Fluid sample cell device for optical measurement

Abstract

The invention belongs to the technical field of fluid thermophysical property measurement, and discloses a fluid sample cell device for optical measurement, which comprises a sample cell body, the center of the sample cell body is provided with a cross-shaped cavity, and the surface of the sample cell body is hermetically provided with four quartz windows corresponding to the cross-shaped cavity. The outer sides of the four quartz windows are each provided with a side window flange in a sealed mode, and light through holes are formed in the centers of the four side window flanges. Wherein the four quartz windows are oppositely arranged in pairs, the sample cell body is also provided with a sample filling interface and a temperature measuring interface, the sample filling interface is connected with the cross-shaped cavity, and a first temperature sensor is arranged at the bottom of the temperature measuring interface close to the cross-shaped cavity. The volume phase property of pure or mixed fluid can be measured in combination with an optical measurement system, and a high-temperature and high-pressure environment can be provided for a sample.

Description

Technical Field

[0001] The present invention relates to a device for measuring the bulk properties of fluids, and particularly to a fluid sample cell device for optical measurement, which combines optical measurement methods to measure the thermal diffusivity of fluids under extreme conditions such as high temperature and high pressure, belonging to the technical field of measuring the thermophysical properties of fluids. Background Art

[0002] Optical measurement techniques are mainly applied in the chemical and biological fields for the analysis of the diameters and structures of macromolecules. Optical measurement methods can also be applied to the measurement of the thermophysical properties of fluids to obtain the thermal diffusivity, mass diffusivity, and sound velocity of the fluid bulk phase, etc. Compared with traditional thermophysical property measurement techniques, optical measurement has many advantages. First of all, optical measurement is a measurement in a state of equilibrium. When traditional methods measure transport properties such as diffusion coefficients, they must utilize their definitions, and the measurement process must meet certain limiting conditions. For example, when measuring the binary mass diffusivity using the interference method, a system that satisfies the one-dimensional diffusion model needs to be designed to measure the mass diffusivity of two fluids. Although the theoretical model of this method is relatively simple, the experimental design in actual measurement often cannot fully meet the requirements of the theoretical model, so various complex corrections must be made to the model. However, optical measurement starts after the fluid to be measured reaches macroscopic thermodynamic equilibrium, and the measurement process does not cause any disturbance to the fluid. Therefore, optical measurement is particularly suitable for measuring the transport properties of fluids in the near-critical region. Secondly, the optical measurement method is an absolute measurement method, and all the parameters required in the theoretical models can be directly or indirectly measured accurately. At the same time, the optical measurement method is a non-contact measurement method, which can avoid the contamination and damage caused by physical contact to the experimental samples.

[0003] However, no one in the prior art has designed an optical measurement device for measuring thermophysical properties such as the thermal diffusivity of fluids. Therefore, in order to realize the measurement of the bulk properties of fluids by the dynamic light method, a fluid sample cell device for optical measurement needs to be designed to meet the requirements for temperature and pressure regulation in actual optical measurement. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a fluid sample cell device for optical measurement, providing a basis for further expanding the measurement range of the optical measurement method and improving the measurement accuracy.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A fluid sample cell device for optical measurement, comprising: a sample cell body, a cross-shaped cavity is provided in the center of the sample cell body, and a first quartz window, a second quartz window, a third quartz window, and a fourth quartz window are respectively and hermetically provided at positions corresponding to the cross-shaped cavity on the surface of the sample cell body. A first side window flange, a second side window flange, a third side window flange, and a fourth side window flange are respectively and hermetically provided outside the first quartz window, the second quartz window, the third quartz window, and the fourth quartz window. A light passing hole is provided in the center of the first side window flange, the second side window flange, the third side window flange, and the fourth side window flange; wherein, the first quartz window and the third quartz window are oppositely arranged, the second quartz window and the fourth quartz window are oppositely arranged, and a sample filling interface and a temperature measurement interface are further provided on the sample cell body. The sample filling interface is connected to the cross-shaped cavity, and a first temperature sensor is provided at the bottom of the temperature measurement interface near the cross-shaped cavity.

[0006] A flange hole communicating with the cross-shaped cavity is further provided at the top of the sample cell body, and an upper flange is provided on the flange hole. The upper flange is fixedly connected to the sample cell body and is hermetically sealed at the top through a first O-ring;

[0007] The sample filling interface and the temperature measurement interface are provided inside the upper flange.

[0008] A chamfer with a radius of 5 mm - 10 mm and an angle of 60° is provided on the outer side of the light passing aperture of the first side window flange, the second side window flange, the third side window flange, and the fourth side window flange to increase the adjustment range of the light beam.

[0009] The fluid sample cell device for optical measurement further includes a second O-ring and a third O-ring provided on the inner and outer sides of the first quartz window, a fourth O-ring and a fifth O-ring provided on the inner and outer sides of the second quartz window, a sixth O-ring and a seventh O-ring provided on the inner and outer sides of the third quartz window, and an eighth O-ring and a ninth O-ring provided on the inner and outer sides of the fourth quartz window.

[0010] The bottom of the temperature measurement interface is 5 mm - 10 mm away from the liquid surface.

[0011] The sample filling interface is a 1 / 8 NPT interface and is connected to a high-temperature and high-pressure valve for realizing vacuum filling of the sample.

[0012] The diameter of the cross-shaped cavity for accommodating the sample solution in the sample cell body is 15 mm - 25 mm, and the sample volume is 10 mL - 25 mL.

[0013] An electric heating wire is provided on the surface of the sample cell body, and a heat-insulating material is coated on the surface of the electric heating wire. A temperature control interface with the same depth as the temperature measurement interface is also provided on the sample cell body. A second temperature sensor is arranged in the temperature control interface. The electric heating wire and the second temperature sensor are connected to a temperature controller to realize the temperature control in the sample cell body.

[0014] A radiation shield is provided outside the first side window flange, the second side window flange, the third side window flange and the fourth side window flange to reduce the influence of natural convection and radiation.

[0015] The fluid sample cell device for optical measurement further includes a first support column, a second support column and a third support column arranged at the bottom of the sample cell body.

[0016] The present invention has the following beneficial effects compared with the prior art:

[0017] 1. The present invention provides a fluid sample cell device for optical measurement. The device includes a sample cell with optical-grade windows, which can provide a sealed environment with high temperature and high pressure for the sample cell to perform precise temperature and pressure control. The temperature range that can be provided is from room temperature to 320 °C, and the pressure range is 0 - 10 MPa.

[0018] 2. The present invention can realize the fluid test conditions of different systems such as pure fluids, mixtures, and different gas phases. Combined with an optical measurement system, it can measure the bulk properties of pure substances or mixed fluids, such as thermal diffusion coefficient, mass diffusion coefficient, viscosity, sound velocity, etc., and is convenient for vacuum filling;

[0019] 3. By providing multiple transparent quartz windows, the present invention can realize visual adjustment of laser beams, improve the test efficiency and the signal-to-noise ratio of the signal; moreover, it has a large adjustment range of scattering angles. Description of the Drawings

[0020] Figure 1 It is the front view of a fluid sample cell device for optical measurement provided by an embodiment of the present invention;

[0021] Figure 2 It is the top view of a fluid sample cell device for optical measurement provided by an embodiment of the present invention;

[0022] Figure 3 It is Figure 2 the AA view of

[0023] Figure 4 It is Figure 2 the BB view of

[0024] In the figure, 1: sample cell body; 2: upper flange; 3: first O-ring seal; 4: sample filling interface; 5: temperature measurement interface; 6: first side window flange; 7: second side window flange; 8: third side window flange; 9: fourth side window flange; 10: second O-ring seal; 11: first quartz window; 12: third O-ring seal; 13: fourth O-ring seal; 14: second quartz window; 15: fifth O-ring seal; 16: sixth O-ring seal; 17: third quartz window; 18: seventh O-ring seal; 19: eighth O-ring seal; 20: fourth quartz window; 21: ninth O-ring seal; 22: first support column; 23: second support column; 24: third support column; 25: temperature control interface. Detailed implementation

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part rather than all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0026] As Figures 1 to 4 shown, an embodiment of the present invention provides a fluid sample cell device for optical measurement, including: a sample cell body 1, a horizontal cross-shaped cavity is provided at the center of the sample cell body 1, and a first quartz window 11, a second quartz window 14, a third quartz window 17, and a fourth quartz window 20 are respectively and hermetically arranged at positions corresponding to the cross-shaped cavity on the surface of the sample cell body 1. A first side window flange 6, a second side window flange 7, a third side window flange 8, and a fourth side window flange 9 are respectively and hermetically arranged outside the first quartz window 11, the second quartz window 14, the third quartz window 17, and the fourth quartz window 20. A light passing hole is provided at the center of the first side window flange 6, the second side window flange 7, the third side window flange 8, and the fourth side window flange 9; wherein, the first quartz window 11 and the third quartz window 17 are arranged oppositely, the second quartz window 14 and the fourth quartz window 20 are arranged oppositely, a sample filling interface 4 and a temperature measurement interface 5 are further provided on the sample cell body 1, the sample filling interface 4 is connected to the cross-shaped cavity, and a first temperature sensor is provided at the bottom of the temperature measurement interface 5 near the cross-shaped cavity.

[0027] Specifically, the first quartz window 11, the second quartz window 14, the third quartz window 17, and the fourth quartz window 20 are arranged at a central angle of 90 degrees on the surface of the sample cell body 1.

[0028] Specifically, as Figures 2 to 4As shown, in this embodiment, a flange hole communicating with the cruciform cavity is further provided at the top of the sample cell body 1, and an upper flange 2 is arranged in the flange hole. The upper flange 2 is fixedly connected to the sample cell body 1 and sealed at the top through a first O-ring 3; the sample filling interface 4 and the temperature measurement interface 5 are arranged in the upper flange 2.

[0029] Specifically, as Figures 3 to 4 shown, in this embodiment, chamfers with a radius of 5 mm - 10 mm and an angle of 60° are provided on the outer sides of the light-passing apertures of the first side window flange 6, the second side window flange 7, the third side window flange 8, and the fourth side window flange 9 to increase the adjustment range of the light beam. Actually, in the optical measurement system, the adjustment range of the scattering angle is 0° - 15° and 75° - 105°.

[0030] Specifically, as Figures 3 to 4 shown, a fluid sample cell device for optical measurement in this embodiment further includes a second O-ring 10 and a third O-ring 12 arranged on the inner and outer sides of the first quartz window 11, a fourth O-ring 13 and a fifth O-ring 14 arranged on the inner and outer sides of the second quartz window 14, a sixth O-ring 16 and a seventh O-ring 18 arranged on the inner and outer sides of the third quartz window 17, and an eighth O-ring 19 and a ninth O-ring 21 arranged on the inner and outer sides of the fourth quartz window 20.

[0031] The direction in which the measuring device of this embodiment is placed is as follows: the axis of the sample cell body 1 is perpendicular to the optical plane, and the test window formed by the four quartz windows is also perpendicular to the optical plane, providing conditions for horizontal detection for the optical measurement system; the four test windows are axially symmetrically distributed. In the optical measurement system, when measuring the thermal diffusion coefficient and the mass diffusion coefficient, especially when they are at different orders of magnitude, a small-angle scattering scheme is adopted. For small-angle optical measurement, any symmetric test window can be selected to construct the optical measurement system; for example, the first quartz window 11 is generally the entrance for incident light or detection light, and the opposite third quartz window 17 is the exit for transmitted light and scattered signal light; when the thermal diffusion coefficient and the mass diffusion coefficient are at the same order of magnitude, a large-angle scattering scheme is generally required; for a large-angle optical measurement system, for example, when the scattering angle is close to 90°, one pair of opposite windows can be selected to construct the detection light path or the incident light path, and the other pair of opposite windows at 90° serve as the exit for scattered light signals and the entrance for reference light; generally, a quartz window is fixedly selected as the incident light entrance window, that is, the first observation window, and the second measurement window, the third measurement window, and the fourth measurement window are arranged in sequence in the counterclockwise order; therefore, the first and third observation windows and the second and fourth observation windows form a group respectively, constituting the paths for detection light and reference light. The sealing structure of each measurement window is the same. The second, fourth, sixth, and eighth O-rings are for external flange sealing, and the third, fifth, seventh, and ninth O-rings are for internal sealing of the observation quartz windows.

[0032] Specifically, in this embodiment, the bottom of the temperature measurement interface 5 is 5 mm - 10 mm away from the liquid surface. This enables the first temperature sensor to more accurately measure the temperature of the sample in the sample cell. The aperture of the temperature measurement interface 5 is 3 mm - 5 mm. The first temperature sensor uses a Pt100 platinum resistance thermometer, and during measurement, it is ensured that the temperature-sensing part of the platinum resistance thermometer is in good contact with the bottom of the temperature measurement interface hole.

[0033] Specifically, in this embodiment, the materials of the first quartz window 11, the second quartz window 14, the third quartz window 17, and the fourth quartz window 20 are fused quartz, with the model JGS1.

[0034] Furthermore, the surface quality of the four quartz windows should reach 1 / 10 to 1 / 4 of the laser wavelength. The laser wavelength is 532 nm, and the parallelism requirement of the windows is 0.05 - 0.1.

[0035] Specifically, in this embodiment, the sample filling interface 4 is a 1 / 8 NPT interface, which is connected to a high-temperature and high-pressure valve for realizing vacuum filling of the sample. The upper temperature limit of the valve is 500 °C, and the upper pressure limit is 20 MPa. In practice, the connection and sealing between 1 / 8 NPT and the upper flange 2 use PTFE film.

[0036] Specifically, in this embodiment, the diameter of the cross-shaped cavity for accommodating the sample solution in the sample cell body 1 is 15 mm - 25 mm, and the sample volume is 10 mL - 25 mL.

[0037] Specifically, in this embodiment, an electric heating wire is provided on the surface of the sample cell body 1, and the surface of the electric heating wire is coated with a heat-insulating material. Specifically, the electric heating wire is evenly wound on the outer surface of the sample cell body 1 on the other surfaces except for the four quartz windows. A temperature control interface 25 with the same depth as the temperature measurement interface 5 is also provided on the sample cell body 1. A second temperature sensor is provided in the temperature control interface 25. The electric heating wire and the second temperature sensor are connected to a temperature controller to achieve temperature control in the sample cell body 1. Specifically, the temperature controller uses a PID control method for temperature control. In addition, the four measurement windows can be heat-insulated or assisted heated under high-temperature conditions to avoid additional heat loss. The second temperature sensor for temperature control uses a platinum resistance of Pt100, which is placed at the bottom of the temperature control interface 25 and is in good contact with the bottom of the hole; the hole depth of the temperature control interface 25 is the same as the depth of the temperature measurement interface 5; in order to achieve a temperature control accuracy of the mk level, a heat-insulating material is evenly coated outside the electric heating wire, especially a radiation shield is placed at the four side flanges to reduce the influence of natural convection and radiation. When the temperature reaches above 200 °C, 2 - 3 layers of radiation shields are added as needed to ensure the influence of natural convection heat dissipation on the temperature of the sample cell body. The pressure is realized by using gas pressurization or the vapor pressure of the sample itself.

[0038] Radiation shields are provided outside the first side window flange 6, the second side window flange 7, the third side window flange 8, and the fourth side window flange 9 to reduce the influence of natural convection and radiation.

[0039] In addition, in this embodiment, the high pressure in the sample cell body 1 is realized by using gas pressurization.

[0040] The fluid sample cell device for optical measurement further includes a first support column 22, a second support column 23, and a third support column 24 provided at the bottom of the sample cell body 1. The three support columns are connected to the bottom of the sample cell body 1 through M4 threads to stably and reliably fix the device on the optical platform.

[0041] Specifically, in this embodiment, the sample cell body 1, the upper flange 2, the first side window flange 6, the second side window flange 7, the third side window flange 8, the fourth side window flange 9, the first support column 22, the second support column 23, the third support column 24 and the flange mating screws are made of 316 steel, and the surface roughness requirement is 1.6, so as to evenly wind the electric heating wire on the other surfaces of the outer surface of the sample cell body 1 except for the four measurement windows and use a PID temperature controller for temperature control.

[0042] This embodiment provides a fluid sample cell device for optical measurement, which can be applied to measure the thermophysical properties of various fluids, such as thermal diffusion coefficient, mass diffusion coefficient and viscosity. With temperature control, the thermophysical property measurement of fluids can be realized at room temperature to 320 °C and pressure up to 10 Mpa, and it can be applied to the experimental research of systems such as refrigerants, fuels, gas-liquid diffusion systems, ionic liquids, refrigerants and lubricating oils.

[0043] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fluid sample cell device for optical measurement, characterized in that, Comprising: A sample cell body (1), a cross-shaped cavity is provided at the center of the sample cell body (1), and a first quartz window (11), a second quartz window (14), a third quartz window (17), and a fourth quartz window (20) are respectively and hermetically provided at positions corresponding to the cross-shaped cavity on the surface of the sample cell body (1). A first side window flange (6), a second side window flange (7), a third side window flange (8), and a fourth side window flange (9) are respectively and hermetically provided outside the first quartz window (11), the second quartz window (14), the third quartz window (17), and the fourth quartz window (20). A light passing hole is provided at the center of the first side window flange (6), the second side window flange (7), the third side window flange (8), and the fourth side window flange (9); wherein, the first quartz window (11) and the third quartz window (17) are oppositely arranged, the second quartz window (14) and the fourth quartz window (20) are oppositely arranged. A sample filling interface (4) and a temperature measurement interface (5) are further provided on the sample cell body (1). The sample filling interface (4) is connected to the cross-shaped cavity, and a first temperature sensor is provided at the bottom of the temperature measurement interface (5) near the cross-shaped cavity.

2. The fluid sample cell device for optical measurement according to claim 1, characterized in that A flange hole communicating with the cross-shaped cavity is further provided at the top of the sample cell body (1), and an upper flange (2) is provided on the flange hole. The upper flange (2) is fixedly connected to the sample cell body (1) and is hermetically sealed at the top through a first O-ring (3); The sample filling interface (4) and the temperature measurement interface (5) are provided inside the upper flange (2).

3. A fluid sample cell device for optical measurement according to claim 1, characterized in that, A chamfer with a radius of 5 mm - 10 mm and an angle of 60° is provided outside the light passing aperture diameter of the first side window flange (6), the second side window flange (7), the third side window flange (8), and the fourth side window flange (9) to increase the adjustment range of the light beam.

4. A fluid sample cell device for optical measurement according to claim 1, characterized in that, Also included are a second O-ring (10) and a third O-ring (12) provided on the inner and outer sides outside the first quartz window (11), a fourth O-ring (13) and a fifth O-ring (14) provided on the inner and outer sides outside the second quartz window (14), a sixth O-ring (16) and a seventh O-ring (18) provided on the inner and outer sides outside the third quartz window (17), and an eighth O-ring (19) and a ninth O-ring (21) provided on the inner and outer sides outside the fourth quartz window (20).

5. A fluid sample cell device for optical measurement according to claim 1, characterized in that, The bottom of the temperature measurement interface (5) is 5 mm - 10 mm away from the liquid level.

6. The fluid sample cell device for optical measurement according to claim 1, characterized in that, The sample filling interface (4) is a 1 / 8 NPT interface and is connected to a high-temperature and high-pressure valve for realizing vacuum filling of the sample.

7. The fluid sample cell device for optical measurement according to claim 1, characterized in that, The diameter of the cross-shaped cavity for accommodating the sample solution in the sample cell body (1) is 15 mm - 25 mm, and the sample volume is 10 mL - 25 mL.

8. A fluid sample cell device for optical measurement according to claim 1, characterized in that, An electric heating wire is provided on the surface of the sample cell body (1), and the surface of the electric heating wire is coated with a heat-insulating material. A temperature control interface (25) with the same depth as the temperature measurement interface (5) is further provided on the sample cell body (1). A second temperature sensor is provided in the temperature control interface (25). The electric heating wire and the second temperature sensor are connected to a temperature controller to achieve temperature control within the sample cell body (1).

9. The fluid sample cell device for optical measurement according to claim 1, wherein A radiation shield is provided outside the first side window flange (6), the second side window flange (7), the third side window flange (8) and the fourth side window flange (9) to reduce the influence of natural convection and radiation.

10. The fluid sample cell device for optical measurement according to claim 1, characterized in that, It further includes a first support column (22), a second support column (23) and a third support column (24) provided at the bottom of the sample cell body (1).

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