1. A test device for measuring the length of a zero-speed envelope surface of a centrifugal separator is characterized in that: the device comprises a centrifugal separator, a water supply device, a discrete particle supply device and an eduction flow collecting device, wherein the discrete particle supply device comprises a discrete phase supply tank and a discrete particle injector, the eduction flow collecting device comprises a first drainage opening regulating valve, a second drainage opening regulating valve and a collecting box, a first eduction opening and a second eduction opening are respectively arranged at the upstream end and the downstream end of the centrifugal separator, the first eduction opening is connected with the first end of the collecting box through the first drainage opening regulating valve, the second eduction opening is connected with the second end of the collecting box through the second drainage opening regulating valve, the centrifugal separator is provided with a hole at the height of the tail end of the impeller, the hole is connected with a discrete particle injector, the discrete phase supply tank is connected with the discrete particle injector through a peristaltic pump, the water supply device is connected with the centrifugal separator through an inlet adjusting valve, and the centrifugal separator is connected with the water supply device through an outlet adjusting valve.

2. A test device for measuring the zero-speed envelope surface length of a centrifugal separator according to claim 1, wherein: the shell of the centrifugal separator is made of transparent organic glass, the cross section of the centrifugal separator is circular, and a rectangular water tank is sleeved outside the centrifugal separator.

3. A test device for measuring the zero-speed envelope surface length of a centrifugal separator according to claim 1, wherein: a pressure sensor is arranged on one side of an outlet of the centrifugal separator, and a differential pressure sensor is arranged between an inlet and an outlet of the centrifugal separator.

4. A test device for measuring the zero-speed envelope surface length of a centrifugal separator according to claim 1, wherein: adding a coloring agent into the discrete phase supply tank; the discrete particle injector is an elongated needle tube that extends vertically, obliquely or horizontally into the interior of the centrifugal separator and has an inner diameter that is interchangeable.

5. A test method for measuring the length of a zero-speed envelope surface of a centrifugal separator is characterized by comprising the following steps:

(1) arranging a test device for measuring the zero-speed envelope surface length of a centrifugal separator according to claim 1 and checking whether each device is in a normal working state;

(2) starting a data acquisition system and an image acquisition system, monitoring the measurement value of each instrument, adjusting the position of a high-speed camera outside a rectangular water tank, and preparing to acquire a discrete particle motion image;

(3) adjusting a discrete particle injector in the centrifugal separator according to test requirements, and determining the size, injection direction and injection position of discrete particles required by the test requirements;

(4) starting a water supply system, adjusting an inlet adjusting valve and an outlet adjusting valve, and determining the flow and pressure required to be reached during the test until the rotational flow field is stable;

(5) starting an extraction flow collecting device, recording the liquid level height in a collecting box within a period of time, and determining the flow dividing ratio and the flow guiding ratio during the test;

(6) starting the discrete particle supply device, adjusting the peristaltic pump, and determining the injection rate of the discrete particles required by the test until the injection rate of the discrete particles is stable;

(7) and (4) shooting the discrete particle track required by the test by the high-speed camera, analyzing the image to obtain the length of the zero-speed envelope surface, and finishing the test.

Background

Centrifugal separators are a common technology and have found wide application in industry. The centrifugal separator realizes two-phase separation under the action of centrifugal force by virtue of incompatibility and density difference among separation media, has the characteristics of large treatment capacity, high separation speed and compact structure, has small volume, and is more suitable for being used in the production process.

The zero-speed envelope surface is a surface formed by points with zero axial speed in a cyclone field of the centrifugal separator, and the shape of the zero-speed envelope surface is an important factor influencing the separation efficiency. The zero-speed envelope surface is an important flow field characteristic in the centrifugal separator, the length of the zero-speed envelope surface is closely related to the strength of a rotational flow field (Xusequentially, Rubia, new progress of flow field research of a hydrocyclone, foreign metal ore dressing, 1989 (11): 39-45), and the separation performance of the separator can be represented to a certain extent. Therefore, effective measurement of the length of the zero-velocity envelope helps to understand the separation mechanism of the separator, and can provide guidance for the design and selection of the separator.

According to the presently disclosed documents and patents, there are direct measurement methods and indirect measurement methods for measuring the flow field inside the separator. However, the current measurement methods have the following problems:

the direct measurement method is to directly arrange measuring points in a flow field for measuring information such as flow field pressure, flow velocity and the like, but the direct arrangement of the measuring points in the flow field often generates certain interference on actual flow, so that a measurement result has certain deviation.

The indirect measurement method usually utilizes the fluidity of some tracer particles in a flow field to obtain the information of the flow field according to the track characteristics of the particles, and the existing indirect measurement methods include a Particle Image Velocimetry (PIV) technology, a laser Doppler velocity measurement technology (LDA) technology and the like. However, the PIV and LDA methods have strong dependence on measuring instruments, complex system structure, large operation difficulty and high requirement on measuring conditions, and the methods are limited to be widely used.

Disclosure of Invention

The invention aims to provide a test device and a test method for measuring the length of the zero-speed envelope surface of a centrifugal separator, which can simply, quickly and effectively obtain the length of the zero-speed envelope surface, thereby providing sufficient test data and reliable technical support for performance evaluation and optimization and improvement of the separator.

The purpose of the invention is realized as follows:

the invention relates to a test device for measuring the length of a zero-speed envelope surface of a centrifugal separator, which is characterized in that: the device comprises a centrifugal separator, a water supply device, a discrete particle supply device and an eduction flow collecting device, wherein the discrete particle supply device comprises a discrete phase supply tank and a discrete particle injector, the eduction flow collecting device comprises a first drainage opening regulating valve, a second drainage opening regulating valve and a collecting box, a first eduction opening and a second eduction opening are respectively arranged at the upstream end and the downstream end of the centrifugal separator, the first eduction opening is connected with the first end of the collecting box through the first drainage opening regulating valve, the second eduction opening is connected with the second end of the collecting box through the second drainage opening regulating valve, the centrifugal separator is provided with a hole at the height of the tail end of the impeller, the hole is connected with a discrete particle injector, the discrete phase supply tank is connected with the discrete particle injector through a peristaltic pump, the water supply device is connected with the centrifugal separator through an inlet adjusting valve, and the centrifugal separator is connected with the water supply device through an outlet adjusting valve.

The test device for measuring the length of the zero-speed envelope surface of the centrifugal separator can further comprise:

1. the shell of the centrifugal separator is made of transparent organic glass, the cross section of the centrifugal separator is circular, and a rectangular water tank is sleeved outside the centrifugal separator.

2. A pressure sensor is arranged on one side of an outlet of the centrifugal separator, and a differential pressure sensor is arranged between an inlet and an outlet of the centrifugal separator.

3. Adding a coloring agent into the discrete phase supply tank; the discrete particle injector is an elongated needle tube that extends vertically, obliquely or horizontally into the interior of the centrifugal separator and has an inner diameter that is interchangeable.

The invention relates to a test method for measuring the length of a zero-speed envelope surface of a centrifugal separator, which is characterized by comprising the following steps of:

(1) arranging a test device for measuring the zero-speed envelope surface length of a centrifugal separator according to claim 1 and checking whether each device is in a normal working state;

(2) starting a data acquisition system and an image acquisition system, monitoring the measurement value of each instrument, adjusting the position of a high-speed camera outside a rectangular water tank, and preparing to acquire a discrete particle motion image;

(3) adjusting a discrete particle injector in the centrifugal separator according to test requirements, and determining the size, injection direction and injection position of discrete particles required by the test requirements;

(4) starting a water supply system, adjusting an inlet adjusting valve and an outlet adjusting valve, and determining the flow and pressure required to be reached during the test until the rotational flow field is stable;

(5) starting an extraction flow collecting device, recording the liquid level height in a collecting box within a period of time, and determining the flow dividing ratio and the flow guiding ratio during the test;

(6) starting the discrete particle supply device, adjusting the peristaltic pump, and determining the injection rate of the discrete particles required by the test until the injection rate of the discrete particles is stable;

(7) and (4) shooting the discrete particle track required by the test by the high-speed camera, analyzing the image to obtain the length of the zero-speed envelope surface, and finishing the test.

The invention has the advantages that: the test device can visually shoot the zero-speed envelope surface, and can meet the requirement of measuring the length of the zero-speed envelope surface under the conditions of different flow rates, flow splitting ratios, flow diversion ratios and the like. The device can realize that:

(1) and recording the motion track of the discrete particles in the swirling flow field, carrying out image analysis on the motion track, and measuring the length of the zero-speed envelope surface according to the positions of the characteristic discrete particles.

(2) The valves at the two drainage ports are adjusted to realize the regulation and control of different drainage ratios, the zero-speed envelope surface length under the conditions of different drainage ratios is obtained through measurement, and a reliable reference basis is provided for the operation regulation and control and the structure optimization of the separator.

(3) The valves at the two outlet ports and the valves at the outlet port of the test section are adjusted to realize the regulation and control of different flow division ratios, the lengths of the zero-speed envelope surfaces under the conditions of different flow division ratios are obtained through measurement, and reliable reference basis is provided for the operation regulation and control and the structure optimization of the separator.

(4) Through the regulation of the outlet valve of the test section, the pressure in the test section is changed, the length of the zero-speed envelope surface under different pressures is obtained through measurement, and a reliable reference basis is provided for the operation rule of the separator.

(5) Through the regulation of the inlet valve of the test section, different test section flows are realized, the zero-speed envelope surface length of the separator under different flows is further obtained, and a reliable reference basis is provided for the operation rule of the separator.

(6) By changing the structural parameters of the separator, the zero-speed envelope surface length of the separator under different flow rates is obtained, and a reliable reference basis is provided for the optimization design of the separator.

(7) Different discrete particle injectors are adopted, so that the size of discrete particles and the injection direction of the discrete particles are controlled, and different discrete particle tracks are realized.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of the test apparatus of the present invention;

FIG. 3 is an enlarged view of the discrete particle injection system of the present invention;

fig. 4 is a block diagram of a discrete particle injector in the discrete particle injection system of the present invention.

Detailed Description

The invention will now be described in more detail by way of example with reference to the accompanying drawings in which:

with reference to fig. 1-4, the test device for measuring the zero-speed envelope surface length of the centrifugal separator mainly comprises an inlet regulating valve 1, a centrifugal separator 2, an outlet regulating valve 3, a vortex shedding flowmeter 4, a thermocouple 5, a differential pressure sensor 6, a pressure sensor 7, a rectangular water tank 8, a discrete particle injector 9, a peristaltic pump 10, a discrete phase supply tank 11, a drainage port regulating valve 12, a collection box 13, a graduated scale 14 and a high-speed camera 15. According to the function division, mainly be water supply installation, experimental section, discrete particle feeding device and extraction flow collection system, water supply installation passes through pipeline connection entry governing valve 1 and gets into experimental section, flows back to water supply installation through export governing valve 3, and discrete particle feeding device connects gradually and disperses looks feed tank 11, peristaltic pump 10, discrete particle injector 9, and extraction flow collection system connects gradually drainage mouth governing valve 12, collection box 13. The test section comprises a centrifugal separator 2 and a rectangular water tank 8, wherein the centrifugal separator 2 is provided with two leading-out ports which are connected with two sides of a collection box 13 through pipelines, and the leading-out flow is adjusted through a drainage port adjusting valve 12. And the collecting box 13 is used for respectively collecting the fluid of the outlet at the upstream end and the outlet at the downstream end of the centrifugal separator 2, measuring the volume of the fluid led out from the two sides within a certain time through a graduated scale on the collecting box 13, and further calculating the led-out flow.

Discrete particles can be injected continuously at the level of the end of the impeller upstream of the centrifugal separator 2, opening the wall of the separation chamber cylinder and connected to a discrete particle injector 9.

The discrete particle injector 9 is an elongated needle structure that can be replaced to control the size of the discrete particles and the injection direction of the discrete particles.

The outlet of the centrifugal separator 2 is connected with an outlet regulating valve 3, and the regulating valve changes the outlet flow of the separator to realize different flow dividing ratios (the ratio of the outlet flow of the separator to the inlet flow of the separator).

The centrifugal separator 2 is provided with a drainage port at the upstream end and the downstream end, and is connected with a drainage port regulating valve 12, and the valve is regulated to control the extraction flow, thereby realizing different drainage ratios (the ratio of the extraction flow of the upstream end extraction port to the extraction flow of the downstream end extraction port).

The centrifugal separator 2 is made of transparent organic glass, visual research can be carried out, and a high-speed camera 15 is arranged on the side surface of the centrifugal separator 2 in parallel to track the motion track of discrete particles; the centrifugal separator 2 is a circular channel, and a rectangular water tank 8 is arranged outside the circular channel, so that visual errors caused by the circular channel are eliminated.

The inlet flow in the test is regulated by an inlet regulating valve and is measured by a turbine flowmeter; the injection rate of the discrete particles is adjusted by a peristaltic pump and is determined by a high-speed camera; the system pressure is regulated by an outlet regulating valve and measured by a pressure sensor.

The collection box is made of transparent materials, liquid level information is obtained through a graduated scale on the surface of the collection box, and then the volume of the fluid led out in unit time is used for calculating the led-out flow.

The fluid temperature at the inlet of the test section is measured by a thermocouple, the differential pressure of the test section is measured by a differential pressure sensor, and the pressure of the test section is measured by a pressure sensor.

Data such as temperature, flow, pressure, differential pressure and the like in the test are input into the PC through the NI data acquisition system, and test data are acquired, calculated and displayed by specially programmed software, so that the real-time monitoring of the test working condition is realized.

The measuring method using the test device for measuring the zero-speed envelope surface length comprises the following steps:

1) and arranging a test device for measuring the length of the zero-speed envelope surface of the centrifugal separator, and checking whether each device is in a normal working state.

2) And starting a data acquisition system and an image acquisition system, monitoring the measured values of all instruments, adjusting the position of the high-speed camera, and preparing to acquire the discrete particle motion image.

3) According to the test requirements, the discrete particle injector in the separation chamber barrel is adjusted to determine the size, injection direction and injection position of the discrete particles required by the test requirements.

4) And starting the water supply system, adjusting the inlet adjusting valve and the outlet adjusting valve, and determining the flow and pressure required to be reached during the test until the rotational flow field is stable.

5) And starting the extraction flow collecting device, recording the liquid level height in a collecting box connected with the extraction port within a certain time, and determining the flow dividing ratio and the flow guiding ratio during the test.

6) Starting the discrete particle feeding device, adjusting the peristaltic pump, and determining the injection rate of the discrete particles required by the test until the injection rate of the discrete particles is stable.

7) And (4) shooting the discrete particle track required by the test by the high-speed camera, analyzing the image to obtain the length of the zero-speed envelope surface, and finishing the test.

When the method is used for the length shooting of the zero-speed envelope surface of the separator, the technical scheme is as follows: before the test, a coloring agent is properly added into the discrete phase supply tank 11 according to the type and the color of the discrete phase so as to distinguish two working media, namely discrete particles and continuous phase; starting a water pump to enable water in a water tank to flow through a turbine flowmeter 4, adjust the flow through an inlet adjusting valve 1 and then enter a centrifugal separator 2; after passing through the inlet turbulator, water generates a swirling flow field and enters the centrifugal separator 2; after the swirling flow field is stabilized, the peristaltic pump 10 is started to enable the discrete phases in the discrete phase supply tank 11 to also enter the centrifugal separator 2 through the discrete particle injector 9, and then the purpose of tracing the track is achieved; the inlet water temperature is measured by a thermocouple 5 at the inlet of the centrifugal separator 2, the pressure drop of a test section is measured by a differential pressure sensor 6, and the pressure of the test section is measured by a pressure sensor 7; in addition to visual observation during the test, the oil drop track is recorded by the high-speed camera 15 to obtain the zero-speed envelope surface length, which is a basic basis for performance evaluation and optimization improvement of the separator. In the test process, the drainage port regulating valve 12 is used for respectively regulating the leading-out flow of the drainage port at the upstream end and the leading-out flow of the drainage port at the downstream end, the total volume of fluid discharged into the two sides of the collection box within a certain time is respectively recorded by a graduated scale on the collection water box, the leading-out flow is calculated, and the split flow ratio and the leading-out ratio are determined. In the test process, different inlet flow, flow distribution ratio and drainage ratio can be realized by adjusting the inlet adjusting valve 1, the outlet adjusting valve 3 and the drainage port adjusting valve 12, and the influence of the inlet flow, the flow distribution ratio and the drainage ratio on the length of the zero-speed envelope surface is measured. In the test process, different test section pressures can be realized by adjusting the outlet adjusting valve 3, and the influence of the test section pressures on the length of the zero-speed envelope surface is measured. In the test process, the injection rate of the discrete particles can be adjusted by controlling the peristaltic pump 10, and the influence of the factors on the length of the zero-speed envelope surface is further researched. The trajectory of the discrete particles obtained by shooting is shown in fig. 2, in which three typical discrete particles are marked, wherein the discrete particles in two green frames gradually move towards two ends, and the discrete particles in the other frame keep fluctuating at the axial height, which can be regarded as that the axial speed of the discrete particles in the frame is zero, so that the length of the zero-speed envelope surface can be obtained by measuring the axial positions of the discrete particles in the frame.

The controllable factors of the test device are further explained by combining the attached figures 3-4:

before the test is carried out, the injection direction of the discrete particles can be changed by replacing the discrete particle injector 9, such as horizontal injection swirl field, inclined injection swirl field and vertical injection swirl field, and the size of the discrete particles can be controlled by the caliber of the discrete particle injector 9. In addition, by controlling the distance of the discrete particle injector 9 inserted into the test section, the distance of the discrete particle injection position from the inner cylinder wall of the test section can be controlled, that is, the injection position can be close to the inner cylinder wall of the test section for injection or far away from the inner wall surface of the test section for injection. The discrete particle injector 9 has a high degree of flexibility and adjustability.