CN101726460B - Device and method for detecting distribution image of each substance in fluid - Google Patents

Abstract

The invention relates to a device and a method for detecting distribution image of each substance in fluid. The existing device has complex structure and low precision. The invention comprises a detection ring and eight sensing units, wherein, a detection stand on the outer side wall of the detection ring can rotate opposite to the detection ring; eight groups of placing slots are distributed on the upper end surface of the detection stand, and each group contains seven placing slots; each sensing unit comprises seven collimators, the middle collimator is connected with the single port of a Y-shaped shunt, and double ports are respectively connected with a laser and a detector; and three adjacent collimators on two sides are respectively connected with three lasers and three detectors. When being detected, the detection ring is installed on a pipeline to be detected; fluid to be detected flows through the detection ring, and a data acquisition card collects to obtain 32 electrical signals; the detection stand rotates for 45 degrees, then the electrical signals are collected again, and the distribution image is obtained by processing. The invention adopts a rotary scanning method to use fewer fiber optic sensor units to obtain higher image reconstruction resolution by independently designing pixels and planar optical circuit structure.

Description

The device and method of each species distribution image in the test fluid

Technical field

The invention belongs to the chromatography imaging technique field, relate to the device of each species distribution image in a kind of test fluid and utilize this device to carry out the method for each species distribution image detection in the fluid.

Background technology

Chromatography imaging technique (CT) is a kind of mode of utilizing source-detector scanning or arranging with fixed sturcture; Object is surveyed; The data for projection that measures is handled through the image reconstruction algorithm relevant with the measuring process physical background, reflects the technology of testee cross section information at last with the form of image.

The CT technology starts from the image reconstruction theory of J.Radon proposition in 1917; U.S. physicist C ormack in 1963 have developed the accurate mathematical method of X ray CT; First x-ray tomography appearance invented by doctor G.N.Hounsfield in 1973; The physical background of CT is very extensive, can be as the carrier of tested parameter information like various rays, electromagnetic field, light, sound etc.Along with scientific research and industrial continuous development, a series of branches of CT arise at the historic moment and are used widely at numerous areas such as medical treatment, biological tissue's research and commercial production, and are effectively promoting different interdisciplinary fusions.

Light CT forms the new branch of nineteen ninety-five OPT by photoreduction process CT (OPT), the relevant CT (OCT) of light and light dispersion CT (DOT) three big sub-branches---and optical fiber process tomography technology (OFPT) is owing to the introducing of optical fiber sensing technology (OFS) is born.The main measuring object of OFPT is extensively to exist in the industrial system and product quality, cost and production safety are had the polyphasic flow of material impact, has general advantages such as OFS resolution is high, volume is little, anti-electromagnetic interference (EMI).Compare with the optical fiber probe metering system, OFPT can obtain the distinct advantages of the whole relevant informations in cross section simultaneously, and OFPT is new research focus in the process tomographic imaging technology.

In patent CN1372165A; The pixel that the inventor has proposed a kind of novel optical fiber process tomography that is applied to circular configuration is distributed and the method for plane light path design; This method has been directed against the weak point of square pixels and scan method in original method, and promptly square pixels and be not suitable for circular cross section can bring theoretic error; And in various scan modes; In quadrature, straight line, three straight lines, Scan Architecture such as fan-shaped, all do not match with circular configuration yet, and new structure to distribute in pixel still be all to be the circle symmetry on the light path layout.

But above-mentioned patent also has weak point, because the method that has adopted sensing unit and number of pixels to be associated makes that the number of pixel is less; Otherwise just need a large amount of sensor units; On the complicacy of system and cost all is worthless, because system's no-raster device makes that the chromatographic imaging system number of projections is less; It is not high to rebuild precision, largely limit the concrete application of this structure.

Summary of the invention

The objective of the invention is deficiency, the device and method of each species distribution image in a kind of test fluid is provided to prior art.This method is through independent design pixel and optical planar circuit structure, and the method for employing rotation sweep, utilizes less Fibre Optical Sensor unit can obtain higher image reconstruction resolution.

Apparatus of the present invention comprise detection ring and eight sensing units.Described detection ring is transparent and cylinder barrel shaped both ends open, is provided with support and monitor station along the circumference of detection ring lateral wall.Described support is an annular, and the madial wall of support is fixedly connected with the lateral wall of detection ring; Described monitor station is an annular, and monitor station is arranged on the support, is provided with bearing between monitor station and the support, is provided with ball between the madial wall of monitor station and the detection ring lateral wall.Monitor station and motor are connected, and monitor station can rotate with respect to detection ring and support on support.

The upper surface of monitor station is along the even eight groups of standing grooves that distribute of annulus circumference; Every group of standing groove comprises into seven standing grooves of fan-shaped distribution; The circular arc that circular arc that the forward terminal of seven standing grooves constitutes and aft terminal constitute has the same center of circle, and this center of circle is positioned on the madial wall of detection ring.Standing groove in the middle of in every group of standing groove is along the radially setting of annulus, and both sides respectively are provided with three standing grooves, and the angle of two adjacent standing grooves is 22.5 degree.

Each sensing unit comprises seven collimating apparatuss, and seven collimating apparatuss are separately positioned on seven standing grooves of one group.The collimating apparatus in the centre of each sensing unit is connected with the single port of Y shape shunt, and a port in the dual-port of Y shape shunt is connected with the output terminal of laser instrument, and another port in the dual-port of Y shape shunt is connected with the input end of detector.Three adjacent collimating apparatuss of each sensing unit on one side is connected with the output terminal of three laser instruments respectively, and three collimating apparatuss that another side is adjacent are connected with the input end of three detectors respectively.Three collimating apparatuss that connect with laser instrument of each sensing unit and the position of three collimating apparatuss in seven collimating apparatuss that is connected with detector are identical.

32 detectors are connected with 32 circuit-switched data capture cards, and 32 circuit-switched data capture cards are connected with PC.

Concrete detection method is:

Step (1) is installed in detection ring on the pipeline to be detected, and detection ring and pipeline co-axial seal to be detected are provided with, and let fluid to be detected flow through detection ring; Open all 32 laser instruments and 32 detectors; The laser that laser instrument sends is through test fluid; Species distribution information on this light path in the test fluid is loaded on the light signal, receives this light signal and convert electric signal into by the detector of correspondence; Data collecting card collects the electric signal of 32 detectors;

Step (2) is with monitor station rotation 45 degree, and data collecting card is gathered the electric signal of 32 detector outputs according to the SF of setting in rotary course;

Step (3) is handled the electric signal that step (1) and step (2) collect by software in the PC, finally obtains the distributed image of each material in the fluid to be detected.

Number of pixels among the present invention, scanning angle and sweep velocity all can be set according to the size and the resolution requirement of scanning space, and the structure efficiency that the present invention designed is high, has wide range of applications.The present invention is mainly used in various two-phase fluids (Gu like gas/liquid, gas/solid, liquid/two-phase flow etc.), also can be used to have the gas/gas of different absorption coefficients, the detection of liquid/liquid species distribution, is with a wide range of applications in commercial production and research field.

The present invention has following beneficial effect than prior art:

1, this device accuracy of detection high, utilize the method for this device realization image imaging simple

2, compare with other optical fiber process tomography, the quantity of information that the Fibre Optical Sensor of similar number extracts is bigger, and efficient is higher.

3, the number of sensor is less, because the layout of sensing unit is the circle symmetrical structure, therefore need not circumference is rotated 2 π, and only needs π/4 to get final product, and has not only reduced the difficulty that system realizes, and, the speed of having accelerated scanning and having handled.

Description of drawings

Fig. 1 is the structural representation of apparatus of the present invention;

Fig. 2 is the local enlarged diagram of Fig. 1;

Fig. 3 is a standing groove schematic layout pattern on the monitor station among Fig. 1;

Fig. 4 is sensing unit structural representation among Fig. 1;

Fig. 5 is the optical planar circuit synoptic diagram;

Fig. 6 is that pixel is distributed synoptic diagram in the image reconstruction zone.

Embodiment:

As shown in Figure 1, the device of each species distribution image comprises detection ring 1 and eight sensing units 2 in the test fluid.

As shown in Figure 2, detection ring 1 is transparent and cylinder barrel shaped both ends open, is provided with support 6 and monitor station 5 along the circumference of detection ring 1 lateral wall.Support 6 is an annular, and the madial wall of support 6 is fixedly connected with the lateral wall of detection ring 1.Monitor station 5 is an annular, and monitor station 5 is arranged on the support 6, is provided with bearing 7 between monitor station 5 and the support 6, is provided with ball 8 between the madial wall of monitor station 5 and detection ring 1 lateral wall.Monitor station 5 is connected with motor, and monitor station 5 can rotate with respect to detection ring 1 and support 6 on support 6.

As shown in Figure 3; The upper surface of monitor station 5 is along the even eight groups of standing grooves that distribute of annulus circumference; Every group of standing groove comprises into seven standing groove 9-1～9-7 of fan-shaped distribution; The circular arc that circular arc that the forward terminal of seven standing grooves constitutes and aft terminal constitute has the same center of circle, and this center of circle is positioned on the madial wall of detection ring 1.Standing groove 9-4 in the middle of in every group of standing groove is along the radially setting of annulus, and both sides respectively are provided with three standing groove 9-1～9-3 and 9-5～9-7, and the angle of two adjacent standing grooves is 22.5 to spend.

As shown in Figure 4, each sensing unit comprises seven collimating apparatus 13-1～13-7, and it is last that seven collimating apparatus 13-1～13-7 are separately positioned on seven standing groove 9-1～9-7 of one group.The collimating apparatus 13-4 in the centre of each sensing unit is connected with the single port of Y shape shunt 10; A port in the dual-port of Y shape shunt 10 is connected with the output terminal of laser instrument 11-4, and another port in the dual-port of Y shape shunt 10 is connected with the input end of detector 12-4.Three adjacent collimating apparatus 13-1～13-3 of each sensing unit on one side is connected with the output terminal of three laser instrument 11-1～11-3 respectively, and three collimating apparatus 13-5～13-7 that another side is adjacent are connected with the input end of three detector 12-1～12-3 respectively.Three collimating apparatuss that connect with laser instrument of each sensing unit and the position of three collimating apparatuss in seven collimating apparatuss that is connected with detector are identical.32 detectors are connected with 32 circuit-switched data capture cards, and 32 circuit-switched data capture cards are connected with PC.

The method of utilizing this device to detect is:

Step (1) is installed in detection ring 1 on the pipeline to be detected 3, and detection ring 1 and pipeline 3 co-axial seal settings to be detected let fluid 4 to be detected flow through detection ring 1; Open all 32 laser instruments and 32 detectors; The laser that laser instrument sends is through test fluid; Species distribution information on this light path in the test fluid is loaded on the light signal, receives this light signal and convert electric signal into by the detector of correspondence; Data collecting card collects the electric signal of 32 detectors;

Step (2) is with monitor station rotation 45 degree, and data collecting card is gathered the electric signal of 32 detector outputs according to the SF of setting in rotary course;

Step (3) is handled the electric signal that step (1) and step (2) collect by software in the PC, finally obtains the distributed image of each material in the fluid to be detected.

Specific as follows:

As shown in Figure 5, the radius of establishing tested disc is R, and great circle is divided into m concentric circles, i.e. m layer, and the area of definition pixel is 1/4 of a center smallest circle area, then total 4m ²Individual pixel (each secter pat is a pixel among the figure), the distance of establishing between the layer is a, a=R/m then, the area of a pixel is π a ²/ 4.

The sensing unit position is respectively (R, 0), (R, π/4), and (R, pi/2), (R, 3 π/4), (R, π), (R, 5 π/4), (R, 3 pi/2s), (R, 7 π/4), that is:

$U_i=(R,{\frac{\mathrm{i\π}}{4}|}_{i=0}^7)---\left(1\right)$

Under the state of rotation, the position of each sensing unit is all changing, if dextrorotation, then sensing unit position being changed to anglec of rotation φ:

$U_i\left(t\right)=[R,{(\frac{i-1}{4}\mathrm{\π}-\mathrm{\φ})|}_{i=1}^7]---\left(2\right)$

Total number of pixels n is:

n＝4m ² (3)

The number of pixel does in each layer

n _i＝4(2i-1) (4)

If the sequence number (each secter pat is a pixel among the figure) as shown in Figure 6 of pixel is then for pixel P _Ij, its distribution range can be expressed as

a(i-1)≤r≤ai (5-1)

$\frac{j-1}{2(2i-1)}\mathrm{\π}\≤{\mathrm{\θ}}_{\mathrm{ij}}\≤\frac{j}{2(2i-1)}\mathrm{\π}---(5-2)$

Wherein, i is the sequence number of layer, and the scope of i be from 1 to m, and j be the sequence number of layer interior pixel, and the scope of j is from 1 to 4 (2i-1), so corresponding to P _IjThe sequence number of the pixel of position can be expressed as:

${N_{\mathrm{ij}}|}_{\underset{j=1\→4(2i-1)}{i=1\→m}}=4{(i-1)}^2+j---\left(6\right)$

Can know by Fig. 5, have 4 kinds of light, i.e. outermost layer light L1, second layer light L2, the 3rd layer of light L3 and innermost layer light L4, totally 32 light, wherein innermost layer light is two-way propagation, each light can be expressed with a unified expression formula, promptly

$r\cos [\frac{(2I-2+J)\mathrm{\&pi;}}{8}-\mathrm{\&theta;}]=\frac{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">m</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2}---(7-1)$

$\frac{(I-1)\mathrm{\&pi;}}{4}\&le;\mathrm{\&theta;}\&le;\frac{(I-1+J)\mathrm{\&pi;}}{4}---(7-2)$

Wherein, sgn is a sign function, and J representes the kind of light, and like skin, the second layer, the 3rd layer and internal layer light etc., I representes the sequence number of the light of different layers.

$\mathrm{sgn}\left(x\right)=\left\{\begin{array}{cc}1& x>0\\ 0& x=0\\ -1& x<0\end{array}\right.---\left(8\right)$

When circumference dextrorotation, equation can be expressed as

$r\cos [\frac{(2I-2+J)\mathrm{\&pi;}}{8}-\mathrm{\&theta;}-\mathrm{\&phi;}]=\frac{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">m</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2}---(9-1)$

$\frac{(I-1)\mathrm{\&pi;}}{4}-\mathrm{\&phi;}\&le;\mathrm{\&theta;}\&le;\frac{(I-1+J)\mathrm{\&pi;}}{4}-\mathrm{\&phi;}---(9-2)$

Geometry by light can be known, light L _I ^JThe polar coordinates scope be:

$\frac{R\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2}\&le;r_I^J\&le;R---\left(10\right)$

$\frac{(I-1)\mathrm{\&pi;}}{4}\&le;{\mathrm{\&theta;}}_I^J\&le;\frac{(I-1+J)\mathrm{\&pi;}}{4}$

Then contrast the pixel equation, can confirm light L earlier _I ^JWhich be distributed on the layer, if light L _I ^JThe pixel layer of the minimum that distributes is k, then order

$\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">R</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2}=a(k-1)---\left(11\right)$

And, can get by definition R=am

$k=\mathrm{INT}[\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">R</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2a}+1]$

(12)

$=\mathrm{INT}[\frac{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">m</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2}+1]$

Wherein, the INT function is that hence one can see that, light l to resulting value round numbers part _I ^JBe distributed in from the k layer to the m layer; Confirm again light has passed through which pixel of which layer, the value of i and j in promptly definite simultaneously pixel equation, method is following; Key is to find the pixel label of light from certain layer to the adjacent layer turnover; Promptly when angle is worth for certain, the label of that pixel that r changes, equations of light ray (12) can be rewritten as:

$r=\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">R</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2\cos [\frac{(2I-2+J)\mathrm{\&pi;}}{8}-\mathrm{\&theta;}]}---\left(13\right)$

When a (k-1)≤r≤ak, pixels illustrated is at the k layer, promptly

$a(k-1)\&le;\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">R</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2\cos [\frac{(2I-2+J)\mathrm{\&pi;}}{8}-\mathrm{\&theta;}]}\&le;\mathrm{ak}---\left(14\right)$

When k is not light l _I ^JDuring the minimum pixel layer that passes through, light is divided into two sections at this pixel layer, order

${\mathrm{\&phi;}}_1=\frac{(2I-2+J)\mathrm{\&pi;}}{8}-\arccos \left[\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">R</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2\mathrm{ak}}\right]---(15-1)$

${\mathrm{\&phi;}}_2=\frac{(2I-2+J)\mathrm{\&pi;}}{8}-\arccos \left[\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">R</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2a(k-1)}\right]---(15-2)$

${\mathrm{\&phi;}}_3=\frac{(2I-2+J)\mathrm{\&pi;}}{8}+\arccos \left[\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">R</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2a(k-1)}\right]---(15-3)$

${\mathrm{\&phi;}}_4=\frac{(2I-2+J)\mathrm{\&pi;}}{8}+\arccos \left[\frac{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">R</figure-callout>}\sqrt{2+\mathrm{sgn}(2-J)\sqrt{2|2-J|}}}{2\mathrm{ak}}\right]---(15-4)$

When k is light l _I ^JDuring the minimum pixel layer that passes through, light is continuous zone, i.e. a φ at this layer ₂=φ ₃=(2I-2+J) π/8, when k=1, θ is definite value, i.e. φ ₁=φ ₂=φ ₃=φ ₄=(2I-2+J) π/8, then light l _I ^JAngular range in the k layer is:

φ ₁≤θ≤φ ₂ (16-1)

φ ₃≤θ≤φ ₄ (16-2)

Because k layer one has the individual pixel of 4 (2k-1), so light l _I ^JThe sequence number of the pixel in the k layer is:

$\frac{2(2k-1){\mathrm{\&phi;}}_1}{\mathrm{\&pi;}}+1\&le;j\&le;\frac{2(2k-1){\mathrm{\&phi;}}_2}{\mathrm{\&pi;}}---(17-1)$

$\frac{2(2k-1){\mathrm{\&phi;}}_3}{\mathrm{\&pi;}}\&le;j\&le;\frac{2(2k-1){\mathrm{\&phi;}}_4}{\mathrm{\&pi;}}---(17-2)$

When system's dextrorotation, light l _I ^JAngular range in the k layer becomes:

φ ₁-Δφ≤θ≤φ ₂-Δφ (18-1)

φ ₃-Δφ≤θ≤φ ₄-Δφ (18-2)

When system rotates, negative value will appear in the angle in the following formula, need add 2 π and revise, and along with the difference of the anglec of rotation, following several kinds of situation will be arranged:

(1) as φ≤φ ₁The time

$\frac{2(2k-1)({\mathrm{\&phi;}}_1-\mathrm{\&phi;})}{\mathrm{\&pi;}}\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_2-\mathrm{\&phi;})}{\mathrm{\&pi;}}---(19-1)$

$\frac{2(2k-1)({\mathrm{\&phi;}}_3-\mathrm{\&phi;})}{\mathrm{\&pi;}}\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_4-\mathrm{\&phi;})}{\mathrm{\&pi;}}---(19-2)$

(2) work as φ ₁≤φ≤φ ₂The time

$\frac{2(2k-1)({\mathrm{\&phi;}}_1-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}\&le;j\&le;4(2k-1)---(20-1)$

$1\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_2-\mathrm{\&phi;})}{\mathrm{\&pi;}}---(20-2)$

$\frac{2(2k-1)({\mathrm{\&phi;}}_3-\mathrm{\&phi;})}{\mathrm{\&pi;}}\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_4-\mathrm{\&phi;})}{\mathrm{\&pi;}}---(20-3)$

(3) work as φ ₂≤φ≤φ ₃The time

$\frac{2(2k-1)({\mathrm{\&phi;}}_1-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_2-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}---(21-1)$

$\frac{2(2k-1)({\mathrm{\&phi;}}_3-\mathrm{\&phi;})}{\mathrm{\&pi;}}\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_4-\mathrm{\&phi;})}{\mathrm{\&pi;}}---(21-2)$

(4) work as φ ₃≤φ≤φ ₄The time

$\frac{2(2k-1)({\mathrm{\&phi;}}_1-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_2-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}---(22-1)$

$\frac{2(2k-1)({\mathrm{\&phi;}}_3-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}\&le;j\&le;4(2k-1)---(22-2)$

$1\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_4-\mathrm{\&phi;})}{\mathrm{\&pi;}}---(22-3)$

(5) work as φ ₄During≤φ≤2 π

$\frac{2(2k-1)({\mathrm{\&phi;}}_1-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_2-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}---(23-1)$

$\frac{2(2k-1)({\mathrm{\&phi;}}_3-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}\&le;j\&le;\frac{2(2k-1)({\mathrm{\&phi;}}_4-\mathrm{\&phi;}+2\mathrm{\&pi;})}{\mathrm{\&pi;}}---(23-2)$

After the pixel sequence number is confirmed, just can confirm the label of pixel according to pixel equation (6).The system of setting up departments is every at a distance from Δ φ angle once sampling, and system's corotation changes π/4 angles, and the optical attenuation equation that then obtains altogether does,

$N_L=\frac{\mathrm{\&pi;}}{4\mathrm{\&Delta;\&phi;}}---\left(24\right)$

Article one, the optical attenuation equation of light can be expressed as:

$I_{\mathrm{out}}=I_{\mathrm{in}}\exp (-\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{z}_i{\mathrm{\&alpha;}}_i)---\left(25\right)$

Promptly

$\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{z}_i{\mathrm{\&alpha;}}_i=\ln \left[\frac{I_{\mathrm{in}}}{I_{\mathrm{out}}}\right]---\left(26\right)$

Wherein, I _InAnd I _OutBe respectively the input and output light intensity, the absorption coefficient of light α of material i _i, can measure the light path z among the material i _i, system design promptly confirms after accomplishing.In fact, tested zone has been divided into the pixel cell that area equates, a kind of material is represented in each unit, therefore, and α _iAnd z _iBe respectively the absorption coefficient of light and the optical path length of material i on the light path.Different light generally has different α _iAnd z _i, for the light of diverse location, the value of i generally is different.If all through measuring, the distribution of material just can solve through the system of equations based on formula (28) in data acquisition phase for all receiving light powers or photosignal.

Therefore all the optical attenuation system of equations of light can be written as:

AX＝B (27)

Wherein A is N _L* n rank matrix, N _LBe equation number (total projection number) that n is the number of pixel total in the system, the i.e. number of unknown number; A represents the optical path length matrix of light in pixel, and the row of A are represented different light rays, and the row of A is represented the optical path length of different light rays through pixel; When number of pixels was a lot, A was a sparse matrix, and X is n * 1 rank matrix; The absorption coefficient of represent pixel, B also are n * 1 rank matrix, are the natural logarithm of the ratio of each road light incident and emergent light intensity; The group of solving an equation (27) can obtain the value of all pixels, thereby confirms the distribution situation of two-phase flow.

Relative resolution on the Systems Theory is:

$\mathrm{\&chi;}=\frac{\frac{1}{4}\mathrm{\&pi;}{\left(\frac{R}{m}\right)}^2}{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="H2009101555162E00011.png,H2009101555162E00031.png"\; state="\{\{state\}\}">R</figure-callout>}}^2}=\frac{1}{4m^2}---\left(28\right)$

If radius of a circle is R=50mm, theoretical relative resolution is set at χ=0.25%, then should be divided into the m=10 layer by formula (30) disc; Number n=400 of total pixel, because the every rotation π of system/4 just set back, so angle only need be rotated by system; If the systematic sampling number of times is 1000 times; The number that projection ray is arranged at every turn is 32, then can set up 32000 optical attenuation equations, and the number of unknown number is 400; Can adopt least square method to improve the precision of equation solution; For the distribution of gas, because therefore not reflection of interface can directly set up simple light transmission model with law of light absorption; If tested is complicated gas/liquid or liquid/liquid two-phase flow; Then need consider the effects such as reflection, refraction at interface, but because the collimation of light path, reflection on any light path and refraction all will make light received by corresponding detector; Because the numerical aperture of optical fiber collimator is very little; Therefore the light that reflects from a light path generally can't be received by the detector of another light path, and material is equivalent to lighttightly in this case, has simplified the complicacy of reconstruction model and algorithm greatly.

Claims (2)

1. the device of each species distribution image in the test fluid comprises detection ring and eight sensing units, it is characterized in that:

Described detection ring is transparent and cylinder barrel shaped both ends open, is provided with support and monitor station along the circumference of detection ring lateral wall; Described support is an annular, and the madial wall of support is fixedly connected with the lateral wall of detection ring; Described monitor station is an annular, and monitor station is arranged on the support, is provided with bearing between monitor station and the support, is provided with ball between the madial wall of monitor station and the detection ring lateral wall; Monitor station and motor are connected, and monitor station can rotate with respect to detection ring and support on support;

The upper surface of monitor station is along the even eight groups of standing grooves that distribute of annulus circumference; Every group of standing groove comprises into seven standing grooves of fan-shaped distribution; The circular arc that circular arc that the forward terminal of seven standing grooves constitutes and aft terminal constitute has the same center of circle, and this center of circle is positioned on the madial wall of detection ring; Standing groove in the middle of in every group of standing groove is along the radially setting of annulus, and both sides respectively are provided with three standing grooves, and the angle of two adjacent standing grooves is 22.5 degree;

Each sensing unit comprises seven collimating apparatuss, and seven collimating apparatuss are separately positioned on seven standing grooves of one group; The collimating apparatus in the centre of each sensing unit is connected with the single port of Y shape shunt, and a port in the dual-port of Y shape shunt is connected with the output terminal of laser instrument, and another port in the dual-port of Y shape shunt is connected with the input end of detector; Three adjacent collimating apparatuss of each sensing unit on one side is connected with the output terminal of three laser instruments respectively, and three collimating apparatuss that another side is adjacent are connected with the input end of three detectors respectively; Three collimating apparatuss that connect with laser instrument of each sensing unit and the position of three collimating apparatuss in seven collimating apparatuss that is connected with detector are identical;

32 detectors are connected with 32 circuit-switched data capture cards, and 32 circuit-switched data capture cards are connected with PC.

2. utilize the method that each species distribution image device detects in the described test fluid of claim 1, it is characterized in that the concrete steps of this method are:

Step (1) is installed in detection ring on the pipeline to be detected, and detection ring and pipeline co-axial seal to be detected are provided with, and let fluid to be detected flow through detection ring; Open all 32 laser instruments and 32 detectors; The laser that laser instrument sends is through test fluid; Species distribution information on this light path in the test fluid is loaded on the light signal, receives this light signal and convert electric signal into by the detector of correspondence; Data collecting card collects the electric signal of 32 detectors;

Step (2) is with monitor station rotation 45 degree, and data collecting card is gathered the electric signal of 32 detector outputs according to the SF of setting in rotary course;

Step (3) is handled the electric signal that step (1) and step (2) collect by software in the PC, finally obtains the distributed image of each material in the fluid to be detected.

Images