CN-122018571-A - Closed-loop control high-precision nitrous oxide flow regulating valve and control method

CN122018571ACN 122018571 ACN122018571 ACN 122018571ACN-122018571-A

Abstract

The invention provides a closed-loop control high-precision nitrous oxide flow regulating valve and a control method, which belong to the technical field of aerospace propulsion, and mainly meet the flow control application requirements of a liquid rocket engine, and simultaneously improve the accuracy of nitrous oxide flow regulation; the invention adopts a movable needle bolt rod, can adjust the flow area of the throat, realizes wide-range adjustable flow, adopts a direct drive motor and a high-precision screw rod to ensure the high-precision movement of the needle bolt rod, adopts a high-precision displacement sensor to feed back the position to realize the closed-loop control of the needle bolt rod position movement, controls the stroke error and the gap error within a certain range, detects and collects nitrous oxide temperature and pressure information at an inlet, controls the motor to adjust, realizes the real-time flow adjustment control according to the real-time physical parameters of nitrous oxide, has good flow control consistency and high precision, and is particularly suitable for high-saturation vapor pressure liquid such as ammonia, carbon dioxide, nitrogen dioxide, sulfur dioxide, formaldehyde and the like.

Inventors

WEI XIANGGENG
LU WEIJIE
XIE YUAN
WU YIFAN
Cheng Haoqiu
LIU XIONGFENG
HE GUOQIANG
ZHANG YINING
Xu Qingdie

Assignees

西北工业大学

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (10)

1. The closed-loop control high-precision nitrous oxide flow regulating valve is characterized by comprising a pintle rod, a valve body, a screw rod transmission part, a driving motor part and a controller; The driving motor part comprises a direct driving motor, a motor protection cover and a motor bottom plate; The motor protection cover comprises a screw rod protection section, a motor protection section and a protection base, wherein the top surface of the protection base is provided with the motor protection section and the screw rod protection section in sequence from bottom to top, the center of the protection base is provided with a base through hole, the center of a motor base plate is provided with a base through hole, the motor protection section and the screw rod protection section are both thin-wall barrels, the motor protection section, the screw rod protection section and the base through hole are coaxial with the base through hole, a direct driving motor is nested in the motor protection section, and the bottom surface of the protection base is fixedly provided with the motor base; The valve body is a cylinder, a cavity is arranged between two end surfaces of the valve body along the axial direction, a coaxial straight section, a throat section and an expansion section are sequentially arranged in the cavity, the throat section comprises a contraction section and a transition section which are sequentially arranged, the transition section is smoothly connected with the expansion section, and the contraction section is smoothly connected with the straight section; the valve comprises a valve body, a liquid outlet, a liquid inlet, a liquid outlet and a liquid outlet, wherein one end face of the valve body is provided with the liquid outlet; the other end face of the valve body is provided with a first counter bore; an end cover is arranged in the first counter bore, and the first counter bore is communicated with an inlet of the straight section; The inner wall of the straight section is provided with a radial liquid inlet through hole, and a liquid inlet pipe is fixedly arranged in the liquid inlet through hole; the center of the end cover is provided with an end cover hole which is a through hole, and the end cover hole and the first countersunk hole are coaxial with the cavity; the needle bolt rod comprises a plug and a needle bolt slide rod which are coaxially arranged, wherein the plug is conical, the bottom surface of the plug is fixedly connected with one end surface of the needle bolt slide rod, the other end surface of the needle bolt slide rod is fixedly connected with a screw rod transmission part, and the plug is coaxially nested in a cavity of the valve body; The pintle slide bar is nested in an end cover hole of the end cover; The screw rod transmission part is nested and coaxially fixedly arranged on a rotating shaft of the direct drive motor, and converts the rotation motion of the direct drive motor into the linear motion of the screw rod transmission part so as to drive the needle bolt slide rod to linearly move; the controller is respectively connected with the direct drive motor, the high-precision laser displacement sensor, the temperature sensor and the pressure sensor; The dynamic position monitoring piece is arranged on the pintle slide bar, the high-precision laser displacement sensor is arranged on the outer wall of the motor protection section, and the controller is connected with the high-precision laser displacement sensor.
2. The closed-loop control high-precision nitrous oxide flow control valve according to claim 1, wherein the cone angle of the plug is The range of the cone angle of the plug is 。
3. The closed-loop control high-precision nitrous oxide flow control valve according to claim 1, wherein a sealing shaft sleeve is arranged at one end of the straight section close to the end cover; The sealing shaft sleeve comprises a sealing shaft sleeve base and a shaft sealing sleeve, wherein the sealing shaft sleeve base and the shaft sealing sleeve are hollow cylinders, the end face of the sealing shaft sleeve base is coaxially provided with the shaft sealing sleeve, the inner diameter of the sealing shaft sleeve base is smaller than that of the shaft sealing sleeve, the outer diameter of the shaft sealing sleeve is smaller than that of the sealing shaft sleeve base, and the outer diameter of the shaft sealing sleeve is identical to that of the straight section.
4. The closed-loop control high-precision nitrous oxide flow control valve according to claim 1, wherein the screw transmission part comprises a pintle connecting structure and a transmission structure; The needle bolt connecting structure comprises a shaft sleeve and a fish eye connecting piece, wherein the fish eye connecting piece is a rod end joint bearing, the shaft sleeve is a cylinder, a first blind hole along the axial direction is formed in the center of the top surface of the shaft sleeve, the first blind hole is fixedly connected with a needle bolt sliding rod through threads, a radial fish eye groove is formed in the outer wall of the shaft sleeve, a bearing head of the fish eye connecting piece is arranged in the fish eye groove, a fixing through hole perpendicular to the axis of the shaft sleeve is formed in the outer wall of the shaft sleeve, a first bolt is arranged in the fixing through hole, and after the bearing head of the fish eye connecting piece is arranged in the fish eye groove, the first bolt limits and fixes the fish eye connecting piece and the shaft sleeve through a mounting hole of the bearing head of the fish eye connecting piece; The transmission structure comprises a screw rod, a screw rod nut, a shaft sleeve, an adapter plate, an anti-turnover roller, a first sliding block and a second sliding block; The screw rod nut comprises a screw rod and a screw rod flange plate, wherein the screw rod is a hollow cylinder, an inner thread is arranged on the inner wall of the screw rod, an outer thread is arranged on the outer wall of the screw rod, the diameter of the inner wall of the screw rod is the same as that of the screw rod, the screw rod flange plate is fixedly arranged on the outer wall of the screw rod, and a plurality of screw rod fixing holes are formed in the end face of the screw rod flange plate; The adapter plate is a ring-shaped flange plate, a plurality of adapter plate fixing holes are respectively arranged on the end face of the adapter plate along the outer circumference and the inner circumference, the adapter plate is fixedly connected with a rotating shaft of the direct drive motor through the adapter plate fixing holes on the outer circumference of the adapter plate by using bolts, the adapter plate is fixedly connected with the stud flange plate through the adapter plate fixing holes on the inner circumference of the adapter plate by using bolts, and the adapter plate is used for connecting a screw rod nut and the direct drive motor and transmitting torque of the motor to the screw rod; The anti-rolling roller is a hollow cylinder, a first sliding block groove and a second sliding block groove are respectively arranged on the outer wall of the anti-rolling roller, a first sliding block is fixedly arranged in the first sliding block groove, and a second sliding block is fixedly arranged in the second sliding block groove; The shaft sleeve comprises a sleeve column and a sleeve flange, wherein the sleeve column is a hollow cylinder, the sleeve flange is fixedly arranged on the outer wall of the sleeve column, a plurality of sleeve flange screw holes are formed in the end face of the sleeve flange, and a first chute and a second chute are respectively formed in the inner wall of the sleeve column along the axial direction; The inner diameter of the anti-turnover roller is the same as the diameter of the screw rod; The screw rod is characterized in that one end face of the screw rod is provided with a displacement blind hole, the outer wall of the other end face of the screw rod is provided with an anti-turnover roller, a thread is arranged in the displacement blind hole, and the displacement blind hole is fixedly connected with a threaded rod end of the fish-eye connecting piece through the thread; The screw rod is sequentially nested with the motor protective cover, the screw rod nut, the adapter plate, the direct drive motor, the motor bottom plate, the anti-turnover roller and the shaft sleeve from left to right; The screw rod nut is in threaded engagement with the screw rod to convert rotary motion into linear motion, the screw rod is in clearance fit with the anti-rolling shaft, the adapter plate is fixedly connected with a stud flange of the screw rod nut through a screw, the stud flange of the screw rod nut is fixedly connected with a rotating shaft of a direct driving motor through a screw, the anti-rolling shaft is nested in a shaft sleeve, the end face of the anti-rolling shaft is flush with the end face of the screw rod, the shaft sleeve is in clearance fit with the anti-rolling shaft, a first sliding block of the anti-rolling shaft is embedded into a first sliding groove, a second sliding block of the anti-rolling shaft is embedded into a second sliding groove, a sleeve flange of the shaft sleeve is fixedly connected with a motor bottom plate through a bolt, and a shaft sleeve cover is arranged on the end face of the shaft sleeve, far away from the motor bottom plate.
5. The closed-loop control high-precision nitrous oxide flow regulating valve according to claim 4 is characterized in that a photoelectric detection plate is fixedly arranged on the end face of the screw rod, which is flush with the rolling prevention shaft, a photoelectric detector is arranged on the inner wall of the shaft sleeve cover, and the photoelectric detector is connected with a controller.
6. The closed-loop control high-precision nitrous oxide flow regulating valve according to claim 1, wherein an end cover groove is formed in the outer wall of the end cover hole, the end cover groove is coaxial with the valve body, and a buffer rubber pad is arranged in the end cover groove.
7. The closed-loop control high-precision nitrous oxide flow regulating valve according to claim 3 is characterized in that a first annular groove is formed in the outer wall of the shaft sealing sleeve, a shaft sleeve sealing ring is arranged in the annular groove, a second annular groove is formed in the inner wall of a sealing shaft sleeve base, a base sealing ring is arranged in the second annular groove, and the shaft sleeve sealing ring and the base sealing ring are O-shaped sealing rings, so that the sealing performance of the valve is effectively improved.
8. The control method for the closed-loop control high-precision nitrous oxide flow regulating valve comprises the following steps: Step S0, initializing, namely when the plug is completely attached to the transition section of the throat section, the corresponding flow area of the throat section is zero, and when the plug stroke is zero, the position of the dynamic position detection sheet is zero; Step S1, a controller collects pressure data of a pressure sensor and temperature data of a temperature sensor in real time, calculates inlet liquid density, calculates a target flow area corresponding to nitrous oxide target flow by using a liquid cavitation venturi flow formula according to the inlet liquid density, wherein the nitrous oxide target flow is a known quantity; Step S2, calculating to obtain a plug stroke according to the target flow area; s3, driving a high-precision laser displacement sensor to detect the real-time position of the dynamic position detection sheet by the controller; When the real-time position of the dynamic position detecting sheet is smaller than or equal to the plug stroke, the controller drives the needle bolt rod to move in the direction away from the throat section, wherein the moving distance is the difference between the real-time position of the dynamic position detecting sheet and the plug stroke; s4, when the plug moves, the controller drives the high-precision laser displacement sensor to detect the real-time position of the dynamic position detection sheet, and when the absolute value of the difference between the real-time position of the dynamic position detection sheet and the plug stroke is smaller than a displacement threshold value, the plug is considered to move to a target position corresponding to the target flow area; and (3) repeating the steps S1-S4 to realize the control of the closed-loop control high-precision nitrous oxide flow regulating valve.
9. The closed-loop control high-precision nitrous oxide flow rate regulating valve according to claim 8, wherein the step of calculating a target flow area corresponding to the target flow rate of nitrous oxide using a liquid cavitation venturi flow rate equation comprises: The flow formula of the liquid cavitation venturi is as follows: ; Wherein, the Is nitrous oxide target flow; Is the flow coefficient; Is the throat flow area; Collecting pressure data of the pressure sensor in real time; is the saturated vapor pressure of the liquid at local temperature conditions; calculating the throat flow area for the density of the inlet liquid Throat flow area The target flow area corresponding to the target flow rate of nitrous oxide is obtained.
10. The closed-loop control high-precision nitrous oxide flow control valve of claim 8, wherein the step of calculating the plug travel comprises: ; (1) Wherein, the Is the target flow area; The length of the plug is the length of the plug, For the stroke of the plug, For the transition length of the laryngeal section, Is the diameter of the inlet of the throat section, Is the diameter of the outlet of the throat section, Is the cone angle of the plug; Wherein, the ; The relation between the length of the plug and the diameter of the inlet of the throat section is as follows: ; Will be And Carrying in formula (1), obtaining a target flow area of: ; Transition length of throat section Then: ;(2) And (3) obtaining the plug stroke according to the formula (2).

Description

Closed-loop control high-precision nitrous oxide flow regulating valve and control method Technical Field The invention belongs to the technical field of aerospace propulsion, and particularly relates to a closed-loop control high-precision nitrous oxide flow regulating valve and a control method. Background Nitrous oxide is a green nontoxic propellant, has the advantages of high saturated vapor pressure, stable property, catalytic decomposition, low cost and the like, can be used for single-component and double-component propulsion, and has great application potential in the field of attitude and orbit control engines. In the actual use process, the saturated vapor pressure of nitrous oxide is obviously increased along with the increase of the ambient temperature, the liquid phase density is obviously reduced, as shown in fig. 1, the nitrous oxide supply flow is obviously reduced according to a liquid cavitation venturi tube flow formula, so that the stable operation of an engine is influenced, meanwhile, the fixed cavitation tube (flow control element) is required to be replaced for a plurality of times in the application to achieve the target flow, so that the experimental efficiency is reduced, the test cost is increased, the fixed cavitation tube cannot be replaced when the engine executes an aerospace task, the existing control valve cannot meet the application requirement, and therefore, the design of an adjustable cavitation tube with closed-loop adjustment is required, the nitrous oxide flow can be accurately adjusted at different temperatures to adapt to the aerospace tasks with different temperatures, and the ground test debugging efficiency is improved. Disclosure of Invention In order to overcome the defects of the prior art, meet the application requirements of flow control of a liquid rocket engine at different temperatures, improve the accuracy of nitrous oxide flow adjustment at different temperatures, and provide a closed-loop control high-precision nitrous oxide flow regulating valve and a control method. The technical scheme adopted by the invention for solving the technical problems is that the high-precision nitrous oxide flow regulating valve comprises a pintle rod 4, a valve body 5, a screw transmission part, a driving motor part and a controller 24; the driving motor part comprises a direct driving motor 20, a motor protection cover 11 and a motor bottom plate 12; The motor protection cover 11 comprises a screw rod protection section, a motor protection section and a protection base, wherein the top surface of the protection base is provided with the motor protection section and the screw rod protection section in sequence from bottom to top, the center of the protection base is provided with a base through hole, the center of the motor base plate 12 is provided with a base through hole, the motor protection section and the screw rod protection section are both in thin-wall barrel shape, the motor protection section, the screw rod protection section and the base through hole are coaxial with the base through hole, the motor protection section is internally nested with a direct driving motor 20, and the bottom surface of the protection base is fixedly provided with the motor base plate 12; The valve body 5 is a cylinder, a cavity is arranged between two end faces of the valve body 5 along the axial direction, a coaxial straight section, a throat section and an expansion section are sequentially arranged in the cavity, the throat section comprises a contraction section and a transition section which are sequentially arranged, the transition section is smoothly connected with the expansion section, and the contraction section is smoothly connected with the straight section; the valve comprises a valve body 5, a liquid outlet, a liquid inlet and a liquid outlet, wherein one end surface of the valve body 5 is provided with a liquid outlet which is a through hole; The valve comprises a valve body 5, a first counter bore, an end cover 8, a second counter bore, a first valve seat and a second valve seat, wherein the other end face of the valve body is provided with the first counter bore; The inner wall of the straight section is provided with a radial liquid inlet through hole, and a liquid inlet pipe is fixedly arranged in the liquid inlet through hole; The center of the end cover 8 is provided with an end cover hole which is a through hole, and the end cover hole and the first countersunk hole are coaxial with the cavity; the needle bolt rod comprises a plug and a needle bolt slide rod which are coaxially arranged, wherein the plug is conical, the bottom surface of the plug is fixedly connected with one end surface of the needle bolt slide rod, the other end surface of the needle bolt slide rod is fixedly connected with a screw rod transmission part, and the plug is coaxially nested in a cavity of the valve body; The pintle slide bar is nested in an end cover hole of the end cover; The s