Experimental Device and Method for Simultaneously Measuring the Quality, Temperature, and Particle Size of Brine Droplets during Evaporation

Abstract

An experimental device and method for simultaneously measuring the mass, temperature and particle size of brine droplets during evaporation, comprising a gas path module, an adjustment module, an evaporation device, a droplet suspension device and a data acquisition and recording module; the gas path module is connected to the evaporation device; the adjustment module is arranged on the gas path module and is used for adjusting the gas flow rate and temperature; the droplet suspension device is arranged above the evaporation device, and the data acquisition and recording module is arranged around the transparent window of the evaporation device and on the droplet suspension device for acquiring the temperature and image data during droplet evaporation. The present invention realizes the simultaneous measurement of the mass, particle size, morphology and temperature of a single brine droplet evaporation process by calibrating the deflection change of the stainless steel suspension wire and the design of the droplet suspension device. The present invention sets a gas path rectifying device to stabilize the gas flow, and the combination of the stainless steel suspension wire and the thermocouple increases the damping characteristics of the suspension device, reducing the vibration problems of the droplet and the stainless steel suspension wire from two aspects.

Description

Technical Field

[0001] The present invention belongs to the technical field of evaporation experimental devices, and particularly relates to an experimental device and method for measuring the evaporation of brine droplets while measuring mass, temperature and particle size simultaneously. Background Art

[0002] Lithium, as a key upstream for transportation electrification and energy storage, is known as the "metal that drives the world forward", and its related industries are growing into a global strategic industry. China's lithium resources account for 10.4% of the total global lithium resources, of which 71.9% are brine lithium resources. Therefore, vigorously developing the technology for extracting lithium from salt lake brine is of great practical significance for getting rid of the dependence on foreign lithium ores and ensuring the resource security of China's strategic emerging industries. The spray evaporation technology plays an important role in the design of crystallization routes, the design and optimization of thermal systems, etc. for extracting lithium from salt lake brine. At present, most of the droplet evaporation models used for CFD calculation of spray evaporation are evaporation models of pure liquid droplets or single-phase liquid mixtures, and the research on the evaporation model of brine droplets containing precipitated crystals is still lacking.

[0003] By using a single-droplet evaporation experimental device, the evaporation law of a single brine droplet can be accurately measured, providing an experimental basis for the establishment of a brine single-droplet evaporation model.

[0004] However, most of the existing single-droplet evaporation experimental devices only measure the droplet particle size and temperature. During the evaporation process of brine droplets, the density changes violently, and the measurement of its mass plays a key role in establishing its evaporation model. The existing experimental devices that can measure the mass change of droplets need to separately measure physical quantities such as mass, particle size, and temperature, and cannot achieve the simultaneous measurement of multiple physical quantities of the same droplet. The randomness and uncertainty of the measurement are relatively large. In addition, due to the asymmetry of the evaporation crystallization of brine droplets, the accuracy of the particle size measurement of the existing measurement devices cannot be guaranteed. Therefore, the simultaneous measurement of the mass, temperature, and particle size during the evaporation process of brine droplets, especially the accurate measurement of the particle size, is an urgent problem to be solved. Summary of the Invention

[0005] The purpose of the present invention is to provide an experimental device and method for measuring the evaporation of brine droplets while measuring mass, temperature and particle size simultaneously to solve the above problems.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] An experimental device for measuring the evaporation of brine droplets while measuring mass, temperature and particle size simultaneously, comprising a gas path module, an adjustment module, an evaporation device, a droplet suspension device and a data acquisition and recording module; the gas path module is connected to the evaporation device; the adjustment module is arranged on the gas path module for adjusting the gas flow rate and temperature; the droplet suspension device is arranged above the evaporation device, and the data acquisition and recording module is arranged on the droplet suspension device for acquiring the temperature and image data of the droplet suspension device and the evaporation device.

[0008] Further, the evaporation device includes a base, a pipe interface, a buffer chamber, a contraction channel, a rectifying grid, a steady-flow evaporation section, and a transparent window; the pipe interface is arranged on the side of the buffer chamber, the contraction channel is arranged at the top of the buffer chamber, the rectifying grid is arranged inside the contraction channel, the top of the contraction channel is the steady-flow evaporation section, and four transparent windows are installed around the steady-flow evaporation section through slots.

[0009] Further, through holes are distributed around the base and fixed to the experimental table by screws.

[0010] Further, the droplet suspension device includes an acrylic round tube, a stainless steel wire, a slider, a suspension device base, and a guide rail; a stepped hole is opened in the vertical direction of the suspension device base, and the stepped hole is fixed to the slider by a suspension device base screw, and the slider is arranged on the guide rail; five through holes are opened in the horizontal direction of the suspension device base, four of which are thick through holes evenly distributed on both sides and an acrylic round tube is inserted inside, and a thin through hole is arranged in the middle and a stainless steel wire bent at ° is inserted inside; the stainless steel wire is located directly above the evaporation device.

[0011] Further, the data acquisition and recording module includes a hub, a temperature transmitter, a data acquisition card, a wire, a first camera, a second camera, an infrared thermal imager, an ambient temperature measurement thermocouple, and a droplet temperature measurement thermocouple; the first camera, the second camera, and the infrared thermal imager are respectively arranged at ° to each other on the top of the evaporation device, and the first camera, the second camera, and the infrared thermal imager are respectively connected to the hub through wires, one end of the hub is connected to the data acquisition card, the data acquisition card is connected to the temperature transmitter, the end of the stainless steel wire is vertically downward, and a droplet temperature measurement thermocouple is fixed by gluing; the ambient temperature measurement thermocouple and the droplet temperature measurement thermocouple are connected to the temperature transmitter.

[0012] Further, the other end of the hub is connected to a computer, and the DC power supply is respectively connected to the temperature transmitter and the data acquisition card.

[0013] Further, the gas path module includes an air generator, a gas flow meter, and a hose; the air generator and the gas flow meter are connected in sequence, and the gas flow meter is connected to the evaporation device through the hose.

[0014] Further, the adjustment system includes a valve and a gas heater; the valve is arranged between the air generator and the gas flow meter, and a gas heater is arranged on the hose.

[0015] Further, the operation method of the brine droplet evaporation experimental device for simultaneous measurement of mass, temperature, and particle size includes the following steps:

[0016] Turn on the air generator and data acquisition system, adjust the valves and gas heaters to make the gas flow rate and ambient temperature reach the experimental values. Pull out the transparent window upwards, suspend the droplet at the junction of the end of the stainless-steel filament and the thermocouple for measuring the droplet temperature, insert the transparent window downwards, and the droplet starts to evaporate.

[0017] During the evaporation process, the signals generated by the ambient temperature measurement thermocouple and the droplet temperature measurement thermocouple are transmitted to the data acquisition card through a two-channel temperature transmitter, and then transmitted to the computer to obtain the changes in the internal and ambient temperatures of the droplet. The infrared thermal imager measures the surface temperature of the droplet and transmits it to the computer through a hub; the first camera and the second camera transmit the pictures and videos of the droplet evaporation process taken to the computer through the hub to obtain the changes in the droplet diameter.

[0018] The measurement of the droplet mass requires calibrating the change in the deflection of the stainless-steel filament with the mass of the suspended droplet before the measurement starts. By processing the change in the position of the marked points in the pictures taken by the second camera, the mass change of the droplet during the evaporation process can be obtained, realizing the simultaneous measurement of the mass, temperature, and diameter of the brine droplet evaporation process.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] The present invention realizes the simultaneous measurement of the mass, diameter, morphology, and temperature of a single brine droplet evaporation process by calibrating the deflection change of the stainless-steel suspension wire and the design of the droplet suspension device.

[0021] The present invention sets up an air path rectifying device to stabilize the air flow, and the combination of the stainless-steel suspension wire and the thermocouple increases the damping characteristics of the suspension device, reducing the vibration problems of the droplet and the stainless-steel suspension wire from two aspects.

[0022] The present invention sets two camera positions that are 90° to each other and measures from multiple angles, solving the problem of asymmetric crystallization during the evaporation process of brine droplets.

[0023] The present invention can synchronously observe and record the real-time temperature of the brine droplet through the thermocouple and the infrared thermal imager, and the temperature distributions on the surface and inside of the droplet can be obtained respectively. Description of the Drawings

[0024] Figure 1 is the system schematic diagram of the present invention.

[0025] Figure 2 is the partial cross-sectional schematic diagram of the main structure of the evaporation device.

[0026] Figure 3 is the partial cross-sectional schematic diagram of the structure of the droplet suspension device.

[0027] Wherein: 1 - hub, 2 - temperature transmitter, 3 - data acquisition card, 4 - computer, 5 - DC power supply, 6 - valve, 7 - air generator, 8 - gas flowmeter, 9 - gas heater, 10 - rubber hose, 11 - evaporation device main body, 12 - wire, 13 - first camera, 14 - second camera, 15 - infrared thermal imager, 16 - droplet suspension device, 17 - steady-flow evaporation section, 18 - rectifying grid, 19 - contraction channel, 20 - buffer chamber, 21 - base, 22 - through hole, 23 - pipe interface, 24 - transparent window, 25 - acrylic round tube, 26 - stainless steel fine wire, 27 - environmental temperature measurement thermocouple, 28 - droplet temperature measurement thermocouple, 29 - slider, 30 - suspension device base body, 31 - guide rail. Specific embodiments

[0028] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments, and any equivalent transformation based on the technical solution of this application falls within the protection scope of the present invention.

[0029] Complying with the above technical solution, as Figures 1 to 3 shown

[0030] An experimental device for measuring the evaporation of brine droplets while measuring mass, temperature, and particle size simultaneously, comprising a gas path system, an adjustment system, an evaporation device main body, a droplet suspension device, and a data acquisition and recording system.

[0031] The gas path system is composed of an air filter, an air compressor, a gas storage tank, a flow rate adjustment device, a flowmeter, a gas heater, a rectifying device, and an evaporation chamber connected in sequence through pipelines;

[0032] The adjustment system includes a flow rate adjustment device and a temperature adjustment device;

[0033] The droplet suspension device includes a stainless steel suspension wire with a 90° bend at the end, an acrylic round tube, an environmental temperature measurement thermocouple, a droplet temperature measurement thermocouple, and a base body. The temperature measurement point of the droplet temperature measurement thermocouple is fixed at the tip of the stainless steel suspension wire by, but not limited to, spot welding, gluing, etc.;

[0034] The data acquisition and recording system includes a gas flowmeter, a light source, two cameras that are perpendicular to each other at 90°, an infrared thermal imager, a two-channel temperature transmitter, a data acquisition card, a DC power supply, a desktop computer, and related software. Among them, the cameras are fixed by a three-dimensional translation stage and can adjust the shooting position and focal length within a certain range;

[0035] The main body of the evaporation chamber has side windows in three directions for the cameras and the infrared thermal imager to shoot and collect data, and there is a switchable window in another direction. Droplets are suspended through the opened window, and evaporation is carried out with the window closed.

[0036] This embodiment provides an experimental device for simultaneously measuring the mass, temperature, and particle size of brine droplets, accurately measuring the evaporation law of a single brine droplet, establishing an evaporation model of brine droplets, and applying it to the calculation of CDF for brine spray evaporation.

[0037] An experimental device for simultaneously measuring the mass, temperature, and particle size of brine droplets according to the present invention includes a gas path system, an adjustment system, a main body 11 of the evaporation device, a droplet suspension device 16, and a data acquisition and recording system.

[0038] The gas path system includes a valve 6, an air generator 7, a gas flowmeter 8, a gas heater 9, a hose 10, and a main body 11 of the evaporation device. The air generator 7, the valve 6, the gas flowmeter 8, the gas heater 9, and the main body 11 of the evaporation device are sequentially connected through a rubber hose 10.

[0039] The adjustment system includes a valve 6 and a gas heater 9, which are respectively responsible for adjusting the gas flow rate and temperature in the evaporation chamber.

[0040] The main body 11 of the evaporation device includes a base 21, a pipe interface 23, a buffer chamber 20, a contraction channel 19, a rectifying grid 18, a steady-flow evaporation section 17, and a transparent window 24. Through holes 22 are distributed around the base 21 and are fixed to the experimental table by screws. Gas enters the buffer chamber 20 through the pipe interface 23 to stabilize the air pressure and flow rate, and then enters the steady-flow evaporation section 17 through the contraction channel 19 and the rectifying grid 18, and then passes into the atmosphere through the upper opening. Four transparent windows 24 are installed around the steady-flow evaporation section 17 through slots, and the windows can be removed for droplet transfer and suspension. The first camera 13 and the second camera 14 are mutually perpendicular at 90°, and the evaporation process of the droplet is photographed through the transparent window 24. The infrared thermal imager 15 photographs the droplet through the transparent window 24. The first camera 13, the second camera 14, the infrared thermal imager 15, and the droplet suspension device 16 are all arranged on the experimental tabletop through three-dimensional translation stages.

[0041] The droplet suspension device 16 includes an acrylic round tube 25, a stainless steel wire 26, an environmental temperature measurement thermocouple 27, a droplet temperature measurement thermocouple 28, a slider 29, a suspension device base 30, and a guide rail 31. The suspension device base 30 is vertically provided with a stepped hole and is fixed to the slider 29 by screws. The slider 29 can translate on the guide rail 31. The suspension device base 30 is horizontally provided with two rows of five through holes in total. Four relatively thick through holes are evenly distributed on both sides and are inserted with acrylic round tubes 25, and the relatively thin through hole is inserted with a stainless steel wire 26 with one end bent 90°. The end of the stainless steel wire 26 is vertically downward for suspending the droplet, and a droplet temperature measurement thermocouple 28 is fixed by adhesion. The environmental temperature measurement thermocouple 27 and the droplet temperature measurement thermocouple 28 are connected to the temperature transmitter 2 through wires 12 passing through the acrylic round tube 25.

[0042] The data acquisition and recording system includes a hub 1, a temperature transmitter 2, a data acquisition card 3, a computer 4, a DC power supply 5, wires 12, a first camera 13, a second camera 14, an infrared thermal imager 15, an ambient temperature measurement thermocouple 27, and a droplet temperature measurement thermocouple 28. Signals generated by the ambient temperature measurement thermocouple 27 and the droplet temperature measurement thermocouple 28 are transmitted to the data acquisition card 3 through the dual-channel temperature transmitter 2, and then connected to the hub 1. The DC power supply 5 is responsible for powering the temperature transmitter 2 and the data acquisition card 3. The first camera 13 and the second camera 14 transmit the captured droplet pictures and videos to the hub 1. The infrared thermal imager 15 is connected to the hub 1. The hub 1 transmits all kinds of data to the computer 4 for recording and processing.

[0043] The working process of the present invention is as follows:

[0044] Turn on the air generator 7 and the data acquisition system. Adjust the valve 6 and the gas heater 9 to make the gas flow rate and the ambient temperature reach the experimental values and stabilize for a period of time. Pull out the transparent window 24 upward, suspend the droplet at the junction of the end of the stainless steel wire 26 and the droplet temperature measurement thermocouple 28, and insert the transparent window 24 downward. The droplet starts to evaporate.

[0045] During the evaporation process, signals generated by the ambient temperature measurement thermocouple 27 and the droplet temperature measurement thermocouple 28 are transmitted to the data acquisition card 3 through the dual-channel temperature transmitter 2, and then transmitted to the computer 4 to obtain the temperature changes inside the droplet and in the environment. The infrared thermal imager 15 measures the surface temperature of the droplet and transmits it to the computer 4 through the hub 1. The first camera 13 and the second camera 14 transmit the captured droplet evaporation process pictures and videos to the computer 4 through the hub 1, and the droplet diameter change situation can be obtained after processing.

[0046] The measurement of the droplet mass requires calibrating the change of the deflection of the stainless steel wire 26 with the suspended droplet mass before the measurement starts. By processing the change of the marked point positions in the pictures taken by the second camera 14, the mass change of the droplet during the evaporation process can be obtained. Thus, the simultaneous measurement of the mass, temperature, and diameter of the brine droplet evaporation process can be realized.

Claims

1. An experimental device for simultaneously measuring the mass, temperature and particle size of brine droplets during evaporation, characterized in that, It includes an air path module, an adjustment module, an evaporation device (11), a droplet suspension device (16), and a data acquisition and recording module; the air path module is connected to the evaporation device (11); the adjustment module is arranged on the air path module and is used to adjust the air flow rate and temperature; the droplet suspension device (16) is arranged above the evaporation device (11), and the data acquisition and recording module is arranged around the transparent window (24) of the evaporation device (11) and on the droplet suspension device (16) for collecting the temperature and image data during droplet evaporation; The droplet suspension device (16) includes an acrylic round tube (25), a stainless steel wire (26), a slider (29), a suspension device base (30), and a guide rail (31); the suspension device base (30) is vertically provided with a stepped hole, and at the stepped hole, the suspension device base (30) is fixed to the slider (29) by screws, and the slider (29) is arranged on the guide rail (31); the suspension device base (30) is horizontally provided with five through holes, four of which are thick through holes evenly distributed on both sides and internally inserted with the acrylic round tube (25), and a thin through hole is arranged in the middle and internally inserted with the stainless steel wire (26) with its end bent 90°; the stainless steel wire (26) is located directly above the evaporation device (11), and its end extends into the stable flow evaporation section (17) of the evaporation device (11); The data acquisition and recording module includes a hub (1), a temperature transmitter (2), a data acquisition card (3), a wire (12), a first camera (13), a second camera (14), an infrared thermal imager (15), an ambient temperature measurement thermocouple (27), and a droplet temperature measurement thermocouple (28); the first camera (13), the second camera (14), and the infrared thermal imager (15) are respectively arranged around the transparent window (24) of the evaporation device (11) at an angle of 90° to each other, and the first camera (13), the second camera (14), and the infrared thermal imager (15) are respectively connected to the hub (1) through the wire (12), one end of the hub (1) is connected to the data acquisition card (3), the data acquisition card (3) is connected to the temperature transmitter (2), the end of the stainless steel wire (26) extends vertically downward, and the droplet temperature measurement thermocouple (28) is fixed by adhesion; the ambient temperature measurement thermocouple (27) and the droplet temperature measurement thermocouple (28) are connected to the temperature transmitter (2); The evaporation device (11) includes a base (21), a pipe interface (23), a buffer chamber (20), a contraction channel (19), a rectifying grid (18), a stable flow evaporation section (17), and a transparent window (24); the pipe interface (23) is arranged on the side of the buffer chamber (20), the top of the buffer chamber (20) is provided with the contraction channel (19), the top of the contraction channel (19) is provided with the rectifying grid (18), the top of the rectifying grid (18) is the stable flow evaporation section (17), and four transparent windows (24) are installed around the stable flow evaporation section (17) through slots.

2. The experimental device for measuring the evaporation of brine droplets while simultaneously measuring mass, temperature, and particle size according to claim 1, characterized in that, The base (21) is distributed with through holes (22) around it and is fixed to the experimental table by screws.

3. The experimental device for measuring the evaporation of brine droplets while simultaneously measuring quality, temperature and particle size according to claim 1, characterized in that, The other end of the hub (1) is connected to the computer (4), and the DC power supply (5) is respectively connected to the temperature transmitter (2) and the data acquisition card (3).

4. The experimental device for measuring the evaporation of brine droplets with simultaneous measurement of mass, temperature and particle size according to claim 1, characterized in that, The gas path module includes an air generator (7), a gas flow meter (8) and a hose (10); the air generator (7) and the gas flow meter (8) are connected in sequence, and the gas flow meter (8) is connected to the evaporation device (11) through the hose (10).

5. The experimental device for measuring the evaporation of brine droplets with simultaneous measurement of mass, temperature and particle size according to claim 4, characterized in that, The adjustment system includes a valve (6) and a gas heater (9); the valve (6) is arranged between the air generator (7) and the gas flow meter (8), and the gas heater (9) is arranged between the gas flow meter (8) and the evaporation device (11).

6. Operating method of the experimental device for evaporating brine droplets with simultaneous measurement of mass, temperature and particle size, characterized in that, The brine droplet evaporation experiment device for simultaneous measurement of mass, temperature and particle size according to any one of claims 1 to 5 includes the following steps: Turn on the air generator and the data acquisition system, adjust the valve and the gas heater to make the gas flow rate and the ambient temperature reach the experimental values, pull out the transparent window upward, suspend the droplet at the joint of the end of the stainless steel wire and the thermocouple for droplet temperature measurement, insert the transparent window downward, and the droplet starts to evaporate; During the evaporation process, the signals generated by the ambient temperature measurement thermocouple and the droplet temperature measurement thermocouple are transmitted to the data acquisition card through the dual-channel temperature transmitter, and then transmitted to the computer to obtain the changes in the internal and ambient temperatures of the droplet. The surface temperature of the droplet measured by the infrared thermal imager is transmitted to the computer through the hub; the first camera and the second camera transmit the pictures and videos of the droplet evaporation process taken through the hub to the computer to obtain the changes in the droplet particle size; The measurement of the droplet mass requires calibrating the change of the deflection of the stainless steel wire with the suspended droplet mass before the measurement starts. By processing the change of the position of the marked point in the picture taken by the second camera, the mass change of the droplet during the evaporation process can be obtained, realizing the simultaneous measurement of the mass, temperature and particle size of the brine droplet evaporation process.

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