Device and method for measuring subcooling of liquid

Abstract

The present invention provides a device and method for measuring the supercooling of a liquid. The device includes a constant temperature chamber, within which a horizontally positioned glass capillary tube is secured by a fixture. The liquid to be measured is placed within the glass capillary tube. The liquid is placed within the horizontal glass capillary tube, the temperature of which is adjusted to below the supercooling value. By observing the freezing process of the glass capillary tube, the axial freezing rate is determined, thereby calculating the supercooling value of the liquid. By utilizing the ultra-fast freezing rate at the inner wall of the glass capillary tube, the present invention enables non-invasive measurement of the liquid's supercooling value, avoiding the influence of test components and contamination of the sample.

Description

Technical Field

[0001] The present invention relates to the field of liquid supercooling measurement, and in particular to a device and method for measuring the supercooling of a liquid. Background Art

[0002] Liquids do not freeze at their theoretical freezing point; freezing occurs only after a certain degree of supercooling. This degree of supercooling is closely related to the impurities and composition of the liquid. For pure water, it has been reported to be between -30°C and -1°C. Currently, the main measurement method uses thermocouples to measure the temperature at which the liquid begins to change phase. This invasive method not only contaminates the sample but also introduces new impurities, affecting the measurement results. Therefore, a non-invasive method for measuring liquid supercooling is urgently needed. Summary of the Invention

[0003] In order to solve the problems of the prior art, the present invention provides a device and method for measuring the supercooling of a liquid. The device and method utilize the ultra-fast freezing rate at the inner wall of a glass capillary to obtain the supercooling of the liquid. The device and method can measure the supercooling of the liquid non-invasively, avoiding the influence of test elements and contamination of the sample.

[0004] The invention comprises a constant temperature box, in which a horizontally placed glass capillary is fixed by a fixing device, and liquid to be tested is arranged in the glass capillary.

[0005] The fixing device comprises a base arranged in a constant temperature box, and the glass capillary is clamped and fixed on the base by a capillary fixing clamp.

[0006] The capillary tube wall is provided with a scale ruler, and a camera facing the scale ruler is provided outside the constant temperature box.

[0007] The thermostat is provided with a temperature regulating device which regulates the temperature range between -40°C and 20°C.

[0008] The liquid to be tested includes ultrapure water, tap water, saline, and deionized water.

[0009] The capillary has a diameter of 0.1 mm to 0.5 mm.

[0010] The thermostat provides a low-temperature environment for the detection of liquid supercooling, so as to enable the liquid to reach supercooling and undergo phase change.

[0011] Glass capillaries are selected as capillaries, and the phase change of liquid in the capillary can be clearly captured.

[0012] The capillary fixing clamp is used to keep the capillary in a stable state and provides a ruler to measure the axial frozen length of the liquid in the capillary using a camera.

[0013] The base tightly assembles the above components.

[0014] The camera records the supercooling freezing process of the liquid in the capillary tube, and the supercooling degree of the liquid is obtained from the freezing speed.

[0015] The present invention also provides a method for measuring the supercooling of a liquid. The liquid is placed in a horizontal glass capillary tube and the temperature is adjusted to below -20°C. By observing the freezing process of the glass capillary tube, the axial freezing rate is obtained, and the supercooling of the liquid is calculated. The calculation formula is: ;

[0016] in, is the diffusion coefficient of the liquid, is the latent heat of the liquid, d is the distance between liquid molecules, is Avogadro's constant, k is Boltzmann's constant, For freezing point.

[0017] The device and method for obtaining the supercooling degree of a liquid by utilizing the ultrafast freezing speed at the inner wall of a glass capillary tube adopt the above-mentioned experimental device and specifically include the following steps:

[0018] 1) Pour the test liquid into the glass capillary and place the capillary in the center of the moving platform;

[0019] 2) Turn on the thermostat and set the thermostat temperature to below the subcooling level, usually below -20°C;

[0020] 3) Open the camera to record;

[0021] 4) After the liquid has axially frozen, view the freezing process of the capillary wall captured by the camera to obtain the axial freezing rate, and calculate the liquid's supercooling.

[0022] The beneficial effects of the present invention are:

[0023] 1. By utilizing the ultra-fast freezing speed at the inner wall of the glass capillary, the present invention can non-invasively measure the supercooling of the liquid, and the measurement results are not affected by impurities.

[0024] 2. The present invention requires less liquid sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1It is a structural schematic diagram of a specific embodiment of the present invention.

[0027] In the figure, 1 is a constant temperature box; 2 is a capillary; 3 is a capillary clamp; 4 is a base; 5 is a sample; 6 is a camera; 7 is a ruler. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] The present invention provides a device for measuring the supercooling degree of a liquid by utilizing the ultrafast freezing speed at the inner wall of a glass capillary tube. A specific embodiment is as follows: Figure 1 As shown, it includes a constant temperature box 1, a base 4 is provided in the constant temperature box 1, a vertical guide rail is provided on the base 4, and a glass capillary 2 is clamped on the top of the vertical guide rail through a capillary fixing clamp 3; the glass capillary 2 is provided with a liquid to be tested.

[0030] The wall of the capillary tube 2 is provided with a scale 7, and a camera 6 facing the scale is provided outside the constant temperature box 1.

[0031] The thermostat 1 can be temperature-adjusted within a range of -40°C to 20°C.

[0032] The liquid sample includes ultrapure water, tap water, saline, and deionized water.

[0033] The diameter of the capillary tube 2 is 0.1 mm to 0.5 mm, and the angle between the capillary tube 2 and the vertical direction is 90°.

[0034] Taking ultrapure water as an example, the following test process is carried out:

[0035] 1. Aspirate the test ultrapure water into the glass capillary and place the capillary in the holder, ensuring that the liquid column is in the middle.

[0036] 2. Open the thermostat and set the thermostat temperature to -40°.

[0037] 3. Turn on the camera to record and shoot the freezing process of the glass tube wall to obtain the freezing speed. Get the liquid subcooling. is the diffusion coefficient of the liquid, is the latent heat of the liquid, d is the distance between liquid molecules, is Avogadro's constant, k is Boltzmann's constant, For freezing point.

[0038] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, the above is only a preferred embodiment of the present invention. Since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited to this. Any technical personnel familiar with this technical field is within the technical scope disclosed by the present invention. For ordinary technical personnel in this technical field, changes or replacements that can be easily thought of should be covered within the protection scope of the present invention without departing from the principle of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for measuring the supercooling of a liquid, comprising a device for measuring the supercooling of a liquid, comprising a thermostat (1), a glass capillary (2) fixed in the thermostat (1) by a fixing device, and a liquid to be measured arranged in the glass capillary (2), characterized in that: Place the liquid in a horizontal glass capillary and adjust the temperature below -20°C. By observing the freezing process of the glass capillary, the axial freezing rate is obtained, and the liquid supercooling is calculated using the following formula: ； Among them, D L is the diffusion coefficient of the liquid, is the latent heat of the liquid, d is the distance between liquid molecules, N A is Avogadro's constant, k is Boltzmann's constant, T f For freezing point.

2. The method for measuring the subcooling degree of a liquid according to claim 1, characterized in that The specific process is as follows: 1) Add the test liquid into the sample box, draw a small amount of liquid with a glass capillary, and place it horizontally on the stand; 2) Turn off the thermostat and set the thermostat temperature; 3) After the temperature of the incubator stabilizes, turn on the camera to record; 4) When the temperature drops below -20°C, use a camera to capture the additional freezing process of the tube wall, obtain the axial freezing velocity, and thus calculate the liquid supercooling.

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