JP6084108B2 - Hybrid rocket engine and its ignition method - Google Patents

Description

  The present invention relates to a hybrid rocket engine using a solid fuel and a liquid or gaseous oxidant and an ignition method thereof.

  Propulsion rocket engines used in space rockets include liquid fuel rocket engines and solid fuel rocket engines.

  A liquid fuel rocket engine is a rocket engine that obtains thrust by storing liquid fuel and a liquid oxidant in separate tanks, supplying them appropriately to a combustion chamber, mixing them in a sprayed state, and igniting them.

  A solid fuel rocket engine is a rocket engine that uses a solid fuel such as an explosive previously kneaded with an oxidant as a propellant.

  On the other hand, a hybrid rocket engine is a rocket engine that uses solid fuel (fuel grain) and a liquid or gaseous oxidant. The hybrid rocket engine can control combustion like a liquid fuel rocket engine by adjusting the flow rate of the oxidant that is a fluid. Moreover, since the hybrid rocket engine uses solid fuel, the structure can be simplified.

FIG. 1 is an explanatory diagram of a conventional hybrid rocket engine 100 disclosed in Non-Patent Document 1. As shown in FIG.
The hybrid rocket engine 100 of Non-Patent Document 1 includes a combustion gas supply device 105 at the front end (left end in FIG. 1) of the motor case 103, supplies an oxidant L0 to the front end of the motor case 103, and ignites from the front. .

  That is, the hybrid rocket engine 100 of Non-Patent Document 1 heats the fuel grain 102 with the combustion gas G0 generated from the combustion gas supply device 105, and then supplies the oxidant L0 from the oxidant supply device 104 to cause the fuel grain 102 to flow. It will ignite.

George Story, Tom Zoladz, Joe Arves, Darren Kearney, Terry Abel, O .; Park, “Hybrid Propulsion Demonstration Program 250K Hybrid Motor”, 39th AIAA / ASME / ASEE Joint Propulsion Conference and Exhibit Huntsville 200, A1-20

  In the hybrid rocket engine 100 of Non-Patent Document 1 described above, since the fuel grain 102 is a solid phase and the oxidant L0 is a liquid phase or a gas phase, the fuel grain 102 is reacted before the fuel grain 102 and the oxidant L0 are reacted. It is necessary to heat the surface of the substrate so that the surface can be gasified. For this reason, the conventional hybrid rocket engine 100 is difficult to ignite and has been required to be improved.

The ignition of the hybrid rocket engine 100 is ideally short from the time when the oxidant L0 is supplied until the fuel grain 102 is ignited (hereinafter referred to as “ignition delay time” in the present invention). .
However, the conventional hybrid rocket engine 100 has a long ignition delay time because the gasification of the fuel grains 102 does not proceed well. Therefore, there is a problem that the hybrid rocket engine 100 cannot obtain sufficient acceleration immediately after launch.

  Further, depending on the ignition mode, if the liquid oxidizer L0 is not gasified, unstable combustion (for example, vibration combustion) may occur.

  The present invention has been developed to solve the above-described problems. That is, an object of the present invention is to improve the ignitability of the fuel grains, thereby shortening the ignition delay time from supplying the oxidizer to igniting the fuel grains and reducing unstable combustion. It is to provide an engine and its ignition method.

According to the present invention, a motor case having a hollow heating chamber and a fuel grain in contact therewith,
A liquid oxidant supply device for supplying a liquid oxidant to the hollow heating chamber;
A combustion gas supply device for supplying combustion gas to the hollow heating chamber,
A hybrid rocket engine that heats and gasifies the fuel grain and the liquid oxidant with the combustion gas, and ignites the fuel grain,
The hollow heating chamber has a hollow cylindrical shape,
Furthermore, there is provided a hybrid rocket engine comprising a hollow cylindrical solid auxiliary fuel installed concentrically with the hollow heating chamber.

  The combustion gas supply device has an injection nozzle that injects the combustion gas in a tangential direction along the cylindrical inner surface of the solid auxiliary fuel.

Further, according to the present invention, a motor case having a hollow heating chamber and a fuel grain in contact therewith,
A liquid oxidant supply device for supplying a liquid oxidant to the hollow heating chamber;
A combustion gas supply device for supplying combustion gas to the hollow heating chamber,
A method for igniting a hybrid rocket engine that heats and gasifies the fuel grain and the liquid oxidant with the combustion gas and ignites the fuel grain,
Forming the hollow heating chamber into a hollow cylindrical shape;
A hollow cylindrical solid auxiliary fuel is installed inside the concentric with the hollow heating chamber,
With the combustion gas, the solid auxiliary fuel is heated and gasified to generate auxiliary fuel gas from the solid auxiliary fuel,
An ignition method for a hybrid rocket engine is provided, wherein the auxiliary fuel gas is used for the gasification of the fuel grain and the liquid oxidant.

In addition, the combustion auxiliary gas heats and gasifies the solid auxiliary fuel, generates auxiliary fuel gas from the solid auxiliary fuel, and fills the hollow heating chamber,
Next, the liquid oxidant is supplied to the hollow heating chamber to ignite part of the auxiliary fuel gas to generate combustion exhaust gas,
With the auxiliary fuel gas and the combustion exhaust gas, the fuel grain and the remainder of the liquid oxidant are heated and gasified, and the gasified fuel grain is combusted with the gasified liquid oxidant.

  Further, the combustion gas supply device injects the combustion gas in a tangential direction along the cylindrical inner surface of the solid auxiliary fuel.

  According to the apparatus and method of the present invention described above, since the concentric solid auxiliary fuel is provided in the hollow heating chamber of the motor case, the auxiliary fuel gas is generated from the solid auxiliary fuel by warming the solid auxiliary fuel with the combustion gas and gasifying it. Can be made.

Further, by supplying the liquid oxidant in a state where the solid auxiliary fuel is gasified by the combustion gas and the surface of the fuel grain is heated, a part of the liquid oxidant and the high-temperature auxiliary fuel gas generated from the solid auxiliary fuel Can be ignited.
Thereby, the hybrid rocket engine of the present invention can improve the ignitability of the fuel grains, and can shorten the ignition delay time from the supply of the liquid oxidant to the ignition of the fuel grains.

  Furthermore, the liquid oxidant can be sufficiently gasified by supplying the liquid oxidant while the solid auxiliary fuel is gasified by the combustion gas and the surface of the fuel grain is heated. Thereby, the hybrid rocket engine of the present invention can reduce unstable combustion.

It is explanatory drawing of the conventional hybrid rocket engine disclosed by the nonpatent literature 1. It is explanatory drawing of the hybrid rocket engine of this invention. It is AA sectional drawing of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 2 is an explanatory diagram of the hybrid rocket engine 10 of the present invention. 3 is a cross-sectional view taken along the line AA in FIG.
The hybrid rocket engine 10 of the present invention includes a motor case 3 having a hollow heating chamber 1 and a fuel grain 2 in contact therewith, a liquid oxidant supply device 4 for supplying a liquid oxidant L to the hollow heating chamber 1, A combustion gas supply device 5 for supplying the combustion gas G1 to the hollow heating chamber 1.

  The hybrid rocket engine 10 of the present invention heats and fuelizes the fuel grains 2 and the liquid oxidant L with the combustion gas G1 to ignite the fuel grains 2.

  The motor case 3 is a pressure vessel that can withstand the high pressure caused by the combustion of the fuel grain 2, has a cylindrical wall surface, and a nozzle 16 for expanding and accelerating and accelerating the gas generated in the motor case 3 at the rear end. It is connected. The material of the motor case 3 is preferably steel, an aluminum alloy, or FRP.

The liquid oxidant supply device 4 includes a hollow oxidant tank 4 a into which the liquid oxidant L is placed, and connects the oxidant tank 4 a and the hollow heating chamber 1 of the motor case 3. It is preferable to have an injector 4b for supplying the agent L. The injector 4 b is preferably connected to the front end of the motor case 3 or the front end of the hollow heating chamber 1.
However, the configuration of the liquid oxidant supply device 4 is not limited to this, and other configurations may be used.

The liquid oxidant L is preferably cryogenic liquid oxygen, nitrous oxide (N ₂ O), or NO _x . Moreover, you may use a gaseous oxidizing agent as an oxidizing agent.

  The fuel grain 2 is a propellant that is a rubber-like viscoelastic substance, and generates high-temperature and high-pressure gas by combustion. The fuel grain 2 is preferably a high-molecular plastic resin such as terminal hydroxyl group polybutadiene (HTPB), wax (WAX), polypropylene (PP) or polyether (PE).

The hollow heating chamber 1 has a hollow cylindrical shape, and further includes a hollow cylindrical solid auxiliary fuel 12 disposed concentrically with the hollow heating chamber 1 inside.
The hollow heating chamber 1 is preferably provided in front of the fuel grain 2 at the front end of the motor case 3. Moreover, it is preferable not to provide a partition between the hollow heating chamber 1 and the fuel grain 2.

In the hollow heating chamber 1, an injector 4 b of the liquid oxidant supply device 4 and an injection nozzle 14 of the combustion gas supply device 5 are opened.
Although the cylindrical wall surface of the motor case 3 and the cylindrical wall surface of the hollow heating chamber 1 are preferably the same, the cylindrical wall surface of the hollow heating chamber 1 may be provided separately from the cylindrical wall surface of the motor case 3. Good.

The solid auxiliary fuel 12 is preferably a hollow cylindrical solid fuel installed concentrically with the hollow heating chamber 1 along the cylindrical wall surface of the hollow heating chamber 1.
However, as long as the swirling combustion gas G1 can come into contact with the solid auxiliary fuel 12 and the surface of the fuel grain 2 can be heated, the present invention is not limited to this, and other configurations may be used. That is, for example, a solid cylindrical solid auxiliary fuel 12 is installed on the central axis of the motor case 3, and between the outer cylindrical surface of the solid cylindrical solid auxiliary fuel 12 and the cylindrical wall surface of the hollow heating chamber 1. Alternatively, the combustion gas G1 may be injected and swirled.

The solid auxiliary fuel 12 may be the same fuel as the fuel grain 2, but it is preferable to select a fuel that is easily vaporized. That is, it is preferable to use, for example, polypropylene (PP) or rubber as the solid auxiliary fuel 12.
The solid auxiliary fuel 12 may be formed integrally with the fuel grain 2.

The combustion gas supply device 5 has an injection nozzle 14 that injects the combustion gas G <b> 1 in a tangential direction along the cylindrical inner surface 12 a of the solid auxiliary fuel 12.
That is, the combustion gas supply device 5 has an injection nozzle 14 that extends in the tangential direction of the motor case 3, and injects the combustion gas G 1 in the tangential direction along the cylindrical inner surface 12 a of the solid auxiliary fuel 12.

  In addition, as shown in FIG. 3, the cross-sectional shape of the cylindrical inner surface 12a of the solid auxiliary fuel 12 by a surface perpendicular to the central axis of the motor case 3 is a circle. The tangential direction refers to the direction in which the straight line extending when the straight line passing through the combustion gas supply device 5 is tangent to the circle (cylindrical inner surface 12a).

The combustion gas supply device 5 is preferably an igniter using a solid explosive mixed with an oxidant as fuel. However, the present invention is not limited to this, and a hybrid igniter may be used.
The temperature of the combustion gas G1 generated when the combustion gas supply device 5 burns is preferably about 3000 degrees.

  The liquid oxidant L is supplied to the hollow heating chamber 1 and ignited after the solid auxiliary fuel 12 is gasified.

  Thus, in the hybrid rocket engine 10 of the present invention, the injection nozzle 14 of the combustion gas supply device 5 is provided on the cylindrical wall surface of the motor case 3 and extends in the tangential direction of the motor case 3. The injected combustion gas G1 is injected in the tangential direction of the cylindrical inner surface 12a of the solid auxiliary fuel 12. Therefore, the hybrid rocket engine 10 of the present invention can swirl the combustion gas G1 of about 3000 degrees along the cylindrical inner surface 12a of the solid auxiliary fuel 12, and the residence time of the combustion gas G1 in the hollow heating chamber 1 is conventionally increased. The hybrid rocket engine 100 can be made longer. Further, by swirling the combustion gas G1, the residence time of the combustion gas G1 in the hollow heating chamber 1 can be extended, so that the solid auxiliary fuel 12 can be easily gasified and the surface of the fuel grain 2 can be warmed. Can do.

  Thereby, the fuel grain 2 can be heated faster than the conventional hybrid rocket engine 100, and the gasification of the fuel grain 2 can be promoted before the liquid oxidant L is supplied into the hollow heating chamber 1.

  Thus, the hybrid rocket engine 10 of the present invention can improve the ignitability of the fuel grain 2, and the time from the supply of the liquid oxidant L to the ignition of the fuel grain 2 (hereinafter referred to as "ignition" in the present invention). The delay time can be shortened compared to the conventional hybrid rocket engine 10.

  In the hybrid rocket engine 10 of the present invention, since the liquid oxidant L is supplied after the inside of the hollow heating chamber 1 is heated, the liquid oxidant L is sufficiently gasified. Thereby, the hybrid rocket engine 10 of the present invention can reduce unstable combustion.

Next, the ignition method of the hybrid rocket engine 10 of the present invention will be described.
In the ignition method of the hybrid rocket engine 10 of the present invention, the solid auxiliary fuel 12 is heated and gasified by the combustion gas G1, the auxiliary fuel gas G2 is generated from the solid auxiliary fuel 12, and the auxiliary fuel gas G2 is combined with the fuel grain 2. It is used for gasification with the liquid oxidant L. That is, the ignition method of the hybrid rocket engine 10 of the present invention is performed by the following steps (S1) to (S4).

(S1) First, the combustion gas supply device 5 is ignited and the combustion gas G1 is supplied into the hollow heating chamber 1.

(S2) Then, the combustion gas G1 is swirled along the cylindrical inner surface 12a of the solid auxiliary fuel 12, the solid auxiliary fuel 12 is heated and gasified by the combustion gas G1, and the auxiliary fuel gas G2 is converted from the solid auxiliary fuel 12. It is generated and filled into the hollow heating chamber 1.
At this time, the surface of the fuel grain 2 is heated by the combustion gas G1 and the auxiliary fuel gas G2, so that the fuel grain 2 is easily gasified.

(S3) Next, the liquid oxidant L is supplied from the liquid oxidant supply device 4 to the hollow heating chamber 1, and a part of the auxiliary fuel gas G2 is ignited to generate the combustion exhaust gas G3.

(S4) Thereafter, the remaining fuel grain 2 and the liquid oxidant L are heated and gasified with the auxiliary fuel gas G2 and the combustion exhaust gas G3, and the gasified fuel grain 2 is burned with the gasified liquid oxidant L. Thus, the hybrid rocket engine 10 is ignited.

In the ignition method of the hybrid rocket engine 10 of the present invention, among the steps (S1) to (S4) described above, the time taken for (S1) and (S2) is the ignition preparation time, and (S3) and ( The time taken for S4) is the ignition delay time.
The ignition preparation time is several hundred milliseconds at the latest.

  According to the apparatus and method of the present invention described above, the combustion gas supply device 5 is installed on the cylindrical wall surface of the motor case 3 and the concentric solid auxiliary fuel 12 is provided in the hollow heating chamber 1. It is possible to generate the auxiliary fuel gas G2 from the solid auxiliary fuel 12 by heating and gasifying with the combustion gas G1.

Further, when the solid auxiliary fuel 12 is gasified by the combustion gas G1 and the liquid oxidant L is supplied while the surface of the fuel grain 2 is heated, a part of the liquid oxidant L and the solid auxiliary fuel 12 are generated. High temperature auxiliary fuel gas G2 can be ignited.
Thereby, the hybrid rocket engine 10 of the present invention can improve the ignitability of the fuel grain 2 and can shorten the ignition delay time from the supply of the liquid oxidant L to the ignition of the fuel grain 2.

  Furthermore, the liquid oxidant L can be sufficiently gasified by supplying the liquid oxidant L in a state where the solid auxiliary fuel 12 is gasified by the combustion gas G1 and the surface of the fuel grain 2 is heated. Thereby, the hybrid rocket engine 10 of the present invention can reduce unstable combustion.

  Note that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

10,100 hybrid rocket engine,
1 hollow heating chamber, 2,102 fuel grain,
3,103 motor case, 4 liquid oxidant supply device,
4a oxidant tank, 4b injector,
5,105 combustion gas supply device,
12 solid auxiliary fuel, 12a cylindrical inner surface,
14 injection nozzles, 16 nozzles,
104 oxidant supply device,
G1, G0 combustion gas, G2 auxiliary fuel gas,
G3 combustion exhaust gas, L liquid oxidizer, L0 oxidizer

Claims (5)

A motor case having a hollow heating chamber and a fuel grain in contact therewith,
A liquid oxidant supply device for supplying a liquid oxidant to the hollow heating chamber;
A combustion gas supply device for supplying combustion gas to the hollow heating chamber,
A hybrid rocket engine that heats and gasifies the fuel grain and the liquid oxidant with the combustion gas, and ignites the fuel grain,
The hollow heating chamber has a hollow cylindrical shape,
The hybrid rocket engine further comprises a hollow cylindrical solid auxiliary fuel disposed concentrically with the hollow heating chamber.   2. The hybrid rocket engine according to claim 1, wherein the combustion gas supply device includes an injection nozzle that injects the combustion gas in a tangential direction along a cylindrical inner surface of the solid auxiliary fuel. A motor case having a hollow heating chamber and a fuel grain in contact therewith,
A liquid oxidant supply device for supplying a liquid oxidant to the hollow heating chamber;
A combustion gas supply device for supplying combustion gas to the hollow heating chamber,
A method for igniting a hybrid rocket engine that heats and gasifies the fuel grain and the liquid oxidant with the combustion gas and ignites the fuel grain,
Forming the hollow heating chamber into a hollow cylindrical shape;
A hollow cylindrical solid auxiliary fuel is installed inside the concentric with the hollow heating chamber,
With the combustion gas, the solid auxiliary fuel is heated and gasified to generate auxiliary fuel gas from the solid auxiliary fuel,
An ignition method for a hybrid rocket engine, wherein the auxiliary fuel gas is used for the gasification of the fuel grain and the liquid oxidant. The combustion gas heats and gasifies the solid auxiliary fuel, generates auxiliary fuel gas from the solid auxiliary fuel, and fills the hollow heating chamber,
Next, the liquid oxidant is supplied to the hollow heating chamber to ignite part of the auxiliary fuel gas to generate combustion exhaust gas,
The fuel grain and the remaining portion of the liquid oxidant are heated and gasified by the auxiliary fuel gas and the combustion exhaust gas, and the gasified fuel grain is combusted with the gasified liquid oxidant. Item 4. The ignition method for a hybrid rocket engine according to Item 3. 5. The ignition method for a hybrid rocket engine according to claim 3, wherein the combustion gas is injected tangentially along the cylindrical inner surface of the solid auxiliary fuel by the combustion gas supply device.

Images