Gas-liquid two-phase flow liquid phase flow measuring device and method, electronic equipment and program product

Abstract

The invention discloses a gas-liquid two-phase flow liquid phase flow measuring device. The liquid phase flow comprises liquid drop flow and liquid film flow. The measuring device comprises a gas-liquid two-phase flow pipeline, a conversion pipe section is arranged in the pipeline, and the conversion pipe section is used for converting a liquid film flowing into the pipe section from the gas-liquid two-phase flow pipeline into liquid drops. An inflow pipe section of the gas-liquid two-phase flow pipeline is connected with an inlet of the conversion pipe section through the before-conversion measuring pipe section, an outlet of the conversion pipe section is connected with an inlet of the after-conversion measuring pipe section, and an outlet of the after-conversion measuring pipe section is connected with an outflow pipe section of the gas-liquid two-phase flow pipeline. And the pipe section formed by combining the before-conversion measuring pipe section, the conversion pipe section and the after-conversion measuring pipe section is horizontally arranged, vertically arranged or obliquely arranged. The measuring pipe section before conversion is made of a transparent material and is provided with a first camera. And the converted measuring pipe section is made of a transparent material and is provided with a second camera.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluid measurement, and in particular relates to a gas-liquid two-phase flow liquid phase flow measurement device, method, electronic equipment, and program product. Background Art

[0002] Gas-liquid two-phase flow is a fluid mechanics phenomenon, which refers to the flow of two media, gas and liquid, in the same flow system. The flow pattern of gas-liquid two-phase flow is not only related to the flow conditions, but also closely related to factors such as the distribution characteristics of the phase interface, movement speed, and flow field geometry. In gas-liquid two-phase flow, the gas phase and liquid phase can appear in the form of continuous phases, such as gas-liquid film systems; they can also appear in discrete forms, such as bubble-liquid systems and droplet-gas systems. The characteristics and behavior of two-phase flow are of great significance for optimizing the design and operation of fluid systems.

[0003] The flow pattern of gas-liquid two-phase flow has different complex forms according to the different gas and liquid velocities and phase contents. For sparse (relatively low liquid content) gas-liquid two-phase flow, part of the liquid exists and flows in the form of discrete droplets, and part of the liquid flows along the wall in the form of a liquid film. In practical applications, sparse gas-liquid two-phase flow may involve specific industrial processes, such as steam flow in boilers, gas-liquid separation in chemical reactors, etc. In these cases, the sparseness of the gas-liquid two-phase flow has an important influence on the flow characteristics and heat and mass transfer efficiency.

[0004] At this time, in order to measure the liquid phase flow, there are mainly two traditional methods. One is to measure the single-phase liquid flow after gas-liquid separation, such as liquid extraction method, but it is often difficult to achieve complete separation, and it interferes with the flow and has poor real-time performance. The second is to measure the gas-liquid two-phase mixture without using a separation device. This is generally done by measuring the total gas-liquid two-phase flow through a throttling flowmeter such as a Venturi tube, and measuring the phase content through capacitance, conductivity, ultrasound, optics, nuclear magnetic resonance and other means to obtain the liquid phase flow; but the flow type and phase content have a very large and complex impact on the above flow and phase content measurements, resulting in large errors in the measurement results.

[0005] In gas-liquid two-phase flow, a liquid film may form on the pipe wall. By measuring the thickness and flow rate of the liquid film, the flow rate of the liquid phase can be calculated. In terms of liquid film flow measurement, the current methods include measuring the liquid film velocity and liquid film thickness separately, and then calculating the liquid film flow rate based on certain theoretical or empirical formulas. In this method, on the one hand, when the liquid film is thin or the liquid film fluctuates greatly in time and space, the measurement result of the liquid film thickness may have a large error; on the other hand, the liquid film velocity is unevenly distributed on the cross section, that is, the liquid film close to the wall has a slow flow velocity, and the general flow velocity away from the wall is faster; therefore, it is difficult to accurately measure the two parameters of liquid film thickness and liquid film velocity. In addition, the use of theoretical or empirical formulas to measure flow further leads to measurement errors. Summary of the invention

[0006] One of the embodiments of the present disclosure is a device for indirectly measuring the flow rate of a liquid film of a gas-liquid two-phase flow. The device comprises a gas-liquid two-phase flow pipeline in which a sudden expansion pipe section is provided. The sudden expansion pipe section is used to convert the liquid film flowing into the pipe section in the gas-liquid two-phase flow pipeline into liquid droplets.

[0007] The inflow pipe section of the gas-liquid two-phase flow pipeline is connected to the inlet of the sudden expansion pipe section through the pre-conversion measuring pipe section, the outlet of the sudden expansion pipe section is connected to the inlet of the post-conversion measuring pipe section, and the outlet of the post-conversion measuring pipe section is connected to the outflow pipe section of the gas-liquid two-phase flow pipeline.

[0008] The pre-conversion measuring tube section is made of a transparent material and is provided with a first camera.

[0009] The converted measuring pipe section is made of transparent material and is provided with a second camera.

[0010] The gas-liquid two-phase flow liquid film flow measurement method includes the following steps:

[0011] Respectively obtaining droplet images of the measuring pipe section before conversion and the measuring pipe section after conversion, calculating the particle size, velocity and concentration of the droplets according to the droplet images, and calculating and obtaining the droplet flow rates of the measuring pipe section before conversion and the measuring pipe section after conversion of the gas-liquid two-phase flow liquid phase pipeline;

[0012] Calculate the total liquid phase flow, which is equal to the droplet flow of the measuring pipe section after conversion.

[0013] The liquid film flow rate is calculated, which is equal to the difference between the droplet flow rate of the measuring pipe section after the conversion and the droplet flow rate of the measuring pipe section before the conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and other objects, features and advantages of the exemplary embodiments of the present invention will become readily understood by reading the detailed description below with reference to the accompanying drawings. In the accompanying drawings, several embodiments of the present invention are shown in an exemplary and non-limiting manner, in which:

[0015] Figure 1 A schematic diagram of a liquid phase flow rate measurement device for a gas-liquid two-phase flow according to one embodiment of the present invention.

[0016] Figure 2 A schematic diagram of a liquid phase flow rate measurement device for a gas-liquid two-phase flow according to one embodiment of the present invention.

[0017] Figure 3 A schematic diagram of a liquid phase flow rate measurement device for a gas-liquid two-phase flow according to one embodiment of the present invention.

[0018] Figure 4 A schematic diagram of a liquid phase flow rate measurement device for a gas-liquid two-phase flow according to one embodiment of the present invention.

[0019] 1——Measurement pipe section before conversion,

[0020] 21 - (with a contraction profile) the first conversion tube section, 22 - the second conversion tube section, 23 - the third conversion tube section, 24 - the fourth conversion tube section,

[0021] 3——Measurement pipe section after conversion,

[0022] 4——Restore the pipe section,

[0023] 5——Liquid film,

[0024] 6 - Droplets,

[0025] 7——Inflow pipe section,

[0026] 8——Outflow pipe section. DETAILED DESCRIPTION

[0027] In order to measure the flow of sparse gas-liquid two-phase flow, the present disclosure proposes a pipeline structure and a measurement method to achieve the measurement of the total liquid phase flow and the liquid film flow. The total liquid phase flow here includes the sum of the droplet flow and the liquid film flow. The concept of the present disclosure is to design a suddenly expanded pipeline measurement section to convert all the liquid phase flowing in the pipeline into droplet form; that is, before the conversion, discrete droplets and wall-attached liquid film exist at the same time, and after the conversion, only discrete droplets exist. The flow of the droplets before and after the conversion is measured, and the difference in the measurement results is the liquid film flow.

[0028] The flow measurement of droplets can be done by using the imaging method. By measuring the droplet size, velocity and concentration, the droplets flowing through the pipe cross section are counted to obtain the flow rate.

[0029] According to one or more embodiments, a liquid film flow measurement device and method thereof can be used to measure the liquid film flow of a sparse gas-liquid two-phase flow. Figure 1 As shown, the measuring device includes a pipeline structure, which includes:

[0030] The inflow pipe section 7 is used for the inflow of gas-liquid two-phase flow.

[0031] The pre-conversion measuring pipe section 1 is connected to the outlet end of the inflow pipe section 7 and is used to measure the droplet flow rate of the gas-liquid two-phase flow before entering the subsequent conversion section structure. This part can be designed to be transparent so as to be measured using optical imaging method.

[0032] The first conversion pipe section 21 with a contraction profile, which can also be called a contraction-sudden expansion section, is connected to the outlet end of the pre-conversion measurement pipe section 1, and the other end is connected to the post-conversion measurement pipe section 3 to form a sudden expansion. This is a key part in the pipeline structure. By designing a specific sudden expansion shape, the liquid film is broken into discrete droplets when passing through this section. In other words, in the flow direction of the measured gas-liquid two-phase flow, this design can ensure that the liquid film is completely converted into droplets, so that there is no longer a wall-adherent liquid film in the post-conversion measurement section.

[0033] The post-conversion measuring pipe section 3 is connected to the outlet end of the first conversion pipe section 21. While forming a sudden expansion shape, it is designed as a transparent section so that the flow rate of the gas-liquid two-phase flow completely in the form of discrete droplets after passing through the first conversion pipe section 21 can be measured using an optical imaging method.

[0034] The outflow pipe section 8 is connected to the output end of the converted measuring pipe section 3 and is used for leading out the gas-liquid two-phase flow.

[0035] like Figure 1 As shown, the outside of the rectangular dotted frame is the pipeline to be measured, and there is a gas-liquid two-phase flow in the form of liquid film and liquid droplets. The inside of the rectangular dotted frame is the liquid phase and liquid film flow measurement pipe section designed with a special structure in the present disclosure, including: a pre-conversion measurement pipe section 1, a first conversion pipe section 21 with a contraction profile, and a post-conversion measurement pipe section 3. When measuring droplets, an optical method, especially an optical imaging method, can be used for measurement. At this time, the pre-conversion measurement pipe section 1 and the post-conversion measurement pipe section 3 should be designed as transparent sections.

[0036] Among them, the cross-sectional area of ​​the tube wall of the first conversion tube section 21 is gradually contracted, and after reaching the input end of the post-conversion measuring tube section 3, the tube wall cross-section of the post-conversion measuring tube section 3 is suddenly expanded. Of course, there are other design options, for example, it can be suddenly expanded first and then contracted to the size of the pipeline to be measured, or the contraction and sudden expansion sections can be designed as a whole. The shape of the contraction tube section can have different profile curve designs, including linear contraction, cubic curves and quintic curves, as well as Witoszinski curves. For example, the Witoszinski curve facilitates the rapid conversion of the liquid film into droplets and ensures a relatively uniform flow rate at the outlet of the conversion section. The Witoszinski profile is a profile used to design the wall surface of the contraction tube. The profile ensures that the gas-liquid two-phase flow is smoothly accelerated in the pipeline and flows out evenly from the outlet. The contraction section design using the Witoszinski profile can make the flow field low in turbulence, help reduce the pressure loss of the gas-liquid two-phase flow during the contraction process, and improve the total pressure recovery coefficient of the gas-liquid two-phase flow.

[0037] like Figure 1 As shown, the contraction profile of the first conversion tube section 21 is a straight line. Figure 2 The contraction profile of the second conversion tube section 22 is curved. Figure 2 Other structures expressed in Figure 1 same.

[0038] And in Figure 3 In the measuring device shown, the third conversion tube section 23 is composed of two parts, one part is a linear contraction profile part, and the other part is a sudden expansion profile part. That is, the third conversion tube section 23 adopts an overall structural design of first contraction and then sudden expansion.

[0039] The embodiment of the present disclosure converts the liquid film into discrete droplets through a special pipeline structure design, thereby realizing accurate measurement of the liquid film flow rate. The liquid phase metering method of the gas-liquid two-phase flow of the embodiment of the present disclosure includes:

[0040] S101, measuring the droplet flow rate, using an image method to measure the droplet flow rate in the measurement section before conversion and the measurement section after conversion. By capturing the image of the droplet, the particle size, velocity and concentration of the droplet are calculated, and the number of droplets flowing through the pipe section is counted to calculate the droplet flow rate.

[0041] S102, calculating the liquid film flow rate, by comparing the droplet flow rates of the measurement section before conversion and the measurement section after conversion, to obtain the liquid film flow rate. Specifically, the liquid film flow rate is equal to the difference between the droplet flow rate of the measurement section after conversion and the droplet flow rate of the measurement section before conversion.

[0042] Therefore, in the embodiment of the present disclosure, the liquid film is completely converted into discrete droplets through the pipeline structure, the total liquid phase flow is calculated by measuring the droplet flow after conversion, and the flow of the liquid film is calculated by measuring the droplet flow before and after conversion, so as to more accurately measure the liquid film flow and avoid the problem that the thickness and speed of the liquid film are difficult to measure directly in the prior method. This method is particularly suitable for sparse gas-liquid two-phase flow, that is, the situation where the liquid content is relatively low, because in this case, the presence of the liquid film has a more significant impact on the flow measurement. By adopting the optical imaging measurement method, a non-invasive measurement method is provided, which can monitor the dynamic changes of the droplets in real time, and there is no interference with the flow state in the pipeline. The embodiment of the present disclosure can be widely used in gas-liquid two-phase flow measurement in the chemical, petroleum, energy and other industries, especially in situations where the total liquid phase flow and liquid film flow need to be accurately controlled and monitored.

[0043] In addition, in the embodiments of the present disclosure, the pipeline structure can be a horizontal pipe or a vertical pipe, and whether the pipeline is set horizontally or vertically does not affect the realization of the purpose of the embodiments of the present disclosure.

[0044] According to one or more embodiments, a method for measuring the liquid phase flow rate of a sparse gas-liquid two-phase flow. Figure 4 As shown, the measuring device includes a pipeline structure, which includes:

[0045] The inflow pipe section 7 is used for the inflow of gas-liquid two-phase flow.

[0046] The pre-conversion measuring pipe section 1 is connected to the outlet end of the inflow pipe section 7 and is used to measure the droplet flow rate of the gas-liquid two-phase flow before entering the subsequent conversion pipe section.

[0047] The outlet end of the pre-conversion measuring pipe section 1 is connected to the fourth conversion pipe section 24, the post-conversion measuring pipe section 3, and the recovery pipe section 4 in sequence. The purpose of the recovery pipe section 4 is to restore the original size of the pipeline to be measured so as to facilitate connection with the pipeline. The recovery pipe section 4 here adopts a contraction profile. Of course, the recovery pipe section 4 here is optional and may not be set. The fourth conversion pipe section 24 may adopt a sudden expansion profile.

[0048] The outflow pipe section 8 is connected to the output end of the recovery pipe section 4 and is used for leading out the gas-liquid two-phase flow.

[0049] Therefore, in the embodiment of the present disclosure, there is also a measurement structure that does not have Figure 4 That is, the outlet end of the pre-conversion measuring pipe section 1 is connected to the fourth conversion pipe section 24 and the post-conversion measuring pipe section 3 in sequence, and then directly connected to the outflow pipe section 8.

[0050] According to one or more embodiments, a method for measuring the liquid phase flow of a gas-liquid two-phase flow includes, in a measuring pipeline of the gas-liquid two-phase flow, a pre-conversion measuring pipe section 1, a first conversion pipe section 21, and a post-conversion measuring pipe section 3. There are no droplets in the liquid two-phase flow in the measuring pipe section 1 before conversion, and only the flow of a liquid film.

[0051] The method includes,

[0052] S201, measuring the droplet flow rate, in the post-conversion measurement section, using an image method to measure the droplet flow rate. By capturing the image of the droplet, the particle size, velocity and concentration of the droplet are calculated, and the number of droplets flowing through the pipe section is counted to calculate the droplet flow rate.

[0053] S202, calculating the liquid film flow rate, which is equal to the droplet flow rate of the measurement section after conversion.

[0054] Here, instead of using the imaging method to measure the droplets, other methods suitable for measuring the droplet flow rate such as optical (extinction, pulsation method), acoustic, electrical, etc. can be used.

[0055] In summary, the beneficial effect of the present disclosure is that, in order to solve the problem that the liquid phase flow rate of the existing gas-liquid two-phase flow is difficult to accurately measure, a method is adopted to avoid directly measuring the thickness and velocity of the liquid film and convert the measurement into the measurement of the droplets. Not only the online real-time liquid film flow rate measurement is realized, but also the total liquid phase flow rate measurement is realized. Since the method disclosed in the present disclosure is a non-contact measurement method, it has a simple structure and a small pressure loss in the measuring section.

[0056] It should be understood that in the embodiments of the present invention, the term "and / or" is only a description of the association relationship of the associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0057] In the several embodiments provided in the present application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0058] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0059] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A gas-liquid two-phase flow liquid phase flow measurement device, wherein the liquid phase flow includes droplet flow and liquid film flow, characterized in that: The measuring device comprises a gas-liquid two-phase flow pipeline, in which a conversion pipe section is arranged, and the conversion pipe section is used to convert the liquid film flowing into the pipe section in the gas-liquid two-phase flow pipeline into liquid droplets.

2. The measuring device according to claim 1, characterized in that The inflow pipe section of the gas-liquid two-phase flow pipeline is connected to the inlet of the conversion pipe section through the pre-conversion measurement pipe section, the outlet of the conversion pipe section is connected to the inlet of the post-conversion measurement pipe section, and the outlet of the post-conversion measurement pipe section is connected to the outflow pipe section of the gas-liquid two-phase flow pipeline. Preferably, the pipe segment formed by the combination of the pre-conversion measuring pipe segment, the conversion pipe segment and the post-conversion measuring pipe segment is arranged horizontally, vertically or inclined.

3. The measuring device according to claim 2, characterized in that The pre-conversion measuring tube section is made of a transparent material and is provided with a first camera.

4. The measuring device according to claim 2, characterized in that The converted measuring pipe section is made of transparent material and is provided with a second camera.

5. The measuring device according to claim 1, characterized in that The contraction profile pipe section adopts a straight contraction profile, a cubic curve, a quintic curve, or a Vidasinski profile.

6. A method for measuring the liquid phase flow rate of a gas-liquid two-phase flow, based on the measuring device as claimed in claims 3 and 4, characterized in that: The following steps are involved: Respectively obtaining droplet images of the measuring pipe section before conversion and the measuring pipe section after conversion, calculating the particle size, velocity and concentration of the droplets according to the droplet images, and calculating and obtaining the droplet flow rates of the measuring pipe section before conversion and the measuring pipe section after conversion of the gas-liquid two-phase flow liquid phase pipeline; The liquid film flow rate is calculated, which is equal to the difference between the droplet flow rate of the measuring pipe section after the conversion and the droplet flow rate of the measuring pipe section before the conversion.

7. A method for measuring the liquid phase flow rate of a gas-liquid two-phase flow, based on the measuring device as claimed in claim 4, characterized in that: The following steps are involved: Acquire a droplet image of the measured pipe section after the conversion, calculate the particle size, velocity and concentration of the droplet according to the droplet image, and calculate the droplet flow rate of the measured pipe section of the gas-liquid two-phase flow liquid phase pipeline after the conversion; Calculate the liquid phase flow rate, which is equal to the droplet flow rate of the measuring pipe section after conversion.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: The processor runs the computer program to implement the method according to any one of claims 6 or 7.

9. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 6 to 7 is implemented.

10. A computer program product, comprising a computer program, characterized in that The computer program is executed by a processor to implement the method according to any one of claims 6 or 7.

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