Optical fiber sensing system and method for micro-dispersion liquid drop detection

Abstract

The invention provides an optical fiber sensing system and method for micro-dispersion liquid drop detection, and belongs to the technical field of chemical multiphase flow detection. The optical fiber sensing system comprises a fluid detection channel (1) used for accessing to-be-measured fluid containing micro-dispersion liquid drops; the diffuse reflection optical fiber sensor (2) is mounted on one side of the fluid detection channel (1) and internally comprises two optical fibers (3 and 4) which are respectively used for emitting light rays and receiving light intensity signals when the micro-dispersion liquid drops pass through the optical fibers (4); the light intensity detector (7) is used for receiving the light intensity signal; and the control system (8) is used for determining the diameter d of the micro-dispersion liquid drop according to the light intensity signal. The movement speed of the liquid drop is measured according to the time of the liquid drop passing through the single optical fiber and the double-optical-fiber structure, and then the diameter of the liquid drop is calculated according to the speed, the time and the correction factor. According to the invention, the diameter distribution of the micro-dispersion liquid drops can be rapidly detected.

Description

Technical Field

[0001] This invention relates to the field of chemical multiphase flow detection technology, specifically to an optical fiber sensing system and method for detecting micro-dispersed droplets. Background Technology

[0002] Microchemical technology, as a major technological innovation in the modern chemical industry, plays a crucial role in enhancing chemical processes. Among them, microdispersion technology is an indispensable part of microchemical technology. The core objective of microdispersion technology is to obtain micro-droplets or bubbles at the micrometer to sub-millimeter scale on a large scale in continuous phase fluids. These microdispersed droplets or bubbles, due to their extremely small size and huge specific surface area, can significantly enhance mass transfer and reaction processes, thereby improving the performance of the entire chemical process.

[0003] For research in microdispersion technology, a deep understanding of the droplet diameter distribution within microdispersion systems is crucial. The droplet diameter distribution directly affects not only the efficiency of the microdispersion process but also the effectiveness of subsequent mass transfer or reactions. Therefore, accurate measurement and in-depth understanding of droplet diameter distribution have become a key focus of fundamental and applied research in microchemical engineering. Due to the extremely small size of microdispersion droplets, past research has primarily employed high-speed microscopy to observe and study their diameter distribution. This method is easy to implement and can meet research needs to a certain extent.

[0004] In the process of realizing this invention, the inventors discovered that the existing solutions have the following drawbacks: First, the amount of information contained in microscopic videos or photographs is enormous, making processing very cumbersome and time-consuming; second, high-speed cameras and precision microscopes are expensive, significantly increasing research costs; more importantly, this method can only record images or videos online, and cannot process images and obtain diameter distribution results in a short time. These shortcomings largely restrict the development of methods for understanding micro-dispersion technology and limit the application of microchemical technology in a wider range of fields. Therefore, research on micro-dispersion technology requires continuous exploration of new measurement methods and techniques to obtain diameter distribution information of micro-dispersed droplets more accurately and efficiently. This will not only help to deeply understand the nature and laws of micro-dispersion processes, but also provide strong support for the further optimization and application of microchemical technology. Summary of the Invention

[0005] The purpose of this invention is to provide a device based on the principle of refraction of light emitted from an optical fiber by a droplet, and the data characteristics of droplet motion and optical fiber detection signals. This device integrates a diffuse reflection optical fiber sensor onto a millimeter-sized fluid detection channel, reducing manufacturing costs. The sensor size, structure, and layout are optimized for the geometric characteristics of microdispersed droplets. A method for increasing light intensity is developed, and it replaces high-speed microscopy for detecting droplet diameter distribution. A reliable method for calculating and correcting droplet diameter is established, enabling rapid detection of droplet diameter distribution within the detection channel. The detection channel has a simple structure, is easy to move, and can be connected to traditional microdispersion experimental platforms. It can rapidly measure hundreds of droplet diameters per second, thereby obtaining this crucial microdispersion data. This optical fiber sensing system has a simple structure, droplet diameter detection precision down to the tens of micrometer level, and the detected droplet motion frequency exceeds 200 Hz. It is an effective tool for basic research and industrial applications in microdispersion, and has promising application prospects.

[0006] To achieve the above objectives, embodiments of the present invention provide an optical fiber sensing system for detecting micro-dispersed droplets. The optical fiber sensing system comprises: a fluid detection channel for receiving a fluid containing micro-dispersed droplets to be measured; at least two diffuse reflection optical fiber sensors, respectively installed upstream and downstream of the fluid on one side of the fluid detection channel; each diffuse reflection optical fiber sensor includes two optical fibers, one connected to a light source as a light emitting end, and the other connected to a light intensity detector as a light intensity signal receiving end; wherein the light source emits light, and the light intensity signal receiving end receives the light intensity signal as the micro-dispersed droplets pass through the optical fiber; the light... A high-intensity detector is used to receive the light intensity signal; and a control system is used to acquire the light intensity signal received by the light intensity detector, and further used to determine the diameter d of the micro-dispersed droplet based on the light intensity signal, including: determining the initial times t1 and t2 when the micro-dispersed droplet reaches the two diffuse reflection fiber optic sensors based on the light intensity signal; determining the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors based on the light intensity signal; and determining the diameter d of the micro-dispersed droplet based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection fiber optic sensors.

[0007] Optionally, the two optical fibers are perpendicular to the flow direction of the fluid; and the two optical fibers are arranged close together inside the diffuse reflection optical fiber sensor, with the ends of the two optical fibers flush.

[0008] Optionally, the fluid detection channel is made of a transparent material.

[0009] Optionally, the fiber optic sensing system further includes: a reflector, installed on the other side of the fluid detection channel, wherein there are at least two reflectors, respectively located opposite the diffuse reflection fiber optic sensor, for increasing the light intensity signal reflected to the light intensity signal receiving end, wherein the center of the reflector is located at the midpoint of the axis of symmetry of the two optical fibers in the diffuse reflection fiber optic sensor.

[0010] Optionally, the diameter of the reflector is not less than twice the diameter of the optical fiber in the diffuse reflection optical fiber sensor, wherein the diameter of the optical fiber does not exceed 1 / 2 of the side length of the cross-section of the fluid detection channel.

[0011] Optionally, the cross-section of the fluid detection channel is square.

[0012] Optionally, the control system sets a light intensity threshold, used to: determine that the light intensity signal below the light intensity threshold is a characteristic signal when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor; and determine that the light intensity acquisition time corresponding to the light intensity signal below the light intensity threshold is the time when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor, wherein the time includes: the initial time t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors; and the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors.

[0013] Optionally, determining the diameter d of the micro-dispersed droplet based on the light intensity signal includes: determining the initial time difference Δt3 of the micro-dispersed droplet reaching the two diffuse reflection fiber optic sensors based on the initial times t1 and t2 when the micro-dispersed droplet reaches the two diffuse reflection fiber optic sensors; determining the velocity v of the micro-dispersed droplet based on the initial time difference Δt3 and the distance between the two diffuse reflection fiber optic sensors; determining the first diameter d1 and the second diameter d2 of the micro-dispersed droplet using the formula d = v × Δt × correction factor based on the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors; and determining the diameter d of the micro-dispersed droplet using an arithmetic mean based on the first diameter d1 and the second diameter d2.

[0014] Optionally, the fiber optic sensing system uses a monochromatic light source.

[0015] Through the above technical solution, this invention integrates a diffuse reflection fiber optic sensor onto a millimeter-sized fluid detection channel. Based on the principle of refraction of light emitted by an optical fiber by a droplet, it utilizes the light intensity decrease caused by the passing of a micro-dispersed droplet through the tiny tip of the diffuse reflection fiber in the fluid detection channel. A light intensity detector and control system record the time it takes for the moving micro-dispersed droplet to pass through a single optical fiber. A dual-fiber structure is then used to accurately measure the velocity of the micro-dispersed droplet. Finally, the diameter of the micro-dispersed droplet is calculated based on the product of velocity and time, plus a correction factor. The fluid detection channel structure used in this invention is simple, and the diffuse reflection fiber optic sensor, light source, and light intensity signal detector can be selected from commercially available electronic components, thereby reducing manufacturing costs. Furthermore, the fluid detection channel is easy to move and connect to traditional micro-dispersion experimental platforms, enabling rapid detection of the diameter distribution of micro-dispersion droplets. The proposed droplet diameter algorithm, after calibration and correction, yields high-accuracy measurement results, meeting the requirements of most micro-dispersion experiments for rapid droplet detection.

[0016] On the other hand, the present invention provides a method for detecting micro-dispersed droplets. The method includes: acquiring light intensity signals from at least two diffuse reflection fiber optic sensors, wherein the at least two diffuse reflection fiber optic sensors are respectively installed upstream and downstream of a fluid detection channel containing micro-dispersed droplets for connection to be measured. Each diffuse reflection fiber optic sensor includes two optical fibers, one connected to a light source as a light emitting end and the other connected to a light intensity detector as a light intensity signal receiving end. The light source is used to emit light, and the light intensity signal receiving end is used to receive the light intensity signal when the micro-dispersed droplet passes through the optical fiber. Based on the light intensity signal, the initial times t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors are determined; based on the light intensity signal, the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors are determined; and the diameter d of the micro-dispersed droplet is determined based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection fiber optic sensors.

[0017] Optionally, the method further includes: increasing the light intensity signal reflected to the light intensity signal receiving end by means of a reflector, wherein the reflector is installed on the other side of the fluid detection channel, and the reflector comprises at least two, respectively located opposite the diffuse reflection fiber optic sensor, and the center of the reflector is located at the midpoint of the axis of symmetry with the two optical fibers in the diffuse reflection fiber optic sensor.

[0018] Optionally, the diameter of the reflector is not less than twice the diameter of the optical fiber in the diffuse reflection optical fiber sensor, wherein the diameter of the optical fiber does not exceed 1 / 2 of the side length of the cross-section of the fluid detection channel.

[0019] Optionally, the method further includes: determining that the light intensity signal below a light intensity threshold is a characteristic signal when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor, wherein the light intensity threshold is set by a control system; and determining that the light intensity acquisition time corresponding to the light intensity signal below the light intensity threshold is the time when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor, wherein the time includes: the initial time t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors; and the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors.

[0020] Optionally, determining the diameter d of the micro-dispersed droplet based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection fiber optic sensors includes: determining the initial time difference Δt3 of the micro-dispersed droplet reaching the two diffuse reflection fiber optic sensors based on the initial times t1 and t2 when the micro-dispersed droplet reaches them; determining the velocity v of the micro-dispersed droplet based on the initial time difference Δt3 and the distance between the two diffuse reflection fiber optic sensors; determining the first diameter d1 and the second diameter d2 of the micro-dispersed droplet using the formula d = v × Δt × correction factor based on the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors; and determining the diameter d of the micro-dispersed droplet using an arithmetic mean based on the first diameter d1 and the second diameter d2.

[0021] The method for detecting micro-dispersed droplets described above has the same advantages over existing technologies as the fiber optic sensing system for detecting micro-dispersed droplets described above, and will not be repeated here.

[0022] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0024] Figure 1 This is a schematic diagram of the structure of an optical fiber sensing system for detecting micro-dispersed droplets provided in an embodiment of the present invention.

[0025] Figure 2 This is a flowchart illustrating the steps of using the fiber optic sensing system for detecting micro-dispersed droplets provided in this embodiment of the invention.

[0026] Figure 3 This is a schematic diagram of the experimental results table of Embodiment 1 provided in this invention.

[0027] Figure 4 This is a schematic diagram of the experimental results table of Embodiment 2 provided in this invention.

[0028] Figure 5 This is a schematic diagram of the droplet diameter distribution in Example 3 provided by the present invention.

[0029] Figure 6 This is a flowchart illustrating the method steps for detecting micro-dispersed droplets provided in an embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures

[0031] 1. Fluid detection channel; 2. Diffuse reflection fiber optic sensor

[0032] 3 optical fibers 4 optical fibers

[0033] 5. Reflector 6. Light source

[0034] 7. Light intensity detector 8. Control system

[0035] A. The micro-dispersed droplet to be detected; B. The spacing between diffuse reflection fiber optic sensors. Detailed Implementation

[0036] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0037] Figure 1 This is a schematic diagram of the structure of an optical fiber sensing system for detecting micro-dispersed droplets provided in an embodiment of the present invention. (See attached diagram.) Figure 1As shown, the fiber optic sensing system for detecting micro-dispersed droplets includes: a fluid detection channel 1 for receiving a fluid containing micro-dispersed droplets to be measured; at least two diffuse reflection fiber optic sensors 2, respectively installed upstream and downstream of the fluid on one side of the fluid detection channel 1; each diffuse reflection fiber optic sensor 2 includes two optical fibers 3 and 4, wherein one optical fiber 3 is connected to a light source 6 as a light emitting end, and the other optical fiber 4 is connected to a light intensity detector 7 as a light intensity signal receiving end; wherein the light source 6 is used to emit light, and the light intensity signal receiving end is used to receive the light intensity signal when the micro-dispersed droplets pass through the optical fiber 4; the light intensity detector 7 is used to receive the light intensity signal when the micro-dispersed droplets pass through the optical fiber 4. The light intensity signal is described above; and the control system 8 is used to acquire the light intensity signal received by the light intensity detector 7, and to determine the diameter d of the micro-dispersed droplet based on the light intensity signal, including: determining the initial times t1 and t2 when the micro-dispersed droplet reaches the two diffuse reflection fiber optic sensors 2 based on the light intensity signal; determining the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors 2 based on the light intensity signal; and determining the diameter d of the micro-dispersed droplet based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection fiber optic sensors 2. Optionally, the fluid containing the micro-dispersed droplet to be measured provided in the embodiment of the present invention is a liquid-liquid two-phase fluid, which includes two liquids, one liquid as the continuous phase of the detection system, and the other liquid as the dispersed phase of the detection system, wherein the dispersed phase liquid of the detection system is the droplet A to be detected in the embodiment of the present invention. Optionally, the fluid detection channel 1 provided in this embodiment of the invention is made of a transparent material, which may be glass, quartz, fluoroethylene-hexafluoropropylene copolymer (FEP), fluoroethylene-perfluoroalkoxy vinyl ether copolymer (PFA), or polymethyl methacrylate (PMMA). In some embodiments, to avoid additional diffuse reflection when the cross-section of the fluid detection channel 1 is curved, the cross-section of the fluid detection channel 1 provided in this embodiment of the invention is square, so that the detection of the micro-dispersed droplets only needs to be performed on one side, wherein the side length of the square is preferably 0.5-1.5 mm.

[0038] In some embodiments, such as Figure 1 As shown, the two optical fibers 3 and 4 are perpendicular to the flow direction of the fluid, that is, perpendicular to... Figure 1The flow direction of the micro-dispersed droplet A to be detected; and the two optical fibers 3 and 4 are arranged closely together inside the diffuse reflection optical fiber sensor 2, with the ends of the two optical fibers 3 and 4 flush. The two optical fibers 3 and 4 are of equal diameter, and the diameter of a single optical fiber does not exceed 1 / 2 of the side length of the square cross-section of the fluid detection channel 1, that is, the diameter of a single optical fiber does not exceed 0.25-0.75 mm.

[0039] In some embodiments, such as Figure 1 As shown, the fiber optic sensing system further includes a reflector 5, installed on the other side of the fluid detection channel 1. At least two reflectors 5 are included, each located opposite the diffuse reflection fiber optic sensor 2, to increase the light intensity signal reflected to the light intensity signal receiving end. The center of the reflector 5 is located at the midpoint of the axis of symmetry of the two optical fibers 3 and 4 within the diffuse reflection fiber optic sensor 2. Optionally, the reflector is circular, and the diameter of the reflector 5 is not less than twice the diameter of the optical fibers 3 and 4 within the diffuse reflection fiber optic sensor 2, i.e., the diameter of the reflector is not less than 0.5-1.5 mm. The reflector provided in this embodiment is preferably white, as a white reflector can uniformly reflect light, avoiding light scattering and uneven distribution. Optionally, the fiber optic sensing system provided in this embodiment preferably uses a monochromatic light source with an emission wavelength range of 400-850 nm.

[0040] In some embodiments, the control system 8 sets a light intensity threshold, used to: determine that the light intensity signal below the light intensity threshold is a characteristic signal when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor 2; and determine that the light intensity acquisition time corresponding to the light intensity signal below the light intensity threshold is the time when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor 2, wherein the time includes: the initial time t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors 2; and the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors 2. Optionally, in this embodiment of the invention, the threshold for identifying the light intensity signal of the micro-dispersed droplet needs to be lower than 90% of the light intensity signal measured under the condition that there is no droplet in the fluid detection channel 1. That is, in this embodiment of the invention, the threshold is preferably 89% of the light intensity signal measured under the condition that there is no droplet in the fluid detection channel 1. When the light intensity signal is lower than 89% of the light intensity signal measured under the condition that there is no droplet in the fluid detection channel 1, the control system 8 determines that the light intensity signal is the characteristic signal of the micro-dispersed droplet passing through the diffuse reflection fiber optic sensor 2, and the light intensity acquisition time corresponding to the light intensity signal is the time when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor 2. Specifically, determining the diameter d of the micro-dispersed droplet based on the light intensity signal includes: determining the initial time difference Δt3 of the micro-dispersed droplet reaching the two diffuse reflection fiber optic sensors 2 based on the initial times t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors 2, using the formula Δt3 = t2 - t1; and determining the initial time difference Δt3 based on the initial time difference Δt3 and the distance B between the two diffuse reflection fiber optic sensors 2, using the formula... Determine the velocity v of the micro-dispersed droplet; based on the time Δt1 and Δt2 required for the micro-droplet to pass through each of the two diffuse reflection fiber optic sensors 2, obtain the droplet diameter data measured by the two diffuse reflection fiber optic sensors 2 using the formula d = v × Δt × correction factor, including: the first diameter d1 and the second diameter d2; and based on the first diameter d1 and the second diameter d2 of the micro-droplet, use the arithmetic mean... The diameter d of the micro-dispersed droplet is determined. Optionally, the correction factor for calculating the diameter d of the micro-dispersed droplet provided in this embodiment of the invention needs to be obtained beforehand by calibrating the fiber optic sensor system with droplets of known true diameters. That is, the correction factor is the ratio of the true diameter of the micro-dispersed droplet to be detected to the diameter d of the micro-dispersed droplet detected by the fiber optic sensor system. The value of the correction factor is preferably between 0.85 and 1. The true diameter of the micro-dispersed droplet to be detected can be obtained by high-speed microscopy.

[0041] Figure 2 This is a flowchart illustrating the steps of using the fiber optic sensing system for detecting micro-dispersed droplets provided in this embodiment of the invention. Figure 2 As shown, the method of using the fiber optic sensing system for detecting micro-dispersed droplets includes the following steps: Step S1, connecting the fluid detection channel 1 to the micro-dispersed solution to be detected, so that the solution flows in the channel at a speed of 0.001 to 0.1 m / s; Step S2, starting the light source 6, the light intensity detector 7, and the control system 8 to begin acquiring light intensity signals; Step S3, setting the light intensity signal threshold, and calculating the diameter of each droplet A passing through the diffuse reflection fiber optic sensor 2 based on the light intensity signal information, acquisition time information, and other conditions; Step S4, calculating the diameter distribution of several droplets A based on the statistical results of the diameters.

[0042] Specifically, in Embodiment 1 provided by the present invention, the structural parameters of the fiber optic sensing system are as follows: the fluid detection channel 1 is made of polymethyl methacrylate (PMMA), the cross-sectional side length of the fluid detection channel 1 is 1mm, the two sets of optical fibers connected inside the diffuse reflection fiber optic sensor 2 have a diameter of 0.25mm, a reflector with a diameter of 0.5mm is set opposite the diffuse reflection fiber optic sensor 2, and the light source 6 is a 650nm red light source.

[0043] Step S1: Using a 3% sodium dodecyl sulfate aqueous solution as the continuous phase of the detection system and n-hexane as the dispersed phase, the flow rate of the continuous phase is set to 800 μL / min, and the flow rate of the dispersed phase is set to 100 μL / min. A micro-dispersed droplet pre-generation device is connected to the fluid detection channel 1 to allow the micro-dispersed droplets (n-hexane droplets) to be detected to flow into the fluid detection channel 1. In this embodiment, a 3D-printed T-shaped microchannel (0.72 mm inner diameter) is used as the micro-dispersed droplet pre-generation device to disperse n-hexane in droplet form into the continuous phase aqueous solution (containing a 3% sodium dodecyl sulfate aqueous solution).

[0044] Step S2: Under the condition that n-hexane droplets are continuously formed in the T-shaped microchannel, turn on the light source 6, light intensity detector 7 and control system 8, set the light intensity threshold to 89%, and start light intensity signal acquisition.

[0045] Step S3: For the initial detection, a correction factor for the diameter of the micro-dispersed droplets to be detected needs to be obtained. Therefore, with the correction factor set to 1, an experiment is conducted, and the average diameter of the n-hexane droplets is measured to be 0.681 mm. High-speed microscopy determines its true diameter to be 0.631 mm, thus the correction factor is 0.927. The flow rates of the continuous and dispersed phases are varied, and the experiment to obtain the correction factor is repeated 5 times under the condition of a total flow rate of 500 μL / min-2000 μL / min, resulting in an average correction factor of 0.919. The correction factor of 0.919 is input into the control system 8, and then the fiber optic sensing system is used to measure the droplet diameter under other experimental conditions. The number of times the correction factor is repeatedly obtained can be selected to be no less than 5 times; in this embodiment of the invention, 5 times is preferred.

[0046] Step S4: Calculate the diameter distribution of several droplets A under other experimental conditions based on the statistical results of the diameters. The experimental results are as follows: Figure 3 As shown.

[0047] Specifically, in Embodiment 2 provided by this invention, the fiber optic sensing system used is different from that in Embodiment 1. The specific structural parameters are as follows: the fluid detection channel 1 is made of tetrafluoroethylene-hexafluoropropylene copolymer (FEP), the cross-sectional side length of the fluid detection channel 1 is 1.5mm, the two sets of optical fibers connected inside the diffuse reflection fiber optic sensor 2 have a diameter of 0.5mm, a reflector with a diameter of 1mm is set opposite the diffuse reflection fiber optic sensor 2, and the light source 6 is a 440nm blue light source.

[0048] Step S1: Example 2 used the same T-shaped microchannel as Example 1 to prepare microdispersed droplets. The experimental system was the same, with a 3% mass fraction sodium dodecyl sulfate aqueous solution as the continuous phase and n-hexane as the dispersed phase.

[0049] Step S2: The operation steps of Example 2 are the same as those of Example 1. The correction factor for the droplet diameter was measured to be 0.903.

[0050] Step S3: The operation steps of Example 2 are the same as those of Example 1.

[0051] Step S4: The T-shaped microchannel in Example 2 is wider than that in Example 1, thus allowing for droplet diameter detection under higher flow conditions. Specific experimental results are as follows: Figure 4 As shown.

[0052] Specifically, in Embodiment 3 provided by the present invention, the fiber optic sensing system used is the same as that in Embodiment 2.

[0053] Step S1: Example 3 used the same experimental system as Example 2, which contained a 3% sodium dodecyl sulfate aqueous solution as the continuous phase and n-hexane as the dispersed phase. However, Example 3 used a micro-sieve array device as the pre-generation device for the micro-dispersed droplets. The internal flow channel of the micro-sieve array device was 1 mm wide and 1 mm deep, with three sieve holes of 0.5 mm diameter arranged on the side of the channel. When n-hexane flowed out of the holes, it was sheared by the 3% sodium dodecyl sulfate aqueous solution in the flow channel, thus forming micro-dispersed droplets. The n-hexane droplets formed by the micro-sieve array device are different from those of the T-shaped microchannel. These n-hexane droplets exhibit polydispersity. When the flow rate of the continuous phase (3% sodium dodecyl sulfate aqueous solution) was 2000 μL / min and the flow rate of the dispersed phase (n-hexane) was 300 μL / min, the droplet diameter distribution was as follows. Figure 5 As shown.

[0054] Figure 6 This is a flowchart illustrating the method steps for detecting micro-dispersed droplets provided in an embodiment of the present invention, as shown below. Figure 6 As shown, the method for detecting micro-dispersed droplets includes: step S10, acquiring the light intensity signals of at least two diffuse reflection fiber optic sensors 2, wherein the at least two diffuse reflection fiber optic sensors 2 are respectively installed upstream and downstream of the fluid detection channel 1 containing micro-dispersed droplets to be measured. Each diffuse reflection fiber optic sensor 2 includes at least two optical fibers 3 and 4, wherein one optical fiber 3 is connected to a light source 6 as a light emitting end, and the other optical fiber 4 is connected to a light intensity detector 7 as a light intensity signal receiving end, wherein the light source 6 is used to emit light, and the light intensity signal receiving end is used to receive light. Step S20: Receive the light intensity signal when the micro-dispersed droplet passes through the optical fiber 4; Step S30: Determine the initial times t1 and t2 when the micro-dispersed droplet reaches the two diffuse reflection optical fiber sensors 2 based on the light intensity signal; Step S40: Determine the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection optical fiber sensors 2 based on the light intensity signal; Step S51: Determine the diameter d of the micro-dispersed droplet based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection optical fiber sensors 2.

[0055] The method for detecting micro-dispersed droplets described above is similar to the embodiment of the fiber optic sensing system for detecting micro-dispersed droplets described above, and will not be repeated here.

[0056] The fiber optic sensing system for detecting micro-dispersed droplets includes a processor and a memory. The fiber optic detection process described above can be stored in the memory as a program unit, and the processor executes the program unit stored in the memory to achieve the corresponding function.

[0057] The processor contains a kernel, which retrieves the corresponding program unit from memory. One or more kernels can be configured, and the diameter of the micro-dispersed droplets can be detected by adjusting the kernel parameters.

[0058] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0059] This invention provides a storage medium storing a program that, when executed by a processor, implements the method for detecting micro-dispersed droplets.

[0060] This invention provides a processor for running a program, wherein the program executes the method for detecting microdispersed droplets.

[0061] This invention provides a device including a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs the following steps: acquiring light intensity signals from at least two diffuse reflection fiber optic sensors 2, wherein the at least two diffuse reflection fiber optic sensors 2 are respectively installed upstream and downstream of a fluid detection channel 1 containing micro-dispersed droplets for measurement. Each diffuse reflection fiber optic sensor 2 includes at least two optical fibers 3 and 4, wherein one optical fiber 3 is connected to a light source 6 as a light emitting end, and the other optical fiber 4 is connected to a light intensity detector 7 as a light intensity signal receiving end. In this configuration, the light source 6 is used to emit light, and the light intensity signal receiving end is used to receive the light intensity signal when the micro-dispersed droplet passes through the optical fiber 4; based on the light intensity signal, the initial times t1 and t2 when the micro-dispersed droplet reaches the two diffuse reflection optical fiber sensors 2 are determined; based on the light intensity signal, the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection optical fiber sensors 2 are determined; and based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection optical fiber sensors 2, the diameter d of the micro-dispersed droplet is determined.

[0062] Furthermore, the light intensity signal reflected to the light intensity signal receiving end is increased by the reflector 5. The reflector 5 is installed on the other side of the fluid detection channel 1. There are at least two reflectors 5, which are located opposite the diffuse reflection fiber optic sensor 2. The center of the reflector 5 is located at the middle position of the axis of symmetry of the two optical fibers 3 and 4 in the diffuse reflection fiber optic sensor 5.

[0063] Furthermore, the diameter of the reflector 5 is not less than twice the diameter of the optical fibers 3 and 4 inside the diffuse reflection optical fiber sensor 2, wherein the diameter of the optical fibers 3 and 4 does not exceed 1 / 2 of the side length of the cross-section of the fluid detection channel 1.

[0064] Further, the light intensity signal below the light intensity threshold is determined to be the characteristic signal when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor 2, wherein the light intensity threshold is set by the control system; and the light intensity acquisition time corresponding to the light intensity signal below the light intensity threshold is determined to be the time when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor 2, wherein the time includes: the initial time t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors 2; and the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors 2.

[0065] Further, determining the diameter d of the micro-dispersed droplet based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection fiber optic sensors 2 includes: determining the initial time difference Δt3 of the micro-dispersed droplet reaching the two diffuse reflection fiber optic sensors 2 based on the initial times t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors 2; determining the velocity v of the micro-dispersed droplet based on the initial time difference Δt3 and the distance between the two diffuse reflection fiber optic sensors 2; determining the first diameter d1 and the second diameter d2 of the micro-dispersed droplet using the formula d = v × Δt × correction factor based on the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors 2; and determining the diameter d of the micro-dispersed droplet using the arithmetic mean of the first diameter d1 and the second diameter d2. The device in this document can be a server, PC, PAD, mobile phone, etc.

[0066] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having the following method steps: acquiring light intensity signals from at least two diffuse reflection fiber optic sensors 2, wherein the at least two diffuse reflection fiber optic sensors 2 are respectively installed upstream and downstream of a fluid detection channel 1 containing micro-dispersed droplets for connection to be measured, each diffuse reflection fiber optic sensor 2 including at least two optical fibers 3 and 4, wherein one optical fiber 3 is connected to a light source 6 as a light emitting end, and the other optical fiber 4 is connected to a light intensity detector 7 as a light intensity signal receiving end, wherein the light source 6... The light intensity signal receiving end is used to emit light and receive the light intensity signal when the micro-dispersed droplet passes through the optical fiber 4; based on the light intensity signal, the initial times t1 and t2 when the micro-dispersed droplet reaches the two diffuse reflection optical fiber sensors 2 are determined; based on the light intensity signal, the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection optical fiber sensors 2 are determined; and based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection optical fiber sensors 2, the diameter d of the micro-dispersed droplet is determined.

[0067] Furthermore, the light intensity signal reflected to the light intensity signal receiving end is increased by the reflector 5. The reflector 5 is installed on the other side of the fluid detection channel 1. There are at least two reflectors 5, which are located opposite the diffuse reflection fiber optic sensor 2. The center of the reflector 5 is located at the middle position of the axis of symmetry of the two optical fibers 3 and 4 in the diffuse reflection fiber optic sensor 5.

[0068] Furthermore, the diameter of the reflector 5 is not less than twice the diameter of the optical fibers 3 and 4 inside the diffuse reflection optical fiber sensor 2, wherein the diameter of the optical fibers 3 and 4 does not exceed 1 / 2 of the side length of the cross-section of the fluid detection channel 1.

[0069] Further, the light intensity signal below the light intensity threshold is determined to be the characteristic signal when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor 2, wherein the light intensity threshold is set by the control system; and the light intensity acquisition time corresponding to the light intensity signal below the light intensity threshold is determined to be the time when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor 2, wherein the time includes: the initial time t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors 2; and the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors 2.

[0070] Further, determining the diameter d of the micro-dispersed droplet based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection fiber optic sensors 2 includes: determining the initial time difference Δt3 of the micro-dispersed droplet reaching the two diffuse reflection fiber optic sensors 2 based on the initial times t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors 2; determining the velocity v of the micro-dispersed droplet based on the initial time difference Δt3 and the distance between the two diffuse reflection fiber optic sensors 2; determining the first diameter d1 and the second diameter d2 of the micro-dispersed droplet using the formula d = v × Δt × correction factor based on the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors 2; and determining the diameter d of the micro-dispersed droplet using the arithmetic mean of the first diameter d1 and the second diameter d2.

[0071] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0072] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0073] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0074] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0075] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0076] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, like read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0077] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0078] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0079] The technical solution of this application states that "the acquisition, transmission, storage, use, and processing of data all comply with the relevant provisions of national laws and regulations" and "it should be noted that in the embodiments of this application, certain software, components, models, and other existing solutions in the industry may be mentioned. These should be considered as exemplary, and their purpose is only to illustrate the feasibility of implementing the technical solution of this application, but it does not mean that the applicant has used or necessarily used the solution."

[0080] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A fiber optic sensing system for detecting micro-dispersed droplets, characterized in that, The fiber optic sensing system includes: Fluid detection channel (1) is used to connect the fluid containing micro-dispersed droplets to be measured; At least two diffuse reflection fiber optic sensors (2) are respectively installed on one side of the fluid detection channel (1) at upstream and downstream positions along the fluid. Each diffuse reflection fiber optic sensor (2) includes two optical fibers (3, 4), one of which (3) is connected to a light source (6) as a light emitting end, and the other optical fiber (4) is connected to a light intensity detector (7) as a light intensity signal receiving end. The light source (6) is used to emit light, and the light intensity signal receiving end is used to receive the light intensity signal when the micro-dispersed droplets pass through the optical fiber (4). The light intensity detector (7) is used to receive the light intensity signal; and The control system (8) is used to acquire the light intensity signal received by the light intensity detector (7) and to determine the diameter d of the micro-dispersed droplet based on the light intensity signal, including: Based on the light intensity signal, determine the initial times t1 and t2 when the micro-dispersed droplets arrive at the two diffuse reflection fiber optic sensors (2); Based on the light intensity signal, determine the times Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors (2); and The diameter d of the micro-dispersed droplet is determined based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection fiber optic sensors (2).

2. The fiber optic sensing system according to claim 1, characterized in that, The two optical fibers (3, 4) are perpendicular to the flow direction of the fluid; and The two optical fibers (3, 4) are arranged close together inside the diffuse reflection optical fiber sensor (2), and the ports of the two optical fibers (3, 4) are flush.

3. The fiber optic sensing system according to claim 1, characterized in that, The fluid detection channel (1) is made of a transparent material.

4. The fiber optic sensing system according to claim 1, characterized in that, The fiber optic sensing system also includes: A reflector (5) is installed on the other side of the fluid detection channel (1). The reflector (5) includes at least two reflectors, which are located opposite the diffuse reflection fiber optic sensor (2) to increase the light intensity signal reflected to the light intensity signal receiving end. The center of the reflector (5) is located at the middle position of the axis of symmetry of the two optical fibers (3, 4) in the diffuse reflection fiber optic sensor (2).

5. The fiber optic sensing system according to claim 4, characterized in that, The diameter of the reflector (5) is not less than twice the diameter of the optical fiber (3, 4) inside the diffuse reflection optical fiber sensor (2), wherein the diameter of the optical fiber (3, 4) does not exceed 1 / 2 of the side length of the cross-section of the fluid detection channel (1).

6. The fiber optic sensing system according to claim 1, characterized in that, The cross-section of the fluid detection channel (1) is square.

7. The fiber optic sensing system according to claim 1, characterized in that, The control system (8) is configured with a light intensity threshold for: The light intensity signal below the light intensity threshold is determined to be a characteristic signal of the micro-dispersed droplet passing through the diffuse reflection fiber optic sensor (2); and The light intensity acquisition time corresponding to the light intensity signal below the light intensity threshold is determined as the time when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor (2), wherein the time includes: The initial times t1 and t2 when the microdispersed droplets reach the two diffuse reflection fiber optic sensors (2); and The time Δt1 and Δt2 required for the microdispersed droplet to pass through each of the two diffuse reflection fiber optic sensors (2) are respectively.

8. The fiber optic sensing system according to claim 1, characterized in that, Determining the diameter d of the micro-dispersed droplet based on the light intensity signal includes: Based on the initial times t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors (2), the initial time difference Δt3 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors (2) is determined; The velocity v of the micro-dispersed droplets is determined based on the initial time difference Δt3 and the distance between the two diffuse reflection fiber optic sensors (2); Based on the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors (2), the first diameter d1 and the second diameter d2 of the micro-dispersed droplet are determined using the formula d = v × Δt × correction factor; and The diameter d of the micro-dispersed droplet is determined by using an arithmetic mean based on the first diameter d1 and the second diameter d2 of the micro-dispersed droplet.

9. The fiber optic sensing system according to claim 1, characterized in that, The fiber optic sensing system uses a monochromatic light source.

10. A method for detecting microdispersed droplets, the method comprising: The light intensity signals of at least two diffuse reflection fiber optic sensors (2) are collected. The at least two diffuse reflection fiber optic sensors (2) are respectively installed on one side of the fluid detection channel (1) containing micro-dispersed droplets to be measured, at the upstream and downstream positions of the fluid. Each diffuse reflection fiber optic sensor (2) includes at least two optical fibers (3, 4). One optical fiber (3) is connected to a light source (6) as a light emitting end, and the other optical fiber (4) is connected to a light intensity detector (7) as a light intensity signal receiving end. The light source (6) is used to emit light, and the light intensity signal receiving end is used to receive the light intensity signal when the micro-dispersed droplets pass through the optical fiber (4). Based on the light intensity signal, determine the initial times t1 and t2 when the micro-dispersed droplets arrive at the two diffuse reflection fiber optic sensors (2); Based on the light intensity signal, determine the times Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors (2); and The diameter d of the micro-dispersed droplet is determined based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection fiber optic sensors (2).

11. The method for detecting microdispersed droplets according to claim 10, characterized in that, The method further includes: The light intensity signal reflected to the light intensity signal receiving end is increased by the reflector (5). The reflector (5) is installed on the other side of the fluid detection channel (1). There are at least two reflectors (5), which are located opposite the diffuse reflection fiber optic sensor (2). The center of the reflector (5) coincides with the axis of symmetry of the two optical fibers (3, 4) in the diffuse reflection fiber optic sensor (5).

12. The method for detecting microdispersed droplets according to claim 11, characterized in that, The diameter of the reflector (5) is not less than twice the diameter of the optical fiber (3, 4) inside the diffuse reflection optical fiber sensor (2), wherein the diameter of the optical fiber (3, 4) does not exceed 1 / 2 of the side length of the cross-section of the fluid detection channel (1).

13. The method for detecting microdispersed droplets according to claim 10, characterized in that, The method further includes: The light intensity signal below a certain threshold is determined to be a characteristic signal of the micro-dispersed droplet passing through the diffuse reflection fiber optic sensor (2), wherein the light intensity threshold is set by the control system; and The light intensity acquisition time corresponding to the light intensity signal below the light intensity threshold is determined as the time when the micro-dispersed droplet passes through the diffuse reflection fiber optic sensor (2), wherein the time includes: The initial times t1 and t2 when the microdispersed droplets reach the two diffuse reflection fiber optic sensors (2); and The time Δt1 and Δt2 required for the microdispersed droplet to pass through each of the two diffuse reflection fiber optic sensors (2) are respectively.

14. The method for detecting microdispersed droplets according to claim 10, characterized in that, The step of determining the diameter d of the micro-dispersed droplet based on the initial times t1 and t2, the times Δt1 and Δt2, and the distance between the two diffuse reflection fiber optic sensors (2) includes: Based on the initial times t1 and t2 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors (2), the initial time difference Δt3 when the micro-dispersed droplet arrives at the two diffuse reflection fiber optic sensors (2) is determined; The velocity v of the micro-dispersed droplets is determined based on the initial time difference Δt3 and the distance between the two diffuse reflection fiber optic sensors (2); Based on the time Δt1 and Δt2 required for the micro-dispersed droplet to pass through each of the two diffuse reflection fiber optic sensors (2), the first diameter d1 and the second diameter d2 of the micro-dispersed droplet are determined using the formula d = v × Δt × correction factor; and The diameter d of the micro-dispersed droplet is determined by using an arithmetic mean based on the first diameter d1 and the second diameter d2 of the micro-dispersed droplet.

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