Ultrasonic monitoring device and method for metal solidification process

Abstract

The present invention provides an ultrasonic monitoring device and method for a metal solidification process, which relates to the field of metal solidification technology. The device includes: a accommodating chamber, an upper temperature control component, a lower temperature control component, a temperature measuring component, and a detection component. The accommodating chamber is used to accommodate molten metal; the upper temperature control component is used to control the temperature at the top of the accommodating chamber; the lower temperature control component is used to control the temperature at the bottom of the accommodating chamber; the temperature measuring component has a plurality of first thermocouples for monitoring the temperature at corresponding heights of the accommodating chamber; and the detection component has a plurality of first ultrasonic probes for detecting the solidification interface of the molten metal. The present invention determines the position of each part of the solidification interface of the molten metal in the accommodating chamber by the echo time of each first ultrasonic probe, thereby determining the morphology of the solidification interface. The advancement speed of the solidification interface of the molten metal is determined based on the echo time of each first ultrasonic probe when the position of the solidification interface is different and the time interval when the solidification interface is 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 a metal solidification process. Background Art

[0002] Liquid metal reactors (LMRs) are an advanced and common type of nuclear reactor in today's society. They use liquid metal as a coolant and are generally highly efficient and safe. When using high-temperature liquid metal (such as sodium or lead-bismuth alloys) as a coolant in LMRs, once the temperature of the liquid metal drops below its melting point, it solidifies, endangering the safety of the reactor. This is especially true in narrow pipes, where solidification can cause serious accidents such as flow blockage and localized overheating. Therefore, research on the solidification process of liquid metal is an important part of LMR research.

[0003] In the prior art, invasive measurement devices are usually used to study the solidification process of liquid metal. Such measurement devices 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 advancement speed of the liquid metal solidification interface. Summary of the Invention

[0004] 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 in the existing technology that the solidification process of liquid metal cannot be studied online in real time and the morphology and advancement speed of the liquid metal solidification interface cannot be obtained.

[0005] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0006] In a first aspect, an embodiment of the present invention provides an ultrasonic monitoring device for a metal solidification process, comprising:

[0007] An accommodating cavity for accommodating molten metal;

[0008] An upper temperature control assembly having a first heating plate, wherein the first heating plate is fixedly mounted on the top of the accommodating cavity and is used to control the temperature of the top of the accommodating cavity;

[0009] A lower temperature control component, comprising a refrigeration fin, fixedly mounted on the bottom of the accommodating cavity, and configured to control the temperature of the bottom of the accommodating cavity;

[0010] A temperature measuring component having a plurality of first thermocouples, wherein the first thermocouples are vertically spaced apart in the accommodating cavity and are used to monitor the temperature at a corresponding height of the accommodating cavity;

[0011] The detection component has a plurality of first ultrasonic probes, wherein the first ultrasonic probes are arranged at the top of the accommodating cavity, and the sensing ends of the first ultrasonic probes are arranged downward in a vertical direction for detecting the solidification interface of the molten metal.

[0012] Furthermore, an embodiment of the present invention provides a first possible implementation of the first aspect, wherein the device further comprises: a verification chamber, the verification chamber being connected to the top of the accommodating chamber via a pipe, the verification chamber being provided with a second heating plate;

[0013] The temperature measurement component further includes a second thermocouple, which is arranged in the verification cavity and is used to monitor the temperature of the molten metal in the verification cavity;

[0014] The detection assembly further includes a second ultrasonic probe, which is disposed at the bottom of the verification chamber, and a sensing end of the second ultrasonic probe is vertically upwardly disposed for detecting the level of the molten metal in the verification chamber;

[0015] The outer peripheral wall of the accommodating cavity is provided with a heat-insulating layer.

[0016] An embodiment of the present invention provides an ultrasonic monitoring device for a metal solidification process, the device comprising: a accommodating chamber, an upper temperature control component, a lower temperature control component, a temperature measuring component and a detection component; the accommodating chamber is used to accommodate molten metal; the upper temperature control component has a first heating plate, which is fixedly mounted on the top of the accommodating chamber and is used to control the temperature of the top of the accommodating chamber; the lower temperature control component has a cooling plate, which is fixedly mounted on the bottom of the accommodating chamber and is used to control the temperature of the bottom of the accommodating chamber; the temperature measuring component has a plurality of first thermocouples, which are vertically spaced in the accommodating chamber and are used to monitor the temperature at a corresponding height of the accommodating chamber; the detection component has a plurality of first ultrasonic probes, which are arranged at the top of the accommodating chamber, and the sensing end of the first ultrasonic probe is arranged vertically downward to detect the solidification interface of the molten metal. The present invention realizes the control of the heat flow gradient of the molten metal in the accommodating cavity through the joint action of the upper temperature control component and the lower temperature control component, thereby controlling the solidification of the molten metal, determining the position of the solidification interface by judging the temperature of the first thermocouple, updating the sound velocity of the ultrasonic wave in the molten metal through the echo time of the first ultrasonic probe located at or closest to the center, determining the position of each part of the molten metal solidification interface through the updated sound velocity and the echo time of each first ultrasonic probe, thereby determining the morphology of the solidification interface, and at the same time, determining the advancement speed of the molten metal solidification interface based on the echo time of each first ultrasonic probe when the solidification interface is at different positions and the time interval when it is located at different positions, realizing real-time online research on the solidification process of the molten metal, and obtaining the morphology and advancement speed of the liquid metal solidification interface.

[0017] In a second aspect, an embodiment of the present invention further provides a method for ultrasonic monitoring of a metal solidification process, using the above-mentioned ultrasonic monitoring device for a metal solidification process, the method comprising:

[0018] Controlling the operation of the first heating plate and the cooling plate so that the temperature of the accommodating chamber gradually increases vertically from bottom to top, wherein the temperature controlled by the cooling plate is lower than the melting point of the metal to be tested, and the temperature controlled by the first heating plate is higher than the melting point of the metal to be tested;

[0019] Numbering N first thermocouples in sequence along the vertical direction and corresponding to N height positions in sequence, wherein N>2, the lowest first thermocouple senses the temperature at the bottom wall of the accommodating chamber, and the uppermost first thermocouple senses the temperature at the height of the sensing end of the first ultrasonic probe in the accommodating chamber;

[0020] Place M first ultrasound probes on the same horizontal plane and number them in the array, M>3;

[0021] determining a height value of the solidification interface based on the temperature value sensed by the first thermocouple;

[0022] Determining the speed of the ultrasonic wave in the molten metal based on the height of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the center;

[0023] Based on the sound velocity of the ultrasonic wave in the molten metal, the position of the solidification interface sensed by each first ultrasonic probe is determined to obtain the interface morphology of the solidification interface.

[0024] Furthermore, an embodiment of the present invention provides a first possible implementation of the second aspect, wherein the step of determining the height of the solidification interface based on the temperature value sensed by the first thermocouple includes:

[0025] Obtain the temperature value 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 .

[0026] Furthermore, an embodiment of the present invention provides a second possible implementation of the second aspect, wherein the first thermocouples are numbered as follows: N first thermocouples are numbered 1, 2, ..., N in a vertical direction from top to bottom; and the spacing between adjacent first thermocouples is marked as follows from top to bottom: , ,..., ; Arrange M first ultrasonic probes in a rectangular array on the same horizontal plane and number them in sequence: 1, 2, ..., M;

[0027] The method of determining the sound velocity of the ultrasonic wave in the molten metal based on the height of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the center includes:

[0028] When the coagulation interface is at the height of the first thermocouple No. N, based on the echo time of the first ultrasonic probe located at or closest to the center , determine the initial sound velocity of the ultrasonic wave in the molten metal for:

[0029]

[0030] Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. N;

[0031] When the coagulation interface advances upward to the height of the first thermocouple i, based on the echo time of the first ultrasonic probe located at or closest to the center , update the sound velocity of the ultrasonic wave in the molten metal for:

[0032] ;

[0033] in, is the distance between the adjacent n+1th first thermocouple and the nth first thermocouple.

[0034] Furthermore, an embodiment of the present invention provides a third possible implementation of the second aspect, wherein the first thermocouples are numbered as follows: N first thermocouples are numbered 1, 2, ..., N in a vertical direction from bottom to top; and the spacing between adjacent first thermocouples is marked as follows from bottom to top: , ,..., ; Arrange M first ultrasonic probes in a rectangular array on the same horizontal plane and number them in sequence: 1, 2, ..., M;

[0035] The method of determining the sound velocity of the ultrasonic wave in the molten metal based on the height of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the center includes:

[0036] When the coagulation interface is at the height of the first thermocouple No. 1, based on the echo time of the first ultrasonic probe located at or closest to the center , determine the initial sound velocity of ultrasound in molten metal for:

[0037]

[0038] Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. N;

[0039] When the coagulation interface advances upward to the height of the first thermocouple i, based on the echo time of the first ultrasonic probe located at or closest to the center , update the sound velocity of ultrasound in molten metal for:

[0040]

[0041] in, is the distance between the adjacent n+1th first thermocouple and the nth first thermocouple.

[0042] Furthermore, an embodiment of the present invention provides a fourth possible implementation of the second aspect, wherein the step 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 and obtaining the interface morphology of the solidification interface includes:

[0043] If the solidification interface advances upward to the height of the first thermocouple i, then based on the updated sound velocity of the ultrasonic wave in the molten metal , the echo time of the first ultrasonic probe j , calculate the distance between the coagulation interface and the sensing end of the first ultrasonic probe No. j for:

[0044]

[0045] Based on the distance between the coagulation interface and the sensing end of the first ultrasonic probe No. j , calculate the coagulation interface height value sensed by the first ultrasonic probe j :

[0046] ;

[0047] The interface morphology of the coagulation interface is obtained based on the height value of the coagulation interface sensed by each first ultrasonic probe, or the distance between the coagulation interface sensed by each first ultrasonic probe and the sensing end of the corresponding first ultrasonic probe.

[0048] Furthermore, the embodiment of the present invention provides a fifth possible implementation of the second aspect, wherein the method further includes:

[0049] If the coagulation interface advances to the height of the first thermocouple i, the average height value of the coagulation interface is determined based on the coagulation interface position sensed by each first ultrasonic probe. ;

[0050] Based on the average height of the solidification interface at the first moment and the average height of the solidification interface at the second moment, the advancement speed of the solidification interface is determined. for:

[0051] ;

[0052] in, is the average height of the solidification interface at the first moment, is the average height of the solidification interface at the second moment, For the first moment, For the second moment.

[0053] Furthermore, an embodiment of the present invention provides a sixth possible implementation of the second aspect, wherein the device further includes a verification chamber; the detection assembly further includes a second ultrasonic probe for detecting the liquid level position of the molten metal in the verification chamber; and the method further includes:

[0054] If the solidification interface advances to the height of the first thermocouple No. i, the height verification value of the solidification interface is determined based on the liquid level value of the molten metal in the verification cavity measured by the second ultrasonic probe. for:

[0055] ;

[0056] in, is the volume change rate of the metal solution solidification, is the cross-sectional area of ​​the accommodating cavity, is the cross-sectional area of ​​the verification cavity; , is the initial liquid level height value of the molten metal in the verification chamber measured by the second ultrasonic probe, is the actual liquid level height value of the molten metal in the verification chamber measured by the second ultrasonic probe;

[0057] Based on the average height value , the height verification value , determine the relative error of the height of the solidification interface for:

[0058] ;

[0059] Based on the relative height error, the height monitoring accuracy of the solidification interface of the molten metal in the accommodating cavity is evaluated:

[0060] like , it is determined that the height of the solidification interface of the molten metal monitored by the first ultrasonic probe meets the accuracy requirement, wherein, is the preset height error.

[0061] Furthermore, the embodiment of the present invention provides a seventh possible implementation of the second aspect, wherein the method further includes:

[0062] Based on the height verification value , determine the verification value of solidification interface advancement speed for:

[0063] ;

[0064] in, 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;

[0065] Based on the propulsion speed , the propulsion speed verification value , determine the relative error of the advancement speed of the solidification interface for:

[0066] ;

[0067] Based on the relative error of the advancing speed, the advancing speed monitoring accuracy of the solidification interface of the molten metal in the accommodating cavity is evaluated:

[0068] like , it is determined that the advancement speed of the metal melt solidification interface monitored by the first ultrasonic probe meets the accuracy requirements, wherein, is the preset propulsion speed error.

[0069] An embodiment of the present invention provides an ultrasonic monitoring method for a metal solidification process, the method comprising: controlling the operation of the first heating plate and the cooling plate so that the temperature of the accommodating chamber gradually increases from bottom to top in the vertical direction, wherein the temperature controlled by the cooling plate is lower than the melting point of the metal to be measured, and the temperature controlled by the first heating plate is higher than the melting point of the metal to be measured; arranging N first thermocouples in sequence in the vertical direction and corresponding to N height positions in sequence, wherein N>2, the first thermocouple at the bottom senses the temperature at the bottom wall of the accommodating chamber, and the first thermocouple at the top senses the temperature at the bottom wall of the accommodating chamber. Measure the temperature at the height of the sensing end of the first ultrasonic probe in the accommodating cavity; arrange M first ultrasonic probes in an array on the same horizontal plane, with M>3; determine the height value of the solidification interface based on the temperature value sensed by the first thermocouple; determine 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 center; determine the position of the solidification interface sensed by each first ultrasonic probe based on the sound velocity of the ultrasonic wave in the molten metal, and obtain the interface morphology of the solidification interface. The present invention controls the first heating plate and the cooling plate to start working, controls the temperature of the accommodating chamber 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 chamber, and thus controls the molten metal to gradually start solidifying from the bottom of the accommodating chamber. When the temperature 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. 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 by the echo time of the first ultrasonic probe located at or closest to the center. When the solidification interface is located at the position of the lower first thermocouple or between the two first thermocouples, the position of each part of the solidification interface of the molten metal is determined based on the sound velocity of the ultrasonic wave in the molten metal and the echo time of each first ultrasonic probe, thereby determining the morphology of the solidification interface and obtaining the advancement speed of the solidification interface. For details, please refer to the beneficial effects of the above-mentioned monitoring device and no further description is given here.

[0070] Other features and advantages of the embodiments of the present invention will be described in the following description, or some features and advantages can be inferred or determined without doubt from the description, or can be learned by implementing the above-mentioned technologies of the embodiments of the present invention.

[0071] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0073] Figure 1 A schematic structural diagram of an ultrasonic monitoring device for a metal solidification process provided by an embodiment of the present invention is shown;

[0074] Figure 2 A schematic diagram showing the arrangement of ultrasonic probes in an ultrasonic monitoring device for a metal solidification process provided by an embodiment of the present invention is shown;

[0075] Figure 3 A schematic flow chart of an ultrasonic monitoring method for a metal solidification process provided by an embodiment of the present invention is shown;

[0076] Figure 4 A schematic diagram of solidification interface correction in an ultrasonic monitoring method for a metal solidification process provided by an embodiment of the present invention is shown.

[0077] Description of reference numerals:

[0078] 1- No. 1 first ultrasound probe; 2- No. 2 first ultrasound probe; 3- No. 3 first ultrasound probe; 4- No. 4 first ultrasound probe; 5- No. 5 first ultrasound probe; 6- No. 6 first ultrasound probe; 7- No. 7 first ultrasound probe; 8- No. 8 first ultrasound probe; 9- No. 9 first ultrasound probe;

[0079] 11-upper temperature control assembly; 12-lower temperature control assembly; 13-temperature measurement assembly; 14-detection assembly; 15-verification chamber; 16-second heating plate; 17-insulation layer; 18-side wall; 19-lower metal plate; 20-upper metal plate; 21-flange. DETAILED DESCRIPTION

[0080] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0081] This embodiment provides an ultrasonic monitoring device for metal solidification process, see Figure 1The schematic diagram of the structure of an ultrasonic monitoring device for a metal solidification process shown in FIG. 1 mainly comprises: an accommodating chamber, an upper temperature control component 11, a lower temperature control component 12, a temperature measuring component 13 and a detection component 14; wherein the accommodating chamber is used to accommodate molten metal; the upper temperature control component 11 has a first heating plate, which is fixedly arranged at the top of the accommodating chamber and is used to control the temperature of the top of the accommodating chamber; the lower temperature control component 12 has a cooling plate, which is fixedly arranged at the bottom of the accommodating chamber and is used to control the temperature of the bottom of the accommodating chamber; the temperature measuring component 13 has a plurality of first thermocouples, which are arranged at intervals along the vertical direction in the accommodating chamber and are used to monitor the temperature at the corresponding height of the accommodating chamber; the detection component 14 has a plurality of first ultrasonic probes, which are arranged at the top of the accommodating chamber, and the sensing end of the first ultrasonic probe is arranged downward in the vertical direction and is used to detect the solidification interface of the molten metal;

[0082] The accommodating cavity of the ultrasonic monitoring device for the metal solidification process is a cylindrical cavity, and in order to ensure that the lateral heat leakage of the accommodating cavity is sufficiently small, the side wall 18 of the cavity is made of low thermal conductivity material. Specifically, when the device monitors the metal solidification process of a metal material with a lower 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 cavity, wherein the thermal conductivity of acrylic material is usually 0.2W / (m·k); if the device monitors the metal solidification process of a metal material with a higher 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 cavity. If the installation stability is poor, a flange 21 needs to be provided on the outside of the side wall 18 of the accommodating chamber, which 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 accommodating chamber; the upper wall and the lower wall of the cavity are made of metal plates made of metal materials, and the upper and lower metal plates are respectively provided with embedding grooves for embedding into the side wall 18 of the accommodating chamber, the upper temperature control component 11 adopts a first heating plate and is arranged on the top of the upper metal plate 20 of the accommodating chamber, and the lower temperature control component 12 adopts a cooling plate and is arranged at the bottom of the lower metal plate 19 of the accommodating chamber. By passing currents of different sizes into the first heating plate and the cooling plate, the temperature of the first heating plate and the cooling plate is adjusted. The temperature in the accommodating chamber is gradually reduced from top to bottom through the first heating plate and the cooling plate, so as to control the directional heat flow gradient in the accommodating chamber;

[0083] like Figure 1As shown, the temperature measuring component 13 has a plurality of first thermocouples. Specifically, seven first thermocouples are arranged in sequence from top to bottom on the central axis of the accommodating cavity. There is a certain interval between each first thermocouple. At the same time, the first thermocouple No. 1 from top to bottom is arranged below the upper metal plate 20 and contacts the upper metal plate 20, and the first thermocouple No. 7 from top to bottom is arranged above the lower metal plate 19 and contacts the lower metal plate 19; the above-mentioned detection component 14 has a plurality of first ultrasonic probes, which are arranged at the top of the accommodating cavity. Specifically, see Figure 2 The figure shows a schematic diagram of the arrangement of the first ultrasonic probes in an ultrasonic monitoring device for a metal solidification process. Nine first ultrasonic probes are provided and arranged in a 3×3 array at the top of the accommodating cavity. Each first ultrasonic probe is fixedly connected to the first heating plate and the upper metal plate 20 by a thread. The sensing end of each first ultrasonic probe is arranged vertically downward. At the same time, the probe surface of each first ultrasonic probe intrudes into the interior of the accommodating cavity to detect the solidification interface of the molten metal.

[0084] The ultrasonic monitoring device for the metal solidification process provided in an embodiment of the present invention controls the heat flow gradient of the molten metal (i.e., liquid metal) in the accommodating chamber through the combined action of an upper temperature control component and a lower temperature control component, thereby controlling the solidification of the molten metal in the accommodating chamber. The position of the solidification interface is determined by judging the temperature of the first thermocouple, and the sound velocity of the ultrasonic wave in the molten metal is updated by the echo time of the first ultrasonic probe located at or closest to the center. The positions of various parts of the molten metal solidification interface are determined by the updated sound velocity and the echo time of each first ultrasonic probe, thereby determining the morphology of the solidification interface. At the same time, the advancement speed of the molten metal solidification interface is determined based on the echo time of each first ultrasonic probe when the solidification interface is at different positions and the time interval when it is located at different positions, thereby realizing real-time online research on the solidification process of the molten metal and obtaining the morphology and advancement speed of the liquid metal solidification interface.

[0085] In one embodiment, the ultrasonic monitoring device for a metal solidification process provided in this embodiment further includes a verification chamber 15, which is connected to the top of the accommodating chamber through a pipe, and the verification chamber 15 is provided with a second heating plate 16; the temperature measuring component 13 further includes a second thermocouple, which is provided in the verification chamber 15 and is used to monitor the temperature of the molten metal in the verification chamber 15; the detection component 14 further includes a second ultrasonic probe, which is provided at the bottom of the verification chamber 15, and the sensing end of the second ultrasonic probe is provided vertically upward, for detecting the liquid level position of the molten metal in the verification chamber 15;

[0086] like Figure 1As shown, the ultrasonic monitoring device for the metal solidification process also includes a verification chamber 15. The molten metal in the accommodating chamber is transported to the verification chamber 15 by shutting off. Specifically, the verification chamber 15 is an open structure with an upper opening. One end of the pipeline is connected to the accommodating chamber through the first heating plate and the top of the accommodating chamber, and the other end is connected to the verification chamber 15 through the side wall of the verification chamber 15. The end of the pipeline is close to the bottom of the verification chamber 15. The second ultrasonic probe in the detection assembly 14 is set at the bottom of the verification chamber 15, and the second ultrasonic probe is fixedly connected to the bottom wall of the verification chamber 15 by a thread; the liquid level change of the molten metal in the verification chamber 15 is determined by the echo time of the second ultrasonic probe, thereby determining the volume change of the molten metal in the verification chamber 15;

[0087] In order to further reduce the lateral heat leakage of the accommodating chamber, a thermal insulation layer 17 is further provided on the side wall 18 of the accommodating chamber. In order to reduce the heat loss when the molten metal is transported from the accommodating chamber to the verification chamber 15, a thermal insulation layer can also be provided on the side wall of the pipe exposed to the air. Specifically, when the device monitors the metal solidification process of a metal material with a lower melting point (such as gallium metal, whose melting point is usually 29.76°C), materials such as polystyrene can be used as the material of the thermal insulation layer on the side wall 18 of the accommodating chamber and the side wall of the pipe; if the device monitors the metal solidification process of a metal material with a higher melting point (such as gallium metal, whose melting point is usually 29.76°C), When monitoring the solidification process of a metal (such as a lead-bismuth eutectic alloy, whose melting point is typically 125°C), materials such as thermal insulation cotton can be used as the material for the thermal insulation layer outside the side wall 18 of the accommodating cavity and the side wall of the pipe. The upper and lower metal plates of the accommodating cavity are both provided with grooves for arranging the thermal insulation layer 17. In order to further ensure the stability of the side wall of the accommodating cavity and the thermal insulation layer 17 when monitoring the interface of the high-melting-point metal melt, a flange 21 is provided outside the thermal insulation layer and fixedly connected to the upper and lower metal plates through the flange 21, thereby pressing the thermal insulation cotton and borosilicate glass to ensure the thermal insulation and sealing effect of the accommodating cavity.

[0088] At the same time, in order to monitor the temperature of the molten metal in the verification chamber 15 in real time, a second thermocouple is provided in the verification chamber 15 (specifically, it can be provided above the bottom wall of the verification chamber 15) and a second heating plate is provided outside the side wall of the verification chamber 15. The temperature of the molten metal in the verification chamber 15 is monitored in real time by the second thermocouple. If the temperature of the molten metal in the verification chamber 15 is lower than the temperature detected by the first thermocouple at the top in the accommodating chamber, current is passed through the second heating plate outside the side wall of the verification chamber 15 to control the second heating plate so that the temperature of the molten metal in the verification chamber 15 gradually increases to the same temperature as the temperature detected by the first thermocouple at the top in the accommodating chamber. The provision of the second thermocouple and the second heating plate can avoid the situation where the volume of the molten metal in the verification chamber 15 changes when the temperature of the verification chamber 15 is different from that of the molten metal in the accommodating chamber.

[0089] The embodiment of the present invention further provides a method for ultrasonic monitoring of a metal solidification process, which can be applied to the ultrasonic monitoring device for the metal solidification process and electronic equipment such as computers, see Figure 3 The figure shows a flow chart of a method for ultrasonic monitoring of a metal solidification process, which mainly includes the following steps:

[0090] Step S301: Controlling the operation of the first heating plate and the cooling plate to gradually increase the temperature of the accommodating chamber vertically from bottom to top, wherein the temperature controlled by the cooling plate is lower than the melting point of the metal to be tested, and the temperature controlled by the first heating plate is higher than the melting point of the metal to be tested;

[0091] Before the experiment begins, molten metal is added to the accommodating chamber and stirred so that the temperature in the accommodating chamber is higher than the melting point of the molten metal. Electric current is passed through the first heating plate and the cooling plate to start working, ensuring that the first heating plate and the cooling plate are heated at a constant temperature so that the temperature of the cooling plate is lower than the melting point of the molten metal and the temperature of the first heating plate is higher than the melting point of the molten metal, so that the temperature of the molten metal in the accommodating chamber gradually increases from bottom to top, causing the molten metal to solidify from the bottom of the accommodating chamber.

[0092] Step S303: Numbering N first thermocouples in sequence along the vertical direction and corresponding to N height positions, where N>2, the lowest first thermocouple senses the temperature at the bottom wall of the accommodating chamber, and the highest first thermocouple senses the temperature at the height of the sensing end of the first ultrasound probe in the accommodating chamber;

[0093] N first thermocouples are arranged on the central axis of the accommodating cavity from top to bottom. Specifically, N=7 (i.e., seven first thermocouples are arranged on the central axis of the accommodating cavity from top to bottom). 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 assumption of the fan-shaped sound wave, when the incident wavelength of the sound wave is When the diameter of the first thermocouple is much smaller than the characteristic size of the obstacle, the diffraction effect of the acoustic wave can be ignored, thereby screening the size of the first thermocouple to avoid the interference of the first thermocouple with the acoustic wave emitted by the first ultrasonic probe. The diameter of the first thermocouple is determined by the relationship formula between the strength of the acoustic wave diffraction effect, the acoustic wave number, and the characteristic size of the obstacle; wherein the relationship formula is expressed as:

[0094]

[0095] in, is the wave number of the sound wave, is the frequency of the sound wave, is the speed of sound waves, is the wavelength of the sound wave, is the characteristic size of the obstacle (i.e., the first thermocouple) in the sound propagation process, such as the characteristic size of a sphere is its radius;

[0096] In a specific embodiment, when When the metal melt is gallium melt, the sound wave partly diffracts. If the frequency of the wave emitted by the first ultrasonic probe is 5 MHz, the speed of the sound wave in the gallium melt at room temperature is 2700 m / s. In order to avoid the influence of the larger first thermocouple on the sound wave, it is necessary to substitute the parameters into the relationship formula to obtain:

[0097]

[0098] At this time, the above , f=5MHz, c=2700m / s, solve for the maximum radius of the first thermocouple at this time The maximum diameter is 0.85 mm and the maximum diameter is 1.7 mm. Therefore, a first thermocouple with a diameter smaller than 1.7 mm can be selected (for example, an armored first thermocouple with a diameter of 1 mm can be used).

[0099] Step S305 , placing M first ultrasound probes in the same horizontal plane and arraying them, where M>3;

[0100] like Figure 2 As shown, taking M=9 as an example, there are 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.

[0101] Step S307, determining a height value of the solidification interface based on the temperature value sensed by the first thermocouple;

[0102] When the temperature sensed by the first thermocouple is greater than the melting point of the metal to be measured, the solidification interface of the molten metal in the accommodating chamber is below the position of the first thermocouple. Conversely, when the temperature sensed by the first thermocouple is less than the melting point of the metal to be measured, the solidification interface of the molten metal in the accommodating chamber is above the position of the first thermocouple.

[0103] Step S309, determining the speed of the ultrasonic wave in the molten metal based on the height of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the center;

[0104] Since the first thermocouple is arranged on the central axis of the accommodating cavity, it can better reflect the temperature of the molten metal in the central part. The sound velocity of the ultrasonic wave 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 velocity of the ultrasonic wave in the molten metal is determined by the echo time of the first ultrasonic probe arranged on the central axis of the accommodating cavity.

[0105] Step S311, based on the sound velocity of the ultrasonic wave in the molten metal, determining the position of the solidification interface sensed by each first ultrasonic probe, and obtaining the interface morphology of the solidification interface;

[0106] Based on the sound velocity of ultrasound in the molten metal and the echo time of each first ultrasonic probe, the position of the solidification interface detected by each probe is determined by the echo reflection method, thereby obtaining the interface morphology of the solidification interface.

[0107] The present invention controls the first heating plate and the cooling plate to start working, controls the temperature of the accommodating chamber 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 chamber, and thus controls the molten metal to gradually start solidifying from the bottom of the accommodating chamber. When the temperature of the lower first thermocouple of two adjacent 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. 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 by the echo time of the first ultrasonic probe located at or closest to the center. When the solidification interface is located at the position of the lower first thermocouple or between the two first thermocouples, the position of each part of the solidification interface of the molten metal is determined based on the sound velocity of the ultrasonic wave in the molten metal and the echo time of each first ultrasonic probe, thereby determining the morphology of the solidification interface and obtaining the advancement speed of the solidification interface. For details, please refer to the beneficial effects of the above-mentioned monitoring device and no further description is given here.

[0108] In one embodiment, this embodiment provides a specific implementation of step S307 including:

[0109] Step S3071: Obtain the temperature value 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. ;

[0110] Generally, the melting point of a metal is the same as its solidification point. 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 is located at the position of the first thermocouple.

[0111] In one embodiment, the first thermocouples provided in this embodiment are numbered as follows: N first thermocouples are numbered 1, 2, ..., N in a vertical direction from top to bottom; and the spacing between adjacent first thermocouples is marked as follows from top to bottom: , ,..., ; Arrange M first ultrasonic probes in a rectangular array on the same horizontal plane and number them in sequence: 1, 2, ..., M;

[0112] In the above steps, specifically, when N=7 and M=9, the first thermocouples are numbered 1, 2, ..., 7 from top to bottom in the vertical direction; and the spacing between adjacent first thermocouples is marked as follows from top to bottom: , ,..., ;like Figure 2 As shown, the first ultrasonic probes are numbered 1, 2, ..., 9 in sequence, that is, the first ultrasonic probes numbered 1-9 represent first ultrasonic probes No. 1 to No. 9 respectively.

[0113] The specific implementation of step S309 includes:

[0114] Step S3091: When the coagulation interface is at the height of the first thermocouple No. N, based on the echo time of the first ultrasonic probe located at or closest to the center, , determine the initial sound velocity of ultrasound in molten metal for:

[0115]

[0116] Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. N;

[0117] In the above steps, the first thermocouple No. 1 is arranged below the upper metal plate of the accommodating chamber and in contact with the upper metal plate, and the first thermocouple No. N is arranged above the lower metal plate of the accommodating chamber and in contact with the lower metal plate. Therefore, the height difference h between the first thermocouple No. 1 and the first thermocouple No. N is the overall height of the accommodating chamber (that is, the height between the upper metal plate and the lower metal plate of the accommodating chamber). When the number of the first thermocouples is 7, specifically, when N=7, when the solidification interface is at the height of the first thermocouple No. 7, based on the echo time of the first ultrasonic probe located on the central axis of the accommodating chamber , determine the initial sound velocity of ultrasound in molten metal for:

[0118]

[0119] Where h is the distance between the first thermocouple No. 1 and the first thermocouple No. N (that is, the overall height h of the accommodating cavity), and the echo time The time 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 is determined.

[0120] Step S3093: When the coagulation interface advances upward to the height of the first thermocouple No. i, based on the echo time of the first ultrasonic probe located at or closest to the center, , update the sound velocity of ultrasound in molten metal for:

[0121] ;

[0122] in, is the distance between the adjacent n+1th first thermocouple and the nth first thermocouple;

[0123] In the above steps, when the solidification interface advances upward to the height of the first thermocouple No. i, based on the echo time of the first ultrasonic probe located on the central axis of the accommodating cavity at this time, Update on the speed of sound of ultrasound in molten metal .

[0124] In one embodiment, the first thermocouples provided in this embodiment are numbered as follows: N first thermocouples are numbered 1, 2, ..., N in a vertical direction from bottom to top; and the spacing between adjacent first thermocouples is marked as follows from bottom to top: , ,..., ; Arrange M first ultrasonic probes in a rectangular array on the same horizontal plane and number them in sequence: 1, 2, ..., M;

[0125] In the above steps, specifically, when N=7 and M=9, the first thermocouples are numbered 1, 2, ..., 7 from bottom to top in the vertical direction; and the spacing between adjacent first thermocouples is marked as follows from bottom to top: , ,..., ;like Figure 2 As shown, the first ultrasonic probes are numbered 1, 2, ..., 9 in sequence.

[0126] The specific implementation of step S309 includes:

[0127] Step S3092: When the coagulation interface is at the height of the first thermocouple No. 1, based on the echo time of the first ultrasonic probe located at or closest to the center, , determine the initial sound velocity of ultrasound in molten metal for:

[0128]

[0129] Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. N;

[0130] In the above steps, the first thermocouple No. 1 is arranged above the lower metal plate of the accommodating chamber and contacts the lower metal plate, and the first thermocouple No. N is arranged below the upper metal plate of the accommodating chamber and contacts the upper metal plate. Therefore, the height difference h between the first thermocouple No. 1 and the first thermocouple No. N is the overall height of the accommodating chamber (i.e., the height between the upper metal plate and the lower metal plate of the accommodating chamber). When the number of the first thermocouples is 7, specifically, when N=7, when the solidification interface is located at the height of the first thermocouple No. 1, based on the echo time of the first ultrasonic probe located on the central axis of the accommodating chamber , confirm that the ultrasound The initial sound speed in for:

[0131]

[0132] Where h is the distance between the first thermocouple No. 1 and the first thermocouple No. 7 (that is, the overall height h of the accommodating cavity), and the echo time It is determined by the time 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.

[0133] Step S3094: When the coagulation interface advances upward to the height of the first thermocouple No. i, based on the echo time of the first ultrasonic probe located at or closest to the center, , update the sound velocity of ultrasound in molten metal for:

[0134]

[0135] in, is the distance between the adjacent n+1th first thermocouple and the nth first thermocouple;

[0136] When the solidification interface advances upward to the height of the first thermocouple No. i, based on the echo time of the first ultrasonic probe located on the central axis of the accommodating cavity at this time Update on the speed of sound of ultrasound in molten metal .

[0137] In one embodiment, this embodiment provides a specific implementation of step S311, including:

[0138] Step S3111: If the solidification interface advances upward to the height of the first thermocouple No. i, then based on the updated sound velocity of the ultrasonic wave in the molten metal , the echo time of the first ultrasonic probe j , calculate the distance between the coagulation interface and the sensing end of the first ultrasonic probe No. j for:

[0139] ;

[0140] In the above steps, when N first thermocouples are numbered 1, 2, ..., N in the vertical direction from top to bottom, 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 first thermocouple No. i is located, it means that the temperature detected by the first thermocouple No. i at this time is ≤ the melting point of the metal to be measured < the temperature detected by the first thermocouple No. i-1. 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 the 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 the first thermocouple at this time, and 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 located above the first thermocouple at this time. Therefore, if the temperature detected by the i-th first thermocouple is ≤ the melting point of the metal to be tested < the temperature detected by the i-1th first thermocouple, it is determined that the solidification interface of the molten metal is located at the position of the i-th first thermocouple or between the i-th first thermocouple and the i-1th first thermocouple. If the solidification interface advances to the position of other first thermocouples or between two other adjacent first thermocouples, it is necessary to use the sound velocity obtained based on the other thermocouples 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 located at the position of the i-1th first thermocouple or between the i-1st first thermocouple and the i-2nd first thermocouple, the sound velocity is used to calculate the distance between the solidification interface and the sensing end of the j-th first ultrasonic probe. Calculate the distance between the coagulation interface and the sensing end of the first ultrasonic probe j ;

[0141] When N first thermocouples are numbered 1, 2, ..., N in the vertical direction from bottom to top, 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 first thermocouple No. i is located, it means that the temperature detected by the first thermocouple No. i at this time is ≤ the melting point of the metal to be tested < the temperature detected by the first thermocouple No. i+1, and it is determined that the solidification interface of the molten metal in the accommodating cavity is located at the position where the first thermocouple No. i is located or at the position where the first thermocouple No. i is located. If the coagulation interface advances to the position of other first thermocouples (e.g., the coagulation interface is located at the position of the first thermocouple No. i+1) or between two other adjacent first thermocouples, the distance between the coagulation interface and the sensing end of the first ultrasonic probe No. j needs to be solved using the sound velocity obtained based on the other thermocouples. For example, when the coagulation interface is located at the position of the first thermocouple No. i+1 or between the first thermocouple No. i+1 and the first thermocouple No. i+2, the distance between the coagulation interface and the sensing end of the first ultrasonic probe No. j needs to be solved based on the sound velocity obtained based on the other thermocouples. Calculate the distance between the coagulation interface and the sensing end of the first ultrasonic probe j .

[0142] Step S3113: Based on the distance between the coagulation interface and the sensing end of the first ultrasonic probe No. j , calculate the coagulation interface height value sensed by the first ultrasonic probe j :

[0143] ;

[0144] The interface morphology of the coagulation interface is obtained based on the height value of the coagulation interface sensed by each first ultrasonic probe, or the distance between the coagulation interface sensed by each first ultrasonic probe and the sensing end of the corresponding first ultrasonic probe.

[0145] In one embodiment, the ultrasonic monitoring method for a metal solidification process provided in this embodiment further includes:

[0146] Step S313: If the coagulation interface advances to the height of the first thermocouple i, then the average height value of the coagulation interface is determined based on the coagulation interface positions sensed by each first ultrasonic probe. ;

[0147] In the above steps, since the positions of the coagulation interfaces monitored by the first ultrasonic probes are different, it is necessary to correct the positions of the coagulation interfaces obtained by the first ultrasonic probes to obtain the corrected values ​​of the overall height values ​​of the coagulation interfaces (i.e., to determine the average height value of the coagulation interfaces). ), for details, see Figure 4 A schematic diagram of solidification interface correction in a method for ultrasonic monitoring of a metal solidification process is 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 of the first thermocouple No. i (that is, the temperature detected by the first thermocouple No. i ≤ the melting point of the metal to be measured < the temperature detected by the first thermocouple No. i adjacent to and above the first thermocouple No. i), the overall solidification interface is divided into 16 sub-interfaces by the 9 first ultrasonic probes. At this time, the distances between the solidification interfaces detected by the first ultrasonic probes No. 1-9 and the sensing ends of their respective first ultrasonic probes are respectively 、 ,..., , where the interface near the edge (including the interface 、 interface ,interface ,interface ,interface ,interface ,interface ,interface ,interface ,interface and interface ) using extrapolation reconstruction (e.g. interface Depend on 、 、 Extrapolated reconstruction, Depend on 、 、 、 Extrapolated reconstruction,), the interface of the central part (including the interface 、 interface and interface ) is reconstructed using bilinear interpolation (e.g. interface Depend on 、 、 、 Interpolation reconstruction), the final correction value of the solidification interface height is obtained (i.e. the average height after reconstruction) is:

[0148]

[0149] Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. N (ie, the overall height of the accommodating cavity).

[0150] Step S315: Determine the advancement 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. for:

[0151] ;

[0152] in, is the average height of the solidification interface at the first moment, is the average height of the solidification interface at the second moment, For the first moment, For the second moment;

[0153] In the above steps, the average height value of the solidification interface at the first moment needs to be solved by the method in step S313, including: according to the sound velocity of the molten metal in the accommodating cavity at the first moment , the echo time of probe j Calculate the distance between the sensing end of each ultrasonic probe and the coagulation interface for:

[0154]

[0155] According to the sound velocity of the metal melt in the accommodating chamber at the second moment , the echo time of probe j Calculate the distance between the sensing end of each ultrasonic probe and the coagulation interface for:

[0156]

[0157] Specifically, the first ultrasonic probes include 9 first ultrasonic probes arranged in a 3×3 array, and the entire coagulation interface is divided into 16 sub-interfaces by the 9 first ultrasonic probes;

[0158] At the first moment, the distances between each sub-interface and each first ultrasonic probe sensing end are respectively , based on distance The solidification interface is reconstructed using bilinear interpolation and extrapolation methods, and the average height of the solidification interface at the first moment (i.e., the corrected value of the height of the solidification interface at the first moment) is obtained as follows:

[0159]

[0160]

[0161] At the second moment, the distances between each sub-interface and each first ultrasonic probe sensing end are , based on distance The solidification interface is reconstructed using bilinear interpolation and extrapolation methods, and the average height of the solidification interface at the second moment (i.e., the corrected value of the height of the solidification interface at the second moment) is obtained as follows:

[0162]

[0163] Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. 7;

[0164] The corrected advancement speed of the solidification interface is calculated for:

[0165]

[0166] in, is the average height of the solidification interface at the first moment, is the average height of the solidification interface at the second moment, For the first moment, For the second moment.

[0167] In one embodiment, the ultrasonic monitoring device for a 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 liquid level position of the molten metal in the verification chamber 15; and the method further includes:

[0168] Step S317: If the solidification interface advances to the height of the first thermocouple No. i, the height verification value of the solidification interface is determined based on the liquid level value of the molten metal in the verification chamber measured by the second ultrasonic probe. for:

[0169] ;

[0170] in, is the volume change rate of the metal solution solidification, is the cross-sectional area of ​​the accommodating cavity, is the cross-sectional area of ​​the verification cavity; , is the initial liquid level height value of the molten metal in the verification chamber measured by the second ultrasonic probe, is the actual liquid level height value of the molten metal in the verification chamber measured by the second ultrasonic probe;

[0171] In the above steps, when the solidification interface in the accommodating chamber advances to the height of the i-th first thermocouple (i.e., the temperature detected by the i-th first thermocouple ≤ the melting point of the metal to be tested < the temperature detected by the first thermocouple adjacent to and above the i-th first thermocouple), the sound velocity of the molten metal in the verification chamber 15 at this time is determined by the temperature detected by the second thermocouple in the temperature measuring assembly 13;

[0172] At this time, the actual liquid level of the molten metal in the verification chamber is determined by the echo time of the second ultrasonic probe in the detection component 14 and the sound velocity of the molten metal in the verification chamber 15. ;

[0173] By verifying the actual liquid level of the molten metal in the cavity 15 at this time And verify the initial liquid level of the molten metal in the cavity 15 , determine the height of the solidification interface of the molten metal in the accommodating cavity at this time ;

[0174] At the same time, since the volume of the molten metal may expand or shrink during the solidification process, Figure 1 As shown, when using the ultrasonic monitoring method of the metal solidification process to monitor the metal melt whose volume expands during the solidification process (for example, the volume expansion rate of gallium during the solidification process is 3%), it is necessary to ensure the height of the initial liquid level in the verification chamber 15 before starting the detection. A certain initial height is required , the 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;

[0175] When using the ultrasonic monitoring method of the metal solidification process to monitor the molten metal whose volume shrinks during the solidification process, it is necessary to ensure that the initial liquid level in the verification chamber 15 is higher than the initial height , and the height of the initial liquid level Need to meet:

[0176] ;

[0177] in, is the volume change rate of the metal solution solidification, at this time Less than 1, h is the overall height of the accommodating cavity.

[0178] Step S319, based on the average height value , the height verification value , determine the relative error of the height of the solidification interface for:

[0179] ;

[0180] Step S321: Based on the relative height error, the height monitoring accuracy of the solidification interface of the molten metal in the accommodating cavity is evaluated:

[0181] like , it is determined that the height of the solidification interface of the molten metal monitored by the first ultrasonic probe meets the accuracy requirement, wherein, is the preset height error.

[0182] In one embodiment, the ultrasonic monitoring method for a metal solidification process provided in this embodiment further includes:

[0183] Step S323, based on the height verification value , determine the verification value of solidification interface advancement speed for:

[0184] ;

[0185] in, 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;

[0186] In the above steps, the sound velocity 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 measuring component 13 at the first moment; the sound velocity 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 measuring component 13 at the second moment;

[0187] The actual liquid level 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 velocity 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 velocity of the molten metal in the verification cavity 15 at the second moment. ;

[0188] By verifying the actual liquid level of the molten metal in the cavity 15 at the first moment And verify the initial liquid level of the molten metal in the cavity 15 , determine the height of the solidification interface of the molten metal in the accommodating cavity at this time Verify the actual liquid level of the molten metal in the chamber 15 by the second moment And verify the initial liquid level of the molten metal in the cavity 15 , determine the height of the solidification interface of the molten metal in the accommodating cavity at this time ;

[0189] Determine the verification value of solidification interface advancement speed for:

[0190] .

[0191] Step S325, based on the propulsion speed , the propulsion speed verification value , determine the relative error of the advancement speed of the solidification interface for:

[0192] ;

[0193] Step S327: Based on the relative error of the advancing speed, the advancing speed monitoring accuracy of the solidification interface of the molten metal in the accommodating cavity is evaluated:

[0194] like , it is determined that the advancement speed of the metal melt solidification interface monitored by the first ultrasonic probe meets the accuracy requirements, wherein, is the preset propulsion speed error;

[0195] In the above steps, the relative error of the solidification interface height and the relative error of the solidification interface advancement speed are used to evaluate whether the reconstructed solidification interface (i.e., the average height value of the solidification interface) meets the requirements. If the relative error of the solidification interface height is less than or equal to the preset height error and the relative error of the solidification interface advancement speed is less than or equal to the preset speed error, then 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.

[0196] Based on the above embodiments, this embodiment provides an ultrasonic monitoring device for a metal solidification process, comprising: a receiving chamber, an upper temperature control component 11, a lower temperature control component 12, a temperature measuring component 13, a detection component 14, and a verification chamber 15;

[0197] The ultrasonic monitoring device for the metal solidification process monitors the solidification interface of low-melting-point metals (i.e., gallium metals), wherein the accommodating chamber and the verification chamber 15 are both cylindrical chambers, and in order to ensure that the lateral heat leakage in the accommodating chamber is sufficiently small, the side wall 18 of the accommodating chamber is made of a low-thermal-conductivity material (including an acrylic material), and a thermal insulation layer 17 is provided outside the side wall 18 of the accommodating chamber, which is made of polystyrene material, and the upper wall and lower wall of the accommodating chamber are made of a metal plate made of a metal material; the upper temperature control component 11 (i.e., the heating plate) is provided above the upper metal plate 20; the lower temperature control component 12 (i.e., the cooling plate) is provided below the lower metal plate 19; the temperature measuring component 13 includes 7 first thermocouples arranged on the central axis of the accommodating chamber from top to bottom, and the first thermocouples are arranged on the central axis of the accommodating chamber from top to bottom. The pairs of numbers are marked as 1, 2, ..., 7 from top to bottom. The first thermocouple No. 1 is arranged below the upper metal plate 20 and in contact with the upper metal plate 20. The first thermocouple No. 7 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. The first thermocouple with little influence on the acoustic wave is selected. Specifically, a 1mm armored first thermocouple can be used. The detection assembly 14 includes 9 first ultrasonic probes, which are arranged at the top of the accommodating cavity in a 3×3 array, and each first ultrasonic probe is fixedly connected to the heating plate and the upper metal plate 20 by a thread. The 9 first ultrasonic probes are numbered 1, 2, ..., 9, and the first ultrasonic probe No. 5 is arranged on the central axis of the accommodating cavity.

[0198] The verification chamber 15 in the device is an open structure with an upper opening. The verification chamber 15 is connected to the accommodating chamber through a pipe (a thermal insulation layer is also provided on the exposed side wall of the pipe, also made of polystyrene), and a heating plate is provided on the outside of the side wall of the verification chamber 15. A second thermocouple is provided above the bottom wall of the verification chamber 15. The second thermocouple and the second heating plate ensure that the temperature of the molten metal in the verification chamber 15 is the same as the temperature of the molten metal in the accommodating chamber (based on the temperature detected by the first thermocouple No. 1 in the accommodating chamber). Based on the temperature detected by the second thermocouple, the sound velocity of the molten metal in the verification chamber 15 is determined by searching the data. The detection component 14 also includes a second ultrasonic probe, which is provided at the bottom of the verification chamber 15. The sensing end of the second ultrasonic probe is vertically upward and is used to detect the liquid level of the molten metal in the verification chamber 15.

[0199] Based on the above embodiment, this embodiment provides a method for ultrasonic monitoring of a metal solidification process for monitoring the solidification process of a gallium metal melt, and is applied to the above-mentioned ultrasonic monitoring device for the metal solidification process. The method comprises the following steps:

[0200] Step S501: When the temperature detected by the first thermocouple No. 7 is the melting point of the molten metal, the echo time of the ultrasonic probe located on the central axis of the accommodating cavity is , determine the initial sound velocity of ultrasound in molten metal for:

[0201]

[0202] Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. 7; the initial liquid level of the molten metal in the verification chamber 15 is determined to be ;

[0203] Step S503: When the temperature detected by the first thermocouple No. i is the melting point of the molten metal, the echo time of the ultrasonic probe located on the central axis of the accommodating cavity is , update the sound velocity of ultrasound in molten metal for:

[0204] ;

[0205] in, is the distance between the adjacent n+1th first thermocouple and the nth first thermocouple;

[0206] At the first moment When the solidification interface is located at the position of the first thermocouple No. i or between the first thermocouple No. i and the first thermocouple No. i-1, the distance between the monitoring end of the central probe and the solidification interface is recorded as the first distance. Based on the updated sound velocity of the ultrasonic wave in the molten metal , and the echo time of each ultrasound probe Determine the distance between the coagulation interface and the sensing end of the jth ultrasonic probe at the first moment , the distances detected by the 9 ultrasonic probes are recorded as ( 、 ,..., ), the coagulation interface detected by each ultrasonic probe is reconstructed by bilinear difference and extrapolation, and the corrected value of the coagulation interface height at this time is obtained as:

[0207]

[0208]

[0209] Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. 7;

[0210] Step S505, determining the sound velocity of the molten metal in the verification chamber 15 at this moment based on the temperature of the molten metal in the verification chamber 15 detected by the second thermocouple at the first moment;

[0211] The height of the molten metal in the verification cavity 15 at the first moment is determined based on the echo time detected by the second ultrasonic probe and the sound velocity of the molten metal in the verification cavity 15 at the first moment. , determine the height of the solidification interface in the verification cavity 15 at this time for:

[0212] = -

[0213]

[0214] in, is the volume change rate of gallium metal solution solidification, is the cross-sectional area of ​​the accommodating cavity, To verify the cross-sectional area of ​​cavity 15, The difference between the actual liquid level of the molten metal in the verification chamber 15 at the first moment and the initial liquid level of the molten metal;

[0215] Step S507, at the second moment When the solidification interface is located between the first thermocouple No. i and the first thermocouple No. i-1, the distance between the monitoring end of the central probe and the solidification interface is recorded as the second distance, and the second distance is smaller than the first distance; based on the updated sound velocity of ultrasonic waves in the molten metal , and the echo time of each ultrasound probe Determine the distance between the coagulation interface and the sensing end of the jth ultrasonic probe at the second moment , the distances detected by the 9 ultrasonic probes are recorded as ( 、 ,..., ), the coagulation interface detected by each ultrasonic probe is reconstructed by bilinear difference and extrapolation, and the corrected value of the coagulation interface height at this time is obtained as:

[0216]

[0217]

[0218] Where h is the distance between thermocouple No. 1 and thermocouple No. 7;

[0219] Step S509, determining the sound velocity 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 second moment;

[0220] The height of the molten metal in the verification cavity 15 at the second moment is determined based on the echo time detected by the second ultrasonic probe and the sound velocity of the molten metal in the verification cavity 15 at the second moment. , determine the height of the solidification interface in the verification cavity 15 at this time for:

[0221]

[0222]

[0223] in, is the volume change rate of the metal solution solidification, is the cross-sectional area of ​​the accommodating cavity, To verify the cross-sectional area of ​​cavity 15, The difference between the actual liquid level of the molten metal in the verification chamber 15 at the second moment and the initial liquid level of the molten metal;

[0224] Step S511, based on and Determine the advancement speed of the reconstruction interface for:

[0225]

[0226] based on and Determine the advancement speed of the solidification interface (ie, the actual interface) determined by the verification cavity 15 for:

[0227]

[0228] Step S515, based on and Relative error of solidification interface height for:

[0229]

[0230] based on and Relative error of solidification interface height for:

[0231]

[0232] based on and Determine the relative error of the solidification interface advancement speed for:

[0233]

[0234] like , and , it is determined that the ultrasonic probe-based monitoring of the metal melt interface height and speed advance meets the accuracy requirements, among which, is the preset height error, is the preset speed error.

[0235] In summary, the ultrasonic monitoring device and method for the metal solidification process provided by the embodiments of the present invention achieve 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 porous interface, avoid the deterioration or even disappearance of sound waves, and achieve measurement of the solidification interface of the molten metal by the ultrasonic probe. The first ultrasonic probe is directly arranged in the accommodating cavity, and no stainless steel is arranged between the first ultrasonic probe and the molten metal. Therefore, the first ultrasonic probe is suitable for situations where the container wall is very thick and the acoustic impedance difference between the wall material and the molten metal to be measured is very large, thereby improving the adaptability of the device. At the same time, the device has no external moving parts and is suitable for environments with high sealing requirements.

[0236] The sound velocity is updated based on the position of the first thermocouple, avoiding the use of the same sound velocity to monitor the solidification interface of the molten metal. This improves the accuracy of the position measurement of the solidification interface of the molten metal. Based on the first ultrasonic probe arranged in a 3×3 array, the actual positions of nine points on the solidification interface are determined. The entire solidification interface is reconstructed using a reconstruction algorithm and compared with the actual interface. The relative error of the solidification interface height and the relative error of the solidification interface advancement speed are obtained.

[0237] The joint action of the upper temperature control component 11 and the lower temperature control component 12 realizes the control of the heat flow gradient of the molten metal (i.e., liquid metal) in the accommodating chamber, thereby controlling the solidification of the molten metal in the accommodating chamber, and obtaining the transient behavior of the physical laws of the molten metal under different temperature gradients. The temperature of the molten metal in the accommodating chamber is accurately determined by the first thermocouple, and it is judged whether the molten metal has reached the melting point, thereby improving the accuracy of the judgment of the position of the solidification interface of the molten metal. When two adjacent first thermocouples among the N first thermocouples, wherein 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 thermocouples. 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 by the echo time of the first ultrasonic probe located at or closest to the center. 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 by the echo time of the first ultrasonic probe located at or closest to the center. When the solid interface is located at the position of the first thermocouple below or between two first thermocouples, the positions of various parts of the solidification interface of the molten metal are determined based on the sound velocity of the ultrasound in the molten metal and the echo time of each first ultrasonic probe, thereby determining the morphology of the solidification interface. At the same time, the advancement speed of the solidification interface of the molten metal is determined 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, thereby realizing real-time online research on the solidification process of the molten metal, obtaining the morphology and advancement speed of the liquid metal solidification interface, and revealing the relationship between the solidification process of the molten metal and the thermal boundary conditions. On the basis of the verification of 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 of the solidification process of the molten metal, and lay the foundation for monitoring and mitigation methods of liquid metal solidification in liquid metal reactors.

[0238] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0239] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-described embodiments within the technical scope disclosed by the present invention, or replace some of the technical features therein with equivalents. Such modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An ultrasonic monitoring device for metal solidification process, characterized in that: include: An accommodating cavity, used for accommodating molten metal; An upper temperature control component (11) has a first heating plate, which is fixed to the top of the accommodating cavity and is used to control the temperature of the top of the accommodating cavity; A lower temperature control component (12) having a refrigeration fin, fixed to the bottom of the accommodating cavity, and used to control the temperature of the bottom of the accommodating cavity; A temperature measuring component (13) has a plurality of first thermocouples, which are arranged at intervals along the vertical direction in the accommodating cavity and are used to monitor the temperature at a corresponding height of the accommodating cavity; wherein the uppermost first thermocouple senses the temperature at the height of the sensing end of the first ultrasonic probe in the accommodating cavity; A detection assembly (14) has a plurality of first ultrasonic probes, wherein the first ultrasonic probes are arranged at the top of the accommodating cavity, and the sensing ends of the first ultrasonic probes are arranged vertically downward for detecting the solidification interface of the molten metal; determining a height value of the solidification interface based on the temperature value sensed by the first thermocouple; Determining the speed of the ultrasonic wave in the molten metal based on the height of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the center; Based on the sound velocity of the ultrasonic wave in the molten metal, determining the position of the solidification interface sensed by each first ultrasonic probe, and obtaining the interface morphology of the solidification interface; a verification chamber (15), the verification chamber (15) being in communication with the top of the accommodating chamber via a pipe, and the verification chamber (15) being provided with a second heating plate (16); The temperature measurement component (13) further includes a second thermocouple, which is arranged in the verification cavity (15) and is used to monitor the temperature of the molten metal in the verification cavity (15); The detection assembly (14) further includes a second ultrasonic probe, which is arranged at the bottom of the verification chamber (15), and the sensing end of the second ultrasonic probe is arranged upward in a vertical direction, and is used to detect the liquid level position of the molten metal in the verification chamber (15); The outer peripheral wall of the accommodating cavity has a heat-insulating layer (17).

2. A method for ultrasonic monitoring of a metal solidification process, characterized in that: Using the device according to claim 1, the method comprises: Controlling the operation of the first heating plate and the cooling plate so that the temperature of the accommodating chamber gradually increases vertically from bottom to top, wherein the temperature controlled by the cooling plate is lower than the melting point of the metal to be tested, and the temperature controlled by the first heating plate is higher than the melting point of the metal to be tested; Numbering N first thermocouples in sequence along the vertical direction and corresponding to N height positions in sequence, wherein N>2, the lowest first thermocouple senses the temperature at the bottom wall of the accommodating chamber, and the uppermost first thermocouple senses the temperature at the height of the sensing end of the first ultrasonic probe in the accommodating chamber; Place M first ultrasound probes on the same horizontal plane and number them in the array, M>3; determining a height value of the solidification interface based on the temperature value sensed by the first thermocouple; Determining the speed of the ultrasonic wave in the molten metal based on the height of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the center; Based on the sound velocity of the ultrasonic wave in the molten metal, the position of the solidification interface sensed by each first ultrasonic probe is determined to obtain the interface morphology of the solidification interface.

3. The method according to claim 2, characterized in that The step of determining the height of the solidification interface based on the temperature sensed by the first thermocouple includes: Obtain the temperature value 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 .

4. The method according to claim 3, characterized in that The first thermocouples are numbered as follows: N first thermocouples are numbered 1, 2, ..., N in a vertical direction from top to bottom; and the spacing between adjacent first thermocouples is marked as follows from top to bottom: , ,..., ; Arrange M first ultrasonic probes in a rectangular array on the same horizontal plane and number them in sequence: 1, 2, ..., M; The method of determining the sound velocity of the ultrasonic wave in the molten metal based on the height of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the center includes: When the coagulation interface is at the height of the first thermocouple No. N, based on the echo time of the first ultrasonic probe located at or closest to the center , determine the initial sound velocity of the ultrasonic wave in the molten metal for: Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. N; When the coagulation interface advances upward to the height of the first thermocouple i, based on the echo time of the first ultrasonic probe located at or closest to the center , update the sound velocity of the ultrasonic wave in the molten metal for: ； in, is the distance between the adjacent n+1th first thermocouple and the nth first thermocouple.

5. The method according to claim 3, characterized in that The first thermocouples are numbered as follows: N first thermocouples are numbered 1, 2, ..., N in a vertical direction from bottom to top; and the spacing between adjacent first thermocouples is marked as follows from bottom to top: , ,..., ; Arrange M first ultrasonic probes in a rectangular array on the same horizontal plane and number them in sequence: 1, 2, ..., M; The method of determining the sound velocity of the ultrasonic wave in the molten metal based on the height of the solidification interface determined by the first thermocouple and the echo time of the first ultrasonic probe located at or closest to the center includes: When the coagulation interface is at the height of the first thermocouple No. 1, based on the echo time of the first ultrasonic probe located at or closest to the center , determine the initial sound velocity of ultrasound in molten metal for: Wherein, h is the distance between the first thermocouple No. 1 and the first thermocouple No. N; When the coagulation interface advances upward to the height of the first thermocouple i, based on the echo time of the first ultrasonic probe located at or closest to the center , update the sound velocity of ultrasound in molten metal for: in, is the distance between the adjacent n+1th first thermocouple and the nth first thermocouple.

6. The method according to claim 4 or 5, characterized in that Based on the updated sound velocity of the ultrasonic wave in the molten metal, the position of the solidification interface sensed by each first ultrasonic probe is determined to obtain the interface morphology of the solidification interface, including: If the solidification interface advances upward to the height of the first thermocouple i, then based on the updated sound velocity of the ultrasonic wave in the molten metal , the echo time of the first ultrasonic probe j , calculate the distance between the coagulation interface and the sensing end of the first ultrasonic probe No. j for: Based on the distance between the coagulation interface and the sensing end of the first ultrasonic probe No. j , calculate the coagulation interface height value sensed by the first ultrasonic probe j : ； The interface morphology of the coagulation interface is obtained based on the height value of the coagulation interface sensed by each first ultrasonic probe, or the distance between the coagulation interface sensed by each first ultrasonic probe and the sensing end of the corresponding first ultrasonic probe.

7. The method according to claim 6, characterized in that The method further comprises: If the coagulation interface advances to the height of the first thermocouple i, the average height value of the coagulation interface is determined based on the coagulation interface position sensed by each first ultrasonic probe. ; Based on the average height of the solidification interface at the first moment and the average height of the solidification interface at the second moment, the advancement speed of the solidification interface is determined. for: ； in, is the average height of the solidification interface at the first moment, is the average height of the solidification interface at the second moment, For the first moment, For the second moment.

8. The method according to claim 7, characterized in that The device further includes a verification chamber; the detection assembly further includes a second ultrasonic probe for detecting the level of the molten metal in the verification chamber; the method further includes: If the solidification interface advances to the height of the first thermocouple No. i, the height verification value of the solidification interface is determined based on the liquid level value of the molten metal in the verification cavity measured by the second ultrasonic probe. for: ； in, is the volume change rate of the metal solution solidification, is the cross-sectional area of ​​the accommodating cavity, is the cross-sectional area of ​​the verification cavity; , is the initial liquid level height value of the molten metal in the verification chamber measured by the second ultrasonic probe, is the actual liquid level height value of the molten metal in the verification chamber measured by the second ultrasonic probe; Based on the average height value , the height verification value , determine the relative error of the height of the solidification interface for: ； Based on the relative height error, the height monitoring accuracy of the solidification interface of the molten metal in the accommodating cavity is evaluated: like , it is determined that the height of the solidification interface of the molten metal monitored by the first ultrasonic probe meets the accuracy requirement, wherein, is the preset height error.

9. The method according to claim 8, characterized in that The method further comprises: Based on the height verification value , determine the verification value of solidification interface advancement speed for: ； in, 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 propulsion speed , the propulsion speed verification value , determine the relative error of the advancement speed of the solidification interface for: ； Based on the relative error of the advancing speed, the advancing speed monitoring accuracy of the solidification interface of the molten metal in the accommodating cavity is evaluated: like , it is determined that the advancement speed of the metal melt solidification interface monitored by the first ultrasonic probe meets the accuracy requirements, wherein, is the preset propulsion speed error.

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