Centrifugal-pintle injector and method for improving combustion efficiency of liquid rocket engine

Abstract

The invention discloses a centrifugal-pintle type injector and a method for improving the combustion efficiency of a liquid rocket engine, a rotary flow channel is designed in a radial flow channel and an axial flow channel of a traditional pintle type injector, a propellant forms a centrifugal rotating state after entering the flow channels of the injector, and then the propellant is jetted out from an outlet of the injector. According to the centrifugal mode, the atomization effect of the injector is improved, the mixing uniformity is improved while the mixing time of a propellant in a combustion chamber is prolonged, and finally the combustion efficiency of an engine is improved.

Description

Technical Field

[0001] The invention discloses a centrifugal-pintle injector and a method for improving the combustion efficiency of a liquid rocket engine, and relates to the design of engine injectors in the fields of machinery, aerospace, etc. Background Art

[0002] After the propellant of a liquid rocket engine enters the injector, it needs to pass through a complex flow channel to be distributed to the injector outlet, and then the propellant is injected into the combustion chamber, where it is atomized, evaporated, mixed and burned to produce high-temperature combustion gas. During the entire process, the reasonable design of the injector can ensure that the propellant is evenly mixed in the combustion chamber, thereby improving the combustion efficiency of the engine.

[0003] The pintle injector is a pintle structure that extends into the combustion chamber. One propellant flows through the central flow channel of the pintle and is radially injected from a series of holes (or gaps) near the pintle head. Another propellant is axially injected through the annular gap outside the pintle. The radial radial jet cross-collides with the axial annular liquid film at 90 degrees, causing the propellant to be atomized and mixed.

[0004] The outlet hole (or gap) of the traditional pintle injector only considers the straight flow path mode, which can only cause the propellants to collide with each other without other effects. Summary of the invention

[0005] The present invention aims to provide a centrifugal-pintle injector and a method for improving the combustion efficiency of a liquid rocket engine, change the jet mixing mode of a traditional injector, promote the atomization and mixing of the propellant in the combustion chamber, and improve the combustion efficiency of the engine.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A centrifugal-pintle injector, comprising:

[0008] a radial hole or first annular gap in the pintle head for radial injection of radiation;

[0009] A second annular gap located outside the pintle head and having the pintle head as the central axis for axial injection, wherein the axial distance from the second annular gap to the combustion chamber head is smaller than the axial distance from the radial hole or the first annular gap to the combustion chamber head;

[0010] The radial hole, the first annular gap and the second annular gap at least include a centrifugal flow channel at their outlets, so that the propellant has a tangential velocity when it is radially ejected through the radial hole and the first annular gap, and has a tangential velocity when it is axially ejected through the second annular gap.

[0011] As a solution, the centrifugal flow channel in the radial hole or the first annular gap is a broken line flow channel, and includes:

[0012] A first flow channel parallel to the radial direction;

[0013] The second flow channel has an angle with the radial direction greater than 0° and less than 90°, the inlet of the second flow channel is connected with the outlet of the first flow channel, and the outlet of the second flow channel forms a radial hole or an outlet of the first annular gap.

[0014] As another solution, the centrifugal flow channel in the radial hole or the first annular gap is a curved flow channel, and the tangent at the inlet of the curved flow channel is parallel to the radial direction, and the angle between the tangent at the outlet of the curved flow channel and the radial direction is greater than 0° and less than 90°.

[0015] As another solution, the centrifugal flow channel in the second annular gap is a zigzag flow channel, and includes:

[0016] a third flow channel parallel to the axial direction;

[0017] The fourth flow channel has an angle with the axial direction greater than 0° and less than 90°, the inlet of the fourth flow channel is connected with the outlet of the third flow channel, and the outlet of the fourth flow channel forms an outlet of the second annular gap.

[0018] As another solution, the centrifugal flow channel in the second annular gap is a curved flow channel, and the tangent line at the inlet of the curved flow channel is parallel to the axial direction, and the angle between the tangent line at the outlet of the curved flow channel and the axial direction is greater than 0° and less than 90°.

[0019] Furthermore, the plurality of centrifugal flow channels are uniformly distributed on the same circumference with the axial direction as the central axis at equal central angles.

[0020] A method for improving the combustion efficiency of a liquid rocket engine comprises: making the propellant ejected from an injector have a tangential velocity in a combustion chamber in addition to an axial and radial velocity, thereby increasing the residence time of the propellant in the combustion chamber.

[0021] As an alternative, the liquid rocket engine adopts the above-mentioned centrifugal-pintle injector.

[0022] Compared with the prior art, the present invention abandons the traditional straight channel design of the pintle injector, and designs the flow channel of the injector outlet into a curved flow channel, such as a curved flow channel or a broken line flow channel, which is in a spiral shape along the axis of the injector. After the propellant flows through the curved flow channel or the broken line flow channel, a spirally rotating fluid is generated, and a tangential velocity is generated during the rotation process, forming a state similar to a centrifugal. In this process, when the propellant flowing through the central flow channel of the pintle is radially injected, a tangential rotating flow along the radial direction of the combustion chamber is also generated. When the propellant is axially injected through the annular gap outside the pintle, a tangential rotating flow along the axial direction of the combustion chamber is also generated. Since the propellant generates tangential rotation, the propellant generates a centrifugal force during the flow process. This centrifugal force causes the propellant to expand into a thin film. Before the two propellants collide, the propellant is subjected to unstable disturbances and is broken into many small droplets, which promotes the atomization and mixing of the propellant in the combustion chamber and improves the combustion efficiency of the engine.

[0023] Since the propellant generates tangential rotation, a component velocity is generated in the tangential direction. After the radial radial jet cross-collides with the axial annular liquid film at 90°, the propellant moves tangentially, which reduces its axial movement speed in the combustion chamber, increases the residence time of the propellant in the combustion chamber, promotes the mixing of the propellant in the combustion chamber, and improves the combustion efficiency of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the curved flow channel on the second annular gap of the centrifugal-pintle injector in the present invention. DETAILED DESCRIPTION

[0025] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but it should not be understood that the scope of the subject matter described in the present invention is limited to the following embodiments. Without departing from the above-mentioned technical ideas of the present invention, various modifications, substitutions and changes made according to the common technical knowledge and customary means in the field are included in the scope of the present invention.

[0026] like Figure 1 As shown, it is the curved flow channel in the centrifugal-pintle injector designed in this embodiment. Figure 1 Only the curved flow channel on the second annular gap for axial injection, which is located outside the needle bolt head and takes the needle bolt head as the central axis, is shown. The curved flow channel is spiral, including a straight flow channel located at arrow A (to obtain axial speed) and a spiral curved surface flow channel located at arrow B (which can be understood as a section of thread, or the helical teeth on the surface of a helical gear, so as to obtain axial and tangential speeds). Multiple curved flow channels are distributed on the circumference with the axis of the needle bolt as the central axis and at equal central angles.

[0027] Figure 1The middle arrow C is the first annular gap located at the pintle head for radial radial injection, on which the same curved flow channel is also processed to obtain radial and tangential velocities.

[0028] Figure 1 That is, the centrifugal-pintle injector of the present invention is formed. When the propellant is injected from the first annular gap and the second annular gap into the combustion chamber, the propellant has a tangential velocity in addition to the traditional axial velocity and radial velocity at the outlet of the first annular gap and the second annular gap. The propellant moves tangentially after the radial velocity and the axial velocity cross-collide at 90 degrees, which reduces its movement speed along the axial direction of the combustion chamber, increases the residence time of the propellant in the combustion chamber, promotes the full mixing of the propellant in the combustion chamber, and finally improves the combustion efficiency of the engine. Considering that the traditional pintle injector is located at the center of the combustion chamber head, its flow field distribution has certain limitations. After adopting the centrifugal-pintle injector of the present invention, the propellant ejected from different annular gaps also has a tangential velocity when colliding with each other (the tangential velocities of the two jets can be superimposed after collision), which changes the original flow field distribution and is a new way to improve combustion efficiency.

[0029] The above are the main concepts of the invention. All injectors designed according to the concepts of the present invention and methods for improving the combustion efficiency of liquid rocket engines fall within the protection scope of the present invention.

Claims

1. A centrifugal pintle injector, characterized in that: include: a radial hole or first annular gap in the pintle head for radial injection of radiation; A second annular gap located outside the pintle head and having the pintle head as the central axis for axial injection, wherein the axial distance from the second annular gap to the combustion chamber head is smaller than the axial distance from the radial hole or the first annular gap to the combustion chamber head; The radial hole, the first annular gap and the second annular gap at least include a centrifugal flow channel at their outlets, so that the propellant has a tangential velocity when it is radially ejected through the radial hole and the first annular gap, and has a tangential velocity when it is axially ejected through the second annular gap.

2. A centrifugal pintle injector according to claim 1, characterized in that: The centrifugal flow channel in the radial hole or the first annular gap is a broken line flow channel, and includes: A first flow channel parallel to the radial direction; The second flow channel has an angle with the radial direction greater than 0° and less than 90°, the inlet of the second flow channel is connected with the outlet of the first flow channel, and the outlet of the second flow channel forms a radial hole or an outlet of the first annular gap.

3. A centrifugal pintle injector according to claim 1, characterized in that: The centrifugal flow channel in the radial hole or the first annular gap is a curved flow channel, and the tangent line at the inlet of the curved flow channel is parallel to the radial direction, and the angle between the tangent line at the outlet of the curved flow channel and the radial direction is greater than 0° and less than 90°.

4. A centrifugal pintle injector according to claim 1, characterized in that: The centrifugal flow channel in the second annular gap is a broken line flow channel, and includes: a third flow channel parallel to the axial direction; The fourth flow channel has an angle with the axial direction greater than 0° and less than 90°, the inlet of the fourth flow channel is connected with the outlet of the third flow channel, and the outlet of the fourth flow channel forms an outlet of the second annular gap.

5. A centrifugal pintle injector according to claim 1, characterized in that: The centrifugal flow channel in the second annular gap is a curved flow channel, and the tangent line at the inlet of the curved flow channel is parallel to the axial direction, and the angle between the tangent line at the outlet of the curved flow channel and the axial direction is greater than 0° and less than 90°.

6. A centrifugal pintle injector according to claim 1, characterized in that: The plurality of centrifugal flow channels are uniformly distributed on the same circumference with the axial direction as the central axis and the same central angle.

7. A method for improving the combustion efficiency of a liquid rocket engine, characterized in that: include: The propellant ejected from the injector has a tangential velocity in the combustion chamber in addition to the axial and radial velocities, thereby increasing the residence time of the propellant in the combustion chamber.

8. A method for improving the combustion efficiency of a liquid rocket engine according to claim 7, characterized in that: The liquid rocket engine adopts the centrifugal-pintle injector described in claim 1.

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