Ultrasonic measurement method, device and system for single bubble in liquid metal

Abstract

The invention provides an ultrasonic measurement method, device and system for a single bubble in liquid metal, and relates to the technical field of ultrasonic measurement. The ultrasonic measurement method for the single bubble in the liquid metal is used for measuring the morphology and the speed of the single bubble in a liquid metal measurement area, and ultrasonic probes are arranged on the two sides of the x axis, the two sides of the y axis and the two sides of the z axis of the measurement area; the ultrasonic measurement method comprises the following steps: acquiring measurement information of an ultrasonic probe on a bubble in a rising motion process of the bubble in a measurement area, wherein the measurement information comprises projection lengths of the bubble on an x axis, a y axis and a z axis, and an included angle between a normal at each detection point on the surface of the bubble and a detection direction of the corresponding ultrasonic probe; and the morphology parameters and the terminal speed of the bubbles are calculated according to the measurement information. According to the ultrasonic measurement method, the morphology parameters and the terminal speed of the bubbles in the liquid metal can be measured at the same time, and the measurement accuracy is high.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic measurement, and in particular, to an ultrasonic measurement method, device and system for a single steam bubble inside a liquid metal. Background Art

[0002] A lead-cooled fast reactor is a fast neutron reactor that uses liquid metal lead or lead-bismuth alloy as a coolant. It has good inherent safety, thermohydraulic and neutron physics characteristics, and can be used for nuclear fuel breeding and transmutation of long-lived fission products, which is of great significance to the sustainable development of nuclear energy.

[0003] The frequently occurring steam generator tube rupture (SGTR) accident (also known as the lead-water reaction accident) is considered to be one of the key problems restricting the development of lead-cooled fast reactors. Among them, the steam bubble generated by the steam generator tube rupture accident follows the liquid metal into the reactor core and causes power fluctuations or even core melting in the reactor core. The movement and morphology evolution of a single steam bubble inside the liquid metal are key parameters for evaluating the force and migration evolution of the steam bubble, and also the key mechanism for determining whether the steam bubble can enter the reactor core. Therefore, it is crucial to measure the movement and morphology evolution of a single steam bubble inside the liquid metal. However, the existing technology cannot synchronously measure the movement and morphology of a single steam bubble in the liquid metal. Summary of the Invention

[0004] The purpose of the present invention is to provide an ultrasonic measurement method, device and system for a single steam bubble inside a liquid metal, so as to solve the technical problem that the existing technology cannot synchronously measure the movement and morphology of a single steam bubble in the liquid metal.

[0005] To solve the above problems, the present invention provides an ultrasonic measurement method for a single steam bubble inside a liquid metal, which is used for measuring the morphology and velocity of a single steam bubble in a liquid metal measurement area. Wherein, ultrasonic probes are arranged on both sides along the x-axis, both sides along the y-axis, and both sides along the z-axis of the measurement area; the ultrasonic measurement method includes: Obtaining the measurement information of the steam bubble by the ultrasonic probe during the upward movement process of the steam bubble in the measurement area, where the measurement information includes the projected lengths of the steam bubble on the x-axis, y-axis and z-axis, and the included angle between the normal line at each detection point on the surface of the steam bubble and the detection direction of the corresponding ultrasonic probe; Calculating the morphology parameters and terminal velocity of the steam bubble according to the measurement information.

[0006] Optionally, in the step of calculating the morphology parameters and terminal velocity of the steam bubble according to the measurement information, it includes: Establishing a system of equations according to the fixed parameters, the projected length and the included angle; Solving the system of equations to obtain the fixed parameters and substituting them into a preset ellipsoid equation; The morphological parameters of the bubble are calculated according to the ellipsoid equation.

[0007] Optionally, the system of equations is as follows: (1); (2); (3); (4); (5); (6); (7); (8); (9); Where: (10); (11); (12); The ellipsoid equation is: (13); Where: (14); (15); (16); In the formula, xyz is the global coordinate system; F is the implicit equation defining the geometry of the ellipsoid, where F(x, y, z) = 0; ( x i , y i , z i ) is the probe coordinate; a, b, c, h, k, l, α, β, and γ are fixed parameters, where a, b, and c are the semi-axis lengths of the ellipsoid on the x-axis, y-axis, and z-axis, respectively; h, k, and l are the x-axis coordinate, y-axis coordinate, and z-axis coordinate of the center of the ellipsoid, respectively; α, β, and γ are the rotation Euler angles around the x-axis, y-axis, and z-axis, respectively; L x , L y and L z are the projection lengths of the bubble on the x-axis, y-axis, and z-axis, respectively; , , , , and The angles between the detection directions of the ultrasonic probes located on the positive x-axis, negative x-axis, positive y-axis, negative y-axis, positive z-axis, and negative z-axis respectively and the normal at the corresponding detection points on the surface of the bubble.

[0008] Optionally, in the step of calculating the morphological parameters and terminal velocity of the bubble according to the measurement information, it includes: Calculating the ellipsoid equation at different moments during the rising process of the bubble, and calculating the centroid coordinates of the bubble according to the ellipsoid equation; Calculating the terminal velocity of the bubble according to the centroid coordinates and the time intervals at different moments.

[0009] Optionally, the ultrasonic probe located above the measurement area along the z-axis is the upper ultrasonic probe, and the ultrasonic probe located below the measurement area is the lower ultrasonic probe; the ultrasonic measurement method further includes: Obtaining the distances between the bubble and the upper ultrasonic probe and the lower ultrasonic probe at different moments; Calculating the real-time rising velocity of the bubble according to the coordinates of the upper ultrasonic probe and the lower ultrasonic probe, the distances, and the time intervals at different moments.

[0010] Optionally, the upper surface of the liquid metal measurement area is covered with a transparent liquid layer, and a camera is provided on one side of the transparent liquid layer; The ultrasonic measurement method further includes: when the bubble rises into the transparent liquid layer, photographing the bubble through the camera to obtain the morphological parameters of the bubble; Comparing the morphological parameters obtained by photographing with the camera and the morphological parameters detected by the ultrasonic probe for verification.

[0011] Optionally, calculating the equivalent diameter, major axis, and / or minor axis of the bubble according to the ellipsoid equation as the morphological parameters.

[0012] The present invention also provides an ultrasonic measurement device for a single bubble inside a liquid metal, which is applied to the above ultrasonic measurement method. The ultrasonic measurement device includes a container for containing the liquid metal. Ultrasonic probes are provided at both ends of the container along the x-axis, both ends along the y-axis, and both ends along the z-axis. The container is provided with an injection structure extending into it for injecting bubbles into the liquid metal.

[0013] The present invention also provides an ultrasonic measurement system for a single bubble inside a liquid metal, including a controller and the above ultrasonic measurement device. The container of the ultrasonic measurement device contains the liquid metal, and the ultrasonic probes of the ultrasonic measurement device are communicatively connected to the controller.

[0014] Optionally, the upper surface of the liquid metal is covered with a transparent liquid layer, and the ultrasonic probe located above along the z-axis can adjust its z-direction position; a camera is provided on one side of the container where the transparent liquid layer is located, and the camera is communicatively connected to the controller.

[0015] The ultrasonic measurement method provided by the present invention arranges six ultrasonic probes around the liquid metal measurement area, and can measure the relationship between the bubble morphology and the terminal velocity of the relative movement of the bubbles in the liquid metal through a simple structure, so as to establish a mechanical model of the bubbles to evaluate whether the bubbles can be captured by the liquid metal under the action of buoyancy and drag force and follow the liquid metal flow. The structure is simple and the measurement results are diverse; at the same time, the number of ultrasonic probes is small, and during the measurement process, the signal interference between them is small, which can effectively ensure the measurement accuracy. Description of the Drawings

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 It is the first process schematic diagram of the ultrasonic measurement method for a single bubble inside the liquid metal provided by the embodiment of the present invention; Figure 2 It is the second process schematic diagram of the ultrasonic measurement method for a single bubble inside the liquid metal provided by the embodiment of the present invention; Figure 3 It is the front view schematic diagram of the first state of the ultrasonic measurement system for a single bubble inside the liquid metal provided by the embodiment of the present invention, where the bubble is located inside the liquid metal; Figure 4 It is the front view schematic diagram of the second state of the ultrasonic measurement system for a single bubble inside the liquid metal provided by the embodiment of the present invention, where the bubble is located inside the transparent liquid layer; Figure 5 It is the top view schematic diagram of the ultrasonic measurement system for a single bubble inside the liquid metal provided by the embodiment of the present invention.

[0018] Description of the Reference Numerals: 100 - Container; 210 - Upper ultrasonic probe; 220 - Lower ultrasonic probe; 230 - First x-axis ultrasonic probe; 240 - Second x-axis ultrasonic probe; 250 - First y-axis ultrasonic probe; 260 - Second y-axis ultrasonic probe; 20A - Horizontal detection area; 300 - Injection structure; 400 - Camera; 500 - Liquid metal; 50A - Measurement area; 600 - Transparent liquid layer; 700 - Bubble. Detailed implementation manners

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not 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 protection scope of the present invention.

[0020] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0021] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0022] This embodiment provides a method, device, and system for ultrasonic measurement of a single vapor bubble 700 inside a liquid metal 500. Among them, the ultrasonic measurement system can execute this ultrasonic measurement method. Specifically, as Figures 3 - 5 shown, the ultrasonic measurement system includes a controller (not shown in the figure) and an ultrasonic measurement device. The ultrasonic measurement device includes a container 100 for containing the liquid metal 500. Ultrasonic probes are provided at both ends of the container 100 along the x-axis, both ends along the y-axis, and both ends along the z-axis. The container 100 is provided with an injection structure 300 extending into it for injecting vapor bubbles 700 into the liquid metal 500. The liquid metal 500 is contained in the container 100, and the ultrasonic probes of the ultrasonic measurement device are communicatively connected to the controller.

[0023] In this ultrasonic measurement system, the x-axis and the y-axis are orthogonal and horizontally extended, and the z-axis is orthogonal to the x-axis and the y-axis and vertically extended; the entire ultrasonic measurement device is in a three-dimensional coordinate system, and the origin of the three-dimensional coordinate system can coincide with the center of the liquid metal 500 in the X-Y plane. The coordinates of the container 100, the ultrasonic probe, and the injection structure 300 are all known. Among them, each ultrasonic probe is in direct contact with the liquid metal 500, and a coupling agent is used to enable the ultrasonic detection signal to enter the liquid metal 500. Among the ultrasonic probes, the ultrasonic probe located on the positive half-axis along the x-axis is the first x-axis ultrasonic probe 230, and the ultrasonic probe located on the negative half-axis is the second x-axis ultrasonic probe 240. The detection directions of the first x-axis ultrasonic probe 230 and the second x-axis ultrasonic probe 240 are both along the x-axis and towards the liquid metal 500; the ultrasonic probe located on the positive half-axis along the y-axis is the first y-axis ultrasonic probe 250, and the ultrasonic probe located on the negative half-axis is the second y-axis ultrasonic probe 260. The detection directions of the first y-axis ultrasonic probe 250 and the second y-axis ultrasonic probe 260 are both along the y-axis and towards the liquid metal 500; the ultrasonic probe located on the upper positive half-axis along the z-axis is the upper ultrasonic probe 210, and the ultrasonic probe located on the lower negative half-axis is the lower ultrasonic probe 220. The detection directions of the upper ultrasonic probe 210 and the lower ultrasonic probe 220 are both along the z-axis and towards the liquid metal 500. The injection end of the injection structure 300 is located between the upper ultrasonic probe 210 and the lower ultrasonic probe 220 along the z-axis.

[0024] Figure 1 FIG. 4 is a first flow chart of the ultrasonic measurement method for measuring a single bubble 700 inside the liquid metal 500 provided by an embodiment of the present invention. As Figure 1 shown, this ultrasonic measurement method uses the above ultrasonic measurement device and ultrasonic measurement system for measuring the morphology and velocity of the bubble 700 in the measurement area 50A of the liquid metal 500, including: S102 Obtain the measurement information of the bubble 700 by the ultrasonic probe during the upward movement of the bubble 700 in the measurement area 50A. The measurement information includes the projected lengths of the bubble 700 on the x-axis, y-axis, and z-axis, and the included angles between the normal lines at each detection point on the surface of the bubble 700 and the detection directions of the corresponding ultrasonic probes.

[0025] During use, the region where the liquid metal 500 is located within the container 100 serves as the measurement region 50A. A single bubble 700 is injected into the liquid metal 500 through the injection structure 300. After the bubble 700 detaches from the injection structure 300, it undergoes an upward movement within the liquid metal 500 under the action of buoyancy, and the rising trajectory of the bubble 700 is approximately collinear with the z-axis. Correspondingly, during the upward movement of the bubble 700, it is always located within the detection regions of the upper ultrasonic probe 210 and the lower ultrasonic probe 220. When the rising speed of the bubble 700 reaches a stable stage, the rising speed of the bubble 700 is taken as its terminal velocity. When the bubble 700 rises to the horizontal detection region 20A of the first x-axis ultrasonic probe 230, the second x-axis ultrasonic probe 240, the first y-axis ultrasonic probe 250, and the second y-axis ultrasonic probe 260 in a stable upward state, the first x-axis ultrasonic probe 230, the second x-axis ultrasonic probe 240, the first y-axis ultrasonic probe 250, and the second y-axis ultrasonic probe 260 can detect the bubble 700 to obtain corresponding detection information such as distance and amplitude, and then feedback the detection information to the controller. The controller calculates the measurement information related to the bubble 700 morphology parameters and the terminal velocity based on the preset calculation program and the stored relevant information. The measurement information can specifically include the projected lengths of the bubble 700 on the x-axis, y-axis, and z-axis, and the angles between the normal lines at each detection point on the surface of the bubble 700 and the detection directions of the corresponding ultrasonic probes.

[0026] S104 Calculate the morphology parameters and the terminal velocity of the bubble 700 based on the measurement information. The controller further calculates the measurement information according to the preset calculation program to obtain the morphology parameters that can characterize the morphology of the bubble 700, and the terminal velocity that can characterize the relative velocity difference between the bubble 700 and the liquid metal 500, so as to obtain the relationship between the morphology of the bubble 700 moving relative to the liquid metal 500 and the terminal velocity. This relationship can be used to establish a mechanical model of the bubble 700 to develop a drag force model of the bubble, which is crucial for the study of the heat transfer tube rupture accident in a nuclear reactor.

[0027] Then, the ultrasonic measurement method provided by the embodiment of the present invention arranges six ultrasonic probes around the measurement region 50A of the liquid metal 500, and can measure the relationship between the morphology of the bubble 700 moving relative to the liquid metal 500 and the terminal velocity through a simple structure, so as to be used to establish a mechanical model of the bubble 700 to evaluate whether the bubble 700 can be captured by the liquid metal under the action of buoyancy and drag force and follow the flow of the liquid metal. The structure is simple and the measurement results are diverse. At the same time, the number of ultrasonic probes is small, and during the measurement process, the signal interference between them is small, which can effectively ensure the measurement accuracy.

[0028] It should be noted that the number of ultrasonic probes provided on the side wall of the container 100 is not limited to four, and can also be eight, etc. Every four ultrasonic probes are orthogonally distributed and cooperate with the two ultrasonic probes located on the z-axis, so as to realize multi-dimensional measurement of the bubble 700.

[0029] Specifically, the steps of measuring the projection lengths of the bubble 700 on the x-axis, y-axis, and z-axis by the ultrasonic probes are as follows: When the bubble 700 rises through the horizontal detection areas 20A of the first x-axis ultrasonic probe 230, the second x-axis ultrasonic probe 240, the first y-axis ultrasonic probe 250, and the second y-axis ultrasonic probe 260, the first x-axis ultrasonic probe 230 and the second x-axis ultrasonic probe 240 can continuously detect the distance a between the surface of the bubble 700 and the first x-axis ultrasonic probe 230 and the distance b from the second x-axis ultrasonic probe 240, and feed the distance information back to the controller. At the same time, the controller can obtain the distance S between the two along the x-axis according to the coordinates of the first x-axis ultrasonic probe 230 and the second x-axis ultrasonic probe 240. x , then S x -a - b is the real-time projection length L of the bubble 700 along the x-axis. x ; Similarly, the projection length L of the bubble 700 on the y-axis can be calculated. y And the projection length L on the z-axis. z .

[0030] Specifically, the steps of measuring the angle between the normal line at each detection point on the surface of the bubble 700 and the detection direction of the corresponding ultrasonic probe by the ultrasonic probe are as follows: When the bubble 700 passes through the horizontal detection area 20A, all six ultrasonic probes can detect the bubble 700. The detection signal reaches the surface of the bubble 700 along the detection direction of the corresponding ultrasonic probe, and the arrival point is used as the detection point corresponding to the ultrasonic probe. The detection signal is reflected by the detection point and then received by the corresponding ultrasonic probe. Among them, the amplitude of the reflected signal is related to the interface curvature of the detection point. Then, each ultrasonic probe feeds the amplitude of the received reflected signal back to the controller. The controller stores the corresponding relationship between the amplitude information and the angle information. According to the amplitude of the reflected signal, the angle between the normal line at each detection point on the surface of the bubble 700 and the detection direction of the corresponding ultrasonic probe can be determined.

[0031] Among them, in transparent substances with a variety of different acoustic impedances, such as water and silicone oil, the reflection amplitude corresponding to the interface of the bubble 700 can be measured by a high-speed camera 400 and calculated by an ultrasonic probe to obtain the relationship between the interface curvature and the reflected signal amplitude information at different acoustic impedances, which is used to calibrate the corresponding relationship between the angle and the signal amplitude of the bubble 700 inside the liquid metal 500, and this corresponding relationship is stored in the controller.

[0032] Specifically, the distance between the injection structure 300 and the first x-axis ultrasonic probe 230 is greater than 100 mm. When the bubble detaches from the injection structure 300 and rises to the horizontal detection area 20A at the height where the first x-axis ultrasonic probe 230 is located, the morphology and terminal velocity of the bubble 700 are basically stable, thereby improving the measurement accuracy.

[0033] In the embodiment of the present invention, in the step of calculating the morphology parameters and terminal velocity of the bubble 700 according to the measurement information in S104, it includes: establishing a system of equations based on fixed parameters, projection lengths, and angles; solving the system of equations to obtain the fixed parameters and substituting them into a preset ellipsoid equation; calculating the morphology parameters of the bubble 700 according to the ellipsoid equation.

[0034] Set the shape of the bubble 700 as an ellipsoid, and establish an ellipsoid equation. According to the fixed parameters, projection lengths L x 、L y 、L z in the ellipsoid equation and the angles between the detection directions of the six ultrasonic probes and the normal lines at the corresponding detection points, establish a system of equations, and solve the system of equations to obtain the numerical values of the fixed parameters. Substitute the numerical values of the fixed parameters into the ellipsoid equation, and further calculate the morphology parameters that can characterize the morphology of the bubble 700 according to the ellipsoid equation. Specifically, at least one of the equivalent diameter, major axis, and minor axis of the bubble 700 can be calculated according to the ellipsoid equation as the morphology parameter.

[0035] Specifically, in the embodiment of the present invention, the system of equations is: (1); (2); (3); (4); (5); (6); (7); (8); (9); Where: (10); (11); (12); The ellipsoid equation is: (13); Where: (14); (15); (16); Wherein, xyz is the global coordinate system; F is an implicit equation defining the geometry of the ellipsoid, where F(x, y, z) = 0; ( x i , y i , z i ) are the probe coordinates; a, b, c, h, k, l, α, β, and γ are fixed parameters, where a, b, and c are the semi-axis lengths of the ellipsoid along the x-axis, y-axis, and z-axis, respectively; h, k, and l are the x-axis coordinate, y-axis coordinate, and z-axis coordinate of the center of the ellipsoid, respectively; α, β, and γ are the rotational Euler angles about the x-axis, y-axis, and z-axis, respectively; L x , L y , and L z are the projected lengths of the bubble along the x-axis, y-axis, and z-axis, respectively; , , , , , and are the angles between the detection directions of the ultrasonic probes located on the positive x-axis, negative x-axis, positive y-axis, negative y-axis, positive z-axis, and negative z-axis and the normal at the corresponding detection points on the bubble surface, respectively; wherein, the global coordinates of each ultrasonic probe are known parameters used to calculate the angle between the bubble surface and the probe normal; X, Y, Z are the local coordinate systems (without rotation) aligned with the geometry of the ellipsoid and are related to the global coordinate system through the rotation angles α, β, and γ.

[0036] The controller stores the above equations (1)-(16). Among them, equations (1)-(9) form a system of equations with 9 unknowns a, b, c, h, k, l, α, β, and γ. Substitute the projected lengths L x , L y , L z measured by each ultrasonic probe when the bubble is in the horizontal detection area into equations (1)-(3) respectively, and substitute the angles , , , , , and Substitute into equations (4)-(9) respectively. Among equations (4)-(12), F is the implicit equation F(x, y, z)=0 that defines the geometric shape of the ellipsoid. By taking the partial derivatives of it, the normal direction of the detection points on the ellipsoid surface can be determined, the angles between the normal and the corresponding coordinate axes can be calculated, and further the angles between the normal of the detection points on the ellipsoid surface and the detection directions of the corresponding ultrasonic probes can be calculated. Specifically, when substituting equations (10)-(12) into equation (4), its x i and y i and z i Select the coordinates of the first x-axis ultrasonic probe. When substituting equations (10)-(12) into equation (5), its x i and y i and z i Select the coordinates of the second x-axis ultrasonic probe. When substituting equations (10)-(12) into equation (6), its x i and y i and z i Select the coordinates of the first y-axis ultrasonic probe. When substituting equations (10)-(12) into equation (7), its x i and y i and z i Select the coordinates of the second y-axis ultrasonic probe. When substituting equations (10)-(12) into equation (8), its x i and y i and z i Select the coordinates of the first z-axis ultrasonic probe. When substituting equations (10)-(12) into equation (9), its x i and y i and z i Select the coordinates of the second z-axis ultrasonic probe; thus, the unique solutions of a, b, c, h, k, l, α, β, and γ are calculated. Substitute the corresponding numerical values into equations (13)-(16), and thus the ellipsoid equation of the bubble is obtained; further, at least one of the equivalent diameter, major axis, and minor axis of the bubble is calculated according to the ellipsoid equation and used as the morphological parameter capable of characterizing the bubble morphology.

[0037] In the embodiments of the present invention, the measurement of the velocity of the bubble 700 involves two methods: the measurement method of the real-time rising velocity when the bubble 700 is in the area outside the horizontal detection area 20A during the rising process, and the measurement method of the terminal velocity when the bubble 700 is in the horizontal detection area 20A during the stable velocity stage of the rising process. Among them, the measurement method of the terminal velocity when the bubble 700 is in the horizontal detection area 20A is as follows: Calculate the ellipsoid equation of the bubble 700 at different moments during the rising process, and calculate the centroid coordinates of the bubble 700 according to the ellipsoid equation; calculate the terminal velocity of the bubble 700 based on the centroid coordinates and the time interval at different moments. During the process of the bubble 700 rising through the horizontal detection area 20A, the six ultrasonic probes emit detection signals outward every time t, and feedback the received reflected signals to the controller. The controller can correspondingly calculate the ellipsoid equation at this moment, and calculate its centroid coordinates according to the ellipsoid equation, and then calculate the terminal velocity of the bubble 700 through the rising distance of the centroid on the z-axis and the time interval nt (n is a positive integer). Specifically, the frame rate of the ultrasonic probe can be 500-1000 frames.

[0038] The method for measuring the real-time rising speed of the bubble 700 when it is outside the horizontal detection area 20A is as follows: Define the ultrasonic probe located above the measurement area 50A along the z-axis as the upper ultrasonic probe 210, and the ultrasonic probe located below the measurement area 50A as the lower ultrasonic probe 220; Obtain the distances between the bubble 700 and the upper ultrasonic probe 210 and the lower ultrasonic probe 220 at different moments; Calculate the real-time rising speed of the bubble 700 according to the coordinates, distances of the upper ultrasonic probe 210 and the lower ultrasonic probe 220, and the time interval at different moments. The detection directions of the upper ultrasonic probe 210 and the lower ultrasonic probe 220 are collinear vertically and pass through the center of the test area. The bubble 700 rises approximately along the detection directions of the upper ultrasonic probe 210 and the lower ultrasonic probe 220. Then, the upper ultrasonic probe 210 and the lower ultrasonic probe 220 emit detection signals towards the bubble 700 every time t, and detect the distance c between the upper ultrasonic probe 210 and the bubble 700 along the z-axis, and the distance d between the lower ultrasonic probe 220 and the bubble 700 along the z-axis, and feedback the distance information to the controller. At the same time, the controller obtains the distance S between the two along the z-axis according to the coordinates of the upper ultrasonic probe 210 and the lower ultrasonic probe 220 z Then, the central position Z of the bubble 700 on the z-axis o =d + (S z - b - c) / 2. By calculating the central positions of the bubble 700 at different moments and dividing the difference between the two by the time interval nt, the real-time rising speed of the bubble 700 is obtained.

[0039] In the embodiment of the present invention, the upper surface of the liquid metal 500 is covered with a transparent liquid layer 600, and the ultrasonic probe located above along the z-axis can adjust the z-axis position; A camera 400 is provided on one side of the container 100 where the transparent liquid layer 600 is located. The camera 400 is used to photograph the bubble 700 located in the transparent liquid layer 600, and the camera 400 is communicatively connected to the controller. Correspondingly, the ultrasonic measurement method further includes: as Figure 4As shown, when the bubble 700 rises into the transparent liquid layer 600, the camera 400 takes pictures of the bubble 700 to obtain the morphological parameters of the bubble 700; the morphological parameters obtained by the camera 400 are compared with those obtained by the ultrasonic probe detection to verify the accuracy of the morphological parameters measured by the ultrasonic measurement method provided by the embodiment of the present invention.

[0040] The transparent liquid layer 600 is a liquid substance that is transparent, non-volatile and insoluble in the liquid metal 500. During the initial test process, as Figure 3 shown, the upper ultrasonic probe 210 passes through the transparent liquid layer 600 to detect the bubble 700 in the liquid metal 500. As Figure 4 shown, when the bubble 700 passes through the horizontal detection area 20A and rises and adheres to the upper ultrasonic probe 210, the upper ultrasonic probe 210 can be lifted upward to make the bubble 700 enter the transparent liquid layer 600 upward. The camera 400 takes a picture of the bubble 700 and feeds the picture back to the controller. The controller calculates the shape and size of the bubble 700, so as to obtain the photographed morphological parameters of the bubble 700; then, the photographed morphological parameters are compared with the measured morphological parameters obtained by the ultrasonic probe detection to verify the accuracy of the morphological parameters, and further verify the feasibility of using the ultrasonic measurement method to measure the morphology of the bubble 700 in the embodiment of the present invention.

[0041] Specifically, the transparent liquid layer 600 can adopt a silicone oil layer.

[0042] Figure 2 This is the second process schematic diagram of the ultrasonic measurement method for measuring a single bubble inside a liquid metal provided by the embodiment of the present invention. As Figure 2 shown, the ultrasonic measurement method includes: S201 Obtain the measurement information of the bubble by the ultrasonic probe during the upward movement process of the bubble in the measurement area. The measurement information includes the projected lengths of the bubble on the x-axis, y-axis and z-axis, and the angles between the normal lines at each detection point on the bubble surface and the detection directions of the corresponding ultrasonic probes.

[0043] S202 Establish a system of equations according to the fixed parameters, projected lengths and angles.

[0044] S203 Solve the system of equations to obtain the fixed parameters and substitute them into the preset ellipsoid equation. Steps S204 and S205 are executed in parallel.

[0045] S204 Calculate the equivalent diameter, major axis and / or minor axis of the bubble according to the ellipsoid equation as the morphological parameters.

[0046] S205 Calculate the ellipsoid equations at different moments during the upward movement of the bubble, and calculate the centroid coordinates of the bubble according to the ellipsoid equations.

[0047] S206 calculates the terminal velocity of the bubble based on the centroid coordinates and the time intervals at different times.

[0048] 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 described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for ultrasonically measuring a single bubble inside a liquid metal, characterized in that: Used for measuring the morphology and velocity of a single bubble (700) in a liquid metal (500) measurement area (50A), wherein the measurement area (50A) is provided with ultrasonic probes on both sides along the x-axis, on both sides along the y-axis, and on both sides along the z-axis; the ultrasonic measurement method comprises: Acquiring measurement information of the bubble (700) by the ultrasonic probe during the upward movement of the bubble (700) in the measurement area (50A), the measurement information comprising the projection lengths of the bubble (700) on the x-axis, the y-axis and the z-axis, and the angle between the normal at each detection point on the surface of the bubble (700) and the corresponding detection direction of the ultrasonic probe; The morphological parameters and terminal velocity of the bubble (700) are calculated based on the measurement information.

2. The ultrasonic measurement method according to claim 1, characterized in that: The step of calculating the morphological parameters and terminal velocity of the bubble (700) according to the measurement information comprises: Establishing a set of equations according to fixed parameters, the projection length and the angle; Solving the set of equations to obtain the fixed parameters and substituting them into a preset ellipsoid equation; The morphological parameters of the bubble (700) are calculated according to the ellipsoid equation.

3. The ultrasonic measurement method according to claim 2, characterized in that: The system of equations is: （1）； （2）； （3）； （4）； （5）； （6）； （7）； （8）； （9）； in: （10）； （11）； （12）； The ellipsoid equation is: （13）； in: （14）； （15）； （16）； Where xyz is the global coordinate system; F is the implicit equation that defines the geometry of the ellipsoid, where F(x, y, z) = 0; ( x i , y i , z i ) is the probe coordinate; a, b, c, h, k, l, α, β and γ are fixed parameters, where a, b and c are the semi-axis lengths of the ellipsoid on the x-axis, y-axis and z-axis respectively; h, k and l are the x-axis coordinates, y-axis coordinates and z-axis coordinates of the center of the ellipsoid respectively; α, β and γ are the Euler angles of rotation around the x-axis, y-axis and z-axis respectively; L x , L y and L z are the projection lengths of the bubble on the x-axis, y-axis and z-axis respectively; , , , , and are the angles between the detection directions of the ultrasonic probe located on the positive x axis, negative x axis, positive y axis, negative y axis, positive z axis and negative z axis and the normal line at the corresponding detection point on the bubble surface.

4. The ultrasonic measurement method according to claim 3, characterized in that: The step of calculating the morphological parameters and terminal velocity of the bubble (700) according to the measurement information comprises: Calculating the ellipsoid equation at different moments during the rising process of the bubble (700), and obtaining the coordinates of the center of mass of the bubble (700) according to the ellipsoid equation; The terminal velocity of the bubble (700) is calculated based on the coordinates of the center of mass and the time intervals at different times.

5. The ultrasonic measurement method according to any one of claims 1 to 4, characterized in that: The ultrasonic probe located above the measurement area (50A) along the z-axis is an upper ultrasonic probe (210), and the ultrasonic probe located below the measurement area (50A) is a lower ultrasonic probe (220); the ultrasonic measurement method further comprises: Acquiring the distance between the bubble (700) and the upper ultrasonic probe (210) and the lower ultrasonic probe (220) at different times; The real-time rising speed of the bubble (700) is calculated based on the coordinates of the upper ultrasonic probe (210) and the lower ultrasonic probe (220), the distance, and the time intervals at different times.

6. The ultrasonic measurement method according to any one of claims 1 to 4, characterized in that: The upper surface of the liquid metal (500) measurement area (50A) is covered with a transparent liquid layer (600), and a camera (400) is provided on one side of the transparent liquid layer (600); The ultrasonic measurement method further comprises: when the bubble (700) rises and enters the transparent liquid layer (600), photographing the bubble (700) by means of the camera (400) to obtain morphological parameters of the bubble (700); The morphological parameters obtained by photographing the camera (400) and the morphological parameters obtained by detecting the ultrasonic probe are compared for verification.

7. The ultrasonic measurement method according to any one of claims 2 to 4, characterized in that: The equivalent diameter, major axis and / or minor axis of the bubble (700) are calculated according to the ellipsoid equation and are used as the morphology parameters.

8. An ultrasonic measuring device for a single bubble inside a liquid metal, characterized in that: An ultrasonic measurement method according to any one of claims 1 to 5 and 7, wherein the ultrasonic measurement device comprises a container (100) for containing liquid metal (500), the container (100) being provided with ultrasonic probes at both ends along the x-axis, at both ends along the y-axis and at both ends along the z-axis, and the container (100) being provided with an injection structure (300) extending therein for injecting bubbles (700) into the liquid metal (500).

9. An ultrasonic measurement system for a single bubble inside a liquid metal, characterized in that: It comprises a controller and the ultrasonic measuring device according to claim 8, wherein the container (100) of the ultrasonic measuring device contains liquid metal (500), and the ultrasonic probe of the ultrasonic measuring device is communicatively connected to the controller.

10. The ultrasonic measurement system according to claim 9, characterized in that: The upper surface of the liquid metal (500) is covered with a transparent liquid layer (600), and the ultrasonic probe located on the upper side along the z-axis can adjust the z-direction position; the container (100) is provided with a camera (400) on one side of the transparent liquid layer (600), and the camera (400) is communicatively connected to the controller.

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