CN113175532B

CN113175532B - Adjustable cavitation venturi

Info

Publication number: CN113175532B
Application number: CN202110469322.0A
Authority: CN
Inventors: 田辉; 张源俊; 谭广; 郭子豪; 王中烁
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2021-04-28
Filing date: 2021-04-28
Publication date: 2023-01-20
Anticipated expiration: 2041-04-28
Also published as: CN113175532A

Abstract

The invention provides an adjustable cavitation venturi, and relates to the technical field of flow regulation equipment. The adjustable cavitation venturi comprises a venturi adjusting mechanism, a differential variable-voltage displacement sensor, a driving mechanism and a controller; the venturi adjusting mechanism comprises a venturi body and a valve core, a fluid channel is formed in the venturi body along the axial direction, and the valve core is arranged in the fluid channel in a penetrating mode; the differential variable-voltage displacement sensor is arranged at one end of the venturi tube body, and the sensing end of the differential variable-voltage displacement sensor is abutted to the valve core; the driving mechanism is arranged at one end of the venturi body, which is far away from the differential variable-voltage displacement sensor, and is used for driving the valve plug to move along the axial direction; the controller is respectively connected with the differential variable-pressure displacement sensor and the driving mechanism to form closed-loop control, displacement information of the valve core is obtained in real time through the differential variable-pressure displacement sensor through the controller, the driving mechanism is controlled to drive the valve core to move to a target position according to the displacement information, the valve core displacement and positioning accuracy is high, the flow regulation is accurate, and the flow control effect is good.

Description

Adjustable cavitation venturi

Technical Field

The invention relates to the technical field of flow regulation equipment, in particular to an adjustable cavitation venturi.

Background

The general adjustable cavitation venturi adjusts the area of a flow cross section at the throat of the venturi through the movement of a valve rod, thereby achieving the purpose of adjusting the flow.

Because errors exist in connection and power transmission among all transmission mechanisms driving the valve rod to move, when power is transmitted to the valve rod, the errors are accumulated to the maximum, and therefore the adjustable cavitation venturi is poor in adjusting precision and poor in flow control effect.

Disclosure of Invention

In order to overcome the defects in the prior art, the application provides the adjustable cavitation venturi tube which is used for solving the problems that the adjustable cavitation venturi tube in the prior art is poor in adjusting precision and poor in flow control effect and the like.

In order to achieve the above object, the present application provides an adjustable cavitation venturi, which includes a venturi adjusting mechanism, a differential variable-voltage displacement sensor, a driving mechanism and a controller;

the venturi adjusting mechanism comprises a venturi body and a valve core, a fluid channel is formed in the venturi body along the axial direction, and the valve core is arranged in the fluid channel in a penetrating mode;

the differential variable-voltage displacement sensor is arranged at one end of the venturi tube body, and the sensing end of the differential variable-voltage displacement sensor is abutted to the valve core;

the driving mechanism is arranged at one end of the venturi tube body, which is far away from the differential variable-pressure displacement sensor, and is used for driving the valve core to move along the axial direction;

the controller is respectively connected with the differential variable-voltage displacement sensor and the driving mechanism, when the valve core is displaced, the controller acquires displacement information of the valve core in real time through the differential variable-voltage displacement sensor, and controls the driving mechanism to drive the valve core to move to a target position according to the displacement information.

In one possible embodiment, the differential transformer displacement sensor comprises a coil, a detection rod and an elastic element;

the detection rod penetrates through the coil and is matched with the coil in an electromagnetic induction mode, and one end, close to the valve core, of the detection rod is the induction end;

the elastic element is arranged at the other end of the detection rod and used for pushing the detection rod to approach the valve core, so that the sensing end is abutted against the valve core.

In a possible implementation manner, the adjustable cavitation venturi further includes a fixing frame and an insulating jacket, one end of the fixing frame is connected to the venturi body, the insulating jacket is disposed at the other end of the fixing frame, and the insulating jacket is used for mounting the differential transformer displacement sensor.

In a possible embodiment, the driving mechanism includes an electric cylinder body and a servo motor, the servo motor is connected to an input end of the electric cylinder body, an output end of the electric cylinder body is connected to the valve core, and the electric cylinder body is configured to convert a rotational motion output by the servo motor into a linear motion.

In a possible embodiment, the electric cylinder body has a folding structure.

In a possible embodiment, a throat portion is formed in the fluid passage to be engaged with the valve element, and the inner diameter of the throat portion increases gradually from the end of the venturi body to the end of the venturi body.

In a possible embodiment, the throat has a trapezoidal cross section along the axial direction, and the valve element is provided with a cone section corresponding to the throat, wherein an outer wall surface of the cone section is parallel to an inner wall surface of the throat.

In a possible embodiment, the adjustable cavitation venturi further comprises a limiting mechanism disposed between the driving mechanism and the venturi body, the limiting mechanism being configured to limit axial displacement of the spool.

In a possible implementation manner, the limiting mechanism comprises a limiting sleeve, the limiting sleeve is sleeved on the valve core, a limiting boss is arranged inside the limiting sleeve, and the limiting boss is in contact fit with a shaft shoulder on the valve core.

In a possible embodiment, the stop collar is circumferentially provided with a first connecting portion and a second connecting portion, which are distributed along the axial direction of the stop collar, wherein the first connecting portion is connected to the driving mechanism, and the second connecting portion is connected to the venturi body.

Compared with the prior art, the beneficial effects of the application are that:

the application provides an adjustable cavitation venturi tube, which comprises a venturi tube adjusting mechanism, a differential variable-voltage displacement sensor, a driving mechanism and a controller, wherein the venturi tube adjusting mechanism is connected with the controller; the venturi adjusting mechanism comprises a venturi body and a valve core, a fluid channel is formed in the venturi body along the axial direction, and the valve core is arranged in the fluid channel in a penetrating mode; the differential variable-voltage displacement sensor is arranged at one end of the venturi tube body, and the sensing end of the differential variable-voltage displacement sensor is abutted to the valve core; the driving mechanism is arranged at one end of the venturi body far away from the differential variable-voltage displacement sensor and is used for driving the valve plug to move axially; the controller is respectively connected with the differential variable-voltage displacement sensor and the driving mechanism, when the valve core is displaced, the controller acquires displacement information of the valve core in real time through the differential variable-voltage displacement sensor and controls the driving mechanism to drive the valve core to move to a target position according to the displacement information. The application provides an adjustable cavitation venturi tube, induction end and case butt through differential vary voltage displacement sensor to obtain the displacement information of case in real time, differential vary voltage displacement sensor converts the displacement volume of case to voltage signal and feeds back to the controller in real time, the controller drives the valve core removal of actuating mechanism again, closed-loop control has been realized, thereby the control of case displacement precision has been improved, make the flow control of adjustable cavitation venturi tube more accurate, control flow's effect is better.

In addition, the repeated positioning error of the differential variable-pressure displacement sensor can reach 1 mu m, and the positioning precision of the valve core is greatly improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic diagram illustrating a three-dimensional structure of an adjustable cavitation venturi according to an embodiment of the present application;

FIG. 2 shows a partial cross-sectional view of the adjustable cavitation venturi of FIG. 1;

FIG. 3 shows an enlarged partial schematic view at A in FIG. 2;

FIG. 4 shows an enlarged partial schematic view at B in FIG. 2;

FIG. 5 is a cross-sectional view of the adjustable cavitation venturi Chinese adjustment mechanism of FIG. 1;

fig. 6 shows a partially enlarged schematic view at C in fig. 5.

Description of the main element symbols:

100-venturi adjustment mechanism; 110-venturi body; 110 a-a fluid channel; 111-an outlet; 112-an inlet; 113-a constriction; 114-throat; 114 a-parallel segment; 115-an expansion section; 120-a valve cartridge; 121-a cone segment; 200-a displacement detection mechanism; 210-differential variable voltage displacement sensor; 211-a detection rod; 211 a-sensing end; 220-a fixing frame; 221-a first seal ring; 222-a second seal ring; 230-an insulating jacket; 300-a drive mechanism; 310-a servo motor; 320-an electric cylinder body; 321-an output shaft; 400-a limiting mechanism; 400 a-a stop collar; 410-limiting boss; 420-positioning the boss; 430-a second connection; 440-a first connection; 450-a third seal ring; 460-fourth seal ring.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the second feature or the first and second features may be indirectly contacting each other through intervening media. Also, a first feature "on," "above," and "over" a second feature may be directly on or obliquely above the second feature, or simply mean that the first feature is at a higher level than the second feature. A first feature "under," "beneath," and "under" a second feature may be directly under or obliquely under the second feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

Example one

Referring to fig. 1 to 6, the present embodiment provides an adjustable cavitation venturi, and in particular, relates to an adjustable cavitation venturi based on feedback of a differential variable-pressure displacement sensor 210, which is applied to the field of rocket engines and used for flow rate adjustment.

Referring to fig. 1 and fig. 2 in combination, the present embodiment provides an adjustable cavitation venturi, including: venturi adjustment mechanism 100, displacement detection mechanism 200, drive mechanism 300, and a controller (not shown). The driving mechanism 300 is disposed at one end of the venturi adjustment mechanism 100, and the driving mechanism 300 is used for driving the venturi adjustment mechanism 100 to adjust so as to control the flow rate of the venturi adjustment mechanism 100. The displacement detection mechanism 200 is disposed at the other end of the venturi adjustment mechanism 100, and the displacement detection mechanism 200 and the driving mechanism 300 are electrically connected to the controller, respectively. The displacement detection mechanism 200, the controller and the driving mechanism 300 form closed-loop control, thereby improving the flow rate regulation precision and the flow rate control effect of the venturi regulation mechanism 100.

Referring to fig. 2 and 5, in detail, the venturi adjustment mechanism 100 includes a venturi body 110 and a valve core 120, a fluid passage 110a is formed in the venturi body 110 along an axial direction, an inlet 112 and an outlet 111 are further disposed on the venturi body 110 and respectively communicate with the fluid passage 110a, the valve core 120 is disposed through the venturi body 110, and the valve core 120 is disposed in the fluid passage 110 a.

A throat portion 114 matched with the valve core 120 is formed in the fluid passage 110a in the venturi body 110, the throat portion 114 is located between the inlet 112 and the outlet 111, and the inner diameters of the two ends of the throat portion 114 respectively increase to the inlet 112 and the outlet 111. In other words, the throat portion 114 is the position with the smallest flow cross-sectional area in the fluid passage 110a, the section from the inlet 112 to the throat portion 114 in the fluid passage 110a is the contraction section 113, and the section from the throat portion 114 to the outlet 111 in the fluid passage 110a is the expansion section 115.

The valve core 120 is of a rod-shaped structure, the outer wall surface of the valve core 120 is matched with the inner wall surface of the throat 114, and the valve core 120 is driven to move along the axial direction, so that the area of a flow cross section formed by matching the valve core 120 and the throat 114 is changed, and the purpose of adjusting the flow is achieved.

Referring to fig. 2, fig. 4 and fig. 5, the driving mechanism 300 is disposed at an end of the venturi body 110 close to the inlet 112, and the driving mechanism 300 is used for driving the valve element 120 to move along the axial direction, so as to change the size of the flow cross section of the throat portion 114.

Specifically, the driving mechanism 300 includes an electric cylinder body 320 and a servo motor 310, the servo motor 310 is connected to an input end of the electric cylinder body 320, an output end of the electric cylinder body 320 is connected to the valve element 120, and the electric cylinder body 320 is configured to convert the rotational motion output by the servo motor 310 into a linear motion.

The output end of the electric cylinder body 320 includes an output shaft 321, the valve element 120 is connected to the output shaft 321, and the electric cylinder body 320 converts the rotary motion output by the servo motor 310 into a linear motion, so as to drive the valve element 120 to move axially. Alternatively, the valve core 120 and the output shaft 321 may be connected by a flange or a screw.

It can be understood that the principle of the electric cylinder body 320 is: the servo motor 310 outputs a rotation motion, the synchronous pulley transmission structure drives the ball screw to rotate, the ball screw and the screw nut are matched to output a linear motion, the output shaft 321 is arranged on the screw nut, and then the output shaft 321 also outputs a linear motion.

In some embodiments, as shown in fig. 2, the electric cylinder body 320 is a folding structure, and the servo motor 310 may be mounted at the abdomen of the electric cylinder body 320, so that the entire structure of the adjustable cavitation venturi is more compact, and the space in the length direction is saved.

In other embodiments, the electric cylinder body 320 may also be a linear structure, and the servo motor 310 may be installed at an end of the electric cylinder body 320 far away from the valve core 120, so as to be able to adapt to a position with a sufficient installation dimension in the length direction.

Referring to fig. 1, 2 and 3, the displacement detecting mechanism 200 includes a differential transformer displacement sensor 210, a fixing frame 220 and an insulating jacket 230. One end of the fixing frame 220 is connected to the venturi tube 110, the other end of the fixing frame 220 is provided with an insulating jacket 230, the insulating jacket 230 is used for mounting the differential variable-voltage displacement sensor 210, so that the differential variable-voltage displacement sensor 210 is located at one end of the venturi tube 110 close to the outflow port 111, and the valve core 120 penetrates through the fixing frame 220 and abuts against the sensing end 211a of the differential variable-voltage displacement sensor 210.

Further, in this embodiment, the fixing frame 220 forms a plug for the end of the venturi tube 110 to prevent the fluid in the fluid passage 110a from flowing out, and a first sealing ring 221 is disposed between the fixing frame 220 and the end of the venturi tube 110. The valve core 120 penetrates through the end of the venturi tube body 110 and the fixed frame 220 to abut against the sensing end 211a, and a second sealing ring 222 is arranged between the valve core 120 and the fixed frame 220. Wherein the first sealing ring 221 and the second sealing ring 222 realize the sealing of the fluid passage 110a in the venturi body 110, and prevent the fluid in the fluid passage 110a from leaking from the matching part of the end parts.

The differential transformer displacement sensor 210 includes a coil (not shown), a detecting rod 211 and an elastic element (not shown), wherein the detecting rod 211 is inserted into the coil and is in electromagnetic induction fit with the coil. That is, the detection rod 211 is suspended in the coil, there is no contact between the detection rod 211 and the coil, and the detection rod 211 does not receive resistance when moving in the axial direction in the coil, resulting in a long service life.

In addition, the differential variable-pressure displacement sensor 210 has the advantages of high resolution, firmness, durability and the like, and the flow control precision of the adjustable cavitation venturi tube is greatly improved.

One end of the detection rod 211 close to the valve core 120 is a sensing end 211a, wherein the sensing end 211a is used for abutting against the valve core 120. The elastic element is disposed at the other end of the detection lever 211, and is used to push the detection lever 211 toward the valve element 120, so that the sensing end 211a abuts against the valve element 120. Specifically, the elastic element is always in a compressed state after being assembled, so that the elastic element can provide a reaction force to the detection rod 211 to overcome the compression deformation, and under the pushing of the reaction force, the detection rod 211 tends to move toward the valve element 120, so that the sensing end 211a of the detection rod 211 abuts against the valve element 120. That is, when the valve core 120 moves to the sensing end 211a away from the sensing rod 211, the sensing rod 211 moves together with the valve core 120 under the driving of the elastic element until the sensing rod 211 returns to the zero position, and the driving mechanism 300 stops driving the valve core 120 to move.

In this embodiment, the sensing end 211a of the sensing rod 211 is in a ball-head shape, and the ball-head-shaped sensing end 211a is in point contact with the end surface of the valve element 120, so as to ensure the coaxiality of the sensing rod 211 and the valve element 120. When the valve core 120 moves towards the sensing end 211a close to the sensing rod 211, the valve core 120 applies a thrust to the sensing rod 211, and the thrust coincides with the axis of the sensing rod 211, so that the force applied to the sensing rod 211 is more balanced, and the sensing rod 211 moves more stably in the sensing coil.

The controller is electrically connected to the differential transformer displacement sensor 210 and the servo motor 310 in the driving mechanism 300, respectively. When the valve core 120 is displaced, the controller obtains displacement information of the valve core 120 in real time through the differential variable pressure displacement sensor 210, and controls the driving mechanism 300 to drive the valve core 120 to move to a target position according to the displacement information.

Further, in the differential transformer displacement sensor 210, since the sensing end 211a abuts against the valve element 120, the detection rod 211 moves synchronously, the detection rod 211 cooperates with the sensing coil to convert the displacement of the valve element 120 into a voltage signal, and the voltage signal is fed back to the controller in real time, and the controller controls the driving mechanism 300 to drive the valve element 120 to move to a target position according to the voltage signal, thereby realizing closed-loop control. Optionally, the controller is a PLC controller.

Specifically, the following illustrates the principles of closed loop control: the differential variable pressure displacement sensor 210 acquires the displacement of the spool 120 in real time through the detection lever 211, and converts the displacement into a voltage value of 0-10V. Then the analog quantity of 0-10V is converted into the digital quantity of 0-32000 through AD conversion simulation in the controller, and the position of the valve core 120 at the moment is obtained through numerical operation. If the current position of the spool 120 is known, the position of the target spool 120 is set based on the target flow rate, and the controller continuously sends pulses to the servo motor 310 based on the difference between the positions of the spools 120. The displacement of the valve core 120 is taken as an output target, the pulse is sent to the servo motor 310 through PID control (proportional integral derivative control), the servo motor 310 drives the valve core 120 to continuously move to a target position through the electric cylinder body 320 until the target position coincides with the current position of the valve core 120, the differential variable pressure displacement sensor 210 obtains the real-time position of the valve core 120 and the target position for subtraction, when the result is 0, the servo motor 310 stops sending the pulse, and at the moment, the valve core 120 reaches the target position.

If the position of the valve element 120 deviates from the target position due to external interference at a certain moment, the differential variable pressure displacement sensor 210 acquires the displacement of the valve element 120 in real time, and the real-time displacement is captured from the target position, so that the valve element 120 is controlled to move forward to the target position and then the valve element 120 returns to the target position. It should be understood that the above description is intended to be illustrative only and should not be taken as limiting the scope of the present application.

The adjustable cavitation venturi provided by the embodiment improves the control of the displacement precision of the valve core 120 through closed-loop control, so that the flow regulation of the adjustable cavitation venturi is more accurate, and the effect of controlling the flow is better.

In addition, the error of the repeated positioning (returning to the initial position from the current position) of the differential variable-pressure displacement sensor 210 can be as low as 1 μm, the minimum flow cross section of the throat 114 can be controlled and adjusted more accurately, and the positioning accuracy of the valve core 120 is greatly improved. And the differential transformer displacement sensor 210 has symmetry in construction, and the zero position can be recovered. Compared with a traditional limit switch, the differential voltage transformation displacement sensor 210 has an origin and is better in repeatability.

Example two

Referring to fig. 1, fig. 2 and fig. 4, the present embodiment provides an adjustable cavitation venturi applied to flow rate adjustment, which is an improvement based on the first embodiment, and compared with the first embodiment, the difference is that:

the adjustable cavitation venturi tube provided in this embodiment further includes a limiting mechanism 400, the limiting mechanism 400 is disposed between the driving mechanism 300 and the venturi tube 110, and the limiting mechanism 400 is configured to limit axial displacement of the valve element 120.

Specifically, the limiting mechanism 400 includes a limiting sleeve 400a, the limiting sleeve 400a is sleeved on the valve core 120, a limiting boss 410 is arranged inside the limiting sleeve 400a, and the limiting boss 410 is in contact fit with a shaft shoulder on the valve core 120. Alternatively, the stopper boss 410 is annular and is provided along the circumferential direction of the inner wall surface of the stopper sleeve 400 a.

In the present embodiment, the limit boss 410 is located at an end of the limit sleeve 400a far away from the driving mechanism 300, the valve core 120 has a stepped shaft structure, and the valve core 120 is formed with the shoulder at the abrupt change of the cross section, and the shoulder is close to an end of the valve core 120 connected with the output shaft 321. After the stop collar 400a is assembled with the valve core 120, the shoulder of the valve core 120 is received in the stop collar 400 a. When the valve element 120 moves towards the direction close to the sensing end 211a and touches the limit boss 410, the displacement of the valve element 120 stops, and due to the existence of the tension of the fluid itself, the fluid cannot pass through the flow cross section formed between the throat 114 of the venturi tube 110 and the valve element 120, that is, the throat 114 and the valve element 120 are matched to form a sealed state.

In some embodiments, a third sealing ring 450 is disposed between the spool 120 and the stop boss 410 of the stop collar 400a, and a fourth sealing ring 460 is disposed between the stop collar 400a and the venturi body 110. Wherein the third sealing ring 450 and the fourth sealing ring 460 both function as a seal to prevent fluid leakage from the fluid passage 110 a.

In some embodiments, the inside of the position-limiting sleeve 400a is provided with an annular positioning boss 420, and the positioning boss 420 is in contact fit with a shoulder of the output shaft 321 on the electric cylinder body 320. It should be noted that, when the positioning boss 420 and the limiting boss 410 are simultaneously disposed in the limiting sleeve 400a, the shoulder of the valve element 120 is moved backward by a predetermined distance along the axial direction of the valve element 120, and when the valve element 120 moves toward the sensing end 211a, the shoulder of the output shaft 321 is firstly in contact fit with the positioning boss 420, and the valve element 120 stops moving, at this time, because of the existence of the surface tension of the fluid, the flow cross section formed between the throat 114 of the venturi tube body 110 and the valve element 120 does not allow the fluid to pass through, and the throat 114 and the valve element 120 are matched to form a sealed state, so that the valve element 120 can be prevented from contacting the throat 114.

The stop collar 400a is circumferentially provided with a first connecting portion 440 and a second connecting portion 430, and the first connecting portion 440 and the second connecting portion 430 are distributed along the axial direction of the stop collar 400 a. Optionally, the first connection portion 440 and the second connection portion 430 are both flange connection portions. The first connection portion 440 is connected to the electric cylinder body 320 of the driving mechanism 300 by a bolt, and the second connection portion 430 is connected to the venturi body 110 by a bolt.

EXAMPLE III

Referring to fig. 2, fig. 5 and fig. 6, the present embodiment provides an adjustable cavitation venturi, which is applied to flow rate adjustment, and is an improvement made on the basis of the technology of the first embodiment or the second embodiment, and compared with the first embodiment or the second embodiment, the difference is that:

in the present embodiment, the throat portion 114 has a trapezoidal cross section in the axial direction, and may preferably be an isosceles trapezoid. That is, the throat 114 is shaped as a through cavity in the shape of a circular truncated cone. The valve core 120 is provided with a cone section 121 corresponding to the throat 114, wherein the outer wall surface of the cone section 121 is parallel to the inner wall surface of the throat 114, so that the minimum flow cross section of the throat 114 of the venturi body 110 is no longer a specific cross section. That is to say, after the outer wall surface of the cone section 121 is parallel to the inner wall surface of the throat 114, a series of flow cross sections with equal area are formed along the axial direction, so that the adjustable venturi can better generate and maintain a cavitation state at the throat 114, has a more stable flow coefficient, and better ensures the stability of a conveying system.

It can be understood that the fluid enters the fluid channel 110a from the inlet 112 and then sequentially passes through the contraction section 113, the parallel section 114a formed by the throat 114 and the valve core 120, and the expansion section 115 connected with the parallel section 114 a.

First, the fluid passes through the contraction section 113, and in the process, the flow cross-sectional area of the fluid passage 110a is gradually reduced, the hydrostatic pressure is gradually reduced, the dynamic pressure is gradually increased, and the fluid speed is increased.

The fluid then passes through the parallel segment 114a, in which the area of the flow cross-section is approximately constant. The fluid has the fastest speed in the parallel section 114a, the pressure is reduced to the lowest, when the static pressure is lower than the saturated vapor pressure of the working medium, the cavitation phenomenon can occur, so that gas-liquid two-phase mixed flow is formed, at the moment, because the static pressure of the parallel section 114a is approximately stabilized to be the saturated vapor pressure, under the condition of ensuring the cavitation of the throat 114, the downstream pressure fluctuation can not influence the upstream pressure and the flow of the adjustable cavitation venturi. The minimum flow area of the flattened section 114a can be changed by displacing the spool 120 by the servo motor 310, thereby controlling the flow rate.

Without the throat 114 having the parallel section 114a, the throttle surface is an annular area of the throat 114, which is simply a face. When the parallel section 114a is added, the cross section position comprises the whole approximate hollow round table surrounded by the throat part 114 and the cone section 121 of the valve core 120, the throttling part is enlarged into a body by a surface, which is equivalent to stretching the original round ring into a cylinder. Because the throttle area is greatly increased, the cavitation can be better ensured and the cavitation can be stabilized. Thereby obtaining a more stable flow coefficient.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without being mutually inconsistent.

Although embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. An adjustable cavitation venturi tube is characterized by comprising a venturi tube adjusting mechanism, a differential variable-voltage displacement sensor, a driving mechanism and a controller;

the differential variable pressure displacement sensor is arranged at one end of the venturi tube body, and the sensing end of the differential variable pressure displacement sensor is abutted with the valve core;

the controller is respectively connected with the differential variable-voltage displacement sensor and the driving mechanism, when the valve core is displaced, the controller acquires displacement information of the valve core in real time through the differential variable-voltage displacement sensor and controls the driving mechanism to drive the valve core to move to a target position according to the displacement information;

a throat part matched with the valve core is formed in the fluid channel, and the inner diameters of the throat part and the two ends of the venturi body are gradually increased;

the section of the throat part along the axial direction is trapezoidal, and the valve core is provided with a cone section corresponding to the position of the throat part, wherein the outer wall surface of the cone section is parallel to the inner wall surface of the throat part;

the adjustable cavitation venturi further comprises a limiting mechanism, the limiting mechanism is arranged between the driving mechanism and the venturi body, and the limiting mechanism is used for limiting the axial displacement of the valve core;

the limiting mechanism comprises a limiting sleeve, the limiting sleeve is sleeved on the valve core, a limiting boss is arranged inside the limiting sleeve, and the limiting boss is in contact fit with a shaft shoulder on the valve core, so that the throat part is matched with the valve core to form a sealing state.

2. The adjustable cavitation venturi according to claim 1, wherein the differential variable pressure displacement sensor comprises a coil, a sensing rod and an elastic element;

the detection rod penetrates through the coil and is matched with the coil in an electromagnetic induction mode, and one end, close to the valve element, of the detection rod is the induction end;

3. The adjustable cavitation venturi according to any one of claims 1 to 2, further comprising a fixing frame and an insulating jacket, wherein one end of the fixing frame is connected to the venturi body, and the other end of the fixing frame is provided with the insulating jacket, and the insulating jacket is used for mounting the differential transformer displacement sensor.

4. The adjustable cavitation venturi of claim 1, wherein the driving mechanism includes a motor cylinder and a servo motor, the servo motor is connected to an input end of the motor cylinder, an output end of the motor cylinder is connected to the valve core, and the motor cylinder is configured to convert a rotational motion output by the servo motor into a linear motion.

5. The adjustable cavitation venturi of claim 4, wherein the electrically powered cylinder body is of a folded configuration.

6. The adjustable cavitation venturi according to claim 1, wherein the stop collar is circumferentially provided with a first connection portion and a second connection portion, the first connection portion and the second connection portion being distributed along an axial direction of the stop collar, wherein the first connection portion is connected to the driving mechanism, and the second connection portion is connected to the venturi body.