CN203405417U - Image method measurement device for gas-liquid two-phase flow in pipeline - Google Patents

Abstract

The utility model discloses a device for measuring gas-liquid two-phase flow in a pipeline through an image method. The device is characterized in that a light source is utilized to light liquid drops to be measured through a transparent pipeline or a window, a laser light source is utilized to light the liquid level of a liquid film, and a telecentric lens and a CCD or CMOS image sensor are utilized to image the liquid drops or the liquid film in a region to be measured; the defocus blurring radius of a single liquid drop image and the size of an admissible confusion circle of a measuring system are compared to remove imaging of the liquid drops outside the field depth range of the lens; images of the moving liquid drops within the field depth range are processed to extract the particle size, the speed and the direction, and through statistics on a large number of liquid drops, particle size distribution, speed distribution and average volume concentration and average volume flow within a statistical time period of the liquid drops in the region to be measured are acquired; the thickness of the liquid film is determined according to the distance from the liquid level in an liquid film image to a pipe wall. The device has the advantages that multiple parameters of the gas-liquid two-phase flow in the pipeline can be simultaneously measured only by one system, the measuring system is simplified, and measuring cost is reduced.

Description

The image method measurement mechanism of biphase gas and liquid flow in pipeline

Technical field

The utility model relates to gas-liquid two-phase flow measuring apparatus in a kind of pipeline, be particularly related to and a kind ofly based on single frames list exposure image method, obtain in pipeline in biphase gas and liquid flow drop grain diameter size and distribute, the device of the information such as liquid drop speed and distribution, concentration of liquid drops and flow and thickness of liquid film.

Background technology

In pipe, biphase gas and liquid flow is a kind of very important liquid form in two-phase flow, extensively being present in the parameter detecting such as ，Qi cross section, field phase content such as the energy, power, oil gas, chemical industry all has very important significance for understanding two-phase flow rule, resource rational exploitation and utilization, safety in production and industrial process control.Existing measuring method comprises separating and measuring method, impedance method, light extinction method etc., or flow causes certain interference, or is subject to the impact of fluidised form, temperature, impurity larger, and can not obtain many kinds of parameters simultaneously.In recent years along with the development of digital camera and computer technology, adopting digital camera to take diphasic flow process is progressively developed to obtain the two-phase flow image measurement instrument of relevant information, but if High Speed Photography is conventionally only for the judgement of flow pattern, still can not obtain and comprise drop grain diameter size and distribute, the parameters such as liquid drop speed and distribution, concentration of liquid drops and flow and thickness of liquid film are in interior details.

Summary of the invention

The purpose of this utility model is will develop a kind ofly based on single frames list exposure image method, obtain in pipeline in biphase gas and liquid flow drop grain diameter size and distribute, the device and method of the information such as liquid drop speed and distribution, concentration of liquid drops and flow and thickness of liquid film, has advantages of that device is simple, easy and simple to handle, with low cost.

Ultimate principle of the present utility model: for the measurement of drop parameter, adopt single frames list exposure method, the proper extension camera exposure time, at this moment, endocorpuscular athletic meeting forms fuzzy movement locus image, because drop can be approximately spheric grain, the minor axis of this movement locus image and major axis have comprised respectively particle diameter and the velocity information of particle; The method has avoided adopting expensive high energy pulse laser instrument " to freeze " particle to obtain grain diameter, be equipped with high-speed camera with employing double-pulse laser device and obtain particle speed by cross correlation process, only with ordinary light source and industrial camera, can meet the requirement of simultaneously measuring particle diameter and velocity information.To adding up by particle diameter and the corresponding speed of pipeline xsect drop, can obtain mean concentration and the flow of drop in this timing statistics section.Measurement for thickness of liquid film on pipeline wall, adopt the laser beam of laser instrument transmitting from transparent pipe external exposure liquid film, laser can produce refraction on liquid film surface, forms the liquid film interface of high brightness, by liquid film imaging on industrial camera, can determine the position of liquid level, i.e. thickness of liquid film.

Inventive principle based on above-mentioned, the technical solution of the utility model is: the image method measurement mechanism of biphase gas and liquid flow in a kind of pipeline, be characterized in, device comprises lighting source, LASER Light Source, telecentric lens, imageing sensor and computing machine, described lighting source is by the particle to be measured in transparent pipeline or form illumination duct, described LASER Light Source is by transparent pipeline or form illumination liquid film liquid level, described telecentric lens is connected with described imageing sensor, and the particle that described imageing sensor shooting obtains and liquid film picture are by described computer acquisition.

Described lighting source adopts halogen light source, xenon source or semiconductor light sources; Described LASER Light Source adopts visible laser; Described mental state head far away is selected zoom or non-zoom telecentric lens; Described imageing sensor is selected CCD or cmos device.

The beneficial effects of the utility model are the image method measuring systems with a kind of directly perceived, simple, non-intrusion type, can obtain drop grain diameter size and distribution in biphase gas and liquid flow in pipeline simultaneously, liquid drop speed and distribution, can also obtain the information such as concentration of liquid drops and flow and thickness of liquid film, and whole process does not adopt complicated cross correlation algorithm or inverse model, improved the reliability of measuring system.

Accompanying drawing explanation

Fig. 1 is the utility model embodiment 1 schematic diagram;

Fig. 2 is the utility model embodiment 2 schematic diagram.

Embodiment

A kind of embodiment 1 based on gas-liquid two-phase flow measuring apparatus in single frames list exposure image method pipe, as shown in Figure 1, be characterized in, device comprises lighting source 1, LASER Light Source 3, telecentric lens 4, imageing sensor 5 and computing machine 6, described lighting source 1 is by transparent pipeline 2 or form 7 illumination particle to be measured, described LASER Light Source 3 is by liquid film liquid level on transparent pipeline 2 or form 7 illumination duct walls, described telecentric lens 4 is connected with described imageing sensor 5, and described imageing sensor 5 is taken the particle and the liquid film picture that obtain and gathered by described computing machine 6.

In a kind of pipe based on above-mentioned single frames list exposure image method, the step of gas-liquid two-phase flow measuring method is:

1. before measuring, first measurement mechanism is demarcated; With transparent calibrated thing as micro-scale or other known physical dimension aobject as measuring object, be placed on the operating distance place of telecentric lens 4, the image that adopts imageing sensor 5 to gather these demarcation objects is also inputted computing machine 6, calculates corresponding physical dimension in this demarcation object imaging anumber of pixels n ₁, pass through formula p= a/n ₁, obtain the physical size of measuring system experiment condition hypograph sensor 5 unit picture element representatives p;

2. connect telecentric lens 4 and imageing sensor 5 and computing machine 6, the intraluminal fluid of take drips as reference object, the midsection in captured region is placed in to the operating distance place of telecentric lens 4, makes drop imaging on imageing sensor 5 in captured region;

3. adopt lighting source 1 with transmission or the reflection mode flow field to be measured of throwing light on, adjustable illuminating light source 1 makes light illuminate region to be measured from different azimuth with distance and the angle in region to be measured, can change voltage swing to regulate the intensity of light source, makes bias light even;

4. regulate the time shutter of imageing sensor 5, the situation of the coincidence of liquid drop movement track and adhesion in 5 imagings of minimizing imageing sensor, and drop to be measured is taken, by the image input computing machine 6 obtaining;

5. adopt liquid film to be measured on LASER Light Source 3 illumination duct 2 walls, regulate distance and the angle of LASER Light Source 3 and telecentric lens 4, make liquid level imaging clearly on imageing sensor 5, take and the image obtaining is inputted to computing machine 6;

6. on computing machine 6, to obtained drop image, first adopt the median filtering algorithm in image processing algorithm to carry out denoising, secondly pass through watershed segmentation algorithm to liquid drop movement Image Segmentation Using, then for single drop image, the restoration of defocus blur image blur radius detection method of utilization based on image step edge diffusion property, first adopt Hough change detection to go out the linear edge in out-of-focus image, calculate line spread function, further utilize the relation between defocus blur radius and line spread function, calculate defocus blur radius r; The depth of field of known camera lens

(being also the degree of depth in cuboid region to be measured), according to depth of field computing formula (1), can obtain and allow blur circle diameter:

…………………………………….（1）

Wherein

for the depth of field of camera lens, ffor lens focus, ffor the shooting f-number of camera lens, lfor the operating distance of camera lens, for allowing blur circle diameter.When image is processed the defocus blur radius obtaining rwith allow blur circle diameter

exist while being related to, think that this drop is outside camera lens field depth, reject corresponding drop image.Then the drop image in remaining field depth is carried out to binary conversion treatment; In the field depth of telecentric lens, object image size does not change with the variation of position, and thinks that drop is approximately spheric grain, like this can be by the width value (minor axis length of movement locus b) obtain the particle size of drop d( d= b); Length value (long axis length in conjunction with movement locus s), by the movement velocity of formula (2) acquisition drop v,

…………………………………….（2）

Wherein

for the time shutter of imageing sensor 5; The angle of while record length direction and pipeline axial θ, can obtain drop along the speed of pipeline axial

; To obtained liquid film image, after medium filtering denoising and binary conversion treatment, adopt Canny operator to carry out rim detection, obtain the distance between tube wall and liquid level position, i.e. thickness of liquid film;

7. in pair a period of time, collect n ₂photo carries out above-mentioned processing, obtains the ithe particle size values of individual drop d _i, velocity reversal velocity amplitude v _iwith the speed of drop along pipeline axial, amount to drop number n ₃individual, thus the distribution of size droplet diameter and speed in this measurement pipeline section obtained; Think that drop is approximately spherical, the cumulative volume of taken drop in this section of time region to be measured by formula (3), calculated,

…………………………………….（3）

The volume in known region to be measured

, wherein w, hwith

be respectively visual field width, visual field height and the depth of field (being the depth of field), in this section of time region to be measured, the average external volume concentration of drop is

; The average external volume flow of drop in this section of time region to be measured qby formula (4), calculated:

…………………………………….（4）。

Embodiment 2:

As shown in Figure 2, for opaque pipeline section, the corresponding transparent window 7 of processing and fabricating is connected with pipeline section, makes form internal passage shape and size and inner-walls of duct shape and measure-alike, with form 7, replace transparent pipeline 2, measuring process is identical with embodiment 1 operating process.

In two above-mentioned embodiment, lighting source adopts halogen light source, xenon source or semiconductor light sources; LASER Light Source adopts visible laser; Mental state head far away is selected zoom or non-zoom telecentric lens; Imageing sensor is all selected CCD or cmos device.

Claims (2)

1. An image measuring device for gas-liquid two-phase flow in a pipeline, characterized in that the device comprises an illumination source, a laser light source, a telecentric lens, an image sensor and a computer, and the illumination source passes through a transparent pipeline or a window illumination pipeline The particles to be measured in the laser light source illuminate the liquid film and liquid surface on the pipe wall through a transparent pipe or window, the telecentric lens is connected to the image sensor, and the particles and liquid film images captured by the image sensor are obtained by The computer collects. 2 . The image measuring device for gas-liquid two-phase flow in a pipeline according to claim 1 , wherein the image sensor is a CCD or CMOS device. 3 .

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