CN116296039A - Pressure measuring device and method for micro-rotating static gap - Google Patents
Pressure measuring device and method for micro-rotating static gap Download PDFInfo
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- G01L11/00—Measuring steady or quasi-steady pressure of a fluid or a fluent solid material by means not provided for in group G01L7/00 or G01L9/00
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- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
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Abstract
The invention discloses a pressure measuring device and a pressure measuring method for a micro-rotating static gap, and belongs to the technical field of measurement and testing. Aiming at the problem that the shear flow pressure of the tiny eccentric rotating static gap of the existing air dynamic pressure bearing is difficult to accurately measure, a pressure device and a method comprising an adjustable mobile station and a plurality of static pressure measuring channels are provided, wherein each static pressure measuring channel comprises: the static pressure stepped through hole, the capillary needle tube, the silica gel hose, the obliquely-installed U-shaped tube and the clamp type ultrasonic flow sensor are arranged on the wall of the static cylinder. The static pressure step through holes with gradually reduced apertures are arranged along the circumferential direction so as to reduce the interference of wall surface openings on shearing flow of a rotary static gap, the static pressure step through holes are utilized to conduct fluid pressure in a tiny eccentric gap to a U-shaped pipe filled with low-density solution, and the measured gap pressure value is converted according to the measured value of the clamp type flowmeter. The invention can rapidly and accurately measure the conventional pressure value in the micro gap and the pressure value of the low pressure area.
Description
Technical Field
The invention discloses a pressure measuring device and a pressure measuring method for a micro-rotating static gap, relates to a technology for directly measuring the pressure in the micro-gap by utilizing an experiment, and belongs to the technical field of measurement and test.
Background
With the rapid development of aerospace, precision machining and other technologies, a bearing structure in a rotary machine is gradually one of key technologies for restricting the development of the bearing structure. In order to break through the defects of the traditional bearing, the gas lubrication bearing takes gas as a working medium, and utilizes the characteristics of diffusivity, viscosity, compressibility, adsorptivity and the like of the gas, when the bearing rotates and works, the effects of static pressure, dynamic pressure and the like are generated, so that a layer of gas film capable of supporting load and reducing friction resistance is formed in a gap, and therefore, compared with the traditional contact bearing, the gas lubrication bearing has the characteristics of high rotating speed, low power consumption, no pollution, long service life and the like. As an important branch of the gas lubrication bearing, the dynamic pressure gas bearing uses air widely existing in the environment as a medium, so that the lubrication system required by other bearings is reduced, and meanwhile, the bearing capacity is provided according to the dynamic pressure effect generated by the wedge-shaped gap of the dynamic pressure gas bearing, so that the dynamic pressure gas bearing has the advantages of simple structure, flexible use, wide application range and the like.
The air dynamic pressure bearing takes air as a lubricant, the working principle is that a wedge-shaped gap is formed between surfaces of the bearing which relatively move during high-speed operation, and due to the viscosity of gas, the dynamic pressure effect causes gas film pressure to be generated in the gap when the gas enters the wedge-shaped gap, so that a bearing capacity is further formed to support a rotating shaft, the gap of the air dynamic pressure bearing flows, and the gap can be regarded as micro-rotating static gap flow under eccentric, and the gap size belongs to the micro-scale of mm to mu m. Compared with the rotational flow of the macro scale, the internal flow mechanism of the gap is obviously different from that of the macro scale, and a plurality of rules are not applicable to the micro gap at the macro scale. Therefore, there is a need for systematic and intensive investigation of the micro-gap rotational shear flow. The pressure distribution formed by the micro rotating static gap under the eccentricity has a region with a higher differential pressure value and a region with a lower differential pressure value, and a high-pressure region with a higher differential pressure value and a low-pressure region with a lower differential pressure value jointly form continuous pressure distribution in the micro rotating static gap.
The pressure of the macro-size static gap is usually detected through a static pressure hole, a pressure measurement Kong Qidao is processed on the wall surface, and the hole gap is directly connected with equipment such as an electronic pressure sensor or a pressure scanning valve to output a pressure value. For example, a rotatable bearing seat is designed by the dynamic air film pressure testing device and the testing method of the dynamic air film pressure testing device of the dynamic and static air bearing, the rotatable bearing seat is respectively provided with a testing hole at the air entraining holes corresponding to the two testing bearings, the testing holes are provided with air entraining pipes connected with pressure sensors, the pressure sensors read out the air film pressure at the corresponding positions during the measurement, and meanwhile, the measurement of different circumferential positions is realized by manually adjusting the angles of the rotatable bearing seat; a plurality of air passages with one ends communicated with an air film gap are formed in a rotor, the other ends of the air passages are connected with a pressure sensor, data measured by the pressure sensor are sent to a receiver through a wireless telemetry device, and the dynamic characteristics of the testing device are prevented from being influenced. The detection methods of the macro-size static gap pressure are all adopted by the electronic pressure sensor, the sampling frequency of the electronic pressure sensor needs to be adjusted to be matched with the rotating speed of the rotor when the pressure is sampled, and meanwhile, the problems of delay response and the like need to be considered; when the circumferential pressure distribution is measured, the positions of the measuring points need to be manually adjusted, and the use is complex.
The difficulties presented by high speed micro-rotor static gap pressure measurements present challenges to gas bearing design and use. The boundary wall surfaces of the rotary gaps are curved surfaces, and equipment such as an electronic pressure sensor or a pressure scanning valve is used in the rotor-stator gaps with high rotating speed and small gaps, so that the smoothness of the wall surfaces is easily damaged, the boundary of a flow field is damaged to a certain extent, the flow field is disturbed, and measurement errors are generated. Therefore, the pressure sensor, the piezoelectric plate and other measuring devices are difficult to install in the micro gap due to the conditions of small scale and curved wall surface, and the traditional pressure sensor and other measuring devices are difficult to effectively measure the micro static gap pressure. Meanwhile, for the pressure distribution formed by the small rotating static gap under the eccentricity, the real pressure measured value is difficult to reflect when the traditional measuring device is used for measuring the low pressure area, on one hand, the traditional equipment has large measuring range, low resolution and poor measuring precision; on the other hand, because the fluid medium in the micro gap is gas, the compressibility of the gas, environmental noise, system vibration and other factors lead the measurement value of the low pressure area to fluctuate greatly, and the measurement accuracy is reduced.
In summary, the present invention is directed to a pressure measuring device and method for a micro-gap to solve the problem of micro-gap pressure measurement.
Disclosure of Invention
The invention aims to solve the technical problems that the macroscopic size static-rotating gap pressure measurement technology is not suitable for the static-rotating gap pressure measurement, and the invention aims to accurately measure the conventional pressure value in the static-rotating gap under the premise of reducing disturbance of a convection field and accurately measure the smaller pressure value lower than 100Pa in the static-rotating gap under the premise of not being influenced by system vibration and environmental noise.
The invention adopts the following technical scheme for realizing the purposes of the invention:
the pressure measuring device with micro static gap comprises a micro static gap formed by the outer wall surface of a rotary cylinder and the inner wall surface of a static cylinder and at least two static pressure measuring channels, wherein the static cylinder is fixed on an adjustable moving platform, and the fixed eccentricity is arranged by transversely adjusting the adjustable moving platform. Each static pressure measurement channel includes: static pressure ladder through-hole, capillary needle tubing, silica gel hose, U-shaped pipe, clamp type ultrasonic flow sensor. The static pressure ladder through hole is processed on static cylinder, the capillary needle tube is inserted into the static pressure ladder through hole from outside of static cylinder, the static pressure ladder through hole is communicated with the U-shaped tube through the silica gel hose, the U-shaped tube is fixed on the vertical plate, one side tube wall of the U-shaped tube is perpendicular to the ground, the clamp type ultrasonic flow sensor is installed on the other side tube wall of the U-shaped tube, and the other side tube wall of the U-shaped tube is communicated with the atmosphere.
Further, the rotating cylinder forming the micro rotating static gap is driven by a high-speed motor, the static cylinder and the rotating cylinder form an annular gap, the static cylinder is ensured not to be bumped and ground under the micro gap, the whole static cylinder is arranged on the adjustable moving table, and the static cylinder and the rotating cylinder form fixed eccentricity through transverse displacement adjustment.
Further, in order to facilitate connection with an external gas circuit and reduce the influence of the opening on the fluid flow on the inner wall surface of the static cylinder, a three-stage stepped hole structure is processed on the wall of the static cylinder to form a static pressure stepped through hole, the aperture of the three-stage stepped hole structure is gradually reduced from the outer wall surface of the static cylinder to the inner wall surface, and the aperture from the outer wall surface to the inner wall surface is respectively 1.5-2mm, 1-1.2mm and 0.4-0.8mm.
Further, static pressure stepped through holes in each static pressure measuring channel are distributed on the axial center section of the static cylinder and surround the wall of the static cylinder for air entraining from the micro static rotating gap. The circumferential included angle of the adjacent static pressure stepped through holes at the side of the minimum gap height is 10-20 degrees, and the circumferential included angle of the adjacent static pressure stepped through holes at the side of the maximum gap height is 20-40 degrees.
Further, the static pressure stepped through holes in each static pressure measuring channel are staggered in the circumferential direction of the wall of the static cylinder, namely, adjacent static pressure stepped through holes are offset in the axial direction, so that the purpose of reducing interference to flow caused by continuous passing through a plurality of holes when fluid flows in the circumferential direction is achieved, and the problem that pressure changes greatly in the axial direction is considered. In order to meet the condition, the axial offset distance of the opening is not smaller than the minimum aperture of the static pressure stepped through hole, and is not too large, namely 0.5-1mm.
Further, a capillary needle tube is inserted into the hole with the largest diameter of the three-stage stepped hole, and a gap at the splicing part is smeared with sealant so as to fix the capillary needle tube and prevent gas in the air passage from leaking. One end of the silica gel hose is inserted into the capillary needle tube, and the other end of the silica gel hose is connected with the wall of one side of the U-shaped tube perpendicular to the ground, so that a pressure measuring air passage is formed. The inclination angle between the pipe walls at the two sides of the U-shaped pipe is 30 degrees to 60 degrees, the inner diameter of the pipe is 5mm to 8mm, and the U-shaped pipe is arranged on the vertical plate.
Furthermore, the solution in the U-shaped tube is a solution with smaller density, and the liquid column can rise to a higher height under the same pressure, so that the dividing value of each scale is reduced, and the reading accuracy is improved. And simultaneously, in order to ensure the safety, a nontoxic solution is selected as much as possible. In the invention, 75% -99% alcohol solution is selected as the solution in the U-shaped pipe, the static liquid level is level when no pressure exists, and the liquid level difference is formed in the U-shaped pipe when the pressure is generated.
Further, a clamp type ultrasonic flow sensor is arranged at a position below the center height of the pipe wall of one side of the U-shaped pipe communicated with the atmosphere, the clamp type ultrasonic flow sensor is connected with a controller, ultrasonic waves in opposite directions and in the same direction are sent to the liquid flowing direction by the sensor, the time difference of the ultrasonic waves in opposite directions and in the same direction is received by the measuring controller, so that the flow rate of the solution is measured, and then the total volume of the solution flowing through the sensor is obtained by integrating the flow rate of the solution in time. The flow measured by the clamp type ultrasonic flow sensor is integrated with time to obtain the volume V of the solution, and the formula is used:
and calculating the liquid level rising vertical height delta h, wherein V is the total volume of the solution flowing through the sensor, a is the cross-sectional area of the U-shaped pipe, and theta is the inclination angle of the U-shaped pipe. The measurement accuracy of the clamp type ultrasonic flow sensor is 0.003mL.
The invention adopts the technical scheme and has the following beneficial effects:
(1) The static pressure stepped holes adopt three-stage stepped through holes with gradually reduced apertures, so that the through holes on the outer wall of the static cylinder, which face the inner wall surface, are transited from larger diameters to smaller diameters, the boundary of the flow field is ensured not to be damaged by overlarge open pores, and the measurement accuracy is improved; the static pressure stepped through holes are staggered in the circumferential direction of the wall of the static cylinder, so that the interference of fluid flowing along the circumferential direction caused by continuous passing through a plurality of static pressure openings can be reduced, and the flow measurement accuracy is further improved.
(2) The invention adopts the U-shaped pipe with the inclination fixed and the clamp type ultrasonic flow sensor fixed on the U-shaped pipe as the flow detection device of each static pressure measuring channel, the pressure in the tiny eccentric rotating static gap is introduced into the U-shaped pipe filled with low-density solution through the static pressure stepped through hole, the capillary needle tube and the silica gel hose, the moving distance of liquid in the pipe under the same pressure can be properly amplified by the U-shaped pipe with the inclination fixed, the response precision of the sensor is improved, the inclination angle of the U-shaped pipe is set to 30 degrees to 60 degrees, the liquid level displacement distance can be theoretically amplified by 1.4 to 2 times, and meanwhile, the liquid in the pipe is ensured not to be subjected to larger viscous resistance due to excessive inclination.
(3) The clamp type ultrasonic flow sensor adopted by the invention can accurately measure the flow product of flowing solution, and convert the flow product into a pressure detection value with accurate height, short response time, high resolution and strong anti-interference capability, and can finish measurement without directly contacting liquid, thereby improving the measurement precision of the whole pressure distribution.
(4) The micro-rotating static clearance pressure measuring device provided by the invention has the advantages of simple structure, convenience in operation, lower cost, no need of additional complex pressure measuring equipment, capability of overcoming the defect that the pressure sensor, the pressure scanning valve and other equipment cannot accurately measure the pressure value in a lower range, capability of rapidly and accurately measuring the low pressure value in a range of 10-100Pa without being influenced by system vibration and environmental noise, time and cost saving, and high efficiency and economy.
Drawings
FIG. 1 is a schematic diagram of a pressure measuring device with a small static clearance.
Fig. 2 is an axial sectional view of a minute rotational static clearance.
Fig. 3 (a) is a schematic view of the distribution of the static pressure step through holes, and fig. 3 (b) is a structural view of the static pressure step through holes.
Fig. 4 is a structural view of an inclined U-shaped pipe.
Fig. 5 is a graph of test results of pressure distribution.
The reference numerals in the figures illustrate: 1. micro static gap, 2, adjustable moving table, 3, static pressure ladder through hole, 4, capillary needle tube, 5, silica gel hose, 6, U-shaped tube, 7, riser, 8, clamp type ultrasonic flow sensor.
Detailed Description
The following describes in detail how the pressure measurement of the minute rotating static gap is achieved by the technical scheme of the invention with reference to the accompanying drawings.
As shown in fig. 1, a pressure measuring device for a minute rotating static gap includes: the rotary cylinder, static cylinder, capillary needle tube 4, silica gel hose 5, U-shaped tube 6, clamp type ultrasonic flow sensor 8, static cylinder is fixed on adjustable mobile station 2, and static cylinder is arranged in the inner space of static cylinder, and static cylinder cover is located the rotatory outside of cylinder, and the rotatory small static clearance 1 that changes that cuts flow of rotating with static cylinder inner wall surface of rotating cylinder outer wall surface, and little static clearance 1 guarantees that rotatory cylinder and static cylinder do not take place to rub and bump, and the displacement of horizontal adjustment static cylinder of adjustable mobile station 2 makes static cylinder and rotatory cylinder produce fixed eccentric. The surface of the rotary cylinder is smooth, one end of the rotary cylinder is connected with the main shaft of the high-speed motor through a coupling, the other end of the rotary cylinder is suspended, and the rotating speed is 10000-30000rpm during working. The static cylinder is provided with a static pressure stepped through hole 3, the front end of a capillary needle tube 4 is inserted into the static pressure stepped through hole 3 from the outer side of the static cylinder, one end of a silica gel hose 5 is connected with the capillary needle tube 4, the other end of the silica gel hose 5 is connected with one side pipe wall of a U-shaped pipe 6 perpendicular to the ground, the U-shaped pipe 6 is fixed on a vertical plate 7, a clamp type ultrasonic flow sensor 8 is fixed on the other side pipe wall of the U-shaped pipe 6, and the other side pipe wall of the U-shaped pipe is communicated with the atmosphere.
As shown in fig. 1, a plurality of static pressure stepped through holes 3 are processed on the wall of the static cylinder, the plurality of static pressure stepped through holes 3 are scattered on the axial middle section of the static cylinder, and the plurality of static pressure stepped through holes 3 circumferentially surround one circle for measuring the pressure distribution formed by the dynamic pressure effect generated by the eccentricity in the micro static rotating gap. The aperture of the three-stage stepped through holes is gradually reduced along the direction from the outer wall to the inner wall of the static cylinder.
In order to reduce the number of holes through which fluid in the micro gap flows in the circumferential direction and reduce the flow interference, adjacent static pressure stepped through holes 3 are offset in the axial direction to form staggered arrangement. The axial sectional view of the micro-rotating static gap is shown in fig. 2, h represents the gap height, the value of the gap height h changes along with the circumferential angle of the micro-gap, the maximum gap is positioned at the circumferential angle theta=0, and the minimum gap is positioned at the circumferential angle theta=pi. The circumferential angle theta of the adjacent static pressure stepped through holes on the side of the minimum clearance height (namely, the clearance circumferential angle range is [ pi/2, 3 pi/2 ]) is 8-10 degrees, the circumferential angle theta of the adjacent static pressure stepped through holes 3 on the side of the maximum clearance height (namely, the clearance circumferential angle range is [3 pi/2, 5 pi/2 ]) is 18-20 degrees, and the adjacent static pressure stepped through holes have an axial offset distance of 0.5-1mm. The distribution of the static pressure step through holes is shown in fig. 3 (a), the vertical axis is expressed as a circumferential angle, and the circumferential angles of adjacent static pressure step through holes are respectively 10 °, 20 °, 30 ° and 40 °; the horizontal axis represents the axial position, and the axial interval of the adjacent static pressure ladder through holes is 1.5mm.
In order to reduce the influence of the opening on the fluid flow of the wall surface of the static cylinder, the inner wall surface of the static cylinder needs a very small aperture, so that the three-stage stepped through hole shown in the figure 3 (b) is adopted as the static pressure stepped through hole, the aperture of the three-stage stepped through hole gradually reduces from the outer wall surface to the inner wall surface, and the apertures are respectively 1.5-2mm, 1-1.2mm and 0.4-0.8mm. And a capillary needle tube 4 with the outer diameter of 1.4-2 mm is inserted into the maximum diameter end of the static pressure stepped through hole 3, the outer diameter of the capillary needle tube 4 is slightly smaller than the maximum diameter of the static pressure stepped through hole so as to be convenient for matching and insertion, and meanwhile, the plug-in port of the capillary needle tube is fixed by glue so as to prevent air leakage. The inner diameter of the silica gel hose 5 is about 1.4-1.8mm, one end of the silica gel hose is inserted on the capillary needle tube, and the other end of the silica gel hose is connected with the wall of one side of the U-shaped tube 6 perpendicular to the ground, and the air leakage prevention measure is taken.
A silica gel hose 5 is inserted on the capillary needle tube 4, and the other end of the silica gel hose 5 is connected with the wall of one side of the U-shaped tube 6 perpendicular to the ground, so that a pressure measuring air passage is formed. As shown in FIG. 4, the U-shaped pipe 6 is made of transparent resin, one side of the U-shaped pipe 6 is vertical to the ground, the other side of the U-shaped pipe is inclined and communicated with the atmosphere, an included angle between the inclined side and the vertical side is 45-60 degrees, the inner diameter of the pipe is 5-8mm, the length of the inclined pipe is 300mm, and 75% -99% ethanol solution is injected into the U-shaped pipe 6. In the test experiment of the invention, in order to measure the pressure of a plurality of measuring points, a plurality of static pressure step through holes 3 are processed on the static cylinder at different azimuth angles of the micro rotary static gap 1, and the static pressure step through holes are connected with corresponding U-shaped pipes in the same way, and the U-shaped pipes and the vertical plate 7 are jointly installed together so as to simultaneously display instantaneous pressure values at different gap positions. The clamp type ultrasonic flow sensor 8 is installed at a position below the middle height of the inclined side of the U-shaped pipe 6, the clamp type ultrasonic flow sensor 8 is connected with the controller, and the clamp type ultrasonic flow sensor 8 calculates the rising height of the liquid level of the inclined side of the U-shaped pipe by measuring the discharge amount, namely the volume of flowing solution. The clamp type ultrasonic flow sensor 8 has a clamping diameter of 6-10mm.
Each static pressure ladder through hole 3, capillary needle tube 4, silica gel hose 5, inclined U-shaped tube 6 and clamp type ultrasonic flow sensor 8 form a set of pressure measurement gas circuit. In order to measure the multipoint pressure value in the circumferential direction of the rotating static gap, a plurality of static pressure measuring channels are built at the same time.
The static pressure hole pressure measurement is based on the Bernoulli principle, and the Bernoulli equation follows the law of conservation of energy and mainly describes the relation between flow rate and height and pressure:
in the formula (2), p represents pressure, ρ represents density, gz represents gravitational potential energy,
representing kinetic energy. In Bernoulli principle, corresponding flow field pressures at different flow rates are also different, and the flow field pressure value can be obtained by arranging static pressure measuring channels in the vertical direction of the flow rate.
When the rotary cylinder is in a static state, the liquid levels at the two sides of the U-shaped pipe are level, and after the rotary cylinder starts to rotate, shearing flow is generated in the micro static gap due to the fluid viscosity effect, and pressure is generated in the micro static gap due to the dynamic pressure effect. And the static pressure measuring channel is arranged in the vertical direction of the flow velocity, so that different height differences delta h are generated in the liquid in the U-shaped pipe, and after the height differences are recorded, the pressure value is calculated through the formula p=ρgdelta h.
After the experimental device is built, the specific implementation process is as follows:
the relative positions of the static cylinder and the rotary cylinder are adjusted by the adjustable mobile station 2, and the adjustable mobile station 2 realizes transverse displacement through a micrometer, and the precision is 0.01mm. And calculating corresponding displacement according to the eccentricity ratio working condition to be measured, and enabling the static cylinder to move to a corresponding position through the adjustable movable table.
The liquid is injected from the inclined side of the U-shaped pipe 6 so that the liquid level is positioned at a datum line, wherein the datum line is a central line of the height of the inclined side or is positioned at the vertical half height position of the U-shaped pipe, and in the test experiment of the invention, the injected solution is ethanol solution with 99 percent concentration, and no pressure is generated in the pipeline in a no-flow state at the moment, so that the inclined side of the U-shaped pipe 6 has no liquid level change. The clamp type ultrasonic flow sensor 8 is powered on and performs initialization correction.
The motor is started to generate shearing flow in the micro static rotating gap, and meanwhile, pressure is generated in the micro static rotating gap due to dynamic pressure effect generated by eccentricity, so that the inclined side of the U-shaped pipe 6 can form a liquid level difference under the action of the pressure according to the static pressure principle. During the formation of the liquid level difference, the clamp type ultrasonic flow sensor 8 records the volume of the flowing liquid, calculates the liquid level from the volume of the liquid, and calculates the pressure value. In the test experiment of the invention, the included angle between the inclined side of the U-shaped pipe 6 and the side vertical to the ground is 60 degrees, so that the liquid displacement distance is amplified by 2 times under the condition that the liquid level rises at the same vertical height, the induction precision can be improved, the liquid level change time is prolonged, and the induction precision of the sensor is further improved. In the experiment, the measurement precision of the clamp type ultrasonic flow sensor is 0.003mL, the inner pipe diameter of the pressure pipe is 5mm, the solution is 99% ethanol solution, and the solution precision is calculated to be 1.74Pa after conversion. Therefore, when the pressure value is 100pa, the measurement accuracy error is less than 2%, and when the pressure value is 50pa, the measurement accuracy error is less than 4%.
In the invention, the pressures at all static pressure holes are measured to obtain pressure values at multiple points, so that a circumferential distribution curve of the pressure in the micro-rotating static gap is fitted. The circumferential pressure measurement results at 0.5mm average gap height and 0.5 eccentricity are shown in fig. 5, the horizontal axis represents the circumferential angle, the vertical axis represents the static pressure value, the circumferential pressure measurement results comprise high-pressure area parts with higher pressure values and low-pressure area parts with pressure values lower than 100pa, and about 70% of the data in the measurement can control the measurement error to be within 4%.
In conclusion, the invention can realize quick and accurate measurement of the pressure in the micro rotating static gap below 0.5mm, can accurately measure the conventional pressure value of the high-pressure area, and can accurately measure the pressure value of the low-pressure area below 100Pa without being influenced by system vibration and environmental noise, thereby obtaining the integral pressure distribution rule of the high-rotating speed micro rotating static gap in an eccentric state.
Claims (10)
1. A pressure measurement device for a minute rotary static gap, comprising: the static cylinder is fixed on the adjustable moving table, and the static cylinder is sleeved outside the rotary cylinder, the inner wall surface of the static cylinder and the outer wall surface of the rotary cylinder form a tiny static gap, and each static pressure measuring channel comprises: the static pressure ladder through hole, capillary needle tube, silica gel hose, U-shaped pipe, clamp type ultrasonic flow sensor of seting up on static drum section of thick bamboo wall, static pressure ladder through hole is inserted from static drum outer wall to the capillary needle tube, the U-shaped pipe is fixed on the riser with one side pipe wall perpendicular to ground's mode, and the opposite side pipe wall of U-shaped pipe is the acute angle with the contained angle of one side pipe wall perpendicular to ground, and one side pipe wall of U-shaped pipe perpendicular to ground passes through silica gel hose and capillary needle tube intercommunication, and clamp type ultrasonic flow sensor installs on the opposite side pipe wall of U-shaped pipe, the opposite side pipe wall of U-shaped pipe communicates with the atmosphere.
2. The pressure measuring device for micro static gap according to claim 1, wherein the static pressure stepped through holes in each static pressure measuring channel are circumferentially wound around the static cylinder at the cross section position, the circumferential included angle of the adjacent two static pressure stepped through holes at the side of the minimum gap height is 8 degrees to 10 degrees, the axial circumferential included angle of the adjacent two static pressure stepped through holes at the side of the maximum gap height is 18 degrees to 20 degrees, and the axial offset interval of the adjacent two static pressure stepped through holes is 0.5mm to 1mm.
3. The pressure measuring device of a micro-rotating static gap according to claim 2, wherein one side of the minimum gap height is a micro-rotating static gap with a circumferential angle of [ pi/2, 3 pi/2 ], and one side of the maximum gap height is a micro-rotating static gap with a circumferential angle of [3 pi/2, 5 pi/2 ].
4. A pressure measuring device for a micro-static gap according to claim 1, 2 or 3, wherein the static pressure stepped through hole is a three-step through hole with decreasing aperture, the through hole with the largest aperture is communicated with the outer wall surface of the static cylinder, and the through hole with the smallest aperture is communicated with the inner wall surface of the static cylinder.
5. The pressure measuring device for micro static gap according to claim 4, wherein the outer diameter of the capillary needle tube is smaller than the maximum aperture of the static pressure stepped through hole, the capillary needle tube is inserted into the through hole with the maximum aperture from the outer wall surface of the static cylinder, and the sealing glue is coated at the joint of the capillary needle tube and the maximum aperture.
6. The pressure measuring device for the micro-static gap according to claim 1, wherein an included angle between the other side pipe wall of the U-shaped pipe and the pipe wall of one side vertical to the ground is 45 degrees to 60 degrees, the inner diameter of the pipe wall of the two sides of the U-shaped pipe is 5mm to 8mm, and the pipe length of the pipe wall of the other side is 300mm.
7. The pressure measuring device for the micro static gap according to claim 1, wherein the clamp type ultrasonic flow sensor is arranged at a position below the center line of the height of the pipe wall at the other side of the U-shaped pipe.
8. A method for measuring pressure in a minute rotating static gap, characterized by being realized by the device of claim 1, comprising the following steps:
calculating the transverse displacement of the adjustable mobile station according to the eccentricity working condition to be measured, and operating the adjustable mobile station to adjust the relative position of the static cylinder and the rotary cylinder until the eccentricity working condition to be measured is met;
injecting 75% -99% ethanol solution into the pipe wall of one side of the U-shaped pipe which is communicated with the atmosphere in each static pressure measuring channel until the liquid level of the ethanol solution is positioned at the position of the central line of the height, electrifying each clamp type ultrasonic flow sensor and carrying out initialization correction;
and driving the rotary cylinder, reading the liquid flow recorded by each clamp type ultrasonic flow sensor, calculating the liquid level difference of the pipe wall of each U-shaped pipe on one side of the atmosphere according to the liquid flow recorded by each clamp type ultrasonic flow sensor, and calculating the pressure detection value of each static pressure measurement channel according to the liquid level difference of the pipe wall of each U-shaped pipe on one side of the atmosphere.
9. The method for measuring pressure in a small rotating static gap according to claim 8, wherein the rotating cylinder is driven by a high-speed motor.
10. The method for measuring pressure of a micro static gap according to claim 8, wherein the expression for calculating the liquid level difference of each U-shaped pipe communicated with the pipe wall at one side of the atmosphere according to the liquid flow recorded by each clamp type ultrasonic flow sensor is as follows:
Δh is the liquid level difference of the pipe wall at one side of the U-shaped pipe communicated with the atmosphere, V is the volume of flowing liquid calculated according to the integral of the liquid flow recorded by the clamp type ultrasonic flow sensor over time, a is the cross-sectional area of the pipe wall of the U-shaped pipe, and θ is the included angle between the pipe wall at the other side of the U-shaped pipe and the pipe wall at one side vertical to the ground.
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| CN202211088774.5A CN116296039A (en) | 2022-09-07 | 2022-09-07 | Pressure measuring device and method for micro-rotating static gap |
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| CN202211088774.5A CN116296039A (en) | 2022-09-07 | 2022-09-07 | Pressure measuring device and method for micro-rotating static gap |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116642438A (en) * | 2023-07-26 | 2023-08-25 | 天璟科技(深圳)有限公司 | Angle measuring device of high-precision turntable |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116642438A (en) * | 2023-07-26 | 2023-08-25 | 天璟科技(深圳)有限公司 | Angle measuring device of high-precision turntable |
| CN116642438B (en) * | 2023-07-26 | 2024-02-09 | 东莞市冠隆机械设备有限公司 | Angle measuring device of high-precision turntable |
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