Water surface evaporation capacity measuring device and method based on light interference principle

Abstract

The invention discloses a water surface evaporation capacity measuring device based on a light interference principle, which comprises a glass plate I. One end of the glass plate I is lapped on a glass plate II, the bottom of the other end of the glass plate I is connected with a vertically arranged light rod, the bottom end of the light rod is connected with a light ball, and the light ball floats on the water surface of an evaporation container. The evaporation container is horizontally placed on the fixed platform; the glass plate II is horizontally connected to the adjusting block, the height of the adjusting block can be adjusted vertically, and a tiny included angle is formed between the glass plate I and the glass plate II; a reading microscope is arranged above the glass plate I. Monochromatic parallel light irradiates to the glass plate I from the right above. Compared with the prior art, the light interference principle is adopted, the measurement precision is high, and the precision can reach several micrometers; in addition, in the measurement process, the evaporation container does not need to be moved, the measurement operation does not interfere with the measurement result, and the measurement accuracy and reliability are guaranteed.

Description

Technical Field

[0001] This invention relates to the field of water evaporation measurement technology, and in particular to a device and method for measuring water surface evaporation based on the principle of optical interference. Background Technology

[0002] Water surface evaporation refers to the amount of water that diffuses into the atmosphere through evaporation over a period of time. The specific value is expressed as the thickness of the water layer evaporated over that period. Currently, the main methods for measuring water surface evaporation include: double-bowl evaporators, small evaporators, evaporation ponds, E-601 type evaporators, and precision balances. Among these, double-bowl evaporators, small evaporators, evaporation ponds, and E-601 type evaporators have insufficient measurement accuracy and are generally used to measure daily or monthly evaporation over long time intervals. However, they are difficult to use for measuring short-term or real-time evaporation. While using a precision balance offers high accuracy and the ability to measure short-term evaporation, the need to move the evaporation container during measurement significantly affects the results. This effect is particularly pronounced when measuring short-term water surface evaporation under windless conditions. Summary of the Invention

[0003] The present invention aims to provide a device and method for measuring water surface evaporation based on the principle of optical interference. By employing the principle of optical interference, the measurement accuracy is high, reaching several micrometers. Furthermore, during the measurement process, there is no need to move the evaporation container, and the measurement operation will not interfere with the measurement results, thus ensuring the accuracy and reliability of the measurement, thereby solving the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A device for measuring water evaporation based on the principle of optical interference includes a glass plate I, one end of which rests on a glass plate II, and the bottom of the other end is connected to a vertically arranged lightweight rod. A lightweight ball is connected to the bottom of the lightweight rod and floats on the water surface of an evaporation container. The evaporation container is placed horizontally on a fixed platform. Glass plate II is horizontally connected to an adjusting block, which can be adjusted vertically. A small angle is formed between glass plate I and glass plate II. A reading microscope is installed above glass plate I, and monochromatic parallel light shines onto glass plate I from directly above.

[0006] A further aspect of the present invention is that glass plate I and glass plate II are optically parallel glass plates, and the thickness of the glass plates is greater than the maximum coherence length of monochromatic parallel light.

[0007] A further aspect of the present invention is that the lightweight rod is a hollow, thin-walled plastic tube, the lightweight rod is conical in shape, and the small end of the lightweight rod is connected to the glass plate I.

[0008] A further aspect of the present invention is that the lightweight sphere is a hollow, thin-walled plastic sphere, and scales are marked on two large, perpendicular circles on the surface of the lightweight sphere.

[0009] A further aspect of the present invention is that the total weight of the glass plate I, the lightweight rod, and the lightweight ball does not exceed the maximum buoyancy that the lightweight ball can withstand.

[0010] A further embodiment of the present invention is that a level bubble and several leveling screws are installed on the fixed platform, a column is connected to the fixed platform, an adjusting block is slidably fitted to the column, and the adjusting block is fixed to the column by a locking screw.

[0011] A further aspect of the present invention is that a semi-transparent and semi-reflective film at a 45° angle is installed at the objective lens end of the reading microscope, and a monochromatic light source is connected to the support in an adjustable manner via a locking screw. The monochromatic parallel light emitted horizontally by the monochromatic light source is reflected after illuminating the semi-transparent and semi-reflective film and then shines on the glass plate I from directly above.

[0012] A further embodiment of the present invention includes a camera and a display, wherein the camera is connected to the eyepiece end of the reading microscope and is electrically connected to the display.

[0013] A method for measuring water surface evaporation based on the principle of optical interference, using the aforementioned water surface evaporation measuring device based on the principle of optical interference, specifically includes:

[0014] Because there is a slight angle between glass plate I and glass plate II At this point, a wedge-shaped air film is formed between the two glass plates, and when the wavelength is... When a monochromatic parallel beam of light is incident perpendicularly on the wedge tip of a wedge-shaped air film from directly above, the monochromatic parallel light is reflected at the upper and lower surfaces of the wedge-shaped air film, forming two coherent reflected beams. The two coherent reflected beams meet near the upper surface of the wedge-shaped air film, forming interference fringes. The total width of the N interference fringes is measured using a reading microscope. Based on the principle of light interference, the distance h from point A at the top of the lightweight rod to the plane containing the upper surface of glass plate II is calculated as follows:

[0015] ;

[0016] Where N is the number of interference fringes; L is the horizontal distance from the top edge of the wedge-shaped air film to point A at the top of the lightweight rod. The wavelength of monochromatic light; Let N be the total width of the interference fringes.

[0017] As evaporation proceeds, the water level in the evaporation container drops. The glass plate I, the lightweight rod, and the lightweight sphere, as a whole, rotate clockwise around the tip edge of the wedge-shaped air film as their axis of rotation; the apex angle of the wedge-shaped air film... As the height h decreases, the interference fringes widen; let the initial total width of the N interference fringes be... At the end, the total width of the N interference fringes is Then the change in height h for:

[0018] ;

[0019] Analysis shows that the change in height at point A is equal to the change in water level in the evaporation container. Therefore, the water level in the evaporation container drops by a certain height. for:

[0020] ;

[0021] Due to the actual evaporation surface area For: the area of ​​the evaporator opening Subtract the area occupied by the lightweight ball. ,Right now Then the evaporation rate of the water surface Distance between the water level drop in the evaporation container The relationship is:

[0022] ;

[0023] The evaporation time is The evaporation rate H from the water surface is:

[0024] ;

[0025] in, The area of ​​the evaporator opening; The area of ​​the water surface occupied by the light ball is N; N is the number of stripes. At the beginning Total width of each stripe; At the end Total width of each stripe; The wavelength of monochromatic light; It is the horizontal distance from the top edge of the wedge-shaped air film to point A.

[0026] The beneficial effects of this invention are:

[0027] This invention, by employing the principle of light interference, has the advantage of high measurement accuracy, which can reach several micrometers.

[0028] This invention eliminates the need to move the evaporation container during the measurement process, ensuring that the measurement operation does not interfere with the measurement results and guaranteeing the accuracy and reliability of the measurement.

[0029] This invention effectively solves the accuracy and measurement operation interference problems encountered in the measurement of water surface evaporation, and can realize the effective measurement of water surface evaporation in short time and near real-time. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0031] Figure 2 This is a partial structural diagram of the present invention.

[0032] Figure 3 This is a schematic diagram of the optical path for the formation of interference fringes during the measurement process of this invention.

[0033] Figure 4 This is a graph showing the relationship between water surface evaporation H and humidity RH according to the present invention.

[0034] In the diagram: 1-Glass plate I, 2-Glass plate II, 3-Lightweight rod, 4-Lightweight ball, 5-Evaporation container, 6-Fixed platform, 7-Adjusting block, 8-Reading microscope, 9-Monochrome light source, 10-Leveling screw, 11-Column, 12-Semi-transparent and semi-reflective film, 13-Support, 14-Camera, 15-Display. Detailed Implementation

[0035] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1 , 2 As shown, a water surface evaporation measuring device based on the principle of optical interference includes a glass plate I1, one end of which rests on a glass plate II2, and the bottom of the other end is connected to a vertically arranged lightweight rod 3. A lightweight ball 4 is connected to the bottom of the lightweight rod 3, and the lightweight ball 4 floats on the water surface of an evaporation container 5, which is horizontally placed on a fixed platform 6. The glass plate II2 is horizontally connected to an adjusting block 7, which can be adjusted up and down, forming a small angle between the glass plate I1 and the glass plate II2. A reading microscope 8 is installed above glass plate I1, and monochromatic parallel light shines on glass plate I1 from directly above.

[0037] Glass plate I1 and glass plate II2 are optically parallel glass plates, and the thickness of the glass plates is greater than the maximum coherence length of monochromatic parallel light. In this embodiment, the dimensions of glass plate I1 and glass plate II2 are 48mm in length × 25mm in width × 5mm in thickness.

[0038] The lightweight rod 3 is a hollow, thin-walled plastic tube. The lightweight rod 3 is generally conical, and its small end is connected to the glass plate I1. In this embodiment, the lightweight rod 3 is a hollow pen tip from a ballpoint pen.

[0039] The lightweight ball 4 is a hollow, thin-walled plastic ball, with markings on two large, perpendicular circles on its surface. In this embodiment, a ping-pong ball is used as the lightweight ball 4.

[0040] The total weight of the glass plate I1, the lightweight rod 3, and the lightweight ball 4 shall not exceed the maximum buoyancy force that the lightweight ball 4 can withstand.

[0041] A spirit level and several leveling screws 10 are installed on the fixed platform 6. A column 11 is connected to the fixed platform 6. An adjusting block 7 is slidably fitted to the column 11 and is fixed to the column 11 by a locking screw.

[0042] The objective lens of the reading microscope 8 is fitted with a semi-transparent, semi-reflective film 12 at a 45° angle. A monochromatic light source 9 is vertically adjustable to the support 13 via a locking screw. The monochromatic parallel light emitted horizontally from the monochromatic light source 9 is reflected after illuminating the semi-transparent, semi-reflective film 12 and then shines onto the glass plate I1 from directly above. The specific optical path of the monochromatic parallel light is shown in [details omitted]. Figure 1 , 2 The red line with an arrow indicates this. In this embodiment, the monochromatic light source 9 is a monochromatic sodium lamp (sodium yellow light wavelength). ).

[0043] It also includes a camera 14 and a display 15. The camera 14 is connected to the eyepiece end of the reading microscope 8 and is electrically connected to the display 15. The interference fringes in the narrow eyepiece are displayed on the computer screen using the camera 14 and the display 15, which facilitates clear observation and accurate measurement of the interference fringe spacing L.

[0044] A method for measuring water surface evaporation based on the principle of optical interference, using the aforementioned water surface evaporation measuring device based on the principle of optical interference, specifically includes:

[0045] Because there is a slight included angle between glass plate I1 and glass plate II2 At this point, a wedge-shaped air film forms between the two glass plates, such as Figure 3 The shaded area is shown. When the wavelength is... When a monochromatic parallel beam of light is incident perpendicularly on the wedge tip of a wedge-shaped air film from directly above, the monochromatic parallel light is reflected at the upper and lower surfaces of the wedge-shaped air film, forming two coherent reflected beams. These two coherent reflected beams meet near the upper surface of the wedge-shaped air film, forming interference fringes, such as... Figure 3 As shown. The total width of N interference fringes was measured using a reading microscope 8. Based on the principle of light interference, the distance h from point A at the top of the lightweight rod 3 to the plane containing the upper surface of the glass plate II2 is obtained as follows:

[0046] ;

[0047] Where N is the number of interference fringes; L is the horizontal distance from the top edge of the wedge-shaped air film to point A at the top of the lightweight rod 3. The wavelength of monochromatic light; Let N be the total width of the interference fringes.

[0048] As evaporation proceeds, the water level in evaporation container 5 drops. The glass plate I1, lightweight rod 3, and lightweight sphere 4, as a whole, rotate clockwise around the top edge of the wedge-shaped air film as their axis of rotation; the apex of the wedge-shaped air film... As the height h decreases, the interference fringes widen; let the initial total width of the N interference fringes be... At the end, the total width of the N interference fringes is Then the change in height h for:

[0049] ;

[0050] Analysis shows that the change in height at point A is equal to the change in water level in evaporation container 5. Therefore, the water level in evaporation container 5 has decreased by a certain height. for:

[0051] ;

[0052] Actual evaporation surface area For: 5 openings of the evaporation container Subtract the area occupied by the light sphere 4 ,Right now Then the evaporation rate of the water surface Distance between the water level drop in evaporation container 5 The relationship is:

[0053] ;

[0054] The evaporation time is The evaporation rate H from the water surface is:

[0055] ;

[0056] in, The area of ​​the evaporation container is 5 openings; denoted as , where is the area of ​​the water surface occupied by the light sphere 4; N is the number of interference fringes. At the beginning Total width of each stripe; At the end Total width of each stripe; The wavelength of monochromatic light; It is the horizontal distance from the top edge of the wedge-shaped air film to point A.

[0057] The following explanation is based on specific experimental data.

[0058] 1. Distance L from the edge of the air wedge to point A; 5 mm diameter of the evaporator container. (The evaporation container selected in this case is a cylindrical evaporation container, then...) The diameter of the water surface area occupied by the ping-pong ball The measurements are detailed in Tables 1, 2, and 3.

[0059]

[0060] .

[0061]

[0062] From the formula The area of ​​the 5 openings of the cylindrical evaporator can be calculated. .

[0063]

[0064] From the formula It is possible to calculate the area of ​​the water surface occupied by the ping-pong ball. .

[0065] II. Start and end of timing (timing time) ), Measurement of the spacing between 30 dark lines.

[0066] Under constant conditions of distance from water surface to container opening, atmospheric pressure, and temperature, different humidity levels Evaporation from the lower water surface The measurement data are shown in Table 4.

[0067]

[0068] Based on the measurement data in Table 4, the different humidity levels were calculated. Below, the evaporation rate of water surface in 10 minutes As shown in Table 5, the relationship between evaporation and humidity is as follows. Figure 4 As shown, relative humidity The larger the value, the greater the evaporation rate from the water surface in 10 minutes. The smaller.

[0069]

[0070] Based on the experimental data above, it can be seen that the present invention effectively solves the problems of measurement accuracy and measurement operation interference in the measurement results of water surface evaporation in a short time under windless conditions, and can realize the effective measurement of water surface evaporation in a short time and near real-time.

[0071] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent transformations or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A device for measuring water surface evaporation based on the principle of optical interference, characterized in that, The container includes a glass plate I (1), one end of which rests on a glass plate II (2), and the bottom of the other end is connected to a vertically arranged lightweight rod (3). A lightweight ball (4) is connected to the bottom of the lightweight rod (3), and the lightweight ball (4) floats on the water surface of the evaporation container (5). The evaporation container (5) is placed horizontally on a fixed platform (6). The glass plate II (2) is horizontally connected to an adjusting block (7), which can be adjusted up and down. An angle is formed between the glass plate I (1) and the glass plate II (2). A reading microscope (8) is provided above the glass plate I (1), and monochromatic parallel light shines on the glass plate I (1) from directly above.

2. The water surface evaporation measuring device based on the principle of optical interference as described in claim 1, characterized in that: The glass plate I (1) and glass plate II (2) are optically parallel glass plates, and the thickness of the glass plates is greater than the maximum coherence length of monochromatic parallel light.

3. The water surface evaporation measuring device based on the principle of optical interference as described in claim 1, characterized in that: The lightweight rod (3) is a hollow thin-walled plastic tube. The lightweight rod (3) is cone-shaped as a whole, and the small end of the lightweight rod (3) is connected to the glass plate I (1).

4. The water surface evaporation measuring device based on the principle of optical interference as described in claim 1, characterized in that: The lightweight ball (4) is a hollow, thin-walled plastic ball with markings on two large, perpendicular circles on its surface.

5. The water surface evaporation measuring device based on the principle of optical interference as described in claim 1, characterized in that: The total weight of the glass plate I (1), the lightweight rod (3), and the lightweight ball (4) shall not exceed the maximum buoyancy that the lightweight ball (4) can withstand.

6. The water surface evaporation measuring device based on the principle of optical interference as described in claim 1, characterized in that: The fixed platform (6) is equipped with a spirit level and several leveling screws (10). A column (11) is connected to the fixed platform (6). An adjusting block (7) is slidably fitted to the column (11) and is fixed to the column (11) by a locking screw.

7. The water surface evaporation measuring device based on the principle of optical interference as described in claim 1, characterized in that: The objective lens of the reading microscope (8) is fitted with a semi-transparent and semi-reflective membrane (12) at a 45° angle. The monochromatic light source (9) is connected to the bracket (13) in an adjustable manner by a locking screw. The monochromatic parallel light emitted horizontally by the monochromatic light source (9) is reflected after shining on the semi-transparent and semi-reflective membrane (12) and shines on the glass plate I (1) from directly above.

8. The water surface evaporation measuring device based on the principle of optical interference as described in claim 1, characterized in that: It also includes a camera (14) and a display (15), with the camera (14) connected to the eyepiece end of the reading microscope (8) and the camera (14) electrically connected to the display (15).

9. A method for measuring water surface evaporation based on the principle of optical interference, using the water surface evaporation measuring device based on the principle of optical interference as described in any one of claims 1-8, characterized in that... include: Because there is a small angle between glass plate I (1) and glass plate II (2) At this point, a wedge-shaped air film is formed between the two glass plates, and when the wavelength is... When a monochromatic parallel beam of light is perpendicularly incident on the wedge tip of the wedge-shaped air film from directly above, the monochromatic parallel light is reflected at the upper and lower surfaces of the wedge-shaped air film, respectively, forming two coherent reflected beams; the two coherent reflected beams meet near the upper surface of the wedge-shaped air film to form interference fringes; the total width of the N interference fringes is measured by a reading microscope (8). Based on the principle of light interference, the distance h from point A at the top of the lightweight rod (3) to the plane containing the upper surface of glass plate II (2) is: ； Where N is the number of interference fringes; L is the horizontal distance from the top edge of the wedge-shaped air film to point A at the top of the lightweight rod (3); The wavelength of monochromatic light; The total width of the N interference fringes; As evaporation proceeds, the water level in the evaporation container (5) drops. The glass plate I (1), the lightweight rod (3), and the lightweight sphere (4), as a whole, rotate clockwise around the top edge of the wedge-shaped air film as their axis of rotation; the top angle of the wedge-shaped air film... As the height h decreases, the interference fringes widen; let the initial total width of the N interference fringes be... At the end, the total width of the N interference fringes is Then the change in height h for: ； Analysis shows that the change in height at point A is equal to the change in water level in the evaporation container (5). Therefore, the water level in the evaporation container (5) drops by a certain height. for: ； Actual evaporation surface area For: the area of ​​the evaporation container (5) opening Subtract the area occupied by the light ball (4). ,Right now Then the evaporation rate of the water surface Distance between the water level drop in the evaporation container (5) The relationship is: ； The evaporation time is The evaporation rate H from the water surface is: ； in, The area of ​​the evaporation container (5) opening; N represents the area of ​​the water surface occupied by the light ball (4); N is the number of stripes. At the beginning Total width of each stripe; At the end Total width of each stripe; The wavelength of monochromatic light; It is the horizontal distance from the top edge of the wedge-shaped air film to point A.

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