System and method for measuring surface tension and viscosity of high-temperature melt under pneumatic suspension condition

Abstract

The invention discloses a system and a method for measuring the surface tension and the viscosity of a high-temperature melt under a pneumatic suspension condition, and belongs to the technical field of material thermophysical property research. The system comprises an optical filtering unit, the front end of the optical filtering unit is arranged on the outer side of an observation window of the pneumatic suspension device and used for conducting spectrum selection and intensity attenuation on incident light signals, the rear end of the optical filtering unit is connected with a photoelectric sensing unit, and the photoelectric sensing unit is used for converting light signals into electric signals. The photoelectric sensing unit is connected with the data acquisition unit, the data acquisition unit is used for converting an electric signal into a digital signal, the data acquisition unit is connected with the information processing unit, and the information processing unit is used for processing the digital signal to realize measurement. According to the invention, the problems of signal quality, acquisition efficiency, environmental adaptability, operation convenience and the like in the prior art are solved, and the surface tension and viscosity value of the high-temperature melt under the pneumatic suspension condition can be accurately obtained based on an integrated optical filtering and high-fidelity photoelectric detection technology.

Description

Technical Field

[0001] This invention relates to the field of materials thermophysical property research technology, specifically to a system and method for measuring the surface tension and viscosity of high-temperature melts under aerodynamic suspension conditions. Background Technology

[0002] Surface tension and viscosity are important thermophysical parameters characterizing material properties, playing a crucial role in elucidating the evolution of their liquid structure, solidification kinetics, and service performance under extreme conditions. Traditional contact-based surface tension and viscosity measurement methods, such as the maximum bubble pressure method, pendant drop method, and rotating column method, are prone to inducing heterogeneous nucleation and cannot obtain the physical properties of liquid metals and ceramic melts in metastable states such as deep supercooling. Containerless technology provides technical support for the measurement of the physical properties of such high-temperature melts. Among them, pneumatic suspension technology, due to its unique advantages such as wide material applicability, high suspension stability, and strong process controllability, is mainly applied to containerless processing of high-melting-point materials such as refractory metals and oxide ceramics.

[0003] Under pneumatic suspension conditions, the droplet oscillation method is used to excite the melt to resonate, and the surface tension and viscosity of the high-temperature melt are calculated based on the resonant frequency and attenuation characteristics. This principle has been relatively maturely applied. However, existing technologies still face challenges in achieving high-precision and high-reliability measurements, mainly due to limitations in signal acquisition and processing.

[0004] Currently, most mainstream image-based methods rely on high-speed camera technology. This involves capturing the contour changes of a high-temperature melt during forced oscillation, extracting the time-varying radius sequence after image processing, and then obtaining physical property parameters through spectral analysis or attenuation fitting. While intuitive, this technique has limitations: First, in terms of data acquisition, the camera's frame rate limits the resolution of the acquired data, resulting in discrete point sequences. This makes it difficult to continuously and completely capture the detailed features of the melt's high-frequency oscillations, especially lacking the ability to describe key signals in the early stages of oscillation attenuation, leading to information loss. Acquiring kilohertz-level data requires extremely high-frame-rate CCD cameras, significantly increasing equipment costs. The massive amount of image data also places extremely high demands on subsequent image processing calculations, exacerbating the time cost and technical difficulty of data processing. Second, regarding signal quality, the high self-radiation intensity and continuous spectrum of the high-temperature melt easily cause local overexposure and edge blurring in the captured images, significantly reducing contour recognition accuracy. Even with backlighting, strong thermal radiation and stray light interference in the near-melt region are difficult to completely eliminate, resulting in a low image signal-to-noise ratio and affecting the reliability of subsequent analysis. Furthermore, in the data processing stage, due to the limitations of the nozzle structure and suspension position in the pneumatic suspension device, the acquired images often need to undergo multiple post-processing steps such as edge detection, ellipse fitting, and noise filtering. The process is complex and time-consuming, and multiple calculations may introduce cumulative errors, making it difficult to meet the experimental requirements for real-time analysis and rapid feedback.

[0005] To overcome the limitations of image-based methods in terms of temporal resolution and processing efficiency, photoelectric detection-based oscillation signal extraction methods have been widely applied in containerless technologies such as electromagnetic levitation. This method converts the optical signals from the oscillations and attenuation of the melt surface into electrical signals and obtains the resonant frequency and attenuation characteristics through Fast Fourier Transform. However, in practical applications of pneumatic levitation technology, the effectiveness of this method is significantly limited: in terms of signal extraction, the oscillation amplitude of the high-temperature melt surface is small, while its own thermal radiation intensity is high and highly volatile, creating strong background noise. Simultaneously, stray light in the experimental environment and the micro-movements of the sample and optical path caused by airflow disturbances further reduce the signal-to-noise ratio. Without a targeted and efficient signal filtering mechanism, effective data can easily be lost. Furthermore, traditional photoelectric detection devices often have fixed optical structures, making it difficult to adapt to the differences in the radiation spectra of different materials and lacking the ability to flexibly and accurately condition signals in high-temperature, high-radiation environments.

[0006] In summary, existing technologies based on the principle of droplet oscillation have significant shortcomings in terms of signal accuracy, acquisition continuity, environmental interference resistance, and system adaptability.

[0007] To address the aforementioned issues, there is an urgent need for a system and method for measuring the surface tension and viscosity of high-temperature melts under pneumatic suspension conditions, in order to resolve the problems associated with traditional methods. Summary of the Invention

[0008] The purpose of this invention is to provide a system and method for measuring the surface tension and viscosity of high-temperature melts under pneumatic suspension conditions. This invention solves the problems of existing technologies in terms of signal quality, acquisition efficiency, environmental adaptability, and ease of operation. Based on integrated optical filtering and high-fidelity photoelectric detection technology, it can achieve high signal-to-noise ratio acquisition and real-time processing of optical signals during melt oscillation, thereby accurately calculating thermophysical parameters and realizing completely non-contact, high-precision, in-situ measurement of the surface tension and viscosity of high-temperature melts.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A system for measuring the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions includes: an optical filtering unit, a photoelectric sensing unit, a data acquisition unit, and an information processing unit. The front end of the optical filtering unit is located outside the observation window of the pneumatic suspension device and is used to perform spectral selection and intensity attenuation of the incident light signal based on the high-temperature spectral characteristics of the melt under test. The rear end of the optical filtering unit is connected to the photoelectric sensing unit, which converts the accurately filtered light signal carrying the oscillation information of the high-temperature melt into an electrical signal. The photoelectric sensing unit is connected to the data acquisition unit, which converts the electrical signal into a digital signal. The data acquisition unit is connected to the information processing unit, which processes the acquired digital signal to achieve the measurement.

[0010] Furthermore, the optical filtering unit includes a protective housing, a filter assembly, a driving assembly, and a heat dissipation assembly. The front end of the protective housing has a circular light-transmitting hole, which faces the outside of the observation window of the pneumatic levitation device. The rear end of the protective housing is provided with a standard optical interface corresponding to the circular light-transmitting hole, and the standard optical interface is provided with a thread, through which the photoelectric sensing unit is connected. The filter assembly, the driving assembly, and the heat dissipation assembly are arranged inside the protective housing, and the driving assembly drives and connects to the filter assembly.

[0011] Furthermore, the filtering assembly includes a filter, a drive shaft, a filter wheel, and a wheel base. The wheel base is located at the bottom of the protective housing near the circular light-transmitting hole, and the drive shaft is located at the top of the wheel base. The filter wheel is mounted on the drive shaft, and multiple filters are mounted on the filter wheel, with each filter corresponding to the circular light-transmitting hole. The drive assembly is connected to the drive shaft and drives the drive shaft to rotate, thereby rotating the selected filter between the circular light-transmitting hole and the standard optical interface to achieve filtering.

[0012] Furthermore, the photoelectric sensing unit includes a focusing lens barrel, a coaxial aiming assembly, and a photodetector. The standard optical interface is connected to the focusing lens barrel via a thread, and the focusing lens barrel is connected to the photodetector. A replaceable focusing lens is fixedly installed at the front end of the focusing lens barrel by a pressure ring, and the coaxial aiming assembly is installed at the rear end of the focusing lens barrel.

[0013] Furthermore, the coaxial aiming assembly includes a beam splitter, an indicator laser, and a fixing fixture. The beam splitter and the fixing fixture are coaxially arranged at the top of the inner rear end of the focusing lens barrel, and the indicator laser is arranged on the fixing fixture.

[0014] Furthermore, the photodetector includes a shielding housing, a photodiode, a signal conditioning circuit, and a driving circuit. The front end of the shielding housing is provided with a standard optical interface, and the standard optical interface is provided with a thread to connect to the rear end of the focusing lens. The photodiode is disposed inside the standard optical interface of the shielding housing, the signal conditioning circuit is disposed inside the shielding housing, and the driving circuit is disposed on the lower side of the interior of the shielding housing. The driving circuit is connected to the signal conditioning circuit, and the signal conditioning circuit is connected to the photodiode.

[0015] Furthermore, the data acquisition unit includes an external high-speed data acquisition card and a data transmission line. The external high-speed data acquisition card is connected to the signal output terminal of the photoelectric sensing unit and the data input terminal of the information processing unit through the data transmission line.

[0016] Furthermore, the information processing unit includes a computer workstation and measurement and control calculation software deployed on the computer workstation. The measurement and control calculation software includes a system control and acquisition module, a signal preprocessing module, a feature analysis module, a physical property calculation module, and a data management module connected in sequence. The system control and acquisition module is connected to the optical filtering unit and is used to change the rotation position of the filter and acquire relevant data by controlling the drive component. The signal preprocessing module is used to perform noise reduction processing on the acquired digital signals. The feature analysis module is used to perform fast Fourier transform to extract the characteristic oscillation frequency of the melt and perform nonlinear fitting to obtain the oscillation decay time of the melt. The physical property calculation module is used to automatically calculate the thermophysical parameters of the high-temperature melt based on the physical formulas of melt surface tension and viscosity. The data management module is used to realize data storage and the generation and export of report results.

[0017] This invention also provides a method for measuring the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions, applied to the aforementioned system for measuring the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions, comprising: Step 1: Prepare the sample to be tested and establish the experimental environment; Step 2: Configure the optical path of the measurement system; Step 3: Set data acquisition parameters; Step 4: Based on the melt properties and radiation spectrum of the sample to be tested, control the filter wheel in the optical filtering unit through the measurement and control calculation software to switch it to the preset filter combination, and adjust the photodetector in the photoelectric sensing unit so that the amplitude of the digital signal output by the measurement system under static conditions is within 5% to 30% of the range of the data acquisition card; Step 5: Initiate the suspension and melting of the solid sample to be tested; Step 6: Excite the sample melt to generate second-order oscillations; Step 7: Acquire the second-order oscillation signal of the melt based on the measurement system; Step 8: Acquire melt damping attenuation signal based on the measurement system; Step 9: Repeat steps 6-8 to obtain multi-temperature data; Step 10: Perform data processing and calculate thermal property parameters based on the collected data.

[0018] Furthermore, the sample to be tested includes metals, inorganic non-metals, and metal ceramics.

[0019] In summary, the present invention has at least one of the following beneficial technical effects: 1. This invention achieves ultra-high resolution continuous acquisition of melt oscillation signals. Employing high-fidelity photoelectric detection technology, it can completely and continuously record the entire process of melt oscillation and attenuation, with a sampling rate reaching the kilohertz level. This fundamentally solves the problems of high-frequency information loss, insufficient temporal resolution, and large data volume and processing difficulties caused by the limited frame rate and data discreteness of image-based methods using high-speed cameras. It provides an efficient and reliable data foundation for accurate analysis of the liquid structure of melts.

[0020] 2. This invention improves the accuracy of the acquired data and the universality of the tested materials. Employing integrated optical filtering technology, this invention effectively suppresses the strong thermal radiation of the melt itself and major background noise such as ambient stray light from the signal source, based on the radiation characteristics of different materials. Combined with the electromagnetic shielding structure of the photoelectric sensing unit and the overall low-noise circuit design of the system, this invention effectively enhances the signal-to-noise ratio of the acquired optical, electrical, and digital signals, thereby improving the accuracy and reliability of extracting melt thermal property information in various material systems such as metals and ceramics.

[0021] 3. This invention employs a modular design and ensures high repeatability of the measurement process and data. The invention constructs a modular optical filtering and photoelectric sensing unit. The core optical components of the optical filtering unit can be flexibly configured and quickly replaced according to material properties and experimental conditions, enhancing the adaptability of the measurement system to different experimental requirements. The system's measurement method adopts integrated automated control and standardized operating procedures, connecting multiple steps such as optical path focusing, parameter optimization, signal acquisition, and data processing, reducing fluctuations caused by human operation, and ensuring that repeatable measurement data can be obtained in different experimental batches and operating environments.

[0022] 4. This invention synergistically optimizes research efficiency and cost-effectiveness. Employing automated data acquisition and intelligent analysis software, the system achieves efficient connectivity from signal acquisition to thermophysical parameter output, transforming the traditional image-based method of calculating and recognizing image contours one by one into a unified processing and analysis of digital signals, significantly improving research efficiency. The system of this invention has a compact structure and is easy to integrate, directly adaptable to existing aerodynamic suspension experimental platforms. It avoids the additional cost of introducing high-speed cameras to pursue high-frequency sampling, effectively reducing hardware investment, maintenance costs, and reliance on specialized technologies, providing a feasible path for technology transfer and large-scale application. Attached Figure Description

[0023] Figure 1 This is a system structure diagram of the present invention; Figure 2 These are the front and side views of the optical filter unit structure. Figure 3 This is a schematic diagram of the photoelectric sensing unit structure; Figure 4 This is a schematic diagram comparing the results measured by this invention with those measured by other methods. Figure 5 This is a schematic diagram of the method flow of the present invention.

[0024] Reference numerals: 1. Pneumatic suspension device; 2. Optical filtering unit; 21. Filter assembly; 21-1. Filter; 21-2. Drive shaft; 21-3. Filter wheel; 21-4. Wheel base; 22. Protective housing; 23. Drive assembly; 24. Heat dissipation assembly; 3. Photoelectric sensing unit; 31. Focusing lens barrel; 31-1. Focusing lens; 31-2. Beam splitter; 31-3. Indicating laser; 31-4. Fixing clamp; 32. Photodetector; 32-1. Drive circuit; 32-2. Electromagnetic shielding inner layer; 32-3. Metal outer shell; 32-4. Photodiode; 32-5. Signal conditioning circuit; 4. Data acquisition unit; 5. Information processing unit. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0026] like Figure 1As shown, this invention provides a system for measuring the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions, comprising: an optical filtering unit 2, a photoelectric sensing unit 3, a data acquisition unit 4, and an information processing unit 5. The front end of the optical filtering unit 2 is disposed outside the observation window of the pneumatic suspension device 1, and is used to perform spectral selection and intensity attenuation of the incident light signal based on the high-temperature spectral characteristics of the melt to be measured. The rear end of the optical filtering unit 2 is connected to the photoelectric sensing unit 3, which is used to convert the accurately filtered light signal carrying the oscillation information of the high-temperature melt into an electrical signal. The photoelectric sensing unit 3 is connected to the data acquisition unit 4, which is used to convert the electrical signal into a digital signal. The data acquisition unit 4 is connected to the information processing unit 5, which is used to process the acquired digital signal to achieve the measurement.

[0027] Each of these units will be introduced and explained in detail: 1. Optical filtering unit like Figure 2 As shown, the optical filtering unit 2 is the front-end signal processing part of this system, including a protective housing 22, a filter assembly 21, a driving assembly 23, and a heat dissipation assembly 24. The front end of the protective housing 22 has a circular light-transmitting hole facing the outside of the observation window of the pneumatic levitation device 1. The rear end of the protective housing 22 has a standard optical interface corresponding to the circular light-transmitting hole, and the standard optical interface has a thread for connecting to the photoelectric sensing unit 3. The filter assembly 21, the driving assembly 23, and the heat dissipation assembly 24 are housed inside the protective housing 22, and the driving assembly 23 drives and connects to the filter assembly 21. The components of the optical filtering unit 2 are described below: (1) Protective casing The protective housing 22 has a rectangular closed structure and is made of high-strength alloy, such as aluminum alloy or stainless steel. The inner wall of the housing is treated with black anodizing to absorb stray light. The front panel of the housing has a circular light-transmitting hole with a diameter of 15~35mm, and the rear panel is machined with standard optical interface internal or external threads for connection and fixation with the focusing lens tube 31 of the photoelectric sensing unit 3 via threads. One side wall of the housing has a flange opening and heat dissipation holes. The flange opening can be used to install a quartz glass observation window, a laser protective glass observation window, a blind plate, etc., for observing the internal structure and the light filtering status. The heat dissipation holes can be in various shapes such as round hole dot matrix, grid, strip, etc., for overall heat dissipation of the unit. The bottom or side of the housing has multiple standard threaded holes, such as M4 and M6 threaded interfaces, for connecting stainless steel optical support rods. Through multiple sets of steering adjustment clamps, the unit is stably installed on the external frame of the observation window of the pneumatic suspension device 1 and can be precisely adjusted. (2) Filter assembly The filtering assembly 21 includes a filter 21-1, a drive shaft 21-2, a filter wheel 21-3, and a wheel base 21-4. The wheel base 21-4 is located at the bottom of the protective housing 22 near the circular light-transmitting hole. The drive shaft 21-2 is located at the top of the wheel base 21-4. The filter wheels 21-3 are located on both sides of the drive shaft 21-2. Multiple filters 21-1 are arranged on the filter wheels 21-3, and the filters 21-1 are arranged corresponding to the circular light-transmitting hole. The drive assembly 23 drives the drive shaft 21-2 to rotate, thereby rotating the selected filter 21-1 between the circular light-transmitting hole and the standard optical interface to achieve filtering.

[0028] This invention provides an embodiment in which the filter roller 21-3 is electrically driven, made of a low thermal expansion alloy or engineering plastic, and has a diameter selectable from 50mm to 200mm. It is mounted on a roller base 21-4 within a protective housing 22 via a support bearing. The roller has 4 to 16 mounting holes evenly distributed along its circumference, each hole having an internal thread for screwing in and fixing a filter 21-1. Depending on the spectral filtering requirements, the filter roller 21-3 can be configured in a single row or multiple rows in parallel, connected in series via a drive shaft to achieve combined installation and continuous use of various filters 21-1. The filters 21-1 can be bandpass or sidepass filters of different wavelengths, including narrow bandpass filters, tunable bandpass filters, short-wavelength filters, neutral density filters, etc. The narrow-bandpass filter is used to precisely transmit light signals of a specific wavelength and strongly suppress background light from melt thermal radiation outside that band; the tunable bandpass filter adjusts its center wavelength through electronic control, temperature control, etc., for dynamic spectral matching and stray light filtering; the short-wavelength pass filter is used to cut off infrared thermal radiation to prevent excessive thermal radiation from damaging the downstream sensor; the neutral density filter is used to uniformly attenuate the light intensity across the entire passband to avoid signal oversaturation.

[0029] (3) Driver components The drive assembly 23 includes a stepper motor and a control circuit. The stepper motor is connected to the drive shaft of the filter rollers 21-3 via a coupling, and is used to control the switching of the rollers, realizing remote control and real-time selection of filter parameters. The control circuit is fixed inside the protective housing 22 with screws, and its integrated drive chip is connected to the stepper electrode. The communication interface and power cable of the drive assembly 23 are led out through a reserved interface at the bottom of the protective housing 22 for receiving control commands.

[0030] (4) Heat dissipation components The heat dissipation component 24 is fixed inside the protective housing 22 by thermally conductive silicone adhesive or mechanical threading, with its fixed position opposite to the external heat dissipation holes of the protective housing 22. The heat dissipation component 24 can be a miniature cooling fan or a heat pipe fin, used to reduce the impact of high-temperature molten heat radiation on the optical stability of the unit.

[0031] 2. Photoelectric sensing unit like Figure 3 As shown, the photoelectric sensing unit 3 includes a focusing lens barrel 31, a coaxial aiming assembly, and a photodetector 32. The standard optical interface is threaded to the focusing lens barrel 31, and the focusing lens barrel 31 is connected to the photodetector 32. A replaceable focusing lens 31-1 is fixedly mounted on the front end of the focusing lens barrel 31 by a retaining ring. The coaxial aiming assembly is located on the rear end of the focusing lens barrel 31. The components of the photoelectric sensing unit 3 will be described in detail below with reference to specific embodiments: (1) Focusing lens tube The focusing lens barrel 31 is a cylindrical light-shielding component with standard optical interface threads at both ends. It can be selected in various specifications such as 40~120mm in length. It is used to shield the light path and reduce stray light. The front thread is used to screw into the corresponding thread interface at the rear end of the protective housing 22 of the optical filter unit 2. The rear thread is used to connect to the corresponding interface at the front end of the housing of the photodetector 32. A replaceable focusing lens is fixedly installed inside the front end of the focusing lens barrel 31 by a pressure ring. Depending on the working distance of the measurement system and the parameters of the pneumatic suspension device 1, a variety of standard optical lenses can be selected for optical focusing, such as plano-convex lenses with a focal length of 200mm~900mm.

[0032] (2) Coaxial aiming assembly The coaxial aiming assembly includes a fixing clamp 31-4, an indicator laser 31-3, and a beam splitter 31-2, all integrated within the rear end of the focusing lens barrel 31. The fixing clamp 31-4 is an adjustable, small indicator laser clamp, fixed to the inner side wall of the lens barrel by screws. The indicator laser 31-3 is mounted in the fixing clamp 31-4 and can be a low-power red semiconductor indicator laser, etc. The beam splitter 31-2 is coaxially mounted with the indicator laser 31-3 in the fixing clamp 31-4. When the indicator laser 31-3 is activated, the laser light is refracted by the beam splitter and passes through the center of the focusing lens to form a spot on the sample under test, used for coaxial aiming and focusing before the experiment.

[0033] (3) Photodetector The photodetector 32 includes a shielding housing, a photodiode 32-4, a signal conditioning circuit 32-5, and a driving circuit 32-1. The shielding housing has a double-layer structure to suppress electromagnetic interference; it can be a metal outer shell 32-3 made of materials such as aluminum alloy or stainless steel, and an electromagnetic shielding inner layer 32-2 made of materials such as permalloy. The photodiode 32-4 converts optical signals into electrical signals and is fixed to the front end of the shielding housing using thermally conductive adhesive or threads, with its photosensitive surface facing the direction of optical signal reception. The signal conditioning circuit 32-5 preprocesses the electrical signals and is fixed inside the shielding housing using support screws. It integrates a low-pass filter, gain amplifier, etc., and is connected to the photodiode 32-4 via a flexible circuit board. The driving circuit 32-1 controls the photodetector 32 and is connected to the signal conditioning circuit 32-5 via connectors or other data lines. The signal output lines, power lines, and control lines of the signal conditioning circuit 32-5 and the driving circuit 32-1 are connected through an interface at the bottom of the shielding housing.

[0034] 3. Data Acquisition Unit The data acquisition unit 4 includes an external high-speed data acquisition card and a data transmission line, used to convert electrical signals into digital signals and upload them to the information processing unit 5. The acquisition card has a maximum sampling rate of not less than 100kHz and a resolution of not less than 16 bits. The data transmission line connects the signal output terminal of the photoelectric sensing unit 3 to the data input terminal of the information processing unit 5, and the connection method can be selected from soldering connection, PCIe connection, USB port external connection, etc.

[0035] 4. Information Processing Unit The information processing unit 5 includes a computer workstation and measurement and control calculation software deployed on the computer workstation. The measurement and control calculation software has a graphical interface and can be developed based on platforms such as LabVIEW, MATLAB, and Python. The software communicates with the driving component 23 of the optical filtering unit 2, the driving circuit 32-1 of the photoelectric sensing unit 3, and the acquisition card of the data acquisition unit 4 through the computer workstation's serial port or USB communication interface to exchange commands and data. The measurement and control calculation software includes a system control and acquisition module, a signal preprocessing module, a feature analysis module, a physical property calculation module, and a data management module connected in sequence. The system control and acquisition module is connected to the optical filtering unit 2 and is used to change the rotation position of the filter 21-1 and acquire relevant data by controlling the drive component 23. The signal preprocessing module is used to perform noise reduction processing on the acquired digital signals. The feature analysis module is used to perform fast Fourier transform to extract the characteristic oscillation frequency of the melt and perform nonlinear fitting to obtain the oscillation decay time of the melt. The physical property calculation module is used to automatically calculate the thermophysical parameters of the high-temperature melt based on the physical formulas of melt surface tension and viscosity. The data management module is used to realize data storage and the generation and export of report results. The melt surface tension... σ With viscosity η The physical formula is as follows: (1) (2) in, ρ The density of the melt. r 0 is the melt radius. ω 2 represents the second-order oscillation frequency of the melt. τ 2 is the decay time constant after the second-order oscillation of the melt.

[0036] like Figure 5 As shown, the present invention also provides a method for measuring the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions, applied to the above-mentioned system for measuring the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions, comprising: Step 1: Prepare the sample to be tested and establish the experimental environment.

[0037] The sample material can be selected from metals, inorganic non-metals, metal ceramics, etc., and near-spherical samples with a diameter of 2~10 mm are prepared using methods such as high-temperature sintering, electric arc melting, and laser melting. The sample is placed in a pneumatic levitation device, and the device cavity is evacuated to 10°C. -3 ~10 -5 Pa, then fill with protective gas to atmospheric pressure, repeating this process 2-6 times. The protective gas can be argon, helium, nitrogen-oxygen mixture, etc., depending on the properties of the sample to be tested and the experimental requirements.

[0038] Step 2: Create the optical path for the measurement system.

[0039] Use the optical support rod and optical support rod steering clamp to fix the optical filter unit of the measurement system to the outside of the observation window of the pneumatic suspension device, at a distance of 100~800mm from the sample. Screw the focusing lens tube at the front end of the photoelectric sensing unit into the standard interface at the rear end of the optical filter unit and lock it in place to complete the mechanical connection of the measurement system. Turn on the indicating laser of the photoelectric sensing unit, and adjust the direction and angle of the optical support rod so that the indicating laser spot is aligned with and focused on the center of the sample to be measured.

[0040] Step 3: Set data acquisition parameters.

[0041] Turn on the control power of each unit of the measurement system. Set parameters such as sampling rate, single sampling duration, and file storage path in the measurement and control calculation software of the information processing unit. The sampling rate is 1kHz~100kHz, and the single sampling duration is 2~20s.

[0042] Step 4: Determine the optical filter band.

[0043] Based on the melt properties and radiation spectrum of the sample to be tested, the filter wheel in the optical filtering unit is controlled by the measurement and control calculation software to switch to the preset filter combination. The photodetector in the photoelectric sensing unit is adjusted so that the amplitude of the digital signal output by the measurement system under static conditions is within 5% to 30% of the range of the data acquisition card.

[0044] Step 5: Suspension and melting of the solid sample to be tested.

[0045] Open the air path of the pneumatic levitation device to stably suspend the sample under the action of airflow, which is the same as the atmosphere inside the device. Start the heating laser to completely melt the sample and continue heating it to a superheated state of 30-500K. Maintain the sample melt in this superheated state for 2-10 seconds to ensure temperature uniformity. The laser can be a fiber laser or a carbon dioxide laser, etc. Adjust the power of the heating laser to stabilize the sample melt temperature at the target measurement value.

[0046] Step 6: Excite the sample melt to generate second-order oscillations.

[0047] After the melt temperature stabilizes, an oscillating excitation is applied to the melt sample under test through an external excitation source to induce the melt to generate second-order intrinsic oscillation. The excitation method can be selected by applying a sinusoidal sound wave of a specific frequency or a short-time pulse signal to the gas path.

[0048] Step 7: Acquire the second-order oscillation signal of the melt.

[0049] While step 6 is being performed, the data acquisition unit is controlled by the measurement and control calculation software to start acquiring and recording the second-order oscillation signal of the melt, with an acquisition duration of 2~20s.

[0050] Step 8: Acquire the melt damping attenuation signal.

[0051] Turn off the external excitation source to allow the melt to enter a damped decay state, and continue to collect and record its decay signal until the oscillation amplitude decays to the baseline. Repeat steps 6 to 8 to collect multiple sets of data.

[0052] Step 9: Obtain multi-temperature data.

[0053] Adjust the output power of the heating laser to stabilize the melt temperature of the sample at the new target measurement value. Repeat steps 6 to 8 to obtain complete oscillation and attenuation data of the sample at different temperatures. To ensure measurement accuracy, each temperature should be measured at least three times independently. After the measurement is completed, turn off the heating laser and the air path of the pneumatic levitation device in sequence.

[0054] Step 10: Data processing and calculation of thermophysical parameters.

[0055] The acquired digital signals are denoised in the measurement and control software. The feature analysis module of the operating software performs a fast Fourier transform on the second-order oscillation signal of the melt to obtain its intrinsic oscillation frequency; and performs nonlinear fitting on the damping attenuation signal of the melt to obtain its attenuation time constant. The physical property calculation module of the operating software automatically calculates and outputs the surface tension and viscosity values ​​of the melt at each temperature point after inputting relevant parameters. After the calculation is completed, the results report is exported, and the measurement system is closed.

[0056] This invention provides a specific embodiment, in which the structural parts will not be described in detail, but the selection of some components will be explained: 1. The focusing lens is a plano-convex focusing lens with a focal length of 450mm; 2. The wavelength of the indicator laser is selected as 650nm; 3. The data acquisition unit uses a data acquisition card with a 100kHz sampling rate and 16-bit resolution. Furthermore, the specific steps of this embodiment are as follows: Step 1: Prepare a high-purity Al₂O₃ sample with a diameter of 2.50 mm and a sphericity deviation within 3% using a CO₂ laser melting process. Place the sample on the suspension nozzle of the pneumatic levitation experimental apparatus, and evacuate the apparatus to 5 × 10⁻⁶ using a mechanical pump and a molecular pump. -3 Pa, then backfill with argon gas to 0.10 MPa, and purge the gas three times.

[0057] Step 2: Install the optical filtering unit 350mm outside the observation window of the pneumatic levitation experimental device, and configure a double-layer filter wheel, coupling an 800nm ​​narrow bandpass filter and a 1% neutral density filter. In the photoelectric sensing unit, select an 80mm long focusing lens tube and a 450mm focal length plano-convex lens, and set the signal gain of the photodetector to 10 times. Turn on the indicator laser and adjust its position and angle to focus the laser spot on the center of the sample to be tested.

[0058] Step 3: Start the measurement and control calculation software of the signal unit, set the sampling rate to 10kHz, the number of samples to 1000, the resolution to 16 bits, the input range to ±2V, and create a new experimental data storage path.

[0059] Step 4: Adjust the air path of the pneumatic suspension experimental device to stabilize the sample suspension, adjust the CO2 laser power to 100W to overheat the sample to 2253K, hold for 5s to ensure complete melting, and then adjust the CO2 laser power to reduce the sample temperature to 2203K.

[0060] Step 5: Turn on the sine wave loudspeaker to make the sample surface oscillate second order, collect the sample second order oscillation signal for 5 seconds, turn off the loudspeaker, collect the sample decay signal until the oscillation ends, and repeat this process 3 to 5 times.

[0061] Step 6: In the measurement and control calculation software of the information processing unit, noise is reduced and the collected data is calculated to obtain the surface tension and viscosity values ​​of Al2O3 melt at the measured temperature. The specific values ​​are shown in Table 1.

[0062] Table 1. Surface tension and viscosity of Al2O3 melt at the measured temperatures.

[0063] The present invention also provides the test results of surface tension and viscosity values ​​of Examples 3 and 4, and the specific test parameters are shown in Table 1.

[0064] A schematic diagram comparing the surface tension and viscosity values ​​of Al2O3 melt in the range of 2173~2653K measured using this invention with those measured using other methods is shown below. Figure 4As shown, the results indicate that the data obtained by this invention covers a wider temperature range and exhibits reduced data fluctuation. Solid dots in the figure represent experimentally measured surface tension values, solid squares represent experimentally measured viscosity values, and the solid line represents the fitting curve based on the experimental values. Hollow dots represent the surface tension measurement results of Gong et al., cited in: YP Gong, L Zhang, YD Yuan, WM Ma, SF Huang. Contactless surfacetension measurement of molten oxides using oscillating drop method in anaerodynamic levitator[J]. Heliyon, 10 (2024), e37992. Hollow squares represent the viscosity measurement results of Kondo et al.: T. Kondo, H. Muta, K. Kurosaki, F. Kargl, A. Yamaji, M. Furuya, Y. Ohishi. Density and viscosity of liquid ZrO2 measured by aerodynamic levitation technique, Heliyon 5 (2019), e02049. The data points in the two papers correspond to Figure 4 Data comparison.

[0065] Embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention may 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.

[0066] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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 illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0067] 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.

[0068] 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.

[0069] Contents not described in detail in this specification are prior art known to those skilled in the art. It is hereby indicated that the above description is intended to help those skilled in the art understand this invention, but does not limit the scope of protection of this invention. Any equivalent substitutions, modifications, improvements, or simplifications of the above descriptions that do not depart from the essential content of this invention fall within the scope of protection of this invention.

Claims

1. A system for measuring the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions, characterized in that, include: The device comprises an optical filtering unit, a photoelectric sensing unit, a data acquisition unit, and an information processing unit. The front end of the optical filtering unit is located outside the observation window of the pneumatic levitation device. It is used to perform spectral selection and intensity attenuation of the incident light signal based on the high-temperature spectral characteristics of the melt to be tested. The rear end of the optical filtering unit is connected to the photoelectric sensing unit. The photoelectric sensing unit is used to convert the accurately filtered light signal carrying the oscillation information of the high-temperature melt into an electrical signal. The photoelectric sensing unit is connected to the data acquisition unit. The data acquisition unit is used to convert the electrical signal into a digital signal. The data acquisition unit is connected to the information processing unit. The information processing unit is used to process the acquired digital signal to achieve the measurement.

2. The system for measuring the surface tension and viscosity of high-temperature melts under pneumatic suspension conditions according to claim 1, characterized in that, The optical filtering unit includes a protective housing, a filter assembly, a driving assembly, and a heat dissipation assembly. The front end of the protective housing has a circular light-transmitting hole, which faces the outside of the observation window of the pneumatic levitation device. The rear end of the protective housing is provided with a standard optical interface corresponding to the circular light-transmitting hole, and the standard optical interface is provided with a thread, which connects to the photoelectric sensing unit. The filter assembly, driving assembly, and heat dissipation assembly are arranged inside the protective housing, and the driving assembly drives and connects to the filter assembly.

3. The system for measuring the surface tension and viscosity of high-temperature melts under pneumatic suspension conditions according to claim 2, characterized in that, The filtering assembly includes a filter, a drive shaft, a filter wheel, and a wheel base. The wheel base is located at the bottom of the protective housing near the circular light-transmitting hole. The drive shaft is located at the top of the wheel base. The filter wheel is mounted on the drive shaft, and multiple filters are mounted on the filter wheel. The filters are arranged corresponding to the circular light-transmitting hole. The drive assembly is connected to the drive shaft and drives the drive shaft to rotate, thereby rotating the selected filter between the circular light-transmitting hole and the standard optical interface to achieve filtering.

4. The system for measuring the surface tension and viscosity of high-temperature melts under pneumatic suspension conditions according to claim 2, characterized in that, The photoelectric sensing unit includes a focusing lens barrel, a coaxial aiming assembly, and a photodetector. The standard optical interface is connected to the focusing lens barrel via a thread. The focusing lens barrel is connected to the photodetector. A replaceable focusing lens is fixedly installed at the front end of the focusing lens barrel by a pressure ring. The coaxial aiming assembly is installed at the rear end of the focusing lens barrel.

5. The system for measuring the surface tension and viscosity of high-temperature melts under pneumatic suspension conditions according to claim 4, characterized in that, The coaxial aiming assembly includes a beam splitter, an indicator laser, and a fixing fixture. The beam splitter and the fixing fixture are coaxially arranged on the top of the inner rear end of the focusing lens barrel, and the indicator laser is arranged on the fixing fixture.

6. The system for measuring the surface tension and viscosity of high-temperature melts under pneumatic suspension conditions according to claim 4, characterized in that, The photodetector includes a shielding housing, a photodiode, a signal conditioning circuit, and a driving circuit. The front end of the shielding housing is provided with a standard optical interface, and the standard optical interface is provided with a thread to connect to the rear end of the focusing lens. The photodiode is disposed inside the standard optical interface of the shielding housing. The signal conditioning circuit is disposed inside the shielding housing. The driving circuit is disposed on the lower side of the interior of the shielding housing. The driving circuit is connected to the signal conditioning circuit, and the signal conditioning circuit is connected to the photodiode.

7. The system for measuring the surface tension and viscosity of high-temperature melts under pneumatic suspension conditions according to claim 4, characterized in that, The data acquisition unit includes an external high-speed data acquisition card and a data transmission line. The external high-speed data acquisition card is connected to the signal output terminal of the photoelectric sensing unit and the data input terminal of the information processing unit through the data transmission line.

8. The system for measuring the surface tension and viscosity of high-temperature melts under pneumatic suspension conditions according to claim 7, characterized in that, The information processing unit includes a computer workstation and measurement and control calculation software deployed on the computer workstation. The measurement and control calculation software includes a system control and acquisition module, a signal preprocessing module, a feature analysis module, a physical property calculation module, and a data management module connected in sequence. The system control and acquisition module is connected to the optical filtering unit and is used to change the rotation position of the filter and acquire relevant data by controlling the drive component. The signal preprocessing module is used to perform noise reduction processing on the acquired digital signals. The feature analysis module is used to perform fast Fourier transform to extract the characteristic oscillation frequency of the melt and perform nonlinear fitting to obtain the oscillation decay time of the melt. The physical property calculation module is used to automatically calculate the thermophysical parameters of the high-temperature melt based on the physical formulas of melt surface tension and viscosity. The data management module is used to realize data storage and the generation and export of report results.

9. A method for determining the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions, applied to the system for determining the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions as described in any one of claims 1-8, characterized in that, include: Step 1: Prepare the sample to be tested and establish the experimental environment; Step 2: Configure the optical path of the measurement system; Step 3: Set data acquisition parameters; Step 4: Based on the melt properties and radiation spectrum of the sample to be tested, control the filter wheel in the optical filtering unit through the measurement and control calculation software to switch it to the preset filter combination, and adjust the photodetector in the photoelectric sensing unit so that the amplitude of the digital signal output by the measurement system under static conditions is within 5% to 30% of the range of the data acquisition card; Step 5: Initiate the suspension and melting of the solid sample to be tested; Step 6: Excite the sample melt to generate second-order oscillations; Step 7: Acquire the second-order oscillation signal of the melt based on the measurement system; Step 8: Acquire melt damping attenuation signal based on the measurement system; Step 9: Repeat steps 6-8 to obtain multi-temperature data; Step 10: Perform data processing and calculate thermal property parameters based on the collected data.

10. The method for determining the surface tension and viscosity of a high-temperature melt under pneumatic suspension conditions according to claim 9, characterized in that, The samples to be tested include metals, inorganic non-metals, and metal ceramics.

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