Liquid rocket engine and liquid rocket

Abstract

The invention provides a liquid rocket engine and a liquid rocket, and relates to the technical field of rocket engine equipment. In the engine, a turbine pump comprises a fuel pump, an oxidizing agent pump and a turbine, and an outlet of the fuel pump and an outlet of the oxidizing agent pump communicate with a thrust chamber and a fuel gas generator correspondingly; the fuel gas generator is provided with a first fuel gas passage connected with the turbine and a second fuel gas passage used for being communicated with the external atmosphere, and the fuel gas adjusting valve is installed on the second fuel gas passage. The reaction type stepping motor is connected with a valve element of the fuel gas adjusting valve through the transmission mechanism, and the controller is electrically connected with the reaction type stepping motor and used for sending pulse signals to the reaction type stepping motor at set control frequency and controlling the power-on time sequence of the reaction type stepping motor so as to drive the reaction type stepping motor to rotate forwards and backwards. And the opening degree of the gas adjusting valve is adjusted. Only one gas adjusting valve is involved in the thrust adjusting process, reliability is high, a reaction type stepping motor is adopted, large output torque can be generated under small current, and needed power is small.

Description

Technical Field

[0001] The present invention relates to the technical field of rocket engine equipment, and in particular to a liquid rocket engine and a liquid rocket. Background Art

[0002] Liquid rocket engines are generally used as the main power unit of launch vehicles. Liquid rocket engines are complex in composition, difficult to develop, and generally designed with fixed thrust in consideration of reliability and other factors. As the demand for launch vehicle recovery and reusability increases, adjustable thrust has become a necessary capability for liquid rocket engines.

[0003] In liquid rocket engines that currently use a gas generator cycle, there are many regulating valves, which increases the weight of the engine, and the control process of multiple flow regulating valves is complicated, which reduces the overall reliability. In addition, the current regulating valves are mostly regulated by permanent magnet motors. When the valve core opening of the regulating valve needs to be changed, the permanent magnet motor needs a large current to overcome the internal magnetic field force, thereby changing the rotor position, and the power consumption is large. Summary of the invention

[0004] The present invention provides a liquid rocket engine and a liquid rocket, which are used to solve the defects of the prior art that a large number of regulating valves are required to realize thrust regulation in liquid rocket engines, the control is complex, the reliability is low, and the motor power consumption is large during the regulating valve regulation process.

[0005] In a first aspect, the present invention provides a liquid rocket engine, comprising: a thrust chamber, a gas generator, a turbo pump, a gas regulating valve, a controller and a reactive stepping motor; The turbo pump comprises a fuel pump, an oxidant pump and a turbine, and the outlet of the fuel pump and the outlet of the oxidant pump are respectively connected to the thrust chamber and the gas generator; The gas generator has a first gas passage and a second gas passage, the first gas passage is connected to the turbine, the second gas passage is used to communicate with the external atmosphere, and the gas regulating valve is installed in the second gas passage; The reactive stepper motor is connected to the valve core of the gas regulating valve through a transmission mechanism, and the controller is electrically connected to the reactive stepper motor. The controller is configured to send a pulse signal to the reactive stepper motor at a set control frequency and control the power-on timing of the reactive stepper motor to drive the reactive stepper motor to rotate forward or reverse, thereby adjusting the opening of the gas regulating valve.

[0006] According to a liquid rocket engine provided by the present invention, the transmission mechanism includes a first gear, a second gear and a rack, the second gear has the same structure as the first gear, the first gear is rigidly connected to the output shaft of the reactive stepping motor, the second gear is connected to the side of the first gear through a torsion spring, and the torsion spring is used to make the second tooth of the second gear and the first tooth of the first gear staggered in the circumferential direction; the rack is respectively meshed with the first gear and the second gear, and the end of the rack is connected to the valve core.

[0007] According to a liquid rocket engine provided by the present invention, the transmission mechanism further comprises a limiting device, which is arranged on a side of the second gear facing away from the first gear and is used to limit the axial position of the second gear; And / or, the transmission mechanism further comprises a linear displacement sensor electrically connected to the controller, wherein the linear displacement sensor is connected to the valve core or the rack and is used to detect the valve core opening of the gas regulating valve.

[0008] According to a liquid rocket engine provided by the present invention, the output shaft of the reactive stepping motor is connected to the first gear via a reduction gear pair, the reduction gear pair is built into the reactive stepping motor, and the reduction ratio of the reduction gear pair is 20:1 to 40:1.

[0009] According to a liquid rocket engine provided by the present invention, the set control frequency of the controller is 500Hz-800Hz, and the power-on timing sequence of the reactive stepping motor is four-phase four-beat.

[0010] According to a liquid rocket engine provided by the present invention, the fuel pump, the oxidant pump and the turbine are coaxially arranged; And / or, the turbine is an impulse turbine.

[0011] According to a liquid rocket engine provided by the present invention, the fuel pump is connected with the gas generator and the thrust chamber through a first three-way pipe; And / or, the oxidant pump is connected to the gas generator and the thrust chamber through a second three-way pipe.

[0012] A liquid rocket engine provided according to the present invention also includes an exhaust nozzle, which is respectively connected to the outlet of the second gas passage and the gas output end of the turbine pump, and the diameter of the exhaust nozzle first decreases and then increases along the flow direction of the fluid.

[0013] According to a liquid rocket engine provided by the present invention, the outlet of the second gas passage is connected to a first exhaust nozzle, and the diameter of the first exhaust nozzle first decreases and then increases along the flow direction of the fluid; and / or, the gas output end of the turbine pump is provided with a second exhaust nozzle, and the diameter of the second exhaust nozzle first decreases and then increases along the flow direction of the fluid.

[0014] In a second aspect, the present invention further provides a liquid rocket, comprising a rocket body and a liquid rocket engine as described in the first aspect, wherein the liquid rocket engine is installed on the rocket body.

[0015] The liquid rocket engine and liquid rocket provided by the present invention have a second gas passage added downstream of the gas generator, and a gas regulating valve is arranged on the second gas passage. The controller controls the valve core opening of the gas regulating valve through the transmission mechanism by controlling the reactive stepping motor, thereby controlling the gas flow entering the turbine pump and adjusting the power of the turbine pump, thereby realizing thrust regulation. The thrust regulation process only involves one gas regulating valve. Compared with the traditional liquid rocket engine, the number of regulating valves is reduced, the complexity of the engine is reduced, and the manufacturing cost is reduced. The regulation process does not involve coupling between regulating valves, and there is no need to set complex decoupling control logic. The control is simple and the reliability is high. Among them, the reactive stepping motor is adopted, which can generate a large output torque under a small current, requires less power, and generates less heat. In addition, the rotor of the reactive stepping motor itself is not magnetic. When the motor changes the current operating state, it only needs to overcome the rotational inertia of the motor rotor itself, and does not need to overcome the magnetic force. Therefore, it is ensured that the motor can still maintain a large output torque margin at the start and stop moment, and the reliability of the control is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic structural diagram of the liquid rocket engine provided by the present invention.

[0018] Figure 2 It is a schematic diagram of the local structure of the liquid rocket engine provided by the present invention.

[0019] Figure 3 It is a schematic diagram of the gear connection of the transmission mechanism provided by the present invention.

[0020] Figure 4 It is a schematic diagram of the transmission meshing of the first gear, the second gear and the rack provided by the present invention.

[0021] Reference numerals: 1. Thrust chamber; 2. Gas generator; 21. First gas passage; 22. Second gas passage; 3. Oxidant pump; 4. Fuel pump; 5. Turbine; 6. Gas regulating valve; 7. Reaction stepper motor; 71. First electrical connector; 72. Second electrical connector; 81. First gear; 810. First tooth; 811. First tooth surface; 82. Second gear; 820. Second tooth; 821. Second tooth surface; 9. Torsion spring; 10. Rack. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The features of the terms "first" and "second" in the specification and claims of the present invention may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0024] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In the related art, the thrust regulation methods vary according to the different circulation modes of variable thrust liquid rocket engines. The circulation modes of variable thrust liquid rocket engines mainly involve gas generator cycle, expansion cycle and regenerative cycle. All three circulation modes of variable thrust liquid rocket engines adjust the engine thrust by adjusting the power of the turbopump. Among them, the regenerative cycle maintains the mixing ratio by adjusting the flow rate entering the thrust chamber. The expansion cycle achieves the stability of the thrust chamber mixing ratio by adjusting the speed of the turbopump. The gas generator cycle adjusts the propellant flow entering the gas generator to change the propellant flow rate in the thrust chamber to achieve thrust regulation.

[0027] In the variable thrust liquid rocket engine currently using the gas generator circulation method, the oxidizer pipeline and the fuel pipeline entering the gas generator are both equipped with regulating valves. The two regulating valves act synchronously to control the gas flow of the gas generator. At the same time, a regulating valve is set in the thrust chamber oxidizer pipeline or fuel pipeline to adjust the combustion mixture ratio of the thrust chamber. The overall solution requires the installation of three regulating valves. The number of regulating valves is large, which will increase the weight of the engine. In addition, the action processes of the three regulating valves are coupled with each other, the control is complicated, and the overall reliability will also be reduced.

[0028] Combine the following Figure 1-Figure 4 The liquid rocket engine of the present invention is described.

[0029] The present invention provides a liquid rocket engine, such as Figure 1 As shown, the liquid rocket engine includes a thrust chamber 1, a gas generator 2, a turbo pump, a gas regulating valve 6, a controller and a reactive stepping motor 7. The thrust chamber 1 and the gas generator 2 are both connected to the turbo pump.

[0030] The turbo pump includes a fuel pump 4, an oxidant pump 3 and a turbine 5. The gas generator 2 is connected to the turbine 5. The outlet of the fuel pump 4 and the outlet of the oxidant pump 3 are connected to the thrust chamber 1 and the gas generator 2 respectively. The fuel pump 4 provides high-pressure fuel to the thrust chamber 1 and the gas generator 2 respectively, and the oxidant pump 3 provides high-pressure oxidant to the thrust chamber 1 and the gas generator 2 respectively. It should be noted that after the liquid rocket engine is started, the outlet of the fuel pump 4 is always in a connected state with the thrust chamber 1, that is, no regulating valve is provided on the connecting passage between the fuel pump 4 and the thrust chamber 1. Similarly, after the liquid rocket engine is started, the outlet of the oxidant pump 3 is always in a connected state with the thrust chamber 1, the outlet of the fuel pump 4 is always in a connected state with the gas generator 2, and the outlet of the oxidant pump 3 is always in a connected state with the gas generator 2.

[0031] The reactive stepper motor 7 is connected to the valve core of the gas regulating valve 8 through a transmission mechanism, and the controller is electrically connected to the reactive stepper motor 7. The controller is configured to send a pulse signal to the reactive stepper motor 7 at a set control frequency and control the power-on timing of the reactive stepper motor 7 to drive the reactive stepper motor 7 to rotate forward or reverse. Among them, the transmission mechanism is used to be connected to the valve core of the gas regulating valve 8; the reactive stepper motor 7 is connected to the transmission mechanism, and is used to drive the transmission mechanism to adjust the opening of the valve core. Specifically, the torque of the reactive stepper motor 7 can be transmitted to the valve core of the gas regulating valve 8 through the transmission mechanism, thereby pushing the valve core of the gas regulating valve 8 to move and realize the adjustment of the valve core opening.

[0032] The controller is electrically connected to the reactive stepper motor 7, and the controller is configured to send a pulse signal to the reactive stepper motor 7 at a set control frequency, so as to accurately control the number of running steps of the reactive stepper motor 7. The control frequency refers to the number of pulses sent to the motor within 1 second. For example, a control frequency of 500Hz means that 500 pulses are sent to the motor within 1 second. In addition, the controller controls the power-on timing of the reactive stepper motor 7, drives the reactive stepper motor 7 to rotate forward or reverse, and realizes precise adjustment of the opening of the valve core of the gas regulating valve 8, thereby accurately achieving the purpose of increasing or decreasing the thrust of the rocket engine. The controller can be integrated into the central controller of the liquid rocket to send control instructions to the reactive stepper motor 7.

[0033] The propellant combination formed by the fuel and the oxidant is a bicomponent propellant such as liquid oxygen methane, liquid oxygen kerosene, liquid oxygen alcohol, unsymmetrical dimethyl hydrazine nitrogen tetroxide, etc. The gas generator 2 has a first gas passage 21 and a second gas passage 22. The first gas passage 21 is connected to the turbo pump and is discharged into the atmosphere after the turbo pump is driven to operate. The second gas passage 22 is used to connect to the external atmosphere, and the gas regulating valve 6 is installed in the second gas passage 22.

[0034] After the oxidant in the oxidant tank is pressurized by the oxidant pump 3, a part of it enters the thrust chamber 1 and burns with the fuel entering the thrust chamber 1 to generate thrust, and the rest enters the gas generator 2 to burn and generate gas to drive the turbine 5 and then discharge into the atmosphere. After the fuel in the fuel tank is pressurized by the fuel pump 4, a part of it enters the thrust chamber 1 and burns with the oxidant entering, and the rest enters the gas generator 2 to burn with the oxidant to generate gas to drive the turbine 5. The gas generator 2 provides dynamic boosting power for the turbine 5 through the first gas passage 21, and the second gas passage 22 is arranged in parallel with the first gas passage 21. A gas regulating valve 6 is arranged on the second gas passage 22. By controlling the opening of the gas regulating valve 6, the gas flow rate of the first gas passage 21 is controlled, and then the power of the turbine pump is controlled to achieve thrust adjustment.

[0035] By controlling the reactive stepper motor 7 through the controller, and then driving the valve core of the gas regulating valve 8 to move through the transmission mechanism, the valve core of the gas regulating valve 8 can be stabilized at a specified position and remain stationary, and the amount of gas entering the first gas passage 21 in the gas generator 2 can be accurately adjusted. The process of the reactive stepper motor 7 controlling the gas regulating valve 8 is open-loop control, which avoids the phenomenon that the motor vibrates back and forth near the steady-state position due to closed-loop control in the related art. On the one hand, it ensures that the motor output torque is not attenuated, and increases the reliability of control; on the other hand, it ensures the stability of the output power control of the liquid rocket engine, and the valve core opening will not fluctuate.

[0036] Specifically, the valve core opening of the gas regulating valve 6 can be adjusted by controlling the reactive stepper motor 7 through the controller according to the thrust adjustment demand. The throttling capacity of the engine is no longer limited by the injection pressure drop of the gas generator 2, but is limited by the combustion injection pressure drop of the thrust chamber 1, thereby improving the thrust adjustment range with less sacrifice of engine performance. Among them, when the controller controls the reactive stepper motor 7 to make the valve core of the gas regulating valve 6 completely closed, the gas generator 2 drives the turbine pump to operate at maximum power, and the entire liquid rocket engine provides maximum thrust; with the operation of the reactive stepper motor 7, the valve core opening of the gas regulating valve 6 gradually increases, the amount of gas entering the turbine pump decreases, and the thrust of the liquid rocket engine gradually decreases; when the controller controls the reactive stepper motor 7 to make the valve core opening of the gas regulating valve 6 maximum, the gas generator 2 drives the turbine 5 to operate at minimum power, and the entire liquid rocket engine provides minimum thrust.

[0037] During the thrust adjustment process, the controller controls the reactive stepper motor 7 to make the equivalent flow area of ​​the gas regulating valve 6 change monotonically. Correspondingly, the thrust of the liquid rocket engine changes monotonically, which simplifies the difficulty of engine control. Only proportional integral control is required to achieve engine closed-loop control. The overall adjustment link is single, the control is simple, and the reliability is high.

[0038] In the liquid rocket engine provided by the embodiment of the present invention, a second gas passage 22 is added downstream of the gas generator 2, and a gas regulating valve 6 is arranged on the second gas passage 22. The controller controls the valve core opening of the gas regulating valve 6 through the transmission mechanism by controlling the reactive stepping motor 7, thereby controlling the gas flow entering the turbo pump and adjusting the power of the turbo pump, thereby realizing thrust regulation. The thrust regulation process involves only one gas regulating valve 6. Compared with the traditional liquid rocket engine, the number of regulating valves is reduced, the complexity of the engine is reduced, and the manufacturing cost is reduced; the regulation process does not involve coupling between regulating valves, and there is no need to set complex decoupling control logic, so the control is simple and the reliability is high. Among them, the reactive stepping motor 7 is used to generate a large output torque under a small current, the required power is small, and the heat generated is small. In addition, the rotor of the reactive stepping motor 7 itself is not magnetic. When the motor changes the current operating state, it only needs to overcome the rotational inertia of the motor rotor itself, and does not need to overcome the magnetic force. Therefore, it is ensured that the motor can still maintain a large output torque margin at the start and stop moment, and the reliability of the control is improved.

[0039] like Figure 2 , Figure 3 and Figure 4 As shown, the transmission mechanism includes a first gear 81, a second gear 82, a torsion spring 9 and a rack 10. The first gear 81 is rigidly connected to the output shaft of the reactive stepping motor 7. The second gear 82 has the same structure as the first gear 81. The second gear 82 is relatively connected to the side of the first gear 81 through a torsion spring 9. The torsion spring 9 is used to make the second tooth 820 of the second gear 82 and the first tooth 810 of the first gear 81 staggered in the circumferential direction. The rack 10 is meshed with the first gear 81 and the second gear 82 respectively, and the end of the rack 10 is connected to the valve core of the gas regulating valve 8.

[0040] The controller sends a driving instruction to the reactive stepper motor 7, driving the reactive stepper motor 7 to rotate, driving the first gear 81 to rotate, and driving the second gear 82 to rotate through the torsion spring 9, that is, the first gear 81 and the second gear 82 rotate on the rack 10, so that the rack 10 makes a relative linear motion, thereby driving the valve core of the gas regulating valve 8 to make a linear motion, and adjusting the valve core opening of the gas regulating valve 8.

[0041] In the related art, a worm gear transmission mechanism is usually used for transmission. Since there is usually a gap at the meshing point of the worm gear transmission during mechanical processing, and the gaps between parts in different batches are usually inconsistent, there is an idling dead zone during the forward and reverse strokes, which leads to a large hysteresis error. During the forward and reverse strokes, under the same instructions, the valve core opening is inconsistent, reducing the adjustment accuracy of the system. Considering that there are errors in the processing of gear racks and mechanical transmission mechanisms, resulting in large or small gaps in the matching of parts, the present invention uses a double gear with a torsion spring 9 to match the rack for transmission. Specifically, as Figure 4 As shown, under the action of the torsion spring 9, opposite forces can be applied to the first gear 81 and the second gear 82, so that the teeth on the first gear 81 and the second gear 82 are staggered at a certain angle along the circumferential direction. The specific angle depends on the size of the processing gap. Then, when the first gear 81 and the second gear 82 rotate, the first tooth surface 811 of the first gear 81 and the second tooth surface 821 of the second gear 82 can always be in close contact with the rack 10, eliminating the gap and thus eliminating the hysteresis error. As a result, when the same step number command is sent to the reaction stepper motor 7, the reaction stepper motor 7 can reach the same position regardless of forward or reverse rotation, and meet the thrust adjustment accuracy requirements under open-loop control.

[0042] In the liquid rocket engine provided by the embodiment of the present invention, the first gear 81 and the second gear 82 are connected by a torsion spring 9, and the first gear 81 and the second gear 82 are both engaged with the rack 10, so that the rotation of the reactive stepper motor 7 is converted into the linear motion of the valve core of the gas regulating valve 8 through the engagement of the gear rack. The reactive stepper motor 7 rotates a certain angle according to the control instruction of the controller, which is converted into a change in the valve core opening, thereby realizing precise adjustment of the thrust of the liquid rocket engine.

[0043] According to an embodiment of the present invention, the pitch circle diameter of the first gear 81 and the second gear 82 is 20 mm. It should be noted that the pitch circle diameter of the first gear 81 and the second gear 82 can be adjusted according to actual needs, and the embodiment of the present invention does not specifically limit the pitch circle diameter of the first gear 81 and the second gear 82.

[0044] In a specific embodiment, the transmission mechanism further includes a limiting device, which is disposed on the side of the second gear 82 facing away from the first gear 81, and is used to limit the axial position of the second gear 82, thereby preventing the second gear 82 from falling off, improving the transmission stability, and thus improving the system reliability. The specific type of the limiting device of the present invention is not particularly limited, and can be designed according to actual use conditions. For example, the limiting device can be a retaining ring, a baffle, or other devices.

[0045] In a specific embodiment, the conventional mechanism further includes a linear displacement sensor for detecting the valve core opening of the gas regulating valve 6. The linear displacement sensor is connected to the valve core or rack 10 of the gas regulating valve 8. The linear displacement sensor is electrically connected to the controller.

[0046] Specifically, the linear displacement sensor detects the distance the valve core moves, and sends the displacement data to the controller for processing to obtain the corresponding opening of the valve core. Among them, under open-loop control, the data of the linear displacement sensor is only used as a monitoring signal to monitor the valve core opening of the gas regulating valve 6, and does not participate in control and regulation. In some other examples, the data collected by the linear displacement sensor participates in the control, and a feedback link is added, that is, the data of the linear displacement sensor is fed back to the controller. The controller repeatedly adjusts according to the deviation between the actual position of the valve core and the target position to achieve closed-loop control, thereby increasing the diversity of system control and making the control method flexible, which can achieve both closed-loop control and open-loop control, but open-loop control is usually used.

[0047] Of course, the traditional mechanism can also be provided with both a limit device and a linear displacement sensor, and their respective configuration methods are as described above and will not be repeated here.

[0048] Optionally, the output shaft of the reactive stepper motor 7 is connected to the first gear 81 via a reduction gear pair, the reduction gear pair is built into the reactive stepper motor 7, and the reduction ratio of the reduction gear pair is 20:1 to 40:1, for example, the reduction ratio is 30:1. By setting the reduction gear pair, the output torque of the motor can be increased, and the valve core of the gas regulating valve 8 can be fine-tuned, which is conducive to improving the resolution of the thrust adjustment of the liquid rocket engine and improving the control accuracy.

[0049] Optionally, the controller sets the control frequency to 500Hz-800Hz, and the power-on sequence of the reactive stepping motor 7 is four-phase four-beat. The present invention adopts the four-phase four-beat control mode and sets the control frequency to 500Hz-800Hz. On the one hand, the motor output torque can be maximized at this time to ensure the reliability of liquid rocket engine regulation; on the other hand, the step angle of the motor can be reduced, so that the resolution of the system (referring to the control accuracy of the valve opening) is high enough.

[0050] Optionally, a liquid medium is stored in the reactive stepper motor 7 for heat conduction. Specifically, the reactive stepper motor 7 is filled with a liquid medium such as kerosene, which can improve the thermal conductivity, so that the heat dissipation effect of the reactive stepper motor 7 is better, thereby improving the reliability of the liquid rocket engine.

[0051] The controller provides a constant current source of 500mA single-phase power or 250mA two-phase power for the reactive stepper motor 7. According to the requirements of the central controller of the liquid rocket, a pulse signal is sent to the motor at a control frequency of 500Hz. Each time a pulse signal is sent, the motor runs one step, and the step angle is 0.5°. By controlling the power-on timing of the internal coil winding of the reactive stepper motor 7, the forward or reverse rotation of the reactive stepper motor 7 is controlled to achieve the purpose of increasing or decreasing the thrust.

[0052] Reference Figure 2 As shown, the reactive stepper motor 7 is provided with a first electrical connector 71 and a second electrical connector 72, and the controller is electrically connected to the reactive stepper motor 7 through the first electrical connector 71 and the second electrical connector 72 to achieve communication. In actual use, the first electrical connector 71 and the second electrical connector 72 are usually used alternately as the main control channel, that is, assuming that the first electrical connector 71 is used as the main control channel during the first start-up, the second electrical connector 72 is used as the main control channel during the second start-up or test, thereby ensuring that the two electrical connectors are basically used for the same number of times, thereby improving the service life of the reactive stepper motor 7. In addition, when there is a fault in the communication between the controller and the reactive stepper motor 7 through the first electrical connector 71, at this time, it can switch to the second electrical connector 72 for communication, thereby improving reliability.

[0053] As the core electrical component of thrust regulation, the reactive stepper motor 7 is the direct executor of the controller command. It receives the pulse signal of the controller and, according to the number of running steps, opens or closes the valve core of the gas regulating valve 8 to the specified opening through the transmission of the first gear 81, the second gear 82 and the rack 10 at a running rate of 2ms / step. For example, when the reactive stepper motor 7 runs one step, when the gear pitch circle diameter is 20mm, the corresponding linear displacement of the valve core is 0.0872mm, and the total stroke of the valve core of the gas regulating valve 8 is about 35mm. Therefore, the maximum number of steps of the reactive stepper motor 7 is about 401 steps, corresponding to the maximum rotation of the motor output shaft of about 200°. Based on this, a mechanical stop structure such as a limit block can be set within the fan-shaped range of about 200° inside the motor to ensure the running stroke and improve accuracy. It is understandable that a mechanical stop structure is provided inside the reactive stepper motor 7, which can play a role in circumferential limiting the output shaft of the reactive stepper motor 7. For example, according to the actual use scenario, the maximum circumferential rotation of the output shaft is only 200°, so the mechanical stop structure can be provided at the positions of 0° and 200° respectively. The cumulative calculation of the number of steps of the reactive stepper motor 7 is calculated from the 0° position. By providing a mechanical stop structure, it can be ensured that the position of the motor automatically resets to the same position each time the power is turned on. If there is no mechanical stop structure, the output shaft can rotate 360° circumferentially, and the 0-step reference cannot be determined. Therefore, the mechanical stop structure can improve the adjustment accuracy during each operation.

[0054] The reactive stepper motor 7 used in the present invention only needs about a dozen watts of power. Under the premise of meeting the control accuracy of the resolution of about 0.0872mm, the dynamic torque can reach 0.2N·m, and the static torque (i.e., holding torque) can reach 0.3N·m. One of the advantages of the reactive stepper motor 7 is that it can drive a larger load with a smaller power. The reactive stepper motor 7 adopts open-loop control, and can stabilize at the current position after running to the target position, preventing the reactive stepper motor 7 from shaking back and forth near the steady-state position, causing the output torque to decay, and optimizing the working environment of the reactive stepper motor 7. In addition, since the rotor material of the reactive stepper motor 7 is an easily magnetized material and does not have magnetism itself, when the reactive stepper motor 7 changes its operating state, the load that the reactive stepper motor 7 itself needs to overcome is only the rotational inertia of the rotor, and a large output torque margin can still be maintained during the motor start and stop process.

[0055] In summary, the liquid rocket engine provided by the present invention adopts a gas regulating valve 6 as a valve body to adjust the thrust, adopts a reactive stepping motor 7 and a transmission mechanism with the function of eliminating hysteresis errors during the thrust adjustment process, and combines the set control frequency of the reactive stepping motor 7 and the open-loop control mode to adjust the thrust of the liquid rocket engine, which plays a positive role in ensuring the reliability of motor operation and the accuracy and stability of thrust adjustment.

[0056] Among them, different operation steps of the reactive stepper motor 7 correspond to different openings of the gas regulating valve 6, and then correspond to different thrusts. Therefore, the variable thrust parameters of the engine are calculated and calibrated before delivering the rocket. When the rocket needs to adjust the variable thrust, the controller accurately sends the corresponding instructions to the reactive stepper motor 7 according to the correspondence between the pre-calibrated instructions and thrust, so that the engine can achieve different thrust adjustments.

[0057] Before the liquid rocket engine provided by the present invention starts working, in addition to other preparatory work, a power-on program self-check operation is first performed. That is, in the no-load state, check whether the full-stroke operation of the reactive stepper motor 7 is normal and perform a reset operation, and the starting position is maintained at 0 steps, and the gas regulating valve 6 is in a closed state. When the engine receives the ignition command to start ignition, the valve core of the gas regulating valve 6 needs to be fully opened according to the timing, and the controller is installed to set the control frequency to send a number of electrical pulse signals to the reactive stepper motor 7, and the reactive stepper motor 7 runs for a number of steps, and the valve core is fully opened within a certain period of time. During the operation of the engine, the controller sends a pulse command of a corresponding number of steps to the reactive stepper motor 7 according to the thrust adjustment demand, and the reactive stepper motor 7 runs a corresponding number of steps according to the set running rate, so that the valve core opening becomes larger or smaller. After the reactive stepper motor 7 executes the pulse command sent by the controller, it stabilizes at the specified position and remains motionless, ensuring the stability of the engine working condition.

[0058] The turbopump is a coaxial turbopump or a non-coaxial turbopump. For example, the turbine 5, the fuel pump 4 and the oxidant pump 3 are installed on the same shaft, are coaxially arranged, and work at the same speed. The turbine 5 is arranged on one side of the fuel pump 4 and the oxidant pump 3 or in the middle of the fuel pump 4 and the oxidant pump 3. Among them, the fuel pump 4 and the oxidant pump 3 can share a turbine 5, or each can be configured with a turbine 5 separately. Specifically, the turbine 5 drives the oxidant pump 3 and the fuel pump 4 through one or more reduction gearboxes; or, the turbine 5 is directly connected to the oxidant pump 3 and the fuel pump 4.

[0059] During the thrust adjustment process, various parameters of the liquid rocket engine will change. Taking the coaxial turbo pump as an example, the pressure after the pump is proportional to the square of the rotation speed, so the inlet pressures of the thrust chamber 1 and the gas generator 2 change proportionally, and the flow resistance of the flow paths of the two combustion components of the thrust chamber 1 and the gas generator 2 is proportional to the square of the flow rate. Therefore, the propellant mixing ratio entering the thrust chamber 1 and the gas generator 2 can be maintained unchanged. In the actual adjustment process, due to interference factors, the mixing ratio of the two combustion components of the thrust chamber 1 and the gas generator 2 will have a slight deviation, but the deviation is within the allowable range.

[0060] The turbine 5 is an impulse turbine. The turbine pressure of the impulse turbine 5 is relatively large, which creates conditions for adding a second gas passage 22 and setting a gas regulating valve 6 on the second gas passage 22. In addition, the liquid rocket engine does not need to add a system to adjust the flow resistance of each flow path separately, and can also reduce the design power of the turbopump accordingly, which can improve the performance of the engine.

[0061] Optionally, the gas regulating valve 6 does not require valve sealing in the locked state, which reduces the design difficulty. Gas leakage that may be caused by the gas regulating valve 6 can be compensated by engine adjustment calculation.

[0062] The oxidant pump 3 and the fuel pump 4 can be single-stage pumps or multi-stage pumps. For example, the fuel pump 4 and the oxidant pump 3 are both single-stage pumps or both multi-stage pumps. The turbine 5 is a single-stage turbine. For example, the turbine 5 is a single-stage impulse turbine or a two-stage or multi-stage impulse turbine.

[0063] like Figure 1 As shown, the fuel pump 4 is connected to the gas generator 2 and the thrust chamber 1 through the first three-way pipe. Specifically, the first three-way pipe is a one-inlet and two-outlet pipe. The input branch pipe of the first three-way pipe is connected to the output end of the fuel pump 4, the first output pipe of the first three-way pipe is connected to the fuel inlet of the thrust chamber 1, and the second output pipe of the first three-way pipe is connected to the fuel inlet of the gas generator 2. By providing the first three-way pipe, the pipeline layout between the fuel pump 4 and the gas generator 2 and the thrust chamber 1 is simplified.

[0064] Similarly, the oxidant pump 3 is connected to the gas generator 2 and the thrust chamber 1 through the second three-way pipe. Specifically, the second three-way pipe is a one-inlet and two-outlet pipe. The input branch pipe of the second three-way pipe is connected to the output end of the oxidant pump 3, the first output pipe of the second three-way pipe is connected to the oxidant inlet of the thrust chamber 1, and the second output pipe of the second three-way pipe is connected to the oxidant inlet of the gas generator 2. By providing the second three-way pipe, the pipeline layout between the oxidant pump 3 and the gas generator 2 and the thrust chamber 1 is simplified.

[0065] In a specific embodiment, the liquid rocket engine further comprises an exhaust nozzle, which is respectively connected to the outlet of the second fuel gas passage 22 and the fuel gas output end of the turbo pump. The diameter of the exhaust nozzle first decreases and then increases along the flow direction of the fluid.

[0066] The gas exhausted through the second gas passage 22 and the gas exhausted by the worm pump are recycled through the exhaust nozzle before being discharged into the atmosphere, so that the two gas passages share one exhaust nozzle, simplifying the structure. Since the diameter of the exhaust nozzle first contracts and then increases, when the airflow flows in the first exhaust nozzle, it first passes through the contraction area and then passes through the expansion area to achieve airflow acceleration, and the exhaust airflow provides thrust for the engine.

[0067] Specifically, the exhaust nozzle is a Laval tube, including a first connecting section and a second connecting section, wherein the large diameter end of the first connecting section is connected to the outlet of the second gas passage 22, and the small diameter end of the first connecting section is connected to the small diameter end of the second connecting section. Optionally, the cross-sections of the first connecting section and the second connecting section are both circular or square.

[0068] Optionally, the outlet of the second gas passage 22 is connected to a first exhaust nozzle, the diameter of which decreases first and then increases along the flow direction of the fluid; and / or, the gas output end of the turbo pump is provided with a second exhaust nozzle, the diameter of which decreases first and then increases along the flow direction of the fluid. The second exhaust nozzle may have the same structure as the first exhaust nozzle, both of which are Laval tubes.

[0069] In the case where only the outlet of the second gas passage 22 is connected to the first exhaust nozzle, the gas discharged from the second gas passage 22 is recycled through the first exhaust nozzle before being discharged into the atmosphere. In the case where only the gas output end of the turbine pump is provided with the second exhaust nozzle, the gas discharged from the turbine pump is recycled through the second exhaust nozzle before being discharged into the atmosphere. In the case where the outlet of the second gas passage 22 is connected to the first exhaust nozzle and the gas output end of the turbine pump is provided with the second exhaust nozzle, two exhaust nozzles are provided in parallel to recycle the gas.

[0070] The embodiment of the present invention further provides a liquid rocket, which includes a rocket body and the liquid rocket engine as described above, wherein the liquid rocket engine is installed on the rocket body.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A liquid rocket engine, characterized in that: include: Thrust chamber, gas generator, turbo pump, gas regulating valve, controller and reactive stepper motor; The turbo pump comprises a fuel pump, an oxidant pump and a turbine, and the outlet of the fuel pump and the outlet of the oxidant pump are respectively connected to the thrust chamber and the gas generator; The gas generator has a first gas passage and a second gas passage, the first gas passage is connected to the turbine, the second gas passage is used to communicate with the external atmosphere, and the gas regulating valve is installed in the second gas passage; The reactive stepper motor is connected to the valve core of the gas regulating valve through a transmission mechanism, and the controller is electrically connected to the reactive stepper motor. The controller is configured to send a pulse signal to the reactive stepper motor at a set control frequency and control the power-on timing of the reactive stepper motor to drive the reactive stepper motor to rotate forward or reverse, thereby adjusting the opening of the gas regulating valve.

2. The liquid rocket engine according to claim 1, characterized in that: The transmission mechanism includes a first gear, a second gear and a rack. The second gear has the same structure as the first gear. The first gear is rigidly connected to the output shaft of the reactive stepping motor. The second gear is connected to the side of the first gear through a torsion spring. The torsion spring is used to stagger the second teeth of the second gear with the first teeth of the first gear in the circumferential direction. The rack is respectively meshed with the first gear and the second gear, and the end of the rack is connected to the valve core.

3. The liquid rocket engine according to claim 2, characterized in that: The transmission mechanism further includes a limiting device, which is arranged on a side of the second gear facing away from the first gear and is used to limit the axial position of the second gear; And / or, the transmission mechanism further comprises a linear displacement sensor electrically connected to the controller, wherein the linear displacement sensor is connected to the valve core or the rack and is used to detect the valve core opening of the gas regulating valve.

4. The liquid rocket engine according to claim 2, characterized in that: The output shaft of the reaction stepping motor is connected to the first gear via a reduction gear pair, the reduction gear pair is built in the reaction stepping motor, and the reduction ratio of the reduction gear pair is 20:1 to 40:

1.

5. The liquid rocket engine according to any one of claims 1 to 4, characterized in that: The setting control frequency of the controller is 500Hz-800Hz, and the power-on timing of the reactive stepping motor is four-phase four-beat.

6. The liquid rocket engine according to claim 1, characterized in that: The fuel pump, the oxidant pump and the turbine are coaxially arranged; And / or, the turbine is an impulse turbine.

7. The liquid rocket engine according to claim 1, characterized in that: The fuel pump is connected to the gas generator and the thrust chamber through a first three-way pipe; And / or, the oxidant pump is connected to the gas generator and the thrust chamber through a second three-way pipe.

8. The liquid rocket engine according to claim 1, characterized in that: It also includes an exhaust nozzle, which is respectively connected to the outlet of the second gas passage and the gas output end of the turbine pump, and the diameter of the exhaust nozzle first decreases and then increases along the flow direction of the fluid.

9. The liquid rocket engine according to claim 1, characterized in that: The outlet of the second gas passage is connected to a first exhaust nozzle, and the diameter of the first exhaust nozzle first decreases and then increases along the flow direction of the fluid; and / or, the gas output end of the turbine pump is provided with a second exhaust nozzle, and the diameter of the second exhaust nozzle first decreases and then increases along the flow direction of the fluid.

10. A liquid rocket, characterized in that: It comprises a rocket body and a liquid rocket engine as described in any one of claims 1 to 9, wherein the liquid rocket engine is installed on the rocket body.

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