JP2018076813A - Rocket injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rocket injector which cools an injection surface by using a fuel as a refrigerant and is advantageous for decreasing individual differences and maintaining and improving the quality.SOLUTION: A rocket injector 3 cools an injection surface 7a facing a combustion chamber C with a liquid fuel and includes: an injection plate 7 including the injection surface 7a; an injection element 8 which penetrates through the injection plate 7 and jets at least the fuel into the combustion chamber C; and a fuel supply chamber 12 which is provided at the opposite side of the combustion chamber C across the injection plate 7 and houses the fuel. The injection plate 7 includes: a porous part 71 through which the fuel in the fuel supply chamber 12 penetrates to the injection surface 7a side; and solid parts 72A, 72B having lower liquid penetrability compared to the porous part 71. The porous part 71 and the solid parts 72A, 72B are an integral structure.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to rocket injectors.

  Patent Document 1 discloses a rocket injector that injects a propellant from an injection surface. A structure for injecting a propellant is provided on the injection surface. This structure includes, for example, a collision type, a pistol type and the like in addition to a nozzle having a double tube structure generally called a coaxial element. The propellant is composed of an oxidant and a fuel. For example, in the case of a nozzle having a double tube structure, the oxidant is injected from the center of the nozzle and the fuel is injected from the periphery thereof. The oxidant and fuel injected from the nozzle are mixed and become combustion gas by ignition in the combustion chamber. Since this combustion gas is extremely hot, it is necessary to take measures against heat on the injection surface facing the combustion chamber.

  The injection surface is made of a perforated plate which is a sintered wire mesh, and the back surface side opposite to the injection surface is in contact with fuel used as a refrigerant. The fuel permeates through the perforated plate and exudes from the injection surface, and contributes to cooling of the perforated plate including the injection surface. The perforated plate is fixed to the peripheral wall of the injector body by welding or the like, and a nozzle for injecting fuel or oxidant is fixed to the perforated plate by welding or the like.

JP 2013-133711 A

  Since the perforated plate with the injection surface is manufactured by sintered wire mesh, it is difficult to apply the welding conditions.In addition, brazing causes the brazing material to penetrate into the mesh and causes individual differences in the amount of bleeding. It was easy to grow. Further, in the conventional sintered wire mesh, even if the injection surface is locally damaged due to insufficient cooling amount, the cooling amount of the entire sintered wire mesh must be increased structurally. For this reason, there is a possibility that the combustion efficiency may be lowered this time due to the increase in the cooling amount, and it has been substantially difficult to optimize the cooling amount. In other words, it has been difficult to improve the quality of the conventional perforated plate from the viewpoint of optimizing the manufacturing surface and the cooling amount.

  The present disclosure provides a rocket injector that is advantageous for improving the quality of a rocket injector that cools an injection surface using fuel as a refrigerant.

  One aspect of the present disclosure is a rocket injector that cools an injection surface facing a combustion chamber with a fluid fuel, the injection plate having the injection surface, and the injection plate penetrating at least the fuel into the combustion chamber A nozzle that injects, and a fuel chamber that is provided on the opposite side of the combustion chamber across the injection plate and that contains fuel, and the injection plate is permeable to the fuel in the fuel chamber toward the injection surface side A porous part and a solid part having a lower fluid permeability than the porous part are provided, and the porous part and the solid part have an integral structure. “Low fluid permeability” includes the case where there is no fluid permeability in the solid portion.

  In this rocket injector, the fuel permeates through the porous portion and oozes out from the injection surface, whereby the injection plate can be cooled. On the other hand, since the solid part has a lower fluid permeability than the porous part, at least the welding conditions are easier than the porous part, and even if brazed, the penetration of the brazing material is small . Therefore, for example, if the solid part is welded or the like, the individual difference can be easily and small, and further, since the porous part and the solid part have an integral structure, the porous part and the solid part are welded or the like. It is not necessary to fix with, and it is advantageous for quality maintenance and improvement. In addition, for example, if a location that is likely to cause melting damage due to an insufficient cooling amount can be specified at the design stage or the prototype test stage, the transmittance at such a location is preferentially made higher than other portions. This makes it easy to optimize the cooling amount. As described above, this rocket injector is advantageous for improving the quality.

  In some embodiments, the solid portion can be a rocket injector having a higher density than the porous portion. By making the density of the solid part larger than that of the porous part, as a result, it becomes easier to realize a solid part having a smaller void than the porous part. As a result, the solid part has lower fluid permeability than the porous part. It becomes easy to realize the part.

  In some embodiments, a rocket injector may be provided that includes an injector body provided with a fuel chamber and the outer edge region of the injector plate connected to the injector body is a solid part. When the injector main body and the injection plate are fixed by welding or the like, the solid portion is welded or the like, so that the quality is stabilized and the workability is further improved.

  In some aspects of the injection surface, the area surrounding the nozzle and connected to the nozzle may be a solid rocket injector. When the nozzle and the injection plate are fixed by welding or the like, the solid portion is welded or the like, so that the quality is stabilized and the workability is further improved.

  One embodiment of the present disclosure may be a rocket combustor including the rocket injector described above and a combustion chamber liner connected to the rocket injector.

  According to some aspects of the present disclosure, it is advantageous to improve the quality of a rocket injector that cools an injection surface using fuel as a refrigerant.

It is sectional drawing of the rocket combustor provided with the rocket injector which concerns on one Embodiment of this indication. It is sectional drawing along the II-II line | wire of FIG. 1, and has shown partially the injection | spray surface of the injection plate welded to the injector main body broken. FIG. 2A is a sectional view taken along line aa in FIG. 2, and FIG. 2B is a sectional view taken along line bb in FIG. It is a graph which shows the permeability | transmittance of the porous part of an injection plate.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size. Further, when embodiments are described with reference to the drawings, the same reference numerals are given to the same elements, and duplicate descriptions are omitted.

  With reference to FIG.1 and FIG.2, the rocket combustor 1 which concerns on one Embodiment is demonstrated. The rocket combustor 1 includes a combustion chamber liner 2 that forms a combustion chamber C therein, and a rocket injector 3 connected to the combustion chamber liner 2. The rocket injector 3 is fixed to the injector body 5, the injector body 5, the injection plate 7 partitioning the combustion chamber C and the injector body 5, and attached to the injection plate 7, toward the combustion chamber C. And a plurality of injection elements (nozzles) 8 for injecting the propellant. The injection plate 7 includes an injection surface 7 a that faces the combustion chamber C.

  The propellant includes, for example, an oxidant and a fuel. The injection element 8 has a double-pipe structure and includes an inner tube portion 8a on the center side for injecting an oxidant and an outer tube portion 8b for injecting fuel from around the inner tube portion 8a. Liquid oxygen is used as the oxidant, and methane, liquid hydrogen, kerosene, or the like is used as the fuel.

  The injection element 8 penetrates the injection plate 7 and is fixed to the injection plate 7 by welding. The injection element 8 may be attached to the injection plate 7 by brazing or other methods, and may not be fixed to the injection plate 7 as long as the gap can be closed. The plurality of injection elements 8 are provided at equal intervals on a plurality of virtual circles that are concentric with the center of the injection plate 7, but can be appropriately arranged according to the specifications of the rocket or the like. .

  An oxidant supply chamber 11 for supplying an oxidant and a fuel supply chamber 12 for supplying fuel are provided inside the injector body 5. The oxidant supply chamber 11 is a dome-shaped space, and the oxidant is introduced into the oxidant supply chamber 11 through the oxidant inlet 11a. The oxidant supply chamber 11 is connected to the inner pipe portion 8a of each injection element 8 so as to communicate therewith. The oxidant introduced into the oxidant supply chamber 11 is injected into the combustion chamber C through the inner pipe portion 8 a of each injection element 8.

  The fuel supply chamber 12 is partitioned from the oxidant supply chamber 11 by the partition wall portion 9, and has a dome-shaped space for containing fluid fuel. The fluid state includes a gaseous state, a liquid state, or a mixed state of a gas and a liquid. The fuel supply chamber 12 is connected to the outer pipe portion 8b of each injection element 8 so as to communicate therewith. The fuel is introduced into the fuel supply chamber 12 through the fuel inlet 12a, and the fuel introduced into the fuel supply chamber 12 is injected into the combustion chamber C through the outer pipe portion 8b of each injection element 8.

  The oxidant and fuel injected from each injection element 8 are mixed in the combustion chamber C, burned by an igniter (not shown), and become combustion gas. Since the combustion chamber liner 2 forming the combustion chamber C and the injection surface 7a of the rocket injector 3 face the combustion chamber C and are exposed to the combustion gas, a cooling structure for cooling the injection surface 7a is required. In the cooling structure according to the present embodiment, a bleed-out cooling method is employed in which fuel that functions as a refrigerant oozes out and cools the injection surface 7a. Hereinafter, this cooling structure will be specifically described.

  An oxidant supply chamber 11 and a fuel supply chamber (fuel chamber) 12 separated by a partition wall 9 are provided in the injector body 5. The fuel supply chamber 12 is disposed on the side close to the injection plate 7 with the partition wall 9 interposed therebetween, and the oxidant supply chamber 11 is disposed on the far side. The fuel supply chamber 12 is disposed on the opposite side of the combustion chamber C with the injection plate 7 interposed therebetween, and the back surface 7b of the injection plate 7, that is, the surface opposite to the injection surface 7a is the fuel supply chamber 12. It is exposed inside. Part of the fuel accommodated in the fuel supply chamber 12 functions as a refrigerant for the injection plate 7, soaks from the back surface 7 b of the injection plate 7, penetrates the injection plate 7, and oozes out from the injection surface 7 a. In addition, in this embodiment, although the back surface 7b of the injection plate 7 is exposed in the fuel supply chamber 12, the aspect which covers the back surface 7b of the injection plate 7 with the layer which can permeate | transmit a fuel may be sufficient.

  The injection plate 7 includes a porous portion 71 through which fuel can permeate and solid portions 72A and 72B having a lower fluid permeability than the porous portion 71. The injection plate 7 is made of nickel alloy, stainless steel (SUS), copper alloy, or the like, and the porous portion 71 and the solid portions 72A and 72B are manufactured as an integral structure by 3D additive manufacturing. The solid portions 72A and 72B have a higher density than the porous portion 71, and the porous portion 71 is designed to have a higher porosity than the solid portions 72A and 72B. Hereinafter, the manufacturing method of the injection plate 7 by 3D additive manufacturing is demonstrated.

  The injection plate 7 according to the present embodiment is formed by a powder bed method using, for example, a laser or an electron beam, but may be a deposition method. In the case of the powder bed method, three-dimensional data of the ejection plate 7 having the porous portion 71 and the solid portions 72A and 72B is input to the control device of the 3D printer. The 3D printer includes, for example, a modeling chamber on the modeling side and a material storage chamber that stores metal powder as a material. The metal powder in the material storage chamber is supplied to the modeling chamber and is made uniform. As a result, a metal powder layer having a predetermined thickness is formed in the modeling chamber.

  In this state, the metal powder layer is irradiated with laser. The laser is irradiated following the shape of one layer obtained by dividing the three-dimensional data of the ejection plate 7 into a plurality of layers. The metal powder is melted and solidified by laser irradiation, and a shape corresponding to one layer of the injection plate 7 is formed. Next, the metal powder is laminated again on this layer so as to have a uniform thickness, and the laser is irradiated again to form the next layer of shape. By repeating this process, the injection plate 7 having a predetermined shape is finally formed.

  In the present embodiment, the porous portion 71 and the solid portions 72A and 72B can be easily manufactured as an integrated structure by 3D additive manufacturing, which is particularly advantageous from the viewpoint of reproducibility. Further, the degree of fuel permeability in the porous portion 71 depends on the porosity of the porous portion 71, but the porosity of the porous portion 71 can be easily adjusted by 3D additive manufacturing modeled based on three-dimensional data. It is. On the other hand, the solid portions 72A and 72B are not formed with a gap through which a fluid such as fuel passes, and basically have a non-permeable structure through which a fluid such as fuel does not pass. According to 3D additive manufacturing, although it is an integral structure, it can be easily manufactured while separating the region of the porous portion 71 and the regions of the solid portions 72A and 72B having different porosity.

  The porous part 71 and the solid parts 72A and 72B having an integral structure means that the porous part 71 and the solid part are physically integrated including the inside, for example, an aspect in which a plurality of members are joined by welding or the like, or The mode in which the boundary between members remains clearly is excluded. In the case of an integral structure, the same material is often used, but different materials may be used. Like this embodiment, the injection plate 7 modeled by 3D additive manufacturing is a representative example of the injection plate according to an integral structure.

  A plurality of through holes 7 d through which the injection element 8 passes are formed in the injection plate 7, and the injection element 8 is welded to the injection plate 7. In the injection plate 7, the area around each through hole 7d is a solid portion 72B. The solid portion 72B is formed in a partial region on the ejection surface 7a side (see FIG. 3B), but may be formed in the entire region in the thickness direction of the ejection plate 7. .

  An end surface 7e along the periphery of the injection plate 7 is in contact with and welded to the inner surface of the peripheral wall of the injector body 5. Attachment of the injection plate 7 to the injector body 5 may be brazing or other methods. In the ejection plate 7, the outer edge region along the periphery is a solid portion 72A. The injection plate 7 is welded in the entire region in the thickness direction in contact with the injector main body 5, thereby realizing strong fixation between the injection plate 7 and the injector main body 5. Therefore, the outer edge region of the injection plate 7 according to the present embodiment has a solid region 72A in the entire region in the thickness direction (see FIG. 3A). However, the outer edge region of the injection plate 7 may be partly solid 72A on the injection surface 7a side depending on the specifications of the rocket.

  Next, the permeability of the injection plate 7 will be described with reference to FIG. FIG. 4 is a graph in which the abscissa indicates the pressure difference with the outside in the fuel supply chamber 12, and the effusion flow rate from the injection surface 7a indicates the ordinate, and three samples of the injection plate 7 having different porous portions 71. The experimental result using is shown. The three types of samples are modeled by 3D additive manufacturing, and are designed so that the porosity of the third sample is the largest and the porosity of the second sample is the smallest.

  As shown in FIG. 4, when the differential pressure is the same, the third sample has the largest fuel exudation flow rate from the injection surface 7a, the first sample has the second largest, and the second sample has the smallest.

  In this embodiment, since the injection plate 7 is manufactured by 3D additive manufacturing, for example, the reproducibility is higher than that of the injection plate 7 made of a sintered wire net, and individual differences can be reduced. That is, when the first sample is manufactured based on the design data for the first sample, it is easy to obtain the same fuel permeability as described above. As a result, if the specifications of the rocket are determined, and the differential pressure with the outside in the fuel supply chamber 12 and the amount of fuel oozing required for cooling are determined, it is possible to manufacture a highly accurate injection plate 7 in accordance with this specification value. .

  As described above, in the rocket injector 3 according to the present embodiment, the fuel penetrates the porous portion 71 and oozes out from the injection surface 7a, whereby the injection plate 7 can be cooled. In particular, in the present embodiment, since the porous portion 71 is formed by 3D additive manufacturing, the reproducibility based on predetermined design data is high, and it is easy to optimize the fuel permeation flow rate through the porous portion 71.

  Further, the injection plate 7 includes solid portions 72A and 72B, and the solid portions 72A and 72B are disposed particularly in an area where welding or the like is required at the time of manufacture. The solid portions 72A and 72B have a lower fluid permeability than the porous portion 71, and the welding conditions are easier than the porous portion 71, and even if brazed, the penetration of the brazing material is small . Furthermore, since the porous portion 71 and the solid portions 72A and 72B have an integral structure, there is no need to fix the porous portion 71 and the solid portions 72A and 72B by welding or the like.

  As described above, the rocket injector 3 according to the above embodiment is advantageous for maintaining and improving quality by reducing individual differences. In particular, in the present embodiment, since the injection plate 7 is manufactured by 3D additive manufacturing, it is more advantageous from the viewpoint of high reproducibility and small individual differences. Moreover, a manufacturing period and manufacturing cost can be reduced significantly by manufacturing by 3D additive manufacturing.

  In the present embodiment, the density of the solid portions 72A and 72B is designed to be larger than the density of the porous portion 71. As a result, it becomes easier to realize a form having a smaller gap than the porous part 71 as a form in the solid parts 72A and 72B, and as a result, the solid parts 72A and 72B having a lower fluid permeability than the porous part 71. It becomes easy to realize.

  Moreover, in this embodiment, since the outer edge area | region of the injection plate 7 connected to the injector main body 5 is the solid part 72A, the solid part 72A of the injection plate 7 is welded to the injector main body 5, Quality is stable and workability is improved.

  In the present embodiment, the region surrounding the injection element 8 and connected to the injection element 8 is the solid portion 72B, and the solid portion 72B is welded to the injection element 8, so that the quality is stable, Workability is also improved.

  The present disclosure can be implemented in various forms including various modifications and improvements based on the knowledge of those skilled in the art including the above-described embodiments. Moreover, it is also possible to configure a modification of each example by using the technical matters described in the above-described embodiments.

  For example, in the above embodiment, both the region connected to the injector main body and the region connected to the injection element are solid parts, but only one of them, for example, the region connected to the injector main body Can be a solid part, and all others can be a porous part. Moreover, in the aspect which installs an igniter in an injection plate, the cylindrical support material for mounting | wearing an igniter may be connected to an injection plate. When such a member is connected to the injection plate by welding or the like, a part of the injection plate connected to various members may be a solid part and the others may be a porous part.

  In addition, regardless of joining by welding or the like, for example, if it is possible to identify a location that is prone to melting damage due to an insufficient cooling amount at the design stage or prototype test stage, the transmittance of such a location is It is also possible to optimize the amount of cooling by preferentially increasing the temperature over other parts. As a result, it is possible to prevent a decrease in combustion efficiency due to an excessive increase in the cooling amount, which is advantageous for improving quality in terms of combustion efficiency.

DESCRIPTION OF SYMBOLS 1 Rocket combustor 3 Rocket injector 5 Injector body 7 Injection plate 7a Injection surface 8 Injection element (nozzle)
12 Fuel supply chamber (fuel chamber)
71 Porous part 72A, 72B Solid part C Combustion chamber

Claims (5)

A rocket injector for cooling the injection surface facing the combustion chamber with a fluid fuel,
An injection plate provided with the injection surface;
A nozzle that penetrates the injection plate and injects at least the fuel into the combustion chamber;
A fuel chamber that is provided on the opposite side of the combustion chamber across the injection plate, and that contains the fuel,
The injection plate includes a porous portion through which the fuel in the fuel chamber can permeate toward the injection surface, and a solid portion having a lower fluid permeability than the porous portion. The solid part is a one-piece rocket injector.   The rocket injector according to claim 1, wherein the solid portion has a density higher than that of the porous portion. An injector body provided with the fuel chamber;
The rocket injector according to claim 1 or 2, wherein an outer edge region of the injection plate connected to the injector main body is the solid portion.   The rocket injector according to any one of claims 1 to 3, wherein a region surrounding the nozzle and connected to the nozzle on the injection surface is the solid portion.   A rocket combustor comprising: the rocket injector according to any one of claims 1 to 4; and a combustion chamber liner connected to the rocket injector.

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