Ultrasonic monitoring device and method for metal solidification process

Abstract

The invention provides an ultrasonic monitoring device and method for a metal solidification process, and relates to the technical field of metal solidification, the device comprises an accommodating cavity, an upper temperature control assembly, a lower temperature control assembly, a temperature measurement assembly and a detection assembly; wherein the accommodating cavity is used for accommodating molten metal; the upper temperature control assembly is used for controlling the top temperature of the accommodating cavity; the lower temperature control assembly is used for controlling the bottom temperature of the accommodating cavity; the temperature measuring assembly is provided with a plurality of first thermocouples used for monitoring the temperature of the corresponding height of the containing cavity. The detection assembly is provided with a plurality of first ultrasonic probes used for detecting the solidification interface of molten metal. The position of each part of the molten metal solidification interface in the accommodating cavity is determined according to the echo time of each first ultrasonic probe, so that the morphology of the solidification interface is determined; and the advancing speed of the molten metal solidification interface is determined based on the echo time of each first ultrasonic probe when the positions of the solidification interface are different and the time intervals when the solidification interface is located at different positions.

Description

Technical Field

[0001] The present invention relates to the technical field of metal solidification, and in particular, to an ultrasonic monitoring device and method for the metal solidification process. Background Art

[0002] The liquid metal reactor is an advanced and common type of nuclear reactor in today's society. It uses liquid metal as a coolant and usually has high efficiency and high safety. When using high-temperature liquid metal (such as sodium, lead-bismuth alloy) as the coolant in the liquid metal reactor, once the temperature of the liquid metal is lower than the melting point, the phenomenon of liquid metal solidification will occur, which will endanger the safety of the reactor. Especially in some narrow pipelines, the solidification of liquid metal will cause serious accidents such as flow blockage and local overheating in the reactor. Therefore, the research on the solidification process of liquid metal is an important part of the research on liquid metal reactors. In the prior art, an intrusive measurement device is usually used to study the solidification process of liquid metal. This measurement device cannot deepen the understanding of the macroscopic mechanism of solidification, and cannot study the solidification process of liquid metal in real-time online, and cannot obtain the morphology and advancing speed of the liquid metal solidification interface. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide an ultrasonic monitoring device and method for the metal solidification process, which can solve the technical problems that in the prior art, the solidification process of liquid metal cannot be studied in real-time online, and the morphology and advancing speed of the liquid metal solidification interface cannot be obtained.

[0004] To achieve the above purpose, the technical solutions adopted in the embodiments of the present invention are as follows: In the first aspect, the embodiments of the present invention provide an ultrasonic monitoring device for the metal solidification process, including: A receiving cavity for receiving the metal melt; An upper temperature control component having a first heating sheet, the first heating sheet is fixedly arranged at the top of the receiving cavity for controlling the temperature at the top of the receiving cavity; A lower temperature control component having a refrigeration sheet, fixedly arranged at the bottom of the receiving cavity for controlling the temperature at the bottom of the receiving cavity; A temperature measuring component having a plurality of first thermocouples, the first thermocouples are arranged at intervals in the vertical direction in the receiving cavity for monitoring the temperature at the corresponding height of the receiving cavity; A detection component having a plurality of first ultrasonic probes, the first ultrasonic probes are arranged at the top of the receiving cavity, and the sensing ends of the first ultrasonic probes are arranged vertically downward for detecting the solidification interface of the metal melt.

[0005] Further, an embodiment of the present invention provides a first possible implementation manner of the first aspect. The device further includes: a verification chamber, which is communicated with the top of the accommodation chamber through a pipeline, and the verification chamber is provided with a second heating sheet; The temperature measurement component further includes a second thermocouple, which is arranged in the verification chamber and is used for monitoring the temperature of the molten metal in the verification chamber; The detection component further includes a second ultrasonic probe, which is arranged at the bottom of the verification chamber, and the sensing end of the second ultrasonic probe is arranged vertically upward for detecting the position of the liquid level of the molten metal in the verification chamber; The outer peripheral wall of the accommodation chamber has a heat insulation layer.

[0006] An embodiment of the present invention provides an ultrasonic monitoring device for the metal solidification process. The device includes: an accommodation chamber, an upper temperature control component, a lower temperature control component, a temperature measurement component, and a detection component; the accommodation chamber is used for accommodating molten metal; the upper temperature control component has a first heating sheet, and the first heating sheet is fixedly arranged at the top of the accommodation chamber for controlling the temperature at the top of the accommodation chamber; the lower temperature control component has a refrigeration sheet, which is fixedly arranged at the bottom of the accommodation chamber for controlling the temperature at the bottom of the accommodation chamber; the temperature measurement component has a plurality of first thermocouples, and the first thermocouples are arranged at intervals in the vertical direction in the accommodation chamber for monitoring the temperature at corresponding heights in the accommodation chamber; the detection component has a plurality of first ultrasonic probes, and the first ultrasonic probes are arranged at the top of the accommodation chamber, and the sensing ends of the first ultrasonic probes are arranged vertically downward for detecting the solidification interface of the molten metal. Through the combined action of the upper temperature control component and the lower temperature control component, the present invention realizes the control of the heat flow gradient of the molten metal in the accommodation chamber, thereby controlling the solidification of the molten metal. The position of the solidification interface is determined by judging the temperature of the first thermocouple. The sound velocity of the ultrasonic wave in the molten metal is updated through the echo time of the first ultrasonic probe located at or closest to the central part. The positions of each part of the solidification interface of the molten metal are determined through the updated sound velocity and the echo time of each first ultrasonic probe, so as to determine the morphology of the solidification interface. At the same time, based on the echo time of each first ultrasonic probe when the solidification interface is located at different positions and the time interval when it is located at different positions, the advancing speed of the solidification interface of the molten metal is determined, realizing the real-time on-line research on the solidification process of the molten metal, and obtaining the morphology and advancing speed of the solidification interface of the liquid metal.

[0007] In a second aspect, an embodiment of the present invention further provides an ultrasonic monitoring method for the metal solidification process, which is applied to the above-mentioned ultrasonic monitoring device for the metal solidification process. The method includes: Controlling the first heating sheet and the refrigeration sheet to work so that the temperature of the accommodation chamber gradually increases from bottom to top in the vertical direction, wherein the temperature controlled by the refrigeration sheet is lower than the melting point of the metal to be measured, and the temperature controlled by the first heating sheet is higher than the melting point of the metal to be measured; Arrange N first thermocouples in sequence in the vertical direction and correspond to N height positions in sequence, where N > 2. The lowermost first thermocouple senses the temperature at the bottom wall of the accommodating cavity, and the uppermost first thermocouple senses the temperature at the height where the sensing end of the first ultrasonic probe in the accommodating cavity is located; Arrange M first ultrasonic probes in an array on the same horizontal plane, where M > 3; Based on the temperature values sensed by the first thermocouples, determine the height value of the solidification interface; Based on the height value of the solidification interface determined by the first thermocouples and the echo time of the first ultrasonic probe located at or closest to the central part, determine the sound speed of the ultrasonic wave in the molten metal; Based on the sound speed of the ultrasonic wave in the molten metal, determine the positions of the solidification interfaces sensed by each first ultrasonic probe to obtain the interface morphology of the solidification interface.

[0008] Furthermore, the embodiment of the present invention provides a first possible implementation manner of the second aspect, where the step of determining the height value of the solidification interface based on the temperature values sensed by the first thermocouples includes: Obtain the temperature values of each first thermocouple, and determine the height value of the i-th first thermocouple whose temperature is equal to the melting point of the metal to be measured as the height value of the solidification interface .

[0009] Furthermore, the embodiment of the present invention provides a second possible implementation manner of the second aspect, where the numbering method of the first thermocouples is as follows: Arrange N first thermocouples in sequence from top to bottom in the vertical direction as: 1, 2,..., N; Mark the distances between adjacent first thermocouples from top to bottom in sequence as: , ,... ; Arrange M first ultrasonic probes in sequence in a rectangular array on the same horizontal plane as: 1, 2,..., M; The step of determining the sound speed of the ultrasonic wave in the molten metal based on the height value of the solidification interface determined by the first thermocouples and the echo time of the first ultrasonic probe located at or closest to the central part includes: When the solidification interface is at the height where the N-th first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , determine the initial sound speed

[0010] of the ultrasonic wave in the molten metal as: When the solidification interface advances upward to the height where the i-th first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , update the sound velocity of the ultrasonic wave in the molten metal to: ; wherein, is the spacing between the adjacent (n + 1)-th first thermocouple and the n-th first thermocouple.

[0011] Furthermore, the embodiment of the present invention provides a third possible implementation manner of the second aspect, wherein the numbering method of the first thermocouples is as follows: Arrange N first thermocouples vertically from bottom to top and number them as: 1, 2,..., N in sequence; mark the spacing between adjacent first thermocouples from bottom to top as: , ,..., ; Arrange M first ultrasonic probes in a rectangular array on the same horizontal plane and number them as: 1, 2,..., M in sequence; Determining the sound velocity of the ultrasonic wave in the molten metal based on the height value of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the central part includes: When the solidification interface is at the height where the 1st first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , determine the initial sound velocity of the ultrasonic wave in the molten metal as:

[0012] wherein, h is the spacing between the 1st first thermocouple and the N-th first thermocouple; When the solidification interface advances upward to the height where the i-th first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , update the sound velocity of the ultrasonic wave in the molten metal to:

[0013] wherein, is the spacing between the adjacent (n + 1)-th first thermocouple and the n-th first thermocouple.

[0014] Furthermore, the embodiment of the present invention provides a fourth possible implementation manner of the second aspect, wherein the steps of determining the position of the solidification interface sensed by each first ultrasonic probe based on the updated sound velocity of the ultrasonic wave in the molten metal to obtain the interface topography of the solidification interface include: If the solidification interface advances upward to the height where the i-th first thermocouple is located, then based on the updated sound speed of the ultrasonic wave in the molten metal , the echo time of the j-th first ultrasonic probe , calculate the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe as:

[0015] Based on the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe , calculate the height value of the solidification interface sensed by the j-th first ultrasonic probe : ; Based on the height values of the solidification interfaces sensed by each first ultrasonic probe, or the distances between the solidification interfaces sensed by each first ultrasonic probe and the corresponding sensing ends of the first ultrasonic probes, obtain the interface topography of the solidification interface.

[0016] Furthermore, the embodiment of the present invention provides a fifth possible implementation manner of the second aspect, wherein the method further includes: If the solidification interface advances to the height where the i-th first thermocouple is located, then based on the positions of the solidification interfaces sensed by each first ultrasonic probe, determine the average height value of the solidification interface ; Based on the average height value of the solidification interface at the first moment and the average height value of the solidification interface at the second moment, determine the advancing speed of the solidification interface as: ; wherein, is the average height value of the solidification interface at the first moment, is the average height value of the solidification interface at the second moment, is the first moment, is the second moment.

[0017] Furthermore, the embodiment of the present invention provides a sixth possible implementation manner of the second aspect, wherein the device further includes a verification cavity; the detection assembly further includes a second ultrasonic probe for detecting the position of the liquid level of the molten metal in the verification cavity; the method further includes: If the solidification interface advances to the height where the i-th first thermocouple is located, then based on the liquid level height value of the molten metal in the verification cavity measured by the second ultrasonic probe, determine the height verification value of the solidification interface as: ; wherein, is the volume change rate of the solidification of the metal solution, is the cross-sectional area of the accommodation cavity, is the cross-sectional area of the verification cavity; , is the initial liquid level height value of the molten metal in the verification cavity measured by the second ultrasonic probe, is the actual liquid level height value of the molten metal in the verification cavity measured by the second ultrasonic probe; Based on the average height value , the height verification value , determine the relative height error of the solidification interface as: ; Based on the relative height error, evaluate the height monitoring accuracy of the solidification interface of the molten metal in the accommodation cavity: If , it is determined that the height of the solidification interface of the molten metal monitored based on the first ultrasonic probe meets the accuracy requirements, where is the preset height error.

[0018] Furthermore, the embodiment of the present invention provides a seventh possible implementation manner of the second aspect, wherein the method further includes: Based on the height verification value , determine the verification value of the solidification interface advancement speed as: ; wherein is the height verification value of the solidification interface at the first moment, is the height verification value of the solidification interface at the second moment; Based on the advancement speed , the verification value of the advancement speed , determine the relative advancement speed error of the solidification interface as: ; Based on the relative advancement speed error, evaluate the advancement speed monitoring accuracy of the solidification interface of the molten metal in the accommodation cavity: If , it is determined that the advancement speed of the solidification interface of the molten metal monitored based on the first ultrasonic probe meets the accuracy requirements, where is the preset advancement speed error.

[0019] An ultrasonic monitoring method for the metal solidification process provided by an embodiment of the present invention includes: controlling the operation of the first heating sheet and the refrigeration sheet to make the temperature of the accommodation cavity gradually increase from bottom to top in the vertical direction, where the temperature controlled by the refrigeration sheet is lower than the melting point of the metal to be measured, and the temperature controlled by the first heating sheet is higher than the melting point of the metal to be measured; numbering N first thermocouples in sequence along the vertical direction and corresponding to N height positions in sequence, where N > 2, the lowermost first thermocouple senses the temperature at the bottom wall of the accommodation cavity, and the uppermost first thermocouple senses the temperature at the height where the sensing end of the first ultrasonic probe in the accommodation cavity is located; arranging M first ultrasonic probes in an array at the same horizontal plane, where M > 3; determining the height value of the solidification interface based on the temperature values sensed by the first thermocouples; determining the sound velocity of ultrasonic waves in the molten metal based on the height value of the solidification interface determined by the first thermocouples and the echo time of the first ultrasonic probe located at or closest to the central part; determining the positions of the solidification interfaces sensed by each first ultrasonic probe based on the sound velocity of the ultrasonic waves in the molten metal to obtain the interface morphology of the solidification interface. By controlling the start of operation of the first heating sheet and the refrigeration sheet, the present invention controls the temperature of the accommodation cavity to gradually increase from bottom to top in the vertical direction, realizes the control of the heat flow gradient of the molten metal in the accommodation cavity, and thus controls the molten metal to gradually start solidifying from the bottom of the accommodation cavity. When the temperature of the lower of two adjacent first thermocouples among the N first thermocouples is less than or equal to the melting point of the metal to be measured, and the temperature of the upper first thermocouple is greater than the melting point of the metal to be measured, it is determined that the solidification interface is located at the position of the lower first thermocouple or between the two first thermocouples at this time. When the solidification interface is located at the position of the lower first thermocouple, the sound velocity of ultrasonic waves in the molten metal is updated through the echo time of the first ultrasonic probe located at or closest to the central part. When the solidification interface is located at the position of the lower first thermocouple or between the two first thermocouples, the positions of each part of the solidification interface of the molten metal are determined based on the sound velocity of the ultrasonic waves in the molten metal and the echo time of each first ultrasonic probe, so as to determine the morphology of the solidification interface and obtain the advancing speed of the solidification interface. For the specific details of the beneficial effects of the above monitoring device, they will not be elaborated here.

[0020] Other features and advantages of the embodiments of the present invention will be described in the subsequent description, or, some features and advantages can be inferred from the description or determined without doubt, or can be known by implementing the above technologies of the embodiments of the present invention.

[0021] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following specific preferred embodiments are given, and in conjunction with the accompanying drawings, the detailed description is as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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 the description of the specific embodiments or the prior art. Obviously, the drawings in the following description 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.

[0023] Figure 1 Fig. 4 shows a schematic structural diagram of an ultrasonic monitoring device for the metal solidification process provided by an embodiment of the present invention; Figure 2 Fig. 7 shows a schematic arrangement diagram of ultrasonic probes in an ultrasonic monitoring device for the metal solidification process provided by an embodiment of the present invention; Figure 3 Fig. 10 shows a schematic flowchart of an ultrasonic monitoring method for the metal solidification process provided by an embodiment of the present invention; Figure 4 Fig. 13 shows a schematic diagram of the correction of the solidification interface in an ultrasonic monitoring method for the metal solidification process provided by an embodiment of the present invention.

[0024] Explanation of reference numerals: 1 - First ultrasonic probe No. 1; 2 - First ultrasonic probe No. 2; 3 - First ultrasonic probe No. 3; 4 - First ultrasonic probe No. 4; 5 - First ultrasonic probe No. 5; 6 - First ultrasonic probe No. 6; 7 - First ultrasonic probe No. 7; 8 - First ultrasonic probe No. 8; 9 - First ultrasonic probe No. 9; 11 - Upper temperature control component; 12 - Lower temperature control component; 13 - Temperature measurement component; 14 - Detection component; 15 - Verification chamber; 16 - Second heating sheet; 17 - Thermal insulation layer; 18 - Side wall; 19 - Lower metal plate; 20 - Upper metal plate; 21 - Flange. Specific embodiments

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will describe the technical solutions of the present invention with reference to the drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention.

[0026] This embodiment provides an ultrasonic monitoring device for the metal solidification process. Refer to Figure 1Schematic structural diagram of an ultrasonic monitoring device for a metal solidification process. The device mainly includes: a containing cavity, an upper temperature control component 11, a lower temperature control component 12, a temperature measurement component 13, and a detection component 14; among them, the containing cavity is used to contain molten metal; the upper temperature control component 11 has a first heating sheet, which is fixedly arranged at the top of the containing cavity and is used to control the temperature at the top of the containing cavity; the lower temperature control component 12 has a refrigeration sheet, which is fixedly arranged at the bottom of the containing cavity and is used to control the temperature at the bottom of the containing cavity; the temperature measurement component 13 has a plurality of first thermocouples, and the first thermocouples are arranged at intervals in the vertical direction in the containing cavity and are used to monitor the temperature at the corresponding height in the containing cavity; the detection component 14 has a plurality of first ultrasonic probes, the first ultrasonic probes are arranged at the top of the containing cavity, and the sensing ends of the first ultrasonic probes are arranged vertically downward and are used to detect the solidification interface of the molten metal. The containing cavity of the ultrasonic monitoring device for the metal solidification process is a columnar cavity. And in order to ensure that the lateral heat leakage of the containing cavity is small enough, the side wall 18 of the cavity is made of a low thermal conductivity material. Specifically, when the device monitors the metal solidification process of a metal material with a relatively low melting point (such as gallium metal, whose melting point is usually 29.76°C), materials such as acrylic can be used as the side wall 18 of the containing cavity of the cavity. Among them, the thermal conductivity of the acrylic material is usually 0.2 W / (m·k); if when the device monitors the metal solidification process of a metal material with a relatively high melting point (such as lead-bismuth alloy, whose melting point is usually 180°C to 230°C), materials such as borosilicate glass can be used as the side wall 18 of the containing cavity of the cavity. Since the installation stability is poor when using borosilicate glass, a flange 21 needs to be arranged outside the side wall 18 of the containing cavity, and the side wall 18 of the containing cavity is fixedly connected to the upper and lower metal plates through the flange 21 to improve the stability of the side wall 18 of the containing cavity; the upper wall and the lower wall of the cavity are made of metal plates composed of metal materials, and the upper and lower metal plates are respectively provided with embedding grooves for embedding the side wall 18 of the containing cavity. The upper temperature control component 11 uses a first heating sheet and is arranged at the top of the upper metal plate 20 of the containing cavity, and the lower temperature control component 12 uses a refrigeration sheet and is arranged at the bottom of the lower metal plate 19 of the containing cavity. By passing currents of different magnitudes through the first heating sheet and the refrigeration sheet, the temperature of the first heating sheet and the refrigeration sheet is adjusted. Through the first heating sheet and the refrigeration sheet, the temperature in the containing cavity gradually decreases from top to bottom, and a directional heat flow gradient is controlled in the containing cavity. As Figure 1 shown, the temperature measurement component 13 has a plurality of first thermocouples. Specifically, seven first thermocouples are sequentially arranged from top to bottom on the central axis in the containing cavity, and there is a certain interval between each first thermocouple. At the same time, the No. 1 first thermocouple from top to bottom is arranged below the upper metal plate 20 and is in contact with the upper metal plate 20, and the No. 7 first thermocouple from top to bottom is arranged above the lower metal plate 19 and is in contact with the lower metal plate 19; the above detection component 14 has a plurality of first ultrasonic probes, which are arranged at the top of the containing cavity. Specifically, seeFigure 2 Schematic diagram of the arrangement of the first ultrasonic probe in an ultrasonic monitoring device for a metal solidification process shown. There are 9 first ultrasonic probes, which are arranged in a 3×3 array at the top of the accommodation cavity. Each first ultrasonic probe is fixedly connected to the first heating sheet and the upper metal plate 20 by threads. The sensing ends of each first ultrasonic probe are arranged vertically downward, and at the same time, the probe surfaces of each first ultrasonic probe penetrate into the interior of the accommodation cavity for detecting the solidification interface of the molten metal.

[0027] Through the combined action of the upper temperature control component and the lower temperature control component in the ultrasonic monitoring device for the metal solidification process provided by the embodiment of the present invention, the control of the heat flow gradient of the molten metal (i.e., liquid metal) in the accommodation cavity is achieved, thereby controlling the solidification situation of the molten metal in the accommodation cavity. The position of the solidification interface is determined by judging the temperature of the first thermocouple. The sound speed of the ultrasonic wave in the molten metal is updated through the echo time of the first ultrasonic probe located at or closest to the central part. The positions of the various parts of the solidification interface of the molten metal are determined through the updated sound speed and the echo time of each first ultrasonic probe, thereby determining the morphology of the solidification interface. At the same time, based on the echo time of each first ultrasonic probe when the solidification interface is at different positions and the time intervals at different positions, the advancing speed of the solidification interface of the molten metal is determined, realizing the real-time online research on the solidification process of the molten metal and obtaining the morphology and advancing speed of the solidification interface of the liquid metal.

[0028] In one embodiment, the ultrasonic monitoring device for the metal solidification process provided in this embodiment further includes a verification cavity 15. The verification cavity 15 is communicated with the top of the accommodation cavity through a pipeline. The verification cavity 15 is provided with a second heating sheet 16. The temperature measurement component 13 further includes a second thermocouple, which is arranged in the verification cavity 15 for monitoring the temperature of the molten metal in the verification cavity 15. The detection component 14 further includes a second ultrasonic probe, which is arranged at the bottom of the verification cavity 15. The sensing end of the second ultrasonic probe is arranged vertically upward for detecting the liquid level position of the molten metal in the verification cavity 15. As Figure 1 Shown, the ultrasonic monitoring device for the metal solidification process further includes a verification cavity 15. The molten metal in the accommodation cavity is transported to the verification cavity 15 through a shut-off. Specifically, the verification cavity 15 is an open structure with an opening at the top. One end of the pipeline is communicated with the interior of the accommodation cavity through the first heating sheet and the top of the accommodation cavity, and the other end is communicated with the verification cavity 15 through the side wall of the verification cavity 15 and this port of the pipeline is close to the bottom of the verification cavity 15. The second ultrasonic probe in the detection component 14 is arranged at the bottom of the verification cavity 15, and the second ultrasonic probe is fixedly connected to the bottom wall of the verification cavity 15 by threads. The change amount of the liquid level height of the molten metal in the verification cavity 15 is determined through the echo time of the second ultrasonic probe, thereby determining the change amount of the volume of the molten metal in the verification cavity 15. In order to further reduce the lateral heat leakage of the accommodation cavity, a heat insulation layer 17 is further provided outside the side wall 18 of the accommodation cavity. In order to reduce the heat loss when the molten metal is transported from the accommodation cavity to the verification cavity 15, a heat insulation layer can also be provided outside the side wall of the pipeline exposed to the air. Specifically, when the device monitors the metal solidification process of a metal material with a relatively low melting point (such as gallium metal, whose melting point is usually 29.76 °C), materials such as polystyrene can be used as the materials of the heat insulation layer outside the side wall 18 of the accommodation cavity and outside the side wall of the pipeline; if the device monitors the metal solidification process of a metal material with a relatively high melting point (such as lead-bismuth eutectic alloy, whose melting point is usually 125 °C), materials such as heat insulation cotton can be used as the materials of the heat insulation layer outside the side wall 18 of the accommodation cavity and outside the side wall of the pipeline. Grooves are provided on the upper and lower metal plates of the accommodation cavity for arranging the heat insulation layer 17. And when monitoring the interface of the high-melting-point molten metal, in order to further ensure the stability of the side wall of the accommodation cavity and the heat insulation layer 17, a flange 21 is provided outside the heat insulation layer, and the flange 21 is fixedly connected to the upper and lower metal plates to compress the heat insulation cotton and borosilicate glass to ensure the heat insulation and sealing effects of the accommodation cavity; Meanwhile, in order to monitor the temperature of the molten metal in the verification cavity 15 in real time, a second thermocouple is provided in the verification cavity 15 (specifically, it can be arranged above the bottom wall of the verification cavity 15), and a second heating sheet is provided outside the side wall of the verification cavity 15. The temperature of the molten metal in the verification cavity 15 is monitored in real time by the second thermocouple. If the temperature of the molten metal in the verification cavity 15 is lower than the temperature detected by the first thermocouple at the uppermost part in the accommodation cavity, an electric current is passed through the second heating sheet outside the side wall of the verification cavity 15, and the second heating sheet is controlled to gradually increase the temperature of the molten metal in the verification cavity 15 to be the same as the temperature detected by the first thermocouple at the uppermost part in the accommodation cavity. The setting of the second thermocouple and the second heating sheet can avoid the situation that the volume of the molten metal in the verification cavity 15 changes when the temperatures of the molten metals in the verification cavity 15 and the accommodation cavity are different.

[0029] The embodiment of the present invention also provides an ultrasonic monitoring method for the metal solidification process. This method can be applied to the above-mentioned ultrasonic monitoring device for the metal solidification process and electronic devices such as computers. Refer to Figure 3 the schematic flow chart of an ultrasonic monitoring method for the metal solidification process shown in Step S301: Control the first heating sheet and the refrigerating sheet to work so that the temperature of the accommodation cavity gradually increases from bottom to top in the vertical direction. Among them, the temperature controlled by the refrigerating sheet is lower than the melting point of the metal to be measured, and the temperature controlled by the first heating sheet is higher than the melting point of the metal to be measured; Before the experiment starts, add the metal melt into the accommodating cavity and stir it so that the temperature in the accommodating cavity is higher than the melting point of the metal melt. By passing an electric current through the first heating sheet and the refrigerating sheet, the first heating sheet and the refrigerating sheet start to work, ensuring that both the first heating sheet and the refrigerating sheet are heated at a constant temperature, so that the temperature of the refrigerating sheet is lower than the melting point of the metal melt, and the temperature of the first heating sheet is higher than the melting point of the metal melt, making the temperature of the metal melt in the accommodating cavity gradually increase from bottom to top, and making the metal melt start to solidify from the bottom of the accommodating cavity.

[0030] Step S303: Number N first thermocouples in sequence along the vertical direction and correspond to N height positions in sequence, where N > 2. The lowermost first thermocouple senses the temperature at the bottom wall in the accommodating cavity, and the uppermost first thermocouple senses the temperature at the height where the sensing end of the first ultrasonic probe in the accommodating cavity is located. N first thermocouples are arranged in sequence from top to bottom on the central axis in the accommodating cavity. Specifically, N = 7 (that is, seven first thermocouples are arranged in sequence from top to bottom on the central axis in the accommodating cavity). There is a certain interval between each first thermocouple. Since the first thermocouple is arranged in the accommodating cavity, it may interfere with the sound wave emitted by the first ultrasonic probe and affect its echo time. Based on the geometric approximation hypothesis of the sector sound wave, when the incident wavelength of the sound wave is much smaller than the characteristic size of the obstacle, the diffraction effect of the sound wave can be ignored. Thus, the size of the first thermocouple is screened to avoid the situation where the first thermocouple interferes with the sound wave emitted by the first ultrasonic probe. The diameter of the first thermocouple is determined by the relationship formula between the strength of the sound wave diffraction effect, the wave number of the sound wave, and the characteristic size of the obstacle; among them, the relationship formula is expressed as:

[0031] Among them, is the wave number of the sound wave, is the frequency of the sound wave, is the speed of the sound wave, is the wavelength of the sound wave, is the characteristic size of the obstacle (i.e., the first thermocouple) during the sound wave propagation process. For example, the characteristic size of a sphere is its radius; In a specific embodiment, when and the metal melt is a gallium metal melt, the sound wave partially diffracts. If the emission frequency of the wave emitted by the first ultrasonic probe at this time is 5 MHz and the sound speed of the sound wave in the gallium melt at normal temperature is 2700 m / s, in order to avoid the influence of a larger-sized first thermocouple on the sound wave, the parameters need to be substituted into the relationship formula, and we get:

[0032] At this time, the above , f = 5 MHz, c = 2700 m / s, the maximum radius of the first thermocouple is obtained by solving, which is 0.85 mm, and the maximum diameter is 1.7 mm. Therefore, a first thermocouple with a diameter less than 1.7 mm can be selected (for example, an armored first thermocouple with a diameter of 1 mm can be used).

[0033] Step S305, arrange M first ultrasonic probes in an array on the same horizontal plane, where M > 3; As Figure 2 shown, taking M = 9 as an example, that is, there are a total of 9 first ultrasonic probes arranged in a 3×3 array on the same horizontal plane, and the first ultrasonic probe at the center of the array is set on the central axis of the accommodating cavity.

[0034] Step S307, determine the height value of the solidification interface based on the temperature value sensed by the first thermocouple; When the temperature value sensed by the first thermocouple is greater than the melting point of the metal to be measured, the solidification interface of the metal melt in the accommodating cavity is below the position of this first thermocouple. Conversely, when the temperature value sensed by the first thermocouple is less than the melting point of the metal to be measured, the solidification interface of the metal melt in the accommodating cavity is above the position of this first thermocouple.

[0035] Step S309, determine the sound speed of ultrasonic waves in the metal melt based on the height value of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the central part; Since the first thermocouple is set on the central axis of the accommodating cavity, it can better reflect the temperature of the metal melt in the central part. The sound speed of ultrasonic waves in the accommodating cavity determined by the echo time of the first ultrasonic probe located at or closest to the central part is more accurate. Specifically, the sound speed of ultrasonic waves in the metal melt is determined by the echo time of the first ultrasonic probe set on the central axis of the accommodating cavity.

[0036] Step S311, determine the positions of the solidification interfaces sensed by each first ultrasonic probe based on the sound speed of ultrasonic waves in the metal melt, and obtain the interface morphology of the solidification interface; Based on the sound speed of ultrasonic waves in the metal melt and the echo times of each first ultrasonic probe, the positions of the solidification interfaces detected by each probe are determined by the echo reflection method, thereby obtaining the interface morphology of the solidification interface.

[0037] The present invention controls the first heating sheet and the refrigerating sheet to start working, controls the temperature of the accommodating cavity to gradually increase from bottom to top in the vertical direction, realizes the control of the heat flow gradient of the molten metal in the accommodating cavity, so as to control the molten metal in the accommodating cavity to gradually start solidifying from the bottom of the accommodating cavity. When the temperatures of two adjacent first thermocouples are such that the temperature of the lower first thermocouple is less than or equal to the melting point of the metal to be measured and the temperature of the upper first thermocouple is greater than the melting point of the metal to be measured, it is determined that the solidification interface is located at the position of the lower first thermocouple or between the two first thermocouples at this time. When the solidification interface is located at the position of the lower first thermocouple, the sound velocity of the ultrasonic wave in the molten metal is updated through the echo time of the first ultrasonic probe located at or closest to the central part. When the solidification interface is located at the position of the lower first thermocouple or between the two first thermocouples, the positions of the respective parts of the solidification interface of the molten metal are determined based on the sound velocity of the ultrasonic wave in the molten metal and the echo time of each first ultrasonic probe, so as to determine the morphology of the solidification interface and obtain the advancing speed of the solidification interface. For the specific details, please refer to the beneficial effects of the above-mentioned monitoring device, which will not be elaborated here.

[0038] In one embodiment, the specific implementation manner of step S307 provided in this embodiment includes: Step S3071, obtaining the temperature values of each first thermocouple, and determining the height value of the i-th first thermocouple whose temperature is equal to the melting point of the metal to be measured as the height value of the solidification interface ; Generally, the melting point of a metal is the same as its solidification point temperature. Therefore, when the temperature detected by the first thermocouple is the same as the melting point of the metal to be measured, it is considered that the solidification interface of the molten metal in the accommodating cavity has reached the position of this first thermocouple.

[0039] In one embodiment, the numbering method of the first thermocouples provided in this embodiment is: arranging N first thermocouples vertically from top to bottom and numbering them as: 1, 2,..., N in sequence; marking the distances between adjacent first thermocouples from top to bottom as: , ,..., ; arranging M first ultrasonic probes in a rectangular array on the same horizontal plane and numbering them as: 1, 2,..., M in sequence; In the above steps, specifically, when N = 7 and M = 9, the first thermocouples are numbered vertically from top to bottom as: 1, 2,..., 7 in sequence; marking the distances between adjacent first thermocouples from top to bottom as: , ,..., ; as Figure 2 shown, numbering the first ultrasonic probes as 1, 2,..., 9 in sequence, that is, the first ultrasonic probes numbered 1 - 9 respectively represent the first ultrasonic probes numbered 1 - 9.

[0040] The specific implementation of step S309 includes: Step S3091, when the solidification interface is at the height where the Nth first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , determine the initial sound velocity of ultrasonic waves in the molten metal It is:

[0041] where h is the distance between the 1st first thermocouple and the Nth first thermocouple; In the above steps, the 1st first thermocouple is arranged below the upper metal plate of the accommodating cavity and in contact with the upper metal plate, and the Nth first thermocouple is arranged above the lower metal plate of the accommodating cavity and in contact with the lower metal plate. Therefore, the height difference h between the 1st first thermocouple and the Nth first thermocouple is the overall height of the accommodating cavity (i.e., the height between the upper metal plate and the lower metal plate of the accommodating cavity). When the number of first thermocouples is 7, specifically, when N = 7, when the solidification interface is at the height where the 7th first thermocouple is located, based on the echo time of the first ultrasonic probe located on the central axis of the accommodating cavity , determine the initial sound velocity of ultrasonic waves in the molten metal It is:

[0042] where h is the distance between the 1st first thermocouple and the Nth first thermocouple (i.e., the overall height h inside the accommodating cavity), and the echo time is determined by the moment corresponding to the maximum value of the amplitude of the echo signal of the first ultrasonic probe on the central axis of the accommodating cavity.

[0043] Step S3093, when the solidification interface advances upward to the height where the ith first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , update the sound velocity of ultrasonic waves in the molten metal It is: ; where is the distance between the adjacent (n + 1)th first thermocouple and the nth first thermocouple; In the above steps, when the solidification interface advances upward to the height where the ith first thermocouple is located, based on the echo time of the first ultrasonic probe located on the central axis of the accommodating cavity at this time update the sound velocity of ultrasonic waves in the molten metal .

[0044] In one embodiment, the numbering method of the first thermocouples in this embodiment is as follows: The N first thermocouples are numbered from bottom to top in the vertical direction as: 1, 2,..., N; the spacing between adjacent first thermocouples is marked from bottom to top in sequence as: , ,..., ; The M first ultrasonic probes are numbered in sequence in a rectangular array on the same horizontal plane as: 1, 2,..., M; In the above steps, specifically, when N = 7 and M = 9, the first thermocouples are numbered from bottom to top in the vertical direction as: 1, 2,..., 7; the spacing between adjacent first thermocouples is marked from bottom to top in sequence as: , ,..., ; As Figure 2 shown, the first ultrasonic probes are numbered as 1, 2,..., 9 in sequence.

[0045] The specific implementation manner of step S309 includes: Step S3092, when the solidification interface is at the height where the 1st first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part, determine the initial sound speed of the ultrasonic wave in the molten metal as:

[0046] where h is the spacing between the 1st first thermocouple and the Nth first thermocouple; In the above steps, the 1st first thermocouple is arranged above the lower metal plate of the accommodating cavity and in contact with the lower metal plate, and the Nth first thermocouple is arranged below the upper metal plate of the accommodating cavity and in contact with the upper metal plate. Therefore, the height difference h between the 1st first thermocouple and the Nth first thermocouple is the overall height of the accommodating cavity (i.e., the height between the upper metal plate and the lower metal plate of the accommodating cavity). When the number of first thermocouples is 7, specifically, when N = 7, when the solidification interface is at the height where the 1st first thermocouple is located, based on the echo time of the first ultrasonic probe located on the central axis of the accommodating cavity, determine the initial sound speed of the ultrasonic wave in as:

[0047] where h is the spacing between the 1st first thermocouple and the 7th first thermocouple (i.e., the overall height h inside the accommodating cavity), and the echo time is determined by the moment corresponding to the maximum value of the echo signal amplitude of the first ultrasonic probe on the central axis of the accommodating cavity.

[0048] Step S3094: When the solidification interface advances upward to the height where the i-th first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , update the sound speed of ultrasonic waves in the molten metal as:

[0049] wherein, is the distance between the adjacent (n + 1)-th first thermocouple and the n-th first thermocouple; When the solidification interface advances upward to the height where the i-th first thermocouple is located, based on the echo time of the first ultrasonic probe located on the central axis of the accommodation cavity at this time update the sound speed of ultrasonic waves in the molten metal .

[0050] In one embodiment, this embodiment provides a specific implementation manner of step S311, including: Step S3111: If the solidification interface advances upward to the height where the i-th first thermocouple is located, then based on the updated sound speed of ultrasonic waves in the molten metal , the echo time of the j-th first ultrasonic probe , calculate the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe as: ; In the above steps, when the N first thermocouples are numbered from top to bottom in the vertical direction as 1, 2,..., N, the position of the solidification interface can be determined by the temperatures detected by two adjacent first thermocouples. If the solidification interface advances upward to the height where the i-th first thermocouple is located, it means that the temperature detected by the i-th first thermocouple at this time ≤ the melting point of the metal to be measured < the temperature detected by the (i - 1)-th first thermocouple. Generally speaking, when the temperature detected by the first thermocouple is greater than the melting point of the metal to be measured, it proves that the solidification interface is still below this first thermocouple at this time. When the temperature detected by the first thermocouple is equal to the melting point of the metal to be measured, it proves that the solidification interface is at the position of this first thermocouple. When the temperature detected by the first thermocouple is less than the melting point of the metal to be measured, it proves that the solidification interface is above this first thermocouple. Therefore, if the temperature detected by the i-th first thermocouple ≤ the melting point of the metal to be measured < the temperature detected by the (i - 1)-th first thermocouple, then it is determined that the solidification interface of the molten metal is at the position of the i-th first thermocouple or between the i-th first thermocouple and the (i - 1)-th first thermocouple. If the solidification interface advances to the position of other first thermocouples or between other two adjacent first thermocouples, the sound speed obtained based on other thermocouples needs to be used to solve the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe. For example, when the solidification interface is at the position of the (i - 1)-th first thermocouple or between the (i - 1)-th first thermocouple and the (i - 2)-th first thermocouple, based on the sound speed Solve the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe ; When the N first thermocouples are numbered from bottom to top in the vertical direction as 1, 2,..., N, the position of the solidification interface can be determined by the temperatures detected by two adjacent first thermocouples. If the solidification interface advances upward to the height where the i-th first thermocouple is located, it means that the temperature detected by the i-th first thermocouple at this time ≤ the melting point of the metal to be measured < the temperature detected by the (i + 1)-th first thermocouple. Then it is determined that the solidification interface of the molten metal in the accommodation cavity is at the position of the i-th first thermocouple or between the i-th first thermocouple and the (i + 1)-th first thermocouple. If the solidification interface advances to the position of other first thermocouples (such as the solidification interface is at the position of the (i + 1)-th first thermocouple) or between other two adjacent first thermocouples, the sound speed obtained based on other thermocouples needs to be used to solve the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe. For example, when the solidification interface is at the position of the (i + 1)-th first thermocouple or between the (i + 1)-th first thermocouple and the (i + 2)-th first thermocouple, based on the sound speed Solve the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe .

[0051] Step S3113, based on the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe , calculate the height value of the solidification interface sensed by the j-th first ultrasonic probe : ; Based on the height values of the solidification interfaces sensed by the respective first ultrasonic probes, or the distances between the solidification interfaces sensed by the respective first ultrasonic probes and the corresponding sensing ends of the first ultrasonic probes, obtain the interface topography of the solidification interface.

[0052] In one embodiment, the ultrasonic monitoring method for the metal solidification process provided in this embodiment further includes: Step S313, if the solidification interface advances to the height where the i-th first thermocouple is located, determine the average height value of the solidification interface based on the positions of the solidification interfaces sensed by the respective first ultrasonic probes ; In the above steps, since the positions of the solidification interfaces monitored by the respective first ultrasonic probes are different, it is necessary to correct the positions of the solidification interfaces obtained by the respective first ultrasonic probes to obtain a corrected value of the overall height value of the solidification interface (that is, determine the average height value of the solidification interface ), specifically, refer to Figure 4 the schematic diagram of solidification interface correction in an ultrasonic monitoring method for a metal solidification process provided. In this embodiment, taking 9 first ultrasonic probes as an example, and the 9 ultrasonic probes are arranged in a 3×3 array. When the solidification interface advances to the height where the i-th first thermocouple is located (that is, when the temperature detected by the i-th first thermocouple ≤ the melting point of the metal to be measured < the temperature detected by the first thermocouple adjacent to the i-th first thermocouple and located above the i-th first thermocouple), the overall solidification interface is divided into 16 sub-interfaces by 9 first ultrasonic probes. At this time, the distances between the solidification interfaces detected by the 1st - 9th first ultrasonic probes and their respective sensing ends of the first ultrasonic probes are , ,... , among which, the interfaces near the edge (including interface , interface , interface , interface , interface , interface , interface , interface , interface , interface and interface ) adopt extrapolation reconstruction (for example, interface is composed of , , Extrapolation reconstruction, from , , , extrapolation reconstruction,), the interfaces in the central part (including interfaces , interface and interface ) are reconstructed by bilinear interpolation (for example, interface from , , , interpolation reconstruction), and the corrected value of the solidification interface height value finally obtained (i.e., the average height after reconstruction) is:[[]]

[0053] where h is the distance between the first thermocouple No. 1 and the first thermocouple No. N (i.e., the overall height inside the accommodation cavity).

[0054] Step S315, based on the average height value of the solidification interface at the first moment and the average height value of the solidification interface at the second moment, determine the advancing speed of the solidification interface as:[[]] ; where is the average height value of the solidification interface at the first moment, is the average height value of the solidification interface at the second moment, is the first moment, is the second moment; In the above steps, it is necessary to solve the average height value of the solidification interface at the first moment by the method in step S313, including: according to the sound speed in the molten metal in the accommodation cavity at the first moment, the echo time of the j-th probe, calculate the distance between the sensing end of each ultrasonic probe and the solidification interface as:[[]]

[0055] According to the sound speed in the molten metal in the accommodation cavity at the second moment, the echo time of the j-th probe, calculate the distance between the sensing end of each ultrasonic probe and the solidification interface as:[[]]

[0056] Specifically, there are 9 first ultrasonic probes, which are arranged in a 3×3 first ultrasonic probe array. The overall solidification interface is divided into 16 sub-interfaces by the 9 first ultrasonic probes; At the first moment, the distances between each sub-interface and the sensing ends of each first ultrasonic probe are respectively , based on the distances The bilinear interpolation method and the extrapolation method are used to reconstruct the solidification interface, and the average height value of the solidification interface at the first moment (i.e., the corrected value of the height value of the solidification interface at the first moment) is:

[0057]

[0058] At the second moment, the distances between each sub-interface and the sensing ends of each first ultrasonic probe are respectively , based on the distances The bilinear interpolation method and the extrapolation method are used to reconstruct the solidification interface, and the average height value of the solidification interface at the second moment (i.e., the corrected value of the height value of the solidification interface at the second moment) is:

[0059]

[0060] where h is the distance between the 1st first thermocouple and the 7th first thermocouple; The advancing speed of the corrected solidification interface is calculated as:

[0061] where is the average height value of the solidification interface at the first moment, is the average height value of the solidification interface at the second moment, is the first moment, is the second moment.

[0062] In one embodiment, the ultrasonic monitoring device for the metal solidification process provided in this embodiment further includes: a verification chamber 15; the detection assembly 14 further includes a second ultrasonic probe for detecting the position of the metal melt liquid level in the verification chamber 15; the method further includes: Step S317, if the solidification interface advances to the height where the i-th first thermocouple is located, then based on the liquid level height value of the metal melt in the verification chamber measured by the second ultrasonic probe, determine the height verification value of the solidification interface as: ; where is the volume change rate of the solidification of the metal solution, is the cross-sectional area of the accommodation cavity, is the cross-sectional area of the verification cavity; , is the initial liquid level height value of the molten metal in the verification cavity measured by the second ultrasonic probe, is the actual liquid level height value of the molten metal in the verification cavity measured by the second ultrasonic probe; In the above steps, when the solidification interface in the accommodation cavity advances to the height where the i-th first thermocouple is located (that is, when the temperature detected by the i-th first thermocouple ≤ the melting point of the metal to be measured < the temperature detected by the first thermocouple adjacent to the i-th first thermocouple and located above the i-th first thermocouple), the sound speed of the molten metal in the verification cavity 15 at this time is determined by the temperature detected by the second thermocouple in the temperature measurement component 13; At this time, the actual liquid level height of the molten metal in the verification cavity is determined by the echo time of the second ultrasonic probe in the detection component 14 and the sound speed of the molten metal in the verification cavity 15 ; By the actual liquid level height of the molten metal in the verification cavity 15 at this time and the initial liquid level height of the molten metal in the verification cavity 15 , the height value of the solidification interface of the molten metal in the accommodation cavity at this time is determined ; At the same time, since the volume of the molten metal may expand or contract during solidification, as Figure 1 shown, when the ultrasonic monitoring method for the metal solidification process is used to monitor the molten metal whose volume will expand during solidification (for example, the volume expansion rate of gallium element during solidification is 3%), it is necessary to ensure the height of the initial liquid level in the verification cavity 15 needs to have a certain initial height , and this initial height is determined by the height difference between the upper side wall of the pipe connected to the verification cavity 15 and the monitoring end of the second ultrasonic probe; When the ultrasonic monitoring method for the metal solidification process is used to monitor the molten metal whose volume will contract during solidification, it is necessary to ensure that the height of the initial liquid level in the verification cavity 15 is higher than the initial height , and the height of the initial liquid level needs to satisfy: ; Among them, is the volume change rate of the solidification of the metal solution, and at this time is less than 1, and h is the overall height of the accommodation cavity.

[0063] Step S319, based on the average height value , the height verification value , determine the relative height error of the solidification interface as: ; Step S321, based on the relative height error, evaluate the height monitoring accuracy of the solidification interface of the molten metal in the accommodating cavity: If , it is determined that the height of the solidification interface of the molten metal monitored based on the first ultrasonic probe meets the accuracy requirements, where is the preset height error.

[0064] In one embodiment, the ultrasonic monitoring method for the metal solidification process provided in this embodiment further includes: Step S323, based on the height verification value , determine the solidification interface advancement speed verification value as: ; where is the height verification value of the solidification interface at the first moment, is the height verification value of the solidification interface at the second moment; In the above steps, the sound speed of the molten metal in the verification cavity 15 at the first moment is determined by the temperature detected by the second thermocouple in the temperature measurement component 13 at the first moment; the sound speed of the molten metal in the verification cavity 15 at the second moment is determined by the temperature detected by the second thermocouple in the temperature measurement component 13 at the second moment; The actual liquid level height of the molten metal in the verification cavity 15 at the first moment is determined by the echo time of the second ultrasonic probe in the detection component 14 at the first moment and the sound speed of the molten metal in the verification cavity 15 at the first moment ; the actual liquid level height of the molten metal in the verification cavity 15 at the second moment is determined by the echo time of the second ultrasonic probe in the detection component 14 at the second moment and the sound speed of the molten metal in the verification cavity 15 at the second moment ; The height value of the solidification interface of the molten metal in the accommodating cavity at this time is determined by the actual liquid level height of the molten metal in the verification cavity 15 at the first moment and the initial liquid level height of the molten metal in the verification cavity 15 ; the height value of the solidification interface of the molten metal in the accommodating cavity at this time is determined by the actual liquid level height of the molten metal in the verification cavity 15 at the second moment and the initial liquid level height of the molten metal in the verification cavity 15 ; Determine the solidification interface advancement speed verification value is: 。

[0065] Step S325, based on the said advancing speed and the said advancing speed verification value , determine the relative error of the advancing speed of the solidification interface is: ; Step S327, based on the relative error of the advancing speed, evaluate the monitoring accuracy of the advancing speed of the solidification interface of the molten metal in the accommodation cavity: If , it is determined that the advancing speed of the solidification interface of the molten metal monitored by the said first ultrasonic probe meets the accuracy requirements, where is the preset advancing speed error; In the above steps, whether the reconstructed solidification interface (i.e., the average height value of the solidification interface) meets the requirements is evaluated through the relative error of the height of the solidification interface and the relative error of the advancing speed of the solidification interface. If the relative error of the height of the solidification interface is less than or equal to the preset height error and the relative error of the advancing speed of the solidification interface is less than or equal to the preset speed error, it is considered that the reconstructed (i.e., corrected) solidification interface meets the requirements; otherwise, it is considered that the reconstructed (i.e., corrected) solidification interface does not meet the requirements, and other methods are used to reconstruct the solidification interface.

[0066] Based on the foregoing embodiments, this embodiment provides an ultrasonic monitoring device for the metal solidification process, including: an accommodation cavity, an upper temperature control component 11, a lower temperature control component 12, a temperature measurement component 13, a detection component 14, and a verification cavity 15; The ultrasonic monitoring device for the above metal solidification process monitors the solidification interface of low melting point metals (i.e., gallium metal). Among them, both the accommodation cavity and the verification cavity 15 are columnar cavities. In order to ensure that the lateral heat leakage in the accommodation cavity is small enough, the side wall 18 of the accommodation cavity is made of a material with low thermal conductivity (including acrylic material), and a thermal insulation layer 17 made of polystyrene material is also provided outside the side wall 18 of the accommodation cavity. The upper and lower walls of the cavity of the accommodation cavity are made of metal plates composed of metal materials; the upper temperature control component 11 (i.e., the heating sheet) is arranged above the upper metal plate 20; the lower temperature control component 12 (i.e., the cooling sheet) is arranged below the lower metal plate 19; the temperature measurement component 13 includes 7 first thermocouples arranged in sequence along the central axis of the accommodation cavity from top to bottom, and the first thermocouples are sequentially numbered 1, 2,..., 7 from top to bottom. The 1st first thermocouple is arranged below the upper metal plate 20 and in contact with the upper metal plate 20. The 7th first thermocouple is arranged above the lower metal plate 19 and in contact with the lower metal plate 19. The maximum diameter of the first thermocouple is determined by the product of the acoustic wave number and the characteristic size of the obstacle, and a first thermocouple with little influence on the acoustic wave is selected. Specifically, a 1mm armored first thermocouple can be used; the detection component 14 includes 9 first ultrasonic probes, which are arranged in a 3×3 array at the top of the accommodation cavity, and each first ultrasonic probe is fixedly connected to the heating sheet and the upper metal plate 20 through a thread. The 9 first ultrasonic probes are sequentially numbered 1, 2,..., 9, and the 5th first ultrasonic probe is arranged on the central axis of the accommodation cavity; In this device, the verification cavity 15 is an open structure with an opening at the top. The verification cavity 15 is connected to the inside of the accommodation cavity through a pipeline (a thermal insulation layer made of polystyrene material is also provided on the side wall of the pipeline exposed outside). A heating sheet is arranged outside the side wall of the verification cavity 15, and a second thermocouple is arranged above the bottom wall inside the verification cavity 15. The temperature of the metal melt in the verification cavity 15 is ensured to be the same as the temperature of the metal melt in the accommodation cavity (taking the temperature detected by the 1st first thermocouple in the accommodation cavity as the standard) through the second thermocouple and the second heating sheet. The sound velocity of the metal melt in the verification cavity 15 is determined by looking up data based on the temperature detected by the second thermocouple. The detection component 14 also includes a second ultrasonic probe, and the second ultrasonic probe is arranged at the bottom of the verification cavity 15. The sensing end of the second ultrasonic probe faces upward in the vertical direction and is used to detect the liquid level height of the metal melt in the verification cavity 15.

[0067] On the basis of the foregoing embodiment, this embodiment provides an ultrasonic monitoring method for the metal solidification process to monitor the solidification process of gallium metal melt, which is applied to the above ultrasonic monitoring device for the metal solidification process. This method includes the following steps: Step S501, when the temperature detected by the 7th first thermocouple is the melting point of the metal melt, based on the echo time of the ultrasonic probe located on the central axis of the accommodation cavity to determine the initial sound velocity of the ultrasonic wave in the metal melt is:

[0068] Among them, h is the distance between the first thermocouple No. 1 and the first thermocouple No. 7; determine that the initial liquid level of the molten metal in the verification chamber 15 at this time is ; Step S503, when the temperature detected by the i-th first thermocouple is the melting point of the molten metal, based on the echo time of the ultrasonic probe located on the central axis of the accommodation chamber , update the sound speed of the ultrasonic wave in the molten metal as: ; Among them, is the distance between the adjacent (n + 1)-th first thermocouple and the n-th first thermocouple; At the first moment , the solidification interface is located at the position of the i-th first thermocouple or between the i-th first thermocouple and the (i - 1)-th first thermocouple. Record the distance between the monitoring end of the central probe and the solidification interface at this time as the first distance. Based on the updated sound speed of the ultrasonic wave in the molten metal , and the echo time of each ultrasonic probe determine the distance between the solidification interface and the sensing end of the j-th ultrasonic probe at the first moment , and the distances detected by the 9 ultrasonic probes are respectively recorded as ( , ,..., ). Reconstruct the solidification interface detected by each ultrasonic probe through bilinear interpolation and extrapolation, and the corrected value of the solidification interface height at this time is:

[0069]

[0070] Among them, h is the distance between the first thermocouple No. 1 and the first thermocouple No. 7; Step S505, determine the sound speed of the molten metal in the verification chamber 15 at this time based on the temperature of the molten metal in the verification chamber 15 detected by the second thermocouple at the first moment; Determine the height of the molten metal in the verification chamber 15 at the first moment based on the echo time detected by the second ultrasonic probe and the sound speed of the molten metal in the verification chamber 15 at the first moment , and determine the height of the solidification interface in the verification chamber 15 at this time as: = -

[0071]

[0072] Among them, is the solidification volume change rate of the gallium metal solution, is the cross-sectional area of the accommodation cavity, is the cross-sectional area of the verification cavity 15, is the difference between the actual liquid level height value of the metal melt in the verification cavity 15 and the initial liquid level height value of the metal melt at the first moment; Step S507, at the second moment when the solidification interface is between the i-th first thermocouple and the (i - 1)-th first thermocouple, record the distance between the monitoring end of the central probe and the solidification interface at this time as the second distance, and the second distance is less than the first distance; based on the updated sound speed of the ultrasonic wave in the metal melt , and the echo time of each ultrasonic probe , determine the distance between the solidification interface and the sensing end of the j-th ultrasonic probe at the second moment , the distances detected by the 9 ultrasonic probes are respectively recorded as (

[0073]

[0074] where h is the distance between the 1st thermocouple and the 7th thermocouple; Step S509, determine the sound speed of the metal melt in the verification cavity 15 at the second moment based on the temperature of the metal melt in the verification cavity 15 detected by the second thermocouple at the second moment; Based on the echo time detected by the second ultrasonic probe and the sound speed of the metal melt in the verification cavity 15 at the second moment, determine the height of the metal melt in the verification cavity 15 at the second moment , and determine the height

[0075]

[0076] where, is the solidification volume change rate of the metal solution, is the cross-sectional area of the accommodation cavity, is the cross-sectional area of the verification cavity 15, is the difference between the actual liquid level height value of the molten metal in the verification chamber 15 at the second moment and the initial liquid level height value of the molten metal; Step S511, based on and determine the advancing speed of the reconstructed interface as:

[0077] Based on and determine the advancing speed of the solidification interface (i.e., the actual interface) determined by the verified chamber 15 as:

[0078] Step S515, based on and the relative error of the solidification interface height as:

[0079] Based on and the relative error of the solidification interface height as:

[0080] Based on and determine the relative error of the solidification interface advancing speed as:

[0081] If , and , it is determined that the monitoring of the metal melt interface height and speed advancement based on the ultrasonic probe meets the accuracy requirements, where is the preset height error, is the preset speed error.

[0082] In summary, the ultrasonic monitoring device and method for the metal solidification process provided by the embodiments of the present invention achieve the directional control of the solidification interface of the molten metal in the accommodating cavity, avoid the absorption and attenuation of sound waves by the rough and porous interface, avoid the situation where the sound waves deteriorate or even disappear, and achieve the measurement of the solidification interface of the molten metal through the ultrasonic probe. Moreover, the first ultrasonic probe is directly arranged in the accommodating cavity, and there is no stainless steel between the first ultrasonic probe and the molten metal, so that the first ultrasonic probe is applicable to the situation where the wall thickness of the container wall is very large and the acoustic impedance difference between the wall material and the molten metal to be measured is very large, improving the adaptability of the device. At the same time, the device does not have external moving parts and can be applicable to environments with high sealing requirements; Update the sound speed based on the position of the first thermocouple, avoid using the same sound speed to monitor the solidification interface of the molten metal, improve the accuracy of measuring the position of the solidification interface of the molten metal. Based on the first ultrasonic probe arranged in a 3×3 array, determine the actual positions of 9 points on the solidification interface, use a reconstruction algorithm to reconstruct the entire solidification interface, and compare it with the actual interface to obtain the relative error of the solidification interface height and the relative error of the solidification interface propagation speed; With the combined action of the upper temperature control component 11 and the lower temperature control component 12, control the heat flow gradient of the molten metal (i.e., liquid metal) in the accommodation cavity, thereby controlling the solidification of the molten metal in the accommodation cavity, and obtain the transient behavior of the physical laws of the molten metal under different temperature gradients. Accurately determine the temperature of the molten metal in the accommodation cavity through the first thermocouple, and judge whether the molten metal reaches the melting point, improving the accuracy of judging the position of the solidification interface of the molten metal. When two adjacent first thermocouples among the N first thermocouples, where the temperature of the lower first thermocouple is less than or equal to the melting point of the metal to be measured, and the temperature of the upper first thermocouple is greater than the melting point of the metal to be measured, then determine that the solidification interface is located at the position of the lower first thermocouple or between the two thermocouples at this time. When the solidification interface is located at the position of the lower first thermocouple, update the sound speed of the ultrasonic wave in the molten metal through the echo time of the first ultrasonic probe located at or closest to the central part. When the solidification interface is located at the position of the lower first thermocouple or between the two first thermocouples, determine the positions of each part of the solidification interface of the molten metal based on the sound speed of the ultrasonic wave in the molten metal and the echo time of each first ultrasonic probe, so as to determine the morphology of the solidification interface. At the same time, based on the echo time of each first ultrasonic probe when the solidification interface is located at different positions and the time interval when located at different positions, determine the propagation speed of the solidification interface of the molten metal, realize the real-time online research on the solidification process of the molten metal, obtain the morphology and propagation speed of the solidification interface of the liquid metal, reveal the relationship between the solidification process of the molten metal and the thermal boundary conditions. On the basis of verifying this experimental result, corresponding numerical simulation or theoretical analysis can be carried out to further study the physical mechanism of the solidification process of the molten metal, deepen the understanding of the macroscopic mechanism in the solidification process of the molten metal, and lay a foundation for the monitoring and mitigation methods of the solidification of the liquid metal in the liquid metal reactor.

[0083] 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 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. Therefore, it should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0084] Finally, it should be noted that the above-described embodiments are only specific embodiments of the present invention, which are used to illustrate the technical solutions of the present invention rather than to limit them. The protection scope of the present invention is not limited thereto. 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 any person skilled in the art within the technical scope disclosed by the present invention can still modify the technical solutions described in the foregoing embodiments or can easily conceive of changes, or perform equivalent replacements for some of the technical features; and these modifications, changes or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention and should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An ultrasonic monitoring device for the metal solidification process, characterized in that Comprising: A receiving cavity for receiving molten metal; An upper temperature control component (11) having a first heating sheet fixedly provided at the top of the receiving cavity for controlling the temperature at the top of the receiving cavity; A lower temperature control component (12) having a refrigeration sheet fixedly provided at the bottom of the receiving cavity for controlling the temperature at the bottom of the receiving cavity; A temperature measurement component (13) having a plurality of first thermocouples spaced vertically in the receiving cavity for monitoring the temperature at corresponding heights in the receiving cavity; A detection component (14) having a plurality of first ultrasonic probes provided at the top of the receiving cavity, with the sensing ends of the first ultrasonic probes arranged vertically downward for detecting the solidification interface of the molten metal; A verification cavity (15) communicating with the top of the receiving cavity through a pipeline, and the verification cavity (15) is provided with a second heating sheet (16); The temperature measurement component (13) further includes a second thermocouple provided in the verification cavity (15) for monitoring the temperature of the molten metal in the verification cavity (15); The detection component (14) further includes a second ultrasonic probe provided at the bottom of the verification cavity (15), with the sensing end of the second ultrasonic probe arranged vertically upward for detecting the liquid level position of the molten metal in the verification cavity (15); The outer peripheral wall of the receiving cavity has a heat insulation layer (17).

2. An ultrasonic monitoring method for the metal solidification process, characterized in that, Applying the device according to claim 1, the method includes: Controlling the first heating sheet and the refrigeration sheet to operate so that the temperature of the receiving cavity gradually increases from bottom to top in the vertical direction, wherein the temperature controlled by the refrigeration sheet is lower than the melting point of the metal to be measured, and the temperature controlled by the first heating sheet is higher than the melting point of the metal to be measured; Numbering N first thermocouples in sequence along the vertical direction and corresponding to N height positions in sequence, where N>2, the lowermost first thermocouple senses the temperature at the inner bottom wall of the receiving cavity, and the uppermost first thermocouple senses the temperature at the height where the sensing end of the first ultrasonic probe in the receiving cavity is located; Numbering M first ultrasonic probes in an array on the same horizontal plane, M>3; Based on the temperature values sensed by the first thermocouples, determining the height value of the solidification interface; Based on the height value of the solidification interface determined by the first thermocouples and the echo time of the first ultrasonic probe located at or closest to the central part, determining the sound speed of ultrasonic waves in the molten metal; Based on the sound speed of the ultrasonic waves in the molten metal, determining the positions of the solidification interfaces sensed by each first ultrasonic probe to obtain the interface morphology of the solidification interface.

3. The method according to claim 2, characterized in that, The determining the height value of the solidification interface based on the temperature values sensed by the first thermocouples includes: Obtain the temperature values of each first thermocouple, and determine the height value of the i-th first thermocouple with a temperature equal to the melting point of the metal to be measured as the height value of the solidification interface .

4. The method according to claim 3, wherein The numbering method of the first thermocouples is as follows: Arrange N first thermocouples vertically from top to bottom and number them as 1, 2,..., N in sequence; Mark the distances between adjacent first thermocouples from top to bottom as: , ,..., ; Arrange M first ultrasonic probes in a rectangular array on the same horizontal plane and number them as 1, 2,..., M in sequence; The determining the sound speed of the ultrasonic waves in the molten metal based on the height value of the solidification interface determined by the first thermocouples and the echo time of the first ultrasonic probe located at or closest to the central part includes: When the solidification interface is at the height where the Nth first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , determine the initial sound velocity of the ultrasonic wave in the molten metal as follows: Where h is the distance between the first thermocouple No. 1 and the first thermocouple No. N; When the solidification interface advances upward to the height where the i-th first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , update the sound velocity of the ultrasonic wave in the molten metal as: ； Among them, is the spacing between the adjacent (n + 1)-th first thermocouple and the n-th first thermocouple.

5. The method according to claim 3, characterized in that The numbering method of the first thermocouples is as follows: Arrange the N first thermocouples vertically from bottom to top and number them successively as: 1, 2,..., N; Mark the distances between adjacent first thermocouples from bottom to top successively as: , ,... ; Arrange the M first ultrasonic probes in a rectangular array on the same horizontal plane and number them successively as: 1, 2,..., M; Determining the sound velocity of ultrasonic waves in the molten metal based on the height value of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the central part, includes: When the solidification interface is at the height where the No. 1 first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , determine the initial sound velocity of the ultrasonic wave in the molten metal It is: Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. N; When the solidification interface advances upward to the height where the i-th first thermocouple is located, based on the echo time of the first ultrasonic probe located at or closest to the central part , update the sound velocity of the ultrasonic wave in the molten metal to be: Among them, is the distance between the adjacent (n + 1)-th first thermocouple and the n-th first thermocouple.

6. The method according to claim 4 or 5, characterized in that, Based on the updated sound velocity of ultrasonic waves in the molten metal, determining the positions of the solidification interfaces sensed by each first ultrasonic probe to obtain the interface morphology of the solidification interface, includes: If the solidification interface advances upward to the height where the i-th first thermocouple is located, then based on the updated sound velocity of the ultrasonic wave in the molten metal , the echo time of the j-th first ultrasonic probe , the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe is calculated as follows: Based on the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe , the height value of the solidification interface sensed by the j-th first ultrasonic probe is calculated : ； Based on the height values of the solidification interfaces sensed by each first ultrasonic probe, or the distances between the solidification interfaces sensed by each first ultrasonic probe and the sensing ends of the corresponding first ultrasonic probes, obtaining the interface morphology of the solidification interface.

7. The method according to claim 6, characterized in that The method further includes: If the solidification interface advances to the height where the i-th first thermocouple is located, the average height value of the solidification interface is determined based on the positions of the solidification interface sensed by each first ultrasonic probe ; Determine the advancing speed of the solidification interface based on the average height value of the solidification interface at the first moment and the average height value of the solidification interface at the second moment It is: ； Among them, is the average height value of the solidification interface at the first moment, is the average height value of the solidification interface at the second moment, is the first moment, is the second moment.

8. The method according to claim 7, wherein The device further includes a verification chamber; the detection assembly further includes a second ultrasonic probe for detecting the position of the molten metal liquid level in the verification chamber; the method further includes: If the solidification interface advances to the height where the i-th first thermocouple is located, the height verification value of the solidification interface is determined based on the liquid level height value of the molten metal in the verification cavity measured by the second ultrasonic probe. It is: ； Among them, is the solidification volume change rate of the metal solution, is the cross-sectional area of the accommodation cavity, is the cross-sectional area of the verification cavity; , is the initial liquid level height value of the metal melt in the verification cavity measured by the second ultrasonic probe, is the actual liquid level height value of the metal melt in the verification cavity measured by the second ultrasonic probe; Based on the average height value and the height verification value , determine the relative error of the height of the solidification interface as follows: ； Based on the relative height error, evaluating the height monitoring accuracy of the solidification interface of the molten metal in the accommodation chamber: If , it is determined that the height of the solidification interface of the molten metal monitored by the first ultrasonic probe meets the accuracy requirements, where is the preset height error.

9. The method according to claim 8, wherein The method further includes: Based on the height verification value , determine the solidification interface advancement speed verification value as follows: ； Among them, is the height verification value of the solidification interface at the first moment, is the height verification value of the solidification interface at the second moment; Based on the said advancing speed and the said advancing speed verification value , determine the relative error of the advancing speed of the solidification interface as follows: ； Based on the relative propulsion velocity error, evaluating the propulsion velocity monitoring accuracy of the solidification interface of the molten metal in the accommodation chamber: If , it is determined that the advancing speed of the metal melt solidification interface monitored based on the first ultrasonic probe meets the accuracy requirements, where is the preset advancing speed error.

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