniting the solid fuel 10. When GAP is used as the solid fuel 10, ignition occurs when the temperature is 250° C. or higher and the pressure is 700 kPa or higher. Therefore, the ignition device 4 is provided with a mechanism for setting the temperature in the combustion chamber 12 to 250° C. or higher and the pressure to 700 kPa or higher. As the ignition device 4, for example, an ignition device 4 using an aluminum-less solid propellant can be used. Note that the configuration of the ignition device 4 is not limited to the above and can be changed according to the design specifications.

[0022] The ignition device 4 preferably includes a mechanism (ignition mechanism) capable of re-igniting the solid fuel 10 whose combustion has stopped. Specifically, at the time of the first combustion, the ignition mechanism is not operated, and ignition is performed by a configuration (e.g., a gas torch, etc.) for pressurizing and heating to meet the ignition conditions. When re-igniting the solid fuel 10 whose combustion has stopped, the ignition mechanism is used. Note that the configuration for pressurizing and heating is not limited to the above and can be changed according to the design specifications.

[0023] In the illustrated example, the ignition device 4 is attached to a portion of the main body 20 of the device on the flange 21 side. In the portion of the main body 20 where the ignition device 4 is attached, a hole 4h (hereinafter also referred to as "ignition hole 4h") is formed that opens to the inner circumferential surface of the portion of the inside of the main body 20 on the flange 21 side. Only one ignition hole 4h is formed. The ignition hole 4h is disposed at equal intervals in the circumferential direction with respect to each of the pair of oxidizer supply holes 3h. In the cross-sectional view of FIG. 1, the ignition hole 4h extends at an incline with respect to the radial direction so as to approach one end surface of the solid fuel 10. Note that the mode (number, arrangement, shape, etc.) of the ignition hole 4h is not limited to the above and can be changed according to design specifications.

[0024] <Combustion chamber pressure measurement section> In the example shown in the figure, a hole 6h (hereinafter also referred to as "pressure measurement hole 6h") is formed in the part of the main body 20 opposite to the part where the ignition device 4 is attached, the hole 6h opening on the inner circumferential surface of the part of the inside of the main body 20 on the flange part 21 side. The pressure measurement hole 6h is disposed on the opposite side of the ignition hole 4h in the radial direction. Only one pressure measurement hole 6h is formed. The pressure measurement hole 6h is disposed at equal intervals in the circumferential direction with respect to each of the pair of oxidizer supply holes 3h. In the cross-sectional view of the figure, the pressure measurement hole 6h extends linearly along the radial direction. Note that the aspect (number, arrangement, shape, etc.) of the pressure measurement hole 6h is not limited to the above and can be changed according to the design specifications.

[0025] The pressure measurement hole 6h is provided with a combustion chamber pressure measurement unit 6 that measures the pressure inside the combustion chamber 12. For example, a pressure sensor or the like can be used as the combustion chamber pressure measurement unit 6. For example, the pressure sensor may be press-fitted into the pressure measurement hole 6h. Note that the aspect (configuration, arrangement, etc.) of the combustion chamber pressure measurement unit 6 is not limited to the above and can be changed according to design specifications.

[0026] <Nozzle> The nozzle 5 is a structure that ejects gas generated by mixing and burning a fuel gas and an oxidizer. The gas generated by mixing and burning a fuel gas and an oxidizer reaches a temperature of 2000°C or higher. Therefore, the nozzle 5 is made of a heat-resistant material such as graphite or a carbon composite material.

[0027] Fig. 2 is a plan view of a cowl 51 according to the embodiment. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2. Fig. 4 is a plan view of a spike 52 according to the embodiment. Fig. 5 is a cross-sectional view taken along line VV in Fig. 4. 1 to 5, the nozzle 5 is disposed on the central axis CL of the fuselage 2. In other words, the nozzle 5 is provided coaxially with the fuselage 2. The nozzle 5 includes a cowl 51 and a spike 52 that form a flow path 50 for ejecting gas.

[0028] The cowl 51 includes a cylindrical portion 51a and a throat portion 51b. The cylindrical portion 51a is formed in a cylindrical shape along the inner circumference of the receiving hole 22 of the flange portion 21. The cylindrical portion 51a extends between the outer circumference of the plate portion 53 and the bottom of the flange portion 21. The throat portion 51b has an inner diameter that gradually decreases toward the downstream side in the gas ejection direction V. The gas ejection direction V corresponds to the rightward direction on the paper in FIG. 1.

[0029] The spike 52 is formed of a single member. In this embodiment, the single member is formed mainly of graphite. The spike 52 includes a plate portion 53 in which a hole 53h communicating with the combustion chamber 12 is formed, and a plug portion 54 connected to the plate portion 53 and forming a flow path 50 for gas flowing out from the hole between the plate portion 53 and the cowl 51. The plate portion 53 and the plug portion 54 constitute a single member. In other words, the plate portion 53 and the plug portion 54 are integrally formed of the same member.

[0030] The plate portion 53 is in the form of a plate having a thickness in the axial direction. A plurality of holes 53h are formed in the plate portion 53. In the example shown in the figure, two holes 53h are formed in the plate portion 53. The holes 53h are circular when viewed in the thickness direction of the plate portion 53. The number of holes 53h is not limited to two, and three or more holes may be formed. For example, the mode (number, shape) of the holes 53h is not limited to the above and can be changed according to design specifications.

[0031] The plate portion 53 is disk-shaped with one surface facing the combustion chamber 12. The multiple holes 53h are arranged at equal intervals in the circumferential direction of the plate portion 53. In the example shown in the figure, two holes 53h (circular holes) of the same size are arranged at equal intervals in the circumferential direction of the plate portion 53. The two holes 53a are lined up across the center of the plate portion 53 when viewed in the thickness direction of the plate portion 53.

[0032] The plug portion 54 extends from the plate portion 53 in the axial direction toward the opposite side to the combustion chamber 12, and protrudes downstream of the cowl 51 in the gas ejection direction V. Specifically, the plug portion 54 includes an extension portion 54a, an enlarged diameter portion 54b, and a tapered portion 54c. The extension portion 54a is a portion that extends from the center portion (between the two holes 53h) of the plate portion 53 toward the opposite side to the combustion chamber 12 in the axial direction. The tapered portion 54c is a portion whose outer shape gradually decreases toward the downstream side in the gas ejection direction V, and forms a flow path 50 for the gas flowing out of the holes 53h between the extension portion 54a and the tapered portion 54c and the throat portion 51b. The enlarged diameter portion 54b is a portion between the extension portion 54a and the tapered portion 54c, and includes a portion that curves toward the radially outward direction. The enlarged diameter portion 54b includes a portion of the plug portion 54 that bulges outward most in the radial direction.

[0033] In the plug portion 54, the outer circumferential surface of the connection portion with the flange portion 21 (the portion of the extending portion 54a on the flange portion 21 side) is curved radially inward. The outer circumferential surface of the connecting portion between the extending portion 54a and the expanded diameter portion 54b is curved so as to smoothly connect to the connection portion with the flange portion 21. The outer circumferential surface of the tapered portion 54c is curved radially inward from the connection portion with the expanded diameter portion 54b to the protruding end of the plug portion 54.

[0034] In this embodiment, the total area of ​​the holes 53h formed in the plate portion 53 is at least twice the minimum value of the flow passage cross-sectional area between the throat portion 51b and the tapered portion 54c. The total area of ​​the holes 53h formed in the plate portion 53 corresponds to the sum of the opening areas of the two holes 53h formed in the plate portion 53. The minimum value of the flow passage cross-sectional area between the throat portion 51b and the tapered portion 54c means the smallest cross-sectional area among the flow passage cross-sectional areas of the flow passage 50 between the throat portion 51b and the tapered portion 54c, including the normal component of the curved surface of the tapered portion 54c.

[0035] <Hybrid rocket propulsion system> Next, an example of a propulsion system of the hybrid rocket 1 of this embodiment will be described. In order to obtain the thrust of the hybrid rocket 1, first, the solid fuel 10 is ignited by the ignition device 4. Then, the ignited solid fuel 10 burns, and combustion gas is generated in the combustion chamber 12.

[0036] Meanwhile, an oxidizer is supplied to the combustion chamber 12 through a supply pipe (not shown) and an oxidizer supply hole 3h. The oxidizer is mixed with the fuel gas generated in the combustion chamber 12 and combusted. The gas generated by the combustion is ejected to the outside from the nozzle 5. This provides the thrust of the hybrid rocket 1.

[0037] In this embodiment, since GAP is used as the solid fuel 10, it has a high fuel packing density, high energy, and self-heating decomposition characteristics, which contributes to miniaturization of the solid fuel 10 and reduction in the amount of residue generated after combustion of the solid fuel 10. In addition, in this embodiment, for example, nitrous oxide (N 2 Since the gas (O) is injected from two places, it is easier to mix with the fuel gas. Furthermore, in this embodiment, an aerospike nozzle is used instead of a conical nozzle (such as a Laval nozzle), and the fluid is collected and expanded outside the nozzle 5, so it is not affected by the surrounding pressure.

[0038] When the mixing and combustion of the fuel gas and the oxidizer is to be stopped, a valve provided on a supply pipe (not shown) is closed, thereby reducing or stopping the supply of the oxidizer to the combustion chamber 12.

[0039] To obtain thrust from the hybrid rocket 1 again, first, the solid fuel 10 is reignited by the ignition device 4. The subsequent steps are the same as those for obtaining thrust from the hybrid rocket 1 described above.

[0040] <Action and effect> As described above, the hybrid rocket 1 of this embodiment includes the vehicle body 2 in which the storage chamber 11 for storing the solid fuel 10 and the combustion chamber 12 for mixing and burning the oxidizer and fuel gas are formed, the oxidizer supply unit 3 for supplying the oxidizer to the combustion chamber 12, the ignition device 4 for igniting the solid fuel 10, and the nozzle 5 for ejecting the gas generated by mixing and burning the fuel gas and the oxidizer. The nozzle 5 includes a cowl 51 and a spike 52 that form a flow path 50 for ejecting the gas. The spike 52 is formed of a single member. According to this configuration, since the spike 52 is formed from a single material, the thermal expansion coefficient of the spike 52 itself is constant. Therefore, when heat is applied to the spike 52, the spike 52 is not damaged due to the difference in the thermal expansion coefficient of each part. In other words, the problem that occurs when the spike is made of multiple materials (when heat is applied to the spike, the spike is damaged due to the difference in the thermal expansion coefficient of each part) does not occur. Therefore, it is possible to provide a hybrid rocket 1 that can improve the durability of the nozzle 5.

[0041] In this embodiment, the spike 52 includes a plate portion 53 in which a hole 53h communicating with the combustion chamber 12 is formed, and a plug portion 54 connected to the plate portion 53 and forming a flow path 50 for gas flowing out from the hole 53h between the plate portion 53 and the cowl 51. The plate portion 53 and the plug portion 54 form a single member. According to this configuration, the plate portion 53 and the plug portion 54 form a single member, so that the thermal expansion coefficients of the plate portion 53 and the plug portion 54 are constant. Therefore, when heat is applied to the plate portion 53 and / or the plug portion 54, the plate portion 53 and / or the plug portion 54 are not damaged due to differences in the thermal expansion coefficients of the respective portions. Therefore, the durability of the plate portion 53 and the plug portion 54 can be improved. In addition, the plate portion 53 that holds the plug portion 54 can be used as a baffle plate to extend the residence time of the gas, thereby promoting the mixing of the liquid oxidizer and the gasified fuel.

[0042] In this embodiment, the plate portion 53 is formed with a plurality of holes 53h. According to this configuration, gas flowing out from a plurality of holes 53h is ejected from nozzle 5, making it easier to increase the thrust of hybrid rocket 1 compared to a case in which only one hole 53h is formed.

[0043] In this embodiment, the plate portion 53 is in the shape of a disk having one surface facing the combustion chamber 12. The multiple holes 53h are arranged in the circumferential direction of the plate portion 53 at equal intervals. According to this configuration, gas flowing out from a plurality of holes 53h arranged at equal intervals around the circumference of the plate portion 53 is ejected from the nozzle 5, so that it is easier to stably increase the thrust of the hybrid rocket 1 compared to a case where the plurality of holes 53h are arranged at uneven intervals around the circumference.

[0044] In this embodiment, the cowl 51 has a throat portion 51b whose inner diameter gradually decreases toward the downstream side in the gas ejection direction V. The plug portion 54 has a tapered portion 54c whose outer shape gradually decreases toward the downstream side in the gas ejection direction V and which forms a flow path 50 for gas flowing out from the hole 53h between the throat portion 51b and the tapered portion 54c. The total area of ​​the holes 53h formed in the plate portion 53 is at least twice the minimum value of the flow path cross-sectional area between the throat portion 51b and the tapered portion 54c. With this configuration, it is easier to increase the thrust of the hybrid rocket 1 compared to when the total area of ​​the holes 53h formed in the plate portion 53 is less than twice the minimum value of the flow path cross-sectional area between the throat portion 51b and the tapered portion 54c.

[0045] In this embodiment, the single member is formed mainly from graphite. According to this configuration, graphite has excellent heat resistance and can withstand rapid thermal changes, thereby further improving the durability of the nozzle 5. In addition, graphite is less susceptible to dimensional change at high temperatures and has increased strength at high temperatures, thereby improving the dimensional accuracy and high-temperature strength of the nozzle 5. In addition, graphite is lighter than metals such as aluminum and is easier to process, so precise machining of the nozzle 5 can be easily performed.

[0046] As described above, in this embodiment, the nozzle 5 includes the cowl 51 and spike 52 which form the flow path 50 for ejecting gas, and the spike 52 includes a plate portion 53 in which a hole 53h communicating with the combustion chamber 12 is formed, and a plug portion 54 which is connected to the plate portion 53 and forms the flow path 50 for the gas flowing out from the hole 53h between the plate portion 53 and the cowl 51. According to this configuration, the plug portion 54, which has the role of directing the combustion gas to the center, and the cowl 51, which has the role of maintaining the exit area of ​​the combustion gas, can provide an optimal expansion ratio regardless of the external air pressure. In addition, the plate portion 53, which serves as a holder for the spike 52 on the upstream side of the gas ejection direction V, can function as a baffle plate that contributes to improving the combustion efficiency. Therefore, even if the oxidizer is changed from gas to liquid, there is a low possibility that the fuel gas and the oxidizer will not be mixed sufficiently, and high performance can be achieved, and there is a low probability that the performance of the rocket will be reduced. In this way, in this embodiment, the upstream plate portion 53 that holds the spike 52 of the aerospike nozzle can be used as a baffle plate to improve the combustion efficiency.

[0047] In the embodiment described above, the solid fuel comprises tetra-ol glycidyl azide polymer (GAP). According to this configuration, by combining it with a direct injection type gas hybrid rocket using GAP, it is possible to achieve even greater effects (such as shortening the overall length). For example, in comparing the length of the part equivalent to the nozzle skirt, in the case of a plug nozzle with a thrust of 500N class, it protrudes from the combustor by about 20mm, while in the case of a conical nozzle (cone-shaped nozzle), with a half apex angle of 15° and an opening ratio of 50, the skirt length is about 150mm, so the skirt length is reduced to about 1 / 8, and at an opening ratio of 100, the total length is 224mm, which is a reduction of about 1 / 10.

[0048] <Modification> In the above-described embodiment, a plurality of holes are formed in the plate portion, but the present invention is not limited to this. For example, only one hole may be formed in the plate portion. For example, the number of holes formed in the plate portion can be changed according to design specifications.

[0049] In the above-described embodiment, the plate portion is disk-shaped with one surface facing the combustion chamber, and the multiple holes are arranged at equal intervals in the circumferential direction of the plate portion. However, the present invention is not limited to this. For example, the multiple holes may be arranged at unequal intervals in the circumferential direction of the plate portion. For example, the arrangement of the multiple holes can be changed according to design specifications.

[0050] In the above-described embodiment, the cowl has a throat portion whose inner diameter gradually decreases toward the downstream side in the gas ejection direction, the plug portion has a tapered portion whose outer shape gradually decreases toward the downstream side in the gas ejection direction and forms a flow path for gas flowing out of the hole between the throat portion and the plug portion, and the total area of ​​the holes formed in the plate portion is at least twice the minimum value of the flow path cross-sectional area between the throat portion and the tapered portion. However, the total area of ​​the holes formed in the plate portion may be less than twice the minimum value of the flow path cross-sectional area between the throat portion and the tapered portion. For example, the magnitude relationship between the total area of ​​the holes formed in the plate portion and the minimum value of the flow path cross-sectional area between the throat portion and the tapered portion can be changed according to the design specifications.

[0051] In the above-described embodiment, an example has been described in which the single member is formed mainly of graphite, but this is not limiting. For example, the single member may be formed mainly of a material other than graphite. For example, the single member may be formed mainly of a carbon composite material. For example, the formation mode of the single member can be changed according to design specifications.

[0052] In the above embodiment, the solid fuel is described as including tetra-ol glycidyl azide polymer (GAP), but is not limited thereto. For example, the solid fuel may include a material other than GAP as a main component. For example, the aspect of the solid fuel can be changed according to the design specifications.

[0053] Although the embodiments of the present invention have been described above, the present invention is not limited to these, and additions, omissions, substitutions, and other modifications of the configuration are possible without departing from the spirit of the present invention, and the above-described embodiments can also be combined as appropriate.

[0054] (Appendix 1) A body having a storage chamber for storing solid fuel and a combustion chamber for mixing and burning an oxidizer and a fuel gas; an oxidizer supply unit for supplying the oxidizer to the combustion chamber; an ignition device for igniting the solid fuel; a nozzle for ejecting a gas generated by mixing and burning the fuel gas and the oxidizer, The nozzle includes a cowl and a spike that form a flow passage for ejecting the gas, The spike is formed of a single member. Hybrid rocket.

[0055] (Appendix 2) The spikes are a plate portion having a hole communicating with the combustion chamber; a plug portion connected to the plate portion and forming a flow path for gas flowing out from the hole between the plug portion and the cowl, The plate portion and the plug portion constitute the single member. Attachment 1: A hybrid rocket.

[0056] (Appendix 3) The hole is formed in a plurality of the plate portions. A hybrid rocket as described in Appendix 2.

[0057] (Appendix 4) The plate portion is in a disk shape having one surface facing the combustion chamber, The holes are arranged at equal intervals in the circumferential direction of the plate portion. A hybrid rocket as described in Appendix 3.

[0058] (Appendix 5) The cowl has a throat portion whose inner diameter gradually decreases toward the downstream side in the gas ejection direction, the plug portion has a tapered portion whose outer shape gradually decreases toward the downstream side in the gas ejection direction and which forms a flow path for the gas flowing out of the hole between the plug portion and the throat portion, The total area of ​​the holes formed in the plate portion is equal to or greater than twice the minimum value of the flow passage cross-sectional area between the throat portion and the tapered portion. 5. A hybrid rocket as claimed in any one of appendixes 2 to 4.

[0059] (Appendix 6) The single member is formed mainly of graphite. 6. A hybrid rocket according to any one of claims 1 to 5.

[0060] (Appendix 7) The solid fuel comprises a tetra-ol glycidyl azide polymer. 7. A hybrid rocket according to any one of appendixes 1 to 6. EXAMPLES

[0061] The hybrid rocket according to the above embodiment of the present invention will be specifically described below by showing an example. Note that the following example is a specific example to which the present invention is applied, and does not limit the present invention.

[0062] Fig. 6 is a cross-sectional view including the nozzle of Comparative Example 1. Fig. 7 is a cross-sectional view including the nozzle of Example 1. Fig. 8 is an explanatory diagram of the results of a combustion experiment of the nozzle of Comparative Example 1. Fig. 9 is an explanatory diagram of the results of a combustion experiment of the nozzle of Example 1.

[0063] Example 1 The hybrid rocket of Example 1 includes a body in which a storage chamber for storing solid fuel and a combustion chamber for mixing and burning an oxidizer and a fuel gas are formed, an oxidizer supply unit for supplying an oxidizer to the combustion chamber, an ignition device for igniting the solid fuel, and a nozzle for ejecting gas generated by mixing and burning the fuel gas and the oxidizer, the nozzle includes a cowl and a spike forming a flow path for ejecting the gas, the spike is formed of a single member, and a spacer is stored in the storage chamber (diameter 80 mm) together with a GAP as a fixed fuel (corresponding to the configuration shown in FIG. 7). The hybrid rocket of Example 1 has the same configuration as that shown in FIG. 1, except that the spacer is stored in the storage chamber (diameter 80 mm).

[0064] Comparative Example 1 The hybrid rocket of Comparative Example 1 was prepared with a conventional conical nozzle (such as a Laval nozzle) and a spacer housed in a storage chamber (diameter 80 mm) together with a GAP as a fixed fuel (corresponding to the configuration shown in Figure 6). The hybrid rocket of Comparative Example 1 had the same configuration as that shown in Example 1 (configuration shown in Figure 7) except that it was equipped with a conventional conical nozzle (such as a Laval nozzle).

[0065] (Experimental conditions) Table 1 shows the combustion experiment conditions. In each of Example 1 and Comparative Example 1, a combustion experiment was carried out under the combustion experiment conditions shown in Table 1.

[0066] [Table 1]

[0067] (Evaluation Results) In each of Example 1 and Comparative Example 1, the thrust, combustion chamber pressure, and the like were measured by a combustion experiment. 8 and 9, it was found that the hybrid rocket of Example 1 had improved thrust and combustion chamber pressure over a wide range compared to the hybrid rocket of Comparative Example 1.

[0068] Tables 2 and 3 show the results of the combustion experiments.

[0069] [Table 2]

[0070] [Table 3]

[0071] Also referring to Table 2, it was found that the hybrid rocket of Example 1 had improved combustion time, thrust, combustion chamber pressure, and nozzle efficiency compared to the hybrid rocket of Comparative Example 1. With reference to Table 3, the characteristic exhaust velocity C * It was found that the specific impulse ISP could achieve an efficiency close to 100%. The efficiency was calculated using the formula: Efficiency = (Experimental value / Theoretical value) x 100. [Explanation of symbols]

[0072] Reference Signs List 1... hybrid rocket, 2... fuselage, 3... oxidizer supply section, 4... ignition device, 5... nozzle, 10... solid fuel, 11... storage chamber, 12... combustion chamber, 50... flow path, 51... cowl, 51b... throat section, 52... spike, 53... plate section, 53h... hole, 54... plug section, 54c... tapered section

Claims

1. A body having a storage chamber for storing solid fuel and a combustion chamber for mixing and burning an oxidizer and a fuel gas; an oxidizer supply unit for supplying the oxidizer to the combustion chamber; an ignition device for igniting the solid fuel; a nozzle for ejecting a gas generated by mixing and burning the fuel gas and the oxidizer, The nozzle includes a cowl and a spike that form a flow passage for ejecting the gas, The spike is formed of a single member. Hybrid rocket.

2. The spikes are a plate portion having a hole communicating with the combustion chamber; a plug portion connected to the plate portion and forming a flow path for gas flowing out from the hole between the plug portion and the cowl, The plate portion and the plug portion constitute the single member. The hybrid rocket of claim 1.

3. The hole is formed in a plurality of the plate portions.

3. The hybrid rocket of claim 2.

4. The plate portion is in a disk shape having one surface facing the combustion chamber, The holes are arranged at equal intervals in the circumferential direction of the plate portion.

4. The hybrid rocket of claim 3.

5. The cowl has a throat portion whose inner diameter gradually decreases toward the downstream side in the gas ejection direction, the plug portion has a tapered portion whose outer shape gradually decreases toward the downstream side in the gas ejection direction and which forms a flow path for the gas flowing out of the hole between the plug portion and the throat portion, The total area of ​​the holes formed in the plate portion is equal to or greater than twice the minimum value of the flow passage cross-sectional area between the throat portion and the tapered portion. A hybrid rocket according to any one of claims 2 to 4.

6. The single member is formed mainly of graphite. A hybrid rocket according to any one of claims 1 to 4.

7. The solid fuel comprises a tetra-ol glycidyl azide polymer. A hybrid rocket according to any one of claims 1 to 4.

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