Aerosol detection method and system based on micro-channel liquid level monitoring and near-field imaging
By using microfluidic liquid level monitoring and near-field imaging technology, the problem that existing methods cannot monitor trace amounts of ultrafine aerosol particles has been solved. This enables simultaneous characterization of aerosol generation rate and particle size distribution, improving the accuracy and resolution of aerosol detection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- TIANJIN UNIV
- Filing Date
- 2026-05-12
- Publication Date
- 2026-06-30
Smart Images
Figure CN122306630A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of micro-nano aerosol monitoring technology, and in particular to an aerosol detection method and system based on microchannel liquid level monitoring and near-field imaging. Background Technology
[0002] Aerosols are dispersion systems composed of solid or liquid particles suspended in a gas. Measuring aerosol particle size distribution and mass output has always been fundamental to aerosol monitoring. In recent years, advancements in microelectromechanical actuators (MEMS) and high-frequency acoustic atomization technology have made it possible to generate trace amounts of ultrafine aerosols (e.g., atomization flow rate < 0.05 mL / min, particle size 0.0005 mm–0.0020 mm). These trace amounts of ultrafine aerosols possess unique advantages in cutting-edge fields such as biomedicine, micro / nano manufacturing, and mass spectrometry due to their high specific surface area, long suspension time, Brownian motion-dominated diffusion, and strong permeability. Examples include achieving efficient deep lung deposition in inhalation therapy, preparing nanoscale functional coatings, and using ionization samplers in mass spectrometry analysis.
[0003] Existing aerosol characterization methods (such as phase Doppler particle analyzer (PDPA) and Malvern laser particle size analyzer) are mainly based on aerodynamics or electromigration characteristics. They are mostly designed for high-volume, large-diameter aerosol particles and can only achieve far-field monitoring. These methods not only cannot detect such trace and ultrafine aerosol particles and are difficult to construct constitutive relationships between aerosol generation rate and particle size distribution, but also cannot accurately obtain the particle size distribution at the instant of atomization in the near field. Summary of the Invention
[0004] In view of this, the present invention provides an aerosol detection method and system based on microchannel liquid level monitoring and near-field imaging, which realizes the monitoring of micro-atomized ultrafine (atomization flow rate < 0.05 mL / min, particle size 0.0005 mm-0.0020 mm) aerosol particles in the near-field instant during atomization, and can construct the constitutive relationship between the aerosol particle generation rate and particle size distribution.
[0005] To achieve the above objectives, the first aspect of this application provides an aerosol detection method based on microchannel liquid level monitoring and near-field imaging, comprising: containing a liquid to be atomized in a microchannel; outputting the liquid to be atomized to an atomization region through the microchannel to atomize and form aerosol droplets; monitoring the change in the liquid level position of the liquid to be atomized in the microchannel in real time, determining the liquid level movement rate based on the change in liquid level position, and determining the volume consumption rate of the liquid to be atomized per unit time based on the liquid level movement rate and the cross-sectional area of the microchannel; emitting a helium-neon laser at a near-field position of the atomization region, acquiring scattered light signals generated by the aerosol at different angles under the helium-neon laser, and determining the particle size distribution function of the aerosol droplets based on the scattered light signals; and determining the instantaneous mass output flux spectrum of the aerosol droplets based on the volume consumption rate and the particle size distribution function.
[0006] As described above, the technical solution provided in this aspect, due to the precise size of the microchannel, allows for high-precision monitoring of liquid surface displacement changes by using the microchannel as the liquid-containing vessel at the atomization front end. This enables the acquisition of liquid consumption rates below microliters per minute without the need for additional flow sensors, resulting in aerosol mass output accuracy down to the nanogram level (ng / s). Furthermore, this aspect utilizes a helium-neon laser emitted near the atomization region, allowing for direct acquisition of scattered light signals at different angles at the near-field location. Compared to existing far-field acquisition methods, this significantly improves the instantaneous spatial and temporal resolution of submicron-sized aerosol particles. By coupling the volume consumption rate and particle size distribution function, this aspect establishes a constitutive relationship between aerosol generation rate and particle size distribution, achieving synchronous, in-situ online characterization of mass output flux and particle size distribution.
[0007] As one possible implementation of the first aspect, determining the liquid surface movement rate based on the change in liquid surface position includes: obtaining the first liquid surface position of the liquid to be atomized in the microchannel at a first moment and the second liquid surface position at a second moment; calculating the difference between the first liquid surface position and the second liquid surface position to obtain the liquid surface displacement; and determining the liquid surface movement rate according to the liquid surface displacement and the time interval; wherein the time interval represents the time interval between the first moment and the second moment.
[0008] As one possible implementation of the first aspect, determining the volume consumption rate of the liquid to be atomized per unit time based on the liquid surface movement rate and the cross-sectional area of the microchannel includes: determining the liquid surface volume change rate based on the liquid surface movement rate and the cross-sectional area; and determining the volume consumption rate based on the liquid surface volume change rate.
[0009] As one possible implementation of the first aspect, determining the particle size distribution function of aerosol droplets based on the scattered light signal includes: acquiring the instantaneous scattering intensity of the aerosol droplets at different scattering angles at a preset frequency; and mapping the instantaneous scattering intensity to the particle size distribution function based on Mie scattering theory.
[0010] As one possible implementation of the first aspect, determining the instantaneous mass output flux spectrum of aerosol droplets based on the volume consumption rate and the particle size distribution function includes: the particle size of the aerosol droplets follows a log-normal distribution; converting the particle size distribution function into a volume distribution function with the aerosol droplet diameter as the independent variable; discretizing the volume distribution function into N particle size intervals according to the droplet diameter, and determining the volume fraction of each particle size interval; determining the total volume of aerosol droplets generated by atomization based on the volume consumption rate and time interval, and determining the volume output of droplets in each particle size interval based on the total volume of aerosol droplets and the volume fraction of each particle size interval; and determining the instantaneous mass output flux spectrum of the aerosol droplets based on the volume output of droplets in each particle size interval and the density of the liquid to be atomized.
[0011] As one possible implementation of the first aspect, the volume distribution function is determined by the following formula:
[0012] In the above formula, Let be the volume distribution function. The diameter of the aerosol droplet is [missing information]. droplet diameter The mean of the natural logarithm, droplet diameter The standard deviation of the natural logarithm.
[0013] As one possible implementation of the first aspect, determining the volume output of droplets for each particle size range based on the total volume of the aerosol droplets and the volume fraction of each particle size range includes: The volume output of the droplet in the k-th particle size range at time t is determined by the following formula:
[0014] In the above formula, Let be the volume output of the droplet in the k-th particle size range at time t. Let be the volume fraction of the k-th particle size range at time t. Let t be the total volume of the aerosol droplets at time t.
[0015] As one possible implementation of the first aspect, determining the volume output of droplets for each particle size range based on the total volume of the aerosol droplets and the volume fraction of each particle size range includes: The volume output of the droplet in the k-th particle size range at time t is determined by the following formula:
[0016] In the above formula, Let be the volume output of the droplet in the k-th particle size range at time t. Let be the volume fraction of the k-th particle size range at time t. Let t be the total volume of the aerosol droplets at time t.
[0017] As one possible implementation of the first aspect, the method is applied to a working condition where the aerosol droplet generation rate should be less than 0.05 mL / min and the aerosol droplet size is in the range of 0.0005 mm to 0.0020 mm.
[0018] A second aspect of this application provides an aerosol detection system based on microchannel liquid level monitoring and near-field imaging, comprising: a microchannel for containing a liquid to be atomized and outputting the liquid to be atomized to an atomization area to form aerosol droplets; a liquid level monitoring module for real-time monitoring of the liquid level position change of the liquid to be atomized in the microchannel, determining the liquid level movement rate based on the liquid level position change, and determining the volume consumption rate of the liquid to be atomized per unit time based on the liquid level movement rate and the cross-sectional area of the microchannel; a helium-neon laser near-field imaging module for emitting a helium-neon laser at the near-field position of the atomization area, acquiring the scattered light signals generated by the aerosol at different angles under the helium-neon laser, and determining the particle size distribution function of the aerosol droplets based on the scattered light signals; and a data processing module for determining the instantaneous mass output flux spectrum of the aerosol droplets based on the volume consumption rate and the particle size distribution function.
[0019] The beneficial effects in this regard can also be found in the descriptions of the beneficial effects in each part of the first aspect above.
[0020] A third aspect of this application provides a computing device, including: a communication interface and at least one processor; wherein the at least one processor is configured to execute program instructions, which, when executed by the at least one processor, cause the computing device to implement any of the methods described in the first aspect above.
[0021] The beneficial effects in this regard can also be found in the descriptions of the beneficial effects in each part of the first aspect above.
[0022] A fourth aspect of this application provides a computer-readable storage medium having program instructions stored thereon, which, when executed by a computer, cause the computer to perform any of the methods described in the first aspect above. Attached Figure Description
[0023] The various features of the present invention and the relationships between them are further explained below with reference to the accompanying drawings. The drawings are exemplary; some features are not shown to scale, and some drawings may omit conventional features in the field of this application that are not essential to this application, or additional features that are not essential to this application may be shown. The combination of features shown in the drawings is not intended to limit the present application. Furthermore, throughout this specification, the same reference numerals refer to the same things. Specific descriptions of the drawings are as follows: Figure 1 A first flowchart of an aerosol detection method based on microchannel liquid level monitoring and near-field imaging provided for embodiments of this application; Figure 2 This is a schematic diagram of the optical path for near-field imaging with a helium-neon laser provided in an embodiment of this application; Figure 3 A second flowchart of an aerosol detection method based on microchannel liquid level monitoring and near-field imaging provided for embodiments of this application; Figure 4 A schematic diagram of the structure of an aerosol detection system based on microchannel liquid level monitoring and near-field imaging provided for an embodiment of this application; Figure 5 A schematic diagram of the optical imaging arrangement of the microchannel and liquid level monitoring module provided in the embodiments of this application; Figure 6 This is a schematic structural diagram of a computing device provided in an embodiment of this application. Detailed Implementation
[0024] To make this application easier to understand, specific embodiments are described below to further illustrate this application. The technical solutions provided by this application are further explained below with reference to the accompanying drawings and examples. It should be understood that the system architecture and business scenarios provided in the embodiments of this application are mainly for illustrating possible implementations of the technical solutions of this application and should not be construed as the sole limitation on the technical solutions of this application. Those skilled in the art will recognize that, with the evolution of system architecture and the emergence of new business scenarios, the technical solutions provided by this application are equally applicable to similar technical problems.
[0025] It should be understood that the embodiments of this application provide an aerosol detection scheme based on microchannel liquid level monitoring and near-field imaging. Since these technical solutions solve the problem in the same or similar way, some repeated parts may not be described again in the following specific embodiments. However, it should be regarded as that these specific embodiments have referenced each other and can be combined with each other.
[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning as set forth in this specification or derived from the content described herein shall prevail.
[0027] Before introducing the embodiments of this application, it should be noted that in this application, aerosols are considered as inert particles that do not undergo phase change due to heat exchange during near-field flight. Only aerodynamic effects, heat transfer, and interparticle interactions are considered, while chemical reactions and mass transfer inside and outside the particles are not taken into account. This assumption applies to most liquid sample scenarios that are mainly physically atomized, especially biopharmaceutical solutions, functional coating precursors, and mass spectrometry injection solutions.
[0028] The solution provided in this application can be applied to scenarios where the aerosol droplet generation rate should be less than 0.05 mL / min and the aerosol droplet size is in the range of 0.0005 mm to 0.0020 mm to monitor aerosol droplets.
[0029] The following description, with reference to the accompanying drawings, details an aerosol detection method based on microchannel liquid level monitoring and near-field imaging provided in this application.
[0030] like Figure 1 The diagram shows a flowchart of an aerosol detection method based on microchannel liquid level monitoring and near-field imaging provided in this application embodiment. The implementation process of this method mainly includes S110-S140: S110: The microchannel contains the liquid to be atomized, and the liquid to be atomized is output to the atomization area through the microchannel to form aerosol droplets.
[0031] In this embodiment, the microchannel is a visible microchannel, such as a transparent microchannel, which allows for easy observation of changes in the liquid level of the liquid to be atomized inside. As one implementation, the cross-section of the microchannel can be rectangular; as another implementation, the cross-section can also be circular; as yet another implementation, the cross-section can also be triangular, etc.
[0032] In this embodiment, a microchannel with a rectangular cross-section is used. For example, the width w of the microchannel is 0.05mm to 0.5mm, the height h is 0.1mm to 0.2mm, and the length L is 2mm to 10mm. One end of the microchannel is connected to the liquid storage chamber, and the other end is connected to a high-frequency acoustic atomizer. This microchannel is used to output a small amount of liquid to be atomized to the high-frequency acoustic atomizer (i.e., the atomization area), thereby atomizing it into ultrafine aerosol droplets.
[0033] S120: Real-time monitoring of the liquid surface position change of the liquid to be atomized in the microchannel, determining the liquid surface movement rate based on the liquid surface position change, and determining the volume consumption rate of the liquid to be atomized per unit time based on the liquid surface movement rate and the cross-sectional area of the microchannel.
[0034] In this embodiment, real-time monitoring of the liquid surface position of the liquid to be atomized in the microchannel can be achieved based on optical imaging technology. For example, a scale with known graduations can be attached to the outside of the microchannel, the objective lens of an optical microscope with a long working distance can be aimed at the sidewall of the microchannel, and an image sequence of the liquid surface of the liquid to be atomized in the microchannel changing over time can be acquired at a high frame rate using a CCD (Charge-Coupled Device Camera). Based on image processing algorithms, the liquid surface position at different times can be extracted, and based on the calibration relationship between image pixels and actual size, the displacement change of image pixels can be converted into the displacement change of actual size.
[0035] In this embodiment, for a cross-sectional area of The microchannel, if the liquid to be atomized in the microchannel at the first moment The first liquid level position at that time In the second moment The second liquid level position at that time So the time interval between the first time point and the second time point The volume change of the liquid to be atomized can be expressed by the following formula:
[0036] In this embodiment, determining the liquid surface movement rate specifically includes: Obtain the liquid to be atomized in the microchannel at the first moment The first liquid level position at that time and at the second moment The second liquid level position at that time ; Calculate the position of the first liquid level Second liquid level position The difference is used to obtain the liquid surface displacement. Then, based on the liquid level displacement and time interval Determine the liquid surface movement rate Specifically, the rate of liquid surface movement. It can be calculated using the following formula:
[0037] in, The liquid surface movement rate, This is the liquid level displacement. The time interval between the first time point and the second time point. For the second moment, The first moment is the liquid level position. In this example, since the second moment is a later moment, the liquid level position at the second moment is subtracted from the liquid level position at the first moment to obtain the liquid level displacement.
[0038] Specifically, determining the volume consumption rate of the liquid to be atomized includes: Firstly, based on the liquid surface movement rate and the cross-sectional area of the microchannel Calculate the rate of change of liquid level volume Then based on the rate of change of liquid level volume Determine the volume consumption rate .
[0039] Specifically, the rate of change of liquid level volume It can be calculated using the following formula:
[0040] Volume consumption rate (That is, the atomized volumetric flow rate) can be calculated using the following formula:
[0041] in, Indicates the rate of volume consumption. This represents the cross-sectional area of the microchannel. This represents the rate of change of liquid level volume. Where the cross-sectional area is rectangular, then... Where w is the width of the microchannel and h is the height of the microchannel; if the cross-sectional area is circular, then .
[0042] In some embodiments, the mass output flux corresponding to the microchannel can also be calculated using the following formula. :
[0043] in, The density is the density of the liquid to be atomized.
[0044] S130: Emits a helium-neon laser to the near-field position of the atomization area, collects the scattered light signals of aerosols at different angles under the helium-neon laser, and determines the particle size distribution function of aerosol droplets based on the scattered light signals.
[0045] See also Figure 2 The schematic diagram of the near-field imaging optical path of a helium-neon laser shown illustrates one implementation method. A helium-neon laser with a wavelength of 632.8 nm can be used as the light source to emit helium-neon laser light towards the exit position of the high-frequency acoustic atomizer (i.e., the near-field position of the atomization region). A Fourier transform lens is used to focus the scattered light at different angles onto a multi-ring fan-shaped photodetector array, and the light is collected at a preset frequency (e.g., a frame rate greater than 10 kHz) to obtain the aerosol droplets at different scattering angles. Instantaneous scattering intensity Then, based on Mie scattering theory or a pre-established calibration curve, the instantaneous scattering intensity is... Mapped to particle size distribution function In this embodiment, the particle size distribution function is used to represent a specific time. Below is the number distribution density of droplets of different sizes in an aerosol, where the droplet size can be determined by the droplet radius. This can also be indicated by the droplet diameter. express.
[0046] In one implementation, the distance between the light source (helium-neon laser) and the collector (photodetector array) does not exceed 150mm.
[0047] S140: Determine the instantaneous mass output flux spectrum of aerosol droplets based on volume consumption rate and particle size distribution function.
[0048] In this embodiment, it is assumed that the droplet size generated by atomization follows a log-normal distribution, and the droplet size distribution function is expressed as follows: Convert to a volume distribution function with aerosol droplet diameter as the independent variable:
[0049]
[0050]
[0051] in, Where is the radius of the aerosol droplet. For time, The diameter of the aerosol droplet is [missing information]. The particle size distribution function is based on radius. The quantity distribution function is based on the diameter. This is an intermediate derivation formula, representing time. Lower volume distribution function, Let be the volume distribution function with aerosol droplet diameter as the independent variable. droplet diameter The mean of the natural logarithm, droplet diameter The standard deviation of the natural logarithm. Wherein, Used to represent the volume distribution of aerosol droplets, that is, how much volume droplets of different sizes occupy.
[0052] It should be understood that, in the above In the formula, by assuming that the droplet size generated by atomization follows a log-normal distribution, the measured droplet size distribution is fitted to obtain the calculated value. and .
[0053] In some embodiments, optionally, the volume distribution function is... Normalize using the following formula:
[0054] Then calculate the median particle size Dv(50) of the aerosol using the following formula:
[0055] It should be understood that in some embodiments, the aerosol size can be represented by the median particle size Dv(50). This application mainly targets particles with Dv(50) falling within the range of 0.0005 mm to 0.0020 mm, i.e., 0.5 μm to 2.0 μm. In this embodiment, the volume distribution function is discretized into N particle size intervals according to the droplet diameter, and the volume fraction of each particle size interval is determined. For example, the volume fraction of the k-th particle size interval at time t is expressed as: The volume fraction of each particle size range represents the proportion of the total volume of droplets within that range to the total volume of all aerosol droplets generated by atomization.
[0056] The total volume of aerosol droplets generated by atomization is determined based on the volume consumption rate (determined by S120) and the time interval. Specifically, the total volume of aerosol droplets at time t can be determined by the following formula:
[0057] in, Let be the total volume of the aerosol droplets at time t. For volume consumption rate, This is the time interval between the first time point and the second time point.
[0058] The volume output of each particle size range is determined based on the total volume of the aerosol droplets and the volume fraction of each particle size range. Specifically, the volume output of the droplets in the k-th particle size range at time t can be determined by the following formula:
[0059] in, Let be the volume output of the droplet in the k-th particle size range at time t. Let be the volume fraction of the k-th particle size range at time t. Let t be the total volume of the aerosol droplets at time t.
[0060] The instantaneous mass output flux spectrum of the aerosol droplets is determined based on the volumetric output of the droplets in each particle size range and the density of the liquid to be atomized. Specifically, it can be determined by the following formula:
[0061] in, This represents the instantaneous mass output flux of the aerosol droplet at time t in the k-th particle size range. This represents the mass output of the droplet in the k-th particle size range at time t. This indicates the density of the liquid to be atomized. Let be the volume output of the droplet in the k-th particle size range at time t. This is the time interval between the first time point and the second time point.
[0062] Based on the above mass output flux spectrum function, the mass output flux can be decomposed into various particle size ranges, thereby obtaining the particle size distribution function related to the output mass. By synchronously acquiring and time-aligning the liquid surface position change data and scattering data in the microchannel, the coupled characterization results of consumption rate (i.e. generation rate) and droplet particle size distribution can be obtained, thereby realizing aerosol detection. Its mass output resolution can reach up to the nanograms per second (ng / s) level.
[0063] In summary, as Figure 3 As shown, this embodiment acquires the liquid surface position change of the liquid to be atomized in the microchannel and calculates the volume consumption rate of the liquid to be atomized. It also acquires the scattered light signals of the aerosol generated by the helium-neon laser at different angles and determines the particle size distribution function of the aerosol droplets. Then, it obtains the mass output of different particle size ranges through the coupled calculation of the volume consumption rate and the particle size distribution function. This realizes the coupled calculation of consumption rate and particle size distribution, and enables the monitoring of aerosols with a droplet generation rate of less than 0.05 mL / min and a droplet size in the range of 0.0005 mm to 0.0020 mm.
[0064] In another embodiment of this application, an aerosol detection system based on microchannel liquid level monitoring and near-field imaging is also provided, such as... Figure 4 As shown, the detection system includes a microchannel 210, a liquid level monitoring module 220, a helium-neon laser near-field imaging module 230, and a data processing module 240.
[0065] The microchannel 210 is used to contain the liquid to be atomized and to output the liquid to be atomized to the atomization area to form aerosol droplets.
[0066] In this embodiment, the microchannel includes an inlet chamber 211 and a transparent channel 212. The transparent channel 212 includes an inlet end and an outlet end. The inlet chamber 211 is used to contain the liquid to be atomized and to transport the liquid to be atomized to the transparent channel 212 through the inlet end. The transparent channel 212 is used to output the liquid to be atomized to the atomization area through the outlet end to atomize and form aerosol droplets.
[0067] The liquid level monitoring module 220 is used to monitor the changes in the liquid level position of the liquid to be atomized in the microchannel in real time, determine the liquid level movement rate based on the changes in the liquid level position, and determine the volume consumption rate of the liquid to be atomized per unit time based on the liquid level movement rate and the cross-sectional area of the microchannel.
[0068] In this embodiment, as Figure 5 As shown, for example, a scale with known graduations is attached to the outside of the transparent channel 212 of the microchannel 210. The objective lens 221 of the optical microscope in the liquid level monitoring module 220 is aligned with the sidewall of the microchannel, and the CCD (Charge-Coupled Device Camera) 222 in the liquid level monitoring module 220 is used to acquire image sequences of the liquid level of the liquid to be atomized in the microchannel changing over time at a high frame rate, thereby obtaining the liquid level position in the transparent channel 212 at different times.
[0069] The helium-neon laser near-field imaging module 230 is used to emit a helium-neon laser to the near-field position of the atomization area, collect the scattered light signals of aerosols at different angles generated by the helium-neon laser, and determine the particle size distribution function of aerosol droplets based on the scattered light signals.
[0070] The data processing module 240 is used to determine the instantaneous mass output flux spectrum of aerosol droplets based on the volume consumption rate and particle size distribution function.
[0071] Figure 6 This is a schematic structural diagram of a computing device 900 provided in an embodiment of this application. This computing device can execute or implement various optional embodiments of the above-described methods. The computing device can be a terminal, or a chip or chip system within the terminal. Figure 6As shown, the computing device 900 includes: a processor 910, a memory 920, and a communication interface 930.
[0072] It should be understood that Figure 6 The communication interface 930 in the computing device 900 shown can be used to communicate with other devices, and may specifically include one or more transceiver circuits or interface circuits.
[0073] The processor 910 can be connected to the memory 920. The memory 920 can be used to store the program code and data. Therefore, the memory 920 can be a storage unit inside the processor 910, an external storage unit independent of the processor 910, or a component that includes both the storage unit inside the processor 910 and the external storage unit independent of the processor 910.
[0074] Optionally, the computing device 900 may also include a bus. The memory 920 and communication interface 930 can be connected to the processor 910 via the bus. The bus can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 The symbol is represented by a line without an arrow, but this does not mean that there is only one bus or one type of bus.
[0075] It should be understood that in the embodiments of this application, the processor 910 may be a central processing unit (CPU). The processor may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor. Alternatively, the processor 910 may employ one or more integrated circuits to execute relevant programs to implement the technical solutions provided in the embodiments of this application.
[0076] The memory 920 may include read-only memory and random access memory, and provides instructions and data to the processor 910. A portion of the processor 910 may also include non-volatile random access memory. For example, the processor 910 may also store device type information.
[0077] When the computing device 900 is running, the processor 910 executes computer execution instructions stored in the memory 920 to perform any of the operational steps of the above method and any of the optional embodiments thereof.
[0078] It should be understood that the computing device 900 according to the embodiments of this application can correspond to the corresponding subject in executing the methods according to the various embodiments of this application, and the above and other operations and / or functions of each module in the computing device 900 are respectively for implementing the corresponding processes of the methods of this embodiment. For the sake of brevity, they will not be described in detail here.
[0079] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.
[0080] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.
[0081] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.
[0082] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.
[0083] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.
[0084] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.
[0085] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, is used to perform the above-described method, which includes at least one of the schemes described in the above embodiments.
[0086] The computer storage medium in this application embodiment can be any combination of one or more computer-readable media. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. For example, a computer-readable storage medium can be, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.
[0087] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.
[0088] The program code contained on a computer-readable medium may be transmitted using any suitable medium, including, but not limited to, wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.
[0089] Computer program code for performing the operations of this application can be written in one or more programming languages or a combination thereof, including object-oriented programming languages such as Java, Smalltalk, and C++, and conventional procedural programming languages such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computer (e.g., via the Internet using an Internet service provider).
[0090] Furthermore, the terms "first, second, third, etc." or similar terms such as module A, module B, and module C used in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of objects. It is understood that, where permissible, a specific order or sequence may be interchanged so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.
[0091] In the above description, the labels of the steps involved, such as S110, S120, etc., do not mean that the steps will necessarily be executed. The order of the steps can be interchanged or executed simultaneously if permitted.
[0092] The term "comprising" as used in the specification and claims should not be construed as limiting itself to what follows; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned feature, integral, step, or component, but does not exclude the presence or addition of one or more other features, integrals, steps, or components, or groups thereof. Thus, the statement "device comprising means A and B" should not be limited to a device consisting solely of components A and B.
[0093] The terms "an embodiment" or "an embodiment" as used in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of this application. Therefore, the terms "in one embodiment" or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics can be combined in any suitable manner, as will be apparent to those skilled in the art from this disclosure.
[0094] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of this application, all of which fall within the scope of protection of this application.
Claims
1. A method for aerosol detection based on microfluidic liquid level monitoring and near-field imaging, characterized in that, include: The microchannel contains a liquid to be atomized, and the liquid to be atomized is output to the atomization area through the microchannel to form aerosol droplets. The liquid surface position change of the liquid to be atomized in the microchannel is monitored in real time. The liquid surface movement rate is determined based on the liquid surface position change. The volume consumption rate of the liquid to be atomized per unit time is determined based on the liquid surface movement rate and the cross-sectional area of the microchannel. A helium-neon laser is emitted towards the near-field position of the atomization area, and the scattered light signals generated by the aerosol at different angles under the helium-neon laser are collected. The particle size distribution function of the aerosol droplets is determined based on the scattered light signals. The instantaneous mass output flux spectrum of aerosol droplets is determined based on the volume consumption rate and the particle size distribution function.
2. The method of claim 1, wherein, The determination of the liquid surface movement rate based on the change in liquid surface position includes: The first liquid surface position of the liquid to be atomized in the microchannel at the first moment and the second liquid surface position at the second moment are obtained; Calculate the difference between the first liquid surface position and the second liquid surface position to obtain the liquid surface displacement. The liquid surface movement rate is determined based on the liquid surface displacement and the time interval; wherein the time interval represents the time interval between the first moment and the second moment.
3. The method of claim 1, wherein, The determination of the volume consumption rate of the liquid to be atomized per unit time based on the liquid surface movement rate and the cross-sectional area of the microchannel includes: The rate of change of liquid surface volume is determined based on the liquid surface movement speed and the cross-sectional area; The volume consumption rate is determined based on the liquid level change rate.
4. The method of claim 1, wherein, The determination of the aerosol droplet size distribution function based on the scattered light signal includes: The instantaneous scattering intensity of the aerosol droplets at different scattering angles is collected according to a preset frequency; The instantaneous scattering intensity is mapped to the particle size distribution function based on the Mie scattering theory.
5. The method of claim 4, wherein, The determination of the instantaneous mass output flux spectrum of aerosol droplets based on the volume consumption rate and the particle size distribution function includes: The particle size of the aerosol droplets follows a log-normal distribution, and the particle size distribution function is converted into a volume distribution function with the aerosol droplet diameter as the independent variable; The volume distribution function is discretized into N particle size intervals according to the droplet diameter, and the volume fraction of each particle size interval is determined. The total volume of aerosol droplets generated by atomization is determined based on the volume consumption rate and time interval, and the volume output of droplets in each particle size range is determined based on the total volume of aerosol droplets and the volume fraction of each particle size range. The instantaneous mass output flux spectrum of the aerosol droplets is determined based on the volume output of droplets in each particle size range and the density of the liquid to be atomized.
6. The method of claim 5, wherein, The volume distribution function is determined by the following formula: ； In the above formulae, is the volume distribution function, is the aerosol droplet diameter, is the droplet diameter is the average of the natural logarithm of the droplet diameter, is the droplet diameter is the standard deviation of the natural logarithm of the droplet diameter.
7. The method of claim 5, wherein, The determination of the droplet volume output for each particle size range based on the total volume of the aerosol droplets and the volume fraction of each particle size range includes: The volume output of the droplet in the k-th particle size range at time t is determined by the following formula: ； In the above formula, Vout(k) is the volume output of the droplets in the kth size interval at time t, Vout(k) is the volume output of the droplets in the kth size interval at time t, Vtot is the total volume of aerosol droplets at time t.
8. The method of claim 5, wherein, The step of determining the instantaneous mass output flux spectrum of the aerosol droplets based on the volume output of droplets in each particle size range and the density of the liquid to be atomized includes: The instantaneous mass output flux spectrum of the aerosol droplets is determined by the following formula: ； In the above formula, is the mass output flux of the kth particle size interval at time t, is the density of the liquid to be atomized, is the volume output of the droplets of the kth particle size interval at time t, is the time interval.
9. The method according to any one of claims 1-8, characterized in that, The method is applicable to working conditions where the aerosol droplet generation rate should be less than 0.05 mL / min and the aerosol droplet size is in the range of 0.0005 mm to 0.0020 mm.
10. An aerosol detection system based on microchannel liquid level monitoring and near-field imaging, characterized in that, include: Microchannels are used to contain the liquid to be atomized and to output the liquid to be atomized into aerosol droplets to the atomization area; The liquid level monitoring module is used to monitor the change in the liquid level position of the liquid to be atomized in the microchannel in real time, determine the liquid level movement rate based on the change in liquid level position, and determine the volume consumption rate of the liquid to be atomized per unit time based on the liquid level movement rate and the cross-sectional area of the microchannel. The helium-neon laser near-field imaging module is used to emit a helium-neon laser to the near-field position of the atomization area, collect the scattered light signals generated by the aerosol at different angles under the helium-neon laser, and determine the particle size distribution function of the aerosol droplets based on the scattered light signals. The data processing module is used to determine the instantaneous mass output flux spectrum of aerosol droplets based on the volume consumption rate and the particle size distribution function.