阅读说明：本技术 变推力发动机流量调节装置及在轨保护方法 (Variable thrust engine flow regulating device and on-orbit protection method ) 是由 韩泉东 潘一力 王浩 李群广 刘锋 李和军 魏青 钟雪莹 兰晓辉 王可立 于 2020-12-29 设计创作，主要内容包括：本发明提供了一种变推力发动机流量调节装置及在轨保护方法,包括针锥、流量调节装置壳体、步进电机、旋转限位结构、最大位置到位开关、最小位置到位开关、滚珠丝杠以及控制器,针锥和流量调节装置壳体配合形成流动通道,控制器控制步进电机转动,通过滚珠丝杠将步进电机的旋转运动转换为直线运动,带动针锥沿轴线方向运动,进而改变流通截面积以实现调节流量。本发明将针锥停放在距离最大极限位置1000步位置,可确保在轨飞行过程中针锥不会损坏最大到位开关和最小到位开关,也不会碰触到流量调节装置的外壳导致针锥型面或壳体内型面受损,可避开流场不稳定的汽蚀过渡区,发动机可以在该位置直接点火,且推力满足要求。(The invention provides a variable thrust engine flow regulating device and an on-orbit protection method, which comprise a needle cone, a flow regulating device shell, a stepping motor, a rotation limiting structure, a maximum position in-place switch, a minimum position in-place switch, a ball screw and a controller, wherein the needle cone and the flow regulating device shell are matched to form a flow channel, the controller controls the stepping motor to rotate, the rotation motion of the stepping motor is converted into linear motion through the ball screw, the needle cone is driven to move along the axial direction, and the flow cross section is further changed to realize flow regulation. The needle cone is parked at the position which is 1000 steps away from the maximum limit position, the maximum in-place switch and the minimum in-place switch cannot be damaged by the needle cone in the rail flight process, the surface of the needle cone or the surface of the inner shell cannot be damaged due to the fact that the needle cone touches the shell of the flow regulating device, a cavitation transition area with an unstable flow field can be avoided, the engine can directly ignite at the position, and the thrust meets the requirement.)

1. A variable thrust engine flow regulating device is characterized by comprising a needle cone (1), a flow regulating device shell (2), a stepping motor (3), a rotation limiting structure (4), a maximum position in-place switch (5), a minimum position in-place switch (6), a ball screw (7) and a controller;

the part with the conical section of the needle cone (1) is inserted into the flow regulating device shell (2) and is matched with the flow regulating device shell (2) to form a propellant flow channel;

the rotation limiting structure (4) is connected with the needle cone (1) to limit the needle cone (1) to rotate;

the part of the needle cone (1) contacting the ball screw (7) is provided with an external thread, and the needle cone (1) is in threaded connection with the ball screw (7);

the tail end of the needle cone (1) is provided with two baffles, one baffle contacts the maximum position in-place switch (5) when the needle cone (1) moves towards the maximum position, and the other baffle contacts the minimum position in-place switch (6) when the needle cone moves towards the minimum position;

the rotation of the stepping motor (3) is controlled and driven by a controller;

the rotor of step motor (3) and the overcoat fixed connection of ball (7), when the rotor of step motor (3) rotated, the rotor drove the overcoat rotation of ball (7), and ball (7) change the rotary motion of step motor (3) into linear motion, and ball (7) drive awl (1) and move between maximum extreme position and minimum extreme position along the axis direction, and then change propellant flow area in order to realize propellant flow regulation.

2. The variable thrust engine flow regulating device according to claim 1, characterized in that the maximum position in-place switch (5) and the minimum position in-place switch (6) are used to output the position of the needle cone (1);

the needle cone (1) automatically stops moving after contacting the maximum position in-place switch (5) or the minimum position in-place switch (6);

the propellant flow area is the largest when the needle cone (1) contacts the maximum position to the position switch (5), and the propellant flow area is the smallest when the needle cone (1) contacts the minimum position to the position switch (6).

3. The variable thrust engine flow regulating device according to claim 1, characterized in that the needle cone (1) is in the maximum limit position, the propellant does not cavitate when flowing through the flow regulating device, the needle cone (1) passes through a cavitation transition zone during the movement to the minimum limit position, and then enters the cavitation zone when continuing to move to the minimum limit position.

4. An on-track protection method for a variable thrust engine flow regulating device, which is characterized by adopting the variable thrust engine flow regulating device of any one of claims 1-3, and comprises the following steps:

step 1, a winding of a stepping motor is electrified;

step 2, moving the needle cone (1) of the flow regulating device to the maximum limit position until the maximum position in-place signal is switched on;

step 3, moving the needle cone (1) of the flow regulating device to the direction of the minimum limit position for 1000 steps;

and 4, powering off the stepping motor winding.

5. The method for protecting a variable thrust engine flow regulator from the rail according to claim 4, wherein the needle cone (1) of the flow regulator in step 3 is positioned at a distance of 1000 steps from the maximum limit position when the rail is stored, in which the propellant does not undergo cavitation when flowing through the flow regulator, and the thrust generated when the engine is ignited is the same as the thrust generated when the needle cone (1) is positioned at the maximum limit position.

6. The on-track protection method for the flow regulating device of the variable thrust engine according to claim 4, characterized in that after the step 4 step of de-energizing the stepping motor winding, the needle cone (1) is kept in position under the self-holding force of the stepping motor (3).

Technical Field

The invention relates to the technical field of spacecraft propulsion, in particular to a variable thrust engine flow adjusting device and an on-orbit protection method.

Background

The spacecraft extraterrestrial celestial body soft landing usually adopts a variable thrust liquid rocket engine (a variable thrust engine for short) to improve the landing precision and the landing reliability and reduce the landing speed. The adoption of the variable thrust rocket engine to replace a plurality of constant thrust engines is also the development trend of the soft landing of extraterrestrial celestial bodies in the future.

The variable thrust engine needs to adjust the flow when the thrust is changed, and the flow adjusting device is used for realizing the flow adjusting. The function of the flow regulating device is to achieve flow regulation by changing the flow area or the flow pressure difference of the propellant. The adjustable cavitation venturi is a common flow regulating device, and the design method thereof is relatively mature. According to different acting force sources of the adjusting cone, the flow adjusting device has different structural forms, known hydraulic action and linear motor action are adopted, and the stroke is limited by a limit block. No public report is found on the protection method of the flow regulator when the flow regulator does not work in the track for a long time.

Generally, a variable thrust engine operates after experiencing a vibratory impulse environment during on-orbit flight, and then needs to be started at maximum thrust conditions when the engine is started. If the end of the needle cone contacts the maximum in-place switch or the minimum in-place switch, the in-place switch is easily damaged when the needle cone is subjected to a severe mechanical environment. If the gap between the needle cone and the flow regulating device shell is too small, the needle cone profile or the inner profile of the flow regulating device shell is easily damaged when the needle cone and the flow regulating device shell are subjected to severe mechanical environment, and further the throttling characteristic of the flow regulating device is deteriorated and even the flow regulating device is in failure.

The liquid rocket engine adopting the flow regulating device has fewer flying cases, and the arrangement of the position of the needle cone of the flow regulating device during storage in the flying process is not reported publicly.

The current conventional method is as follows: in the scheme A, the needle cone is stopped at the maximum limit position (namely, the tail end of the needle cone contacts the maximum in-place switch) so as to facilitate the subsequent ignition starting; in the case of the variant B, the needle cone of the flow control device is held in a position between the maximum limit position and the minimum limit position, possibly in the cavitation transition region or the cavitation region. In fact, with the scheme A, the end of the needle cone is contacted with the in-place switch for a long time, and when the needle cone is subjected to vibration impact, the contact collision between the end of the needle cone and the in-place switch is easy to cause abnormal output when the in-place switch works. For the scheme B, the position can be a cavitation transition area or a cavitation area, the flow rate can be unstable when ignition is directly started, unstable combustion of the engine is easily caused, and the engine can be damaged in an extreme case (except for a specific allowable checked needle cone stopping position), so that the needle cone must be set to a maximum limit position or a specific allowable position before ignition. Although the failure occurrence probability can be reduced by tightening the quality control, the needle cone can not be guaranteed to be adjusted to a desired position before ignition, so that the scheme B is not recommended to be used in occasions with particularly high requirements on reliability and safety.

Patent document CN105863882B (application number: CN201610270582.4) discloses a flow positioning adjustable direct current injector suitable for a high-concentration hydrogen peroxide variable thrust solid-liquid rocket engine, which comprises a head cover, an injector shell, a valve core, an upper cover and an inlet joint. An inlet joint is arranged at the top of the head cover; is fixed in the inner cavity of the head cover, and a gap is formed between the head cover and the inner cavity of the head cover; the outer wall of the injector shell is provided with a propellant inlet, and the bottom end of the injector shell is provided with a propellant outlet; the top of the injector shell is also provided with an upper cover. The valve core is arranged in the cavity of the injector shell; propellant entering the inner cavity of the head cover through the inlet joint enters the inner cavity of the injector shell through the propellant inlet, the valve core is driven to move through the spring and the air-hydraulic pressure difference, the valve core is separated from the propellant outlet, and the propellant is sprayed out.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a variable thrust engine flow regulating device and an on-track protection method.

The variable thrust engine flow regulating device provided by the invention comprises a needle cone, a flow regulating device shell, a stepping motor, a rotation limiting structure, a maximum position in-place switch, a minimum position in-place switch, a ball screw and a controller;

the part with the conical section of the needle cone is inserted into the shell of the flow regulating device and is matched with the shell of the flow regulating device to form a propellant flow channel;

the rotation limiting structure is connected with the needle cone to limit the needle cone to rotate;

the part of the needle cone, which is in contact with the ball screw, is provided with an external thread, and the needle cone is in threaded connection with the ball screw;

the tail end of the needle cone is provided with two baffles, one baffle contacts the maximum position in-place switch when the needle cone moves towards the maximum position, and the other baffle contacts the minimum position in-place switch when the needle cone moves towards the minimum position;

the rotation of the stepping motor is controlled and driven by a controller;

step motor's rotor and ball's overcoat fixed connection, when step motor's rotor rotated, the rotor drove ball's overcoat and rotates, and ball changes step motor's rotary motion into linear motion, and ball drives the awl and moves between maximum extreme position and minimum extreme position along the axis direction, and then changes propellant flow area in order to realize propellant flow control.

Preferably, the maximum position in-place switch and the minimum position in-place switch are adopted to output the position of the needle cone;

the needle cone automatically stops moving after contacting the maximum position in-place switch or the minimum position in-place switch;

the propellant flow area is the largest when the needle cone contacts the maximum position to position switch, and the propellant flow area is the smallest when the needle cone contacts the minimum position to position switch.

Preferably, when the needle cone is at the maximum limit position, the propellant does not undergo cavitation when flowing through the flow regulating device, and the needle cone passes through the cavitation transition region during the movement towards the minimum limit position and then enters the cavitation region when continuing to move towards the minimum limit position.

The invention provides an on-orbit protection method for a flow regulating device of a variable thrust engine, which comprises the following steps:

step 1, a winding of a stepping motor is electrified;

step 2, moving the needle cone of the flow regulating device to the maximum limit position until the maximum position in-place signal is switched on;

step 3, moving the needle cone of the flow regulating device to the direction of the minimum limit position for 1000 steps;

and 4, powering off the stepping motor winding.

Preferably, in step 3, the needle cone of the flow regulator is located at a position 1000 steps away from the maximum limit position when the rail is stored, in which the propellant flows through the flow regulator without cavitation, and the engine is ignited with the same thrust as the needle cone when it is located at the maximum limit position.

Preferably, after the step 4 is powered off, the needle cone is held in position under the self-holding force of the step motor.

Compared with the prior art, the invention has the following beneficial effects:

1. the variable thrust engine flow regulating device has a simple structure and is easy to process and manufacture;

2. the invention can ensure that the needle cone does not contact the in-place switch in the rail flying process, and when the flow regulating device is subjected to a severe mechanical environment, the needle cone does not contact the maximum in-place switch and the minimum in-place switch, so that the in-place switch is prevented from being damaged;

3. the invention can ensure that the needle cone of the flow regulating device can not touch the shell of the flow regulating device when the needle cone is subjected to a severe mechanical environment in the rail flying process, thereby preventing the profile of the needle cone or the profile in the shell of the flow regulating device from being damaged;

4. if the needle cone cannot be moved to the maximum limit position before ignition, the needle cone can be directly ignited at the position, and the generated thrust is equivalent to that at the maximum limit position and is within an allowable range.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

fig. 1 is a schematic view of a variable thrust engine flow regulating device provided by the invention.

FIG. 2 is a schematic diagram of the position of the needle cone of the flow regulating device provided by the present invention at the rail storage position during the entire range of needle cone movement.

FIG. 3 is a flowchart illustrating an embodiment of a needle cone on-track protection method for a flow regulator according to the present invention.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

Example (b):

as shown in fig. 1, the variable thrust engine flow regulating device provided by the invention comprises a needle cone 1, a flow regulating device shell 2, a stepping motor 3, a rotation limiting structure 4, a maximum position in-place switch 5, a minimum position in-place switch 6, a ball screw 7 and a controller. The needle cone 1 and the flow regulating device shell 2 are matched to form an adjustable cavitation venturi tube, and the propellant flows through a gap formed by the matching of the needle cone 1 and the flow regulating device shell 2. The controller calculates the rotation direction and the rotation step number of the stepping motor 3 in each control period according to the variable thrust requirement and the in-place switch signal, and controls and drives the stepping motor 3 to rotate. The ball screw 7 converts the rotary motion of the stepping motor 3 into linear motion, drives the needle cone 1 to move linearly along the axis direction, and further changes the flow cross section area of the propellant to realize propellant flow regulation.

The rotation limiting structure 4 is connected with the needle cone 1 to limit the needle cone 1 to rotate;

the part of the needle cone 1, which is in contact with the ball screw 7, is provided with an external thread, and the needle cone 1 is in threaded connection with the ball screw 7;

the tail end of the needle cone 1 is provided with two baffles, one baffle contacts the maximum position in-place switch 5 when the needle cone 1 moves towards the maximum position, and the other baffle contacts the minimum position in-place switch 6 when the needle cone moves towards the minimum position;

step motor 3's rotor and ball 7's overcoat fixed connection, when step motor 3's rotor rotated, the rotor drove ball 7's overcoat and rotates, and ball 7 changes step motor 3's rotary motion into linear motion, and ball 7 drives awl 1 and moves between maximum extreme position and minimum extreme position along the axis direction, and then changes propellant flow area in order to realize propellant flow control.

Preferably, the maximum position in-place switch 5 and the minimum position in-place switch 6 are adopted to output the position of the needle cone 1;

the needle cone 1 automatically stops moving after contacting the maximum position in-place switch 5 or the minimum position in-place switch 6;

when the needle cone 1 contacts the maximum position to the position switch 5, the propellant flow area is maximum, and when the needle cone 1 contacts the minimum position to the position switch 6, the propellant flow area is minimum.

As shown in fig. 2, the needle cone of the flow regulating device is reciprocally movable between a maximum limit position and a minimum limit position. When the needle cone 1 of the flow regulating device is at the maximum limit position, the propellant does not generate cavitation when flowing through the flow regulating device, and the thrust generated when the engine is ignited is the maximum. The needle cone 1 passes through the cavitation transition zone during the movement towards the minimum limit direction. Then the needle cone 1 enters a cavitation area when continuing to move to the minimum limit position. The flow field in the cavitation transition zone is unstable and should pass as quickly as possible, otherwise the engine may be burned out. When the needle cone is at the minimum limit position, the thrust generated when the engine is ignited is the minimum. In the cavitation zone, the engine can operate with continuously variable thrust.

Referring to fig. 3, the on-orbit protection method for the flow regulating device of the variable thrust engine comprises the following steps:

step 1, a winding of a stepping motor is electrified;

step 2, moving the needle cone of the flow regulating device to the maximum limit position until the maximum position in-place signal is switched on;

step 3, moving the needle cone of the flow regulating device to the direction of the minimum limit position for 1000 steps;

and 4, powering off the stepping motor winding.

The invention discloses a variable thrust engine flow regulating device and an on-orbit protection method, which are successfully applied to ground tests of certain types of propulsion systems.

When the needle cone of the flow regulating device is stored on the track, the needle cone is positioned 1000 degrees from the maximum limit position, wherein the 1000-step position refers to a position which has a certain safety distance from the maximum position to the position switch and the transitional cavitation area, and is not an absolute 1000-step position.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

Those skilled in the art will appreciate that, in addition to implementing the systems, apparatus, and various modules thereof provided by the present invention in purely computer readable program code, the same procedures can be implemented entirely by logically programming method steps such that the systems, apparatus, and various modules thereof are provided in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Therefore, the system, the device and the modules thereof provided by the present invention can be considered as a hardware component, and the modules included in the system, the device and the modules thereof for implementing various programs can also be considered as structures in the hardware component; modules for performing various functions may also be considered to be both software programs for performing the methods and structures within hardware components.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.