Lead bismuth alloy flow solidification experimental device and method

Abstract

This invention discloses an experimental apparatus and method for the flow and solidification of lead-bismuth alloy. The apparatus includes an experimental inlet section, a solidification section, an outlet section, a connecting flange, a water-cooling channel, thermocouples, and heating wires. The experimental inlet section ensures the full development of the liquid lead-bismuth alloy flow; the solidification section is a rectangular channel where the liquid lead-bismuth alloy solidifies on the side closest to the water-cooling channel; the outlet section ensures stable outflow of lead-bismuth; the connecting flange connects the inlet, solidification, and outlet sections and can also connect the experimental apparatus to the liquid lead-bismuth alloy circuit; the water-cooling channel is a rectangular channel with circular pipes connecting its inlet and outlet, and is connected to one side of the solidification section to cool the liquid lead-bismuth alloy, causing it to solidify; thermocouples are densely arranged in the solidification section to determine the position of the solid-liquid interface of the lead-bismuth alloy; the heating wires are used to preheat the experimental section to reach the initial experimental temperature. This invention can be used to study the flow and solidification characteristics of liquid lead-bismuth alloys and obtain key parameters such as the solidification layer distribution, maximum thickness, and temperature distribution under different cooling conditions.

Description

Technical Field

[0001] This invention relates to the field of lead-bismuth reactor technology, specifically to an experimental apparatus and method for the solidification of liquid lead-bismuth alloy. Background Technology

[0002] The high melting point of the coolant in lead-bismuth reactors means that solidification may occur under certain accident conditions. Once solidification occurs, it can cause changes in the dimensions of the flow channels or localized blockages, leading to increased thermal resistance, reduced core residual heat removal capacity, and ultimately threatening reactor operational safety and causing serious accidents. Therefore, studying the flow and solidification characteristics of liquid lead-bismuth alloys and clarifying the influence of cooling conditions on key parameters such as solidification location, solidified layer thickness, and solidified layer temperature distribution is crucial for the safety design of lead-bismuth reactors.

[0003] Due to the opaque nature of liquid lead-bismuth alloys, their solidification process cannot be visualized. Currently, there are very few experimental studies on lead-bismuth solidification, and no experiments related to the flow and solidification of lead-bismuth are available. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention aims to provide an experimental apparatus and method for the flow solidification of liquid lead-bismuth alloy, used to study the flow solidification mechanism of liquid lead-bismuth coolant and obtain experimental data on key parameters such as solidification location, solidified layer thickness distribution, and solidified layer temperature distribution under steady-state and transient conditions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A lead-bismuth alloy flow solidification experimental apparatus, characterized in that it includes an inlet section 1, a solidification section 2, an outlet section 3, a connecting flange 4, a water-cooling channel 5, a heating wire 6, and a thermocouple; the inlet section 1 is a rectangular channel, connected to the lead-bismuth experimental circuit via the connecting flange 4, to ensure sufficient flow development of lead-bismuth before entering the solidification section 2; the solidification section 2 includes a solidification section substrate 202 and a cover plate 204, the solidification section substrate 202 is a rectangular channel with a rectangular opening on its long side wall, and threaded seats 203 are arranged around the rectangular opening; the cover plate 204 is connected to the solidification section substrate 202 by a first screw 205, after the experiment... The removable cover plate 204 is used to observe the solidified layer formed in the solidification section substrate 202; the outlet section 3 has the same shape as the inlet section 1 to ensure stable lead-bismuth flow; the water-cooling channel 5 is a rectangular channel with the same width as the solidification section 2, sharing a wall with the solidification section 2, and the inlet and outlet of the channel are circular tubes; the heating wires 6 are arranged in all positions of the experimental device except the water-cooling channel to preheat the device before the experiment; the thermocouples are respectively arranged at the inlet and outlet of the inlet section 1, the inlet and outlet of the outlet section 3, the inlet and outlet of the water-cooling channel, and the solidification section 2, and the thermocouples in the solidification section 2 are inserted into the solidification section 2 from the wall opposite to the cover plate 204.

[0007] The inlet section 1, solidification section 2, and outlet section 3 are made of corrosion-resistant stainless steel. The inlet section is equipped with an inlet thermocouple 101 and an outlet thermocouple 102, respectively. The outlet section is equipped with an outlet thermocouple 301 and an outlet thermocouple 302, respectively.

[0008] The connecting flange 4 is made of stainless steel, and there are 4 sets in total, which are respectively arranged between the inlet section 1 and the lead-bismuth experimental circuit, between the solidification section 2 and the inlet section 1, between the solidification section 2 and the outlet section 3, and between the outlet section 3 and the lead-bismuth experimental circuit.

[0009] The cover plate 204 consists of two rectangular plates connected and pressed together by a second screw 207. The smaller rectangular plate is the same size as the rectangular opening of the solidification section substrate, and the larger rectangular plate has screw holes around its perimeter and a handle 206 for easy disassembly of the solidification section. A high-temperature resistant gasket 208 is arranged at the connection between the solidification section substrate 202 and the cover plate 204. The solidification section thermocouples 201 are vertically inserted into the solidification section substrate 202 on the side opposite to the cover plate 204 to the center position. The thermocouples are arranged in 7 horizontal rows with a horizontal spacing of 5 mm and 7 vertical rows with a vertical spacing of 100 mm.

[0010] The water-cooling channel 5 consists of a circular pipe inlet section 501, a rectangular water-cooling channel, a circular pipe outlet section 502, a circular pipe inlet section temperature measuring thermocouple 503, and a circular pipe outlet section temperature measuring thermocouple 504. The diameters of the circular pipe inlet section 501 and the circular pipe outlet section 502 are smaller than the width of the rectangular water-cooling channel. The width of the rectangular water-cooling channel is the same as the width of the solidification section 2 and shares the same wall surface with the solidification section 2.

[0011] The heating wire 6 is evenly wound around the inlet section 1, the solidification section substrate 202, the solidification section cover plate 204 and the outlet section 3 for preheating before the experiment and temperature control during the experiment.

[0012] The experimental method of the lead-bismuth alloy flow solidification experimental apparatus involves connecting the apparatus to the lead-bismuth experimental circuit via a connecting flange 4. The heating power of the heating wire 6 in the solidification section is controlled to raise the solidification section temperature above the lead-bismuth solidification point of 125°C. Lead-bismuth is introduced into the lead-bismuth experimental circuit, and then the circuit is started. The temperature of the inlet thermocouple 102 is stabilized at the experimental temperature, and the flow rate in inlet section 1 is stabilized at the experimental flow rate. Data recording begins. At this time, cooling water is turned on and its flow rate is controlled. Lead-bismuth begins to solidify in solidification section 2. The temperature change of the thermocouple 201 in the solidification section is monitored. During the experiment, [further details are needed]. The transient changes of the solid-liquid interface along the horizontal direction are determined by the time it takes for the temperature of the horizontally arranged thermocouples to reach the freezing point. At the same time, the transient changes of the solid-liquid interface along the vertical direction are determined by the temperature of the vertically arranged thermocouples. The two are combined to obtain the transient distribution of the lead-bismuth solidified layer in solidification section 2. After the temperature stabilizes for more than 2000s, the cooling water is stopped and the lead-bismuth in the circuit is drained, ending the experiment. After the temperature of the experimental section drops to room temperature, solidification section 2 is completely disassembled. Then, the first screw 205 is removed, the cover plate 204 is taken off, and the lead-bismuth solidified layer inside solidification section 2 is photographed and recorded, and its spatial distribution and maximum thickness are measured.

[0013] This invention can be used for experimental research on the flow and solidification of lead-bismuth coolant in lead-bismuth reactors, obtaining transient and steady-state solidification layer parameters under different cooling conditions, filling a relevant gap, and contributing to the industrial application of lead-bismuth reactors, thus possessing broad application prospects. Compared with existing technologies, this invention has the following advantages:

[0014] 1. The experimental apparatus of the present invention uses a rectangular solidification section. Lead and bismuth solidify on one side of the solidification section. The solidified layer changes only in the direction perpendicular to the cooling wall and in the flow direction. The transient spatial distribution of the solidified layer in the solidification section can be obtained by using close-packed thermocouples.

[0015] 2. It can obtain key parameters such as the spatial distribution, thickness, and temperature distribution of the transient solidified layer after lead and bismuth solidifies during the flow process, revealing the flow solidification mechanism of lead and bismuth under different flow velocities and cooling conditions.

[0016] 3. After each set of experiments, the cover plate can be removed to observe the morphology of the solidified layer without cutting. The experimental device can be reused, thereby reducing experimental costs. Attached Figure Description

[0017] Figure 1a , Figure 1b , Figure 1c and Figure 1d These are the front view, rear view, left view, and top view of the overall structure of the present invention.

[0018] Figure 2a , Figure 2b and Figure 2c These are, respectively, the solidification section matrix, the cover plate front view, and the cover plate side view of the solidification section structure of the present invention.

[0019] Figure 3 This is an assembly diagram of the solidification section of the present invention. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] As shown in Figure 1, a lead-bismuth alloy flow solidification experimental apparatus includes an inlet section 1, a solidification section 2, an outlet section 3, a connecting flange 4, a water-cooled channel 5, a heating wire 6, and a thermocouple. The inlet section 1 is a rectangular channel that can be connected to the lead-bismuth experimental circuit via the connecting flange 4 to ensure that the lead-bismuth fully develops its flow before entering the solidification section 2 from the bismuth experimental circuit. The solidification section 2 includes a solidification section substrate 202 and a cover plate 204. The solidification section substrate 202 is a rectangular channel with a rectangular opening on its long side wall. Threaded seats 203 are arranged around the opening. The cover plate 204 is connected to the solidification section substrate 202 via a first screw 205. After the experiment, the cover plate 204 can be removed to observe the solidified layer formed in the solidification section substrate 202. The outlet section 3 has the same shape as the inlet section 1 to ensure stable outflow of lead-bismuth. There are four sets of connecting flanges 4, respectively arranged between the inlet section 1 and the lead-bismuth circuit, between the solidification section 2 and the inlet section 1, and between the solidification section 2 and the outlet section 3. Between the inlet section 3 and the outlet section 3 and the lead-bismuth circuit; the water-cooling channel 5 is a rectangular channel with the same width as the solidification section 2, sharing a wall with the solidification section 2, and the inlet and outlet of the channel are circular tubes; the heating wires are arranged in all positions of the experimental device except for the water-cooling channel 5, for preheating of the device before the experiment; the thermocouples are respectively arranged at the inlet and outlet of the inlet section 1, the inlet and outlet of the outlet section 3, the inlet and outlet of the water-cooling channel 5 and the solidification section 2; in the solidification section 2, the thermocouples are inserted into the middle of the solidification section 2 from the opposite wall of the cover plate 204, starting from the inlet of the water-cooling channel 5, arranged in 7 rows with a vertical spacing of 100mm and a horizontal spacing of 7 rows with a horizontal spacing of 5mm. In the experiment, the transient change of the solid-liquid interface along the horizontal direction can be judged by the time it takes for the temperature of the horizontally arranged thermocouples to reach the solidification point, and the transient change of the solid-liquid interface along the vertical direction can be judged by the temperature of the vertically arranged thermocouples. The combination of the two can yield the transient distribution of the lead-bismuth solidified layer in the solidification section 2.

[0022] Thermocouples are installed at the inlet and outlet of inlet section 1 and outlet section 2 to monitor their temperature.

[0023] As shown in Figure 2 and Figure 3 As shown, the solidification section 2 consists of a solidification section substrate 202 and a cover plate 204. One side of the solidification section substrate 202 has a rectangular opening, and threaded seats 203 are formed around the rectangular opening. The solidification section substrate 202 and the cover plate 204 are connected by a first screw 205. The cover plate 204 is composed of two stainless steel sheets of different sizes pressed together; the smaller stainless steel sheet is the same size as the rectangular opening of the solidification section substrate. After the experiment, the cover plate 204 is disassembled, and the shape of the solidified layer inside the solidification section 2 is observed through the rectangular opening. A handle 206 is provided on the cover plate for easy disassembly.

[0024] The water-cooling channel 5 consists of a circular pipe inlet section 501, a rectangular water-cooling channel, a circular pipe outlet section 502, a circular pipe inlet section temperature measuring thermocouple 503, and a circular pipe outlet section temperature measuring thermocouple 504. The diameters of the circular pipe inlet section 501 and the circular pipe outlet section 502 are smaller than the width of the rectangular water-cooling channel. The width of the rectangular water-cooling channel is the same as the width of the solidification section 2 and shares the same wall surface with the solidification section 2.

[0025] The experimental method of this invention is as follows: The lead-bismuth flow solidification experimental device is connected to the lead-bismuth experimental circuit through the connecting flange 4. The heating power of the heating wire 6 in the solidification section is controlled so that the temperature of the solidification section reaches the lead-bismuth solidification point of 125°C or higher. Lead-bismuth is introduced into the lead-bismuth experimental circuit, and then the experimental circuit is started. The temperature of the outlet thermocouple 102 of the inlet section is controlled to be stable at the experimental temperature, and the flow rate of the inlet section is controlled to be stable at the experimental flow rate. Data recording begins. At this time, the cooling water is turned on and the flow rate of the cooling water is controlled. Lead-bismuth in the solidification section 2 begins to solidify. The temperature change of the thermocouple 201 in the solidification section is monitored. After the temperature is stable for more than 2000 seconds, the cooling water is stopped, and the lead-bismuth in the circuit is drained, and the experiment ends. After the temperature of the experimental section drops to room temperature, the solidification section 2 is completely disassembled. Then the first screw 205 is removed, the cover plate 204 is taken off, and the lead-bismuth solidification layer inside the experimental section is photographed and recorded. Its spatial distribution, maximum thickness and other parameters are measured.

Claims

1. An experimental apparatus for the flow solidification of a lead-bismuth alloy, characterized in that: The system includes an inlet section (1), a solidification section (2), an outlet section (3), a connecting flange (4), a water-cooling channel (5), a heating wire (6), and a thermocouple. The inlet section (1) is a rectangular channel connected to the lead-bismuth experimental circuit via the connecting flange (4) to ensure sufficient flow development of lead-bismuth before it enters the solidification section (2). The solidification section (2) includes a solidification section substrate (202) and a cover plate (204). The solidification section substrate (202) is a rectangular channel with a rectangular opening on its long side wall. Threaded seats (203) are arranged around the rectangular opening. The cover plate (204) is connected to the solidification section substrate (202) via a first screw (205). The cover plate (204) can be removed after the experiment. 04) Observe the solidified layer formed in the solidification section substrate (202); the outlet section (3) has the same shape as the inlet section (1) to ensure stable lead-bismuth flow; the water-cooling channel (5) is a rectangular channel with the same width as the solidification section (2) and shares a wall with the solidification section (2), and the inlet and outlet of the channel are round tubes; the heating wire (6) is arranged in all positions of the experimental device except the water-cooling channel to preheat the device before the experiment; the thermocouples are respectively arranged at the inlet and outlet of the inlet section (1), the inlet and outlet of the outlet section (3), the inlet and outlet of the water-cooling channel and the solidification section (2), and the thermocouples in the solidification section (2) are inserted into the solidification section (2) from the cover plate (204) opposite to the wall; The cover plate (204) consists of two rectangular plates connected and pressed together by a second screw (207). The smaller rectangular plate is the same size as the rectangular opening of the solidification section substrate. The larger rectangular plate has screw holes around its perimeter and a handle (206) for easy disassembly of the solidification section. A high-temperature resistant gasket (208) is arranged at the connection between the solidification section substrate (202) and the cover plate (204). The solidification section thermocouple (201) is vertically inserted into the center position on the side of the solidification section substrate (202) opposite to the cover plate (204). The thermocouples are arranged in 7 rows horizontally with a horizontal spacing of 5 mm and 7 rows vertically with a vertical spacing of 100 mm.

2. The experimental apparatus for the flow solidification of a lead-bismuth alloy according to claim 1, characterized in that: The inlet section (1), solidification section (2), and outlet section (3) are made of corrosion-resistant stainless steel. The inlet section is equipped with an inlet thermocouple (101) and an outlet thermocouple (102), respectively. The outlet section is equipped with an outlet thermocouple (301) and an outlet thermocouple (302), respectively.

3. The experimental apparatus for the flow solidification of a lead-bismuth alloy according to claim 1, characterized in that: The connecting flanges (4) are made of stainless steel and consist of four sets, which are respectively arranged between the inlet section (1) and the lead-bismuth experimental circuit, between the solidification section (2) and the inlet section (1), between the solidification section (2) and the outlet section (3), and between the outlet section (3) and the lead-bismuth experimental circuit.

4. The experimental apparatus for the flow solidification of a lead-bismuth alloy according to claim 1, characterized in that: The water-cooling channel (5) consists of a circular pipe inlet section (501), a rectangular water-cooling channel, a circular pipe outlet section (502), a circular pipe inlet section temperature measuring thermocouple (503), and a circular pipe outlet section temperature measuring thermocouple (504). The diameters of the circular pipe inlet section (501) and the circular pipe outlet section (502) are smaller than the width of the rectangular water-cooling channel. The width of the rectangular water-cooling channel is the same as the width of the solidification section (2) and shares the same wall surface with the solidification section (2).

5. The experimental apparatus for the flow solidification of a lead-bismuth alloy according to claim 1, characterized in that: The heating wire (6) is evenly wound around the inlet section (1), the solidification section substrate (202), the solidification section cover plate (204) and the outlet section (3) for preheating before the experiment and temperature control during the experiment.

6. The experimental method of the lead-bismuth alloy flow solidification experimental apparatus according to any one of claims 1 to 5, characterized in that: The lead-bismuth alloy flow solidification experimental apparatus is connected to the lead-bismuth experimental circuit via a connecting flange (4). The heating power of the heating wire (6) in the solidification section is controlled to make the solidification section temperature reach above the lead-bismuth solidification point of 125℃. Lead-bismuth is introduced into the lead-bismuth experimental circuit, and then the experimental circuit is started. The temperature of the outlet thermocouple (102) of the inlet section is controlled to be stable at the experimental temperature, and the flow rate of the inlet section (1) is stabilized at the experimental flow rate. Data recording begins. At this time, the cooling water is turned on and the flow rate of the cooling water is controlled. Lead-bismuth begins to solidify in the solidification section (2). The temperature change of the thermocouple (201) in the solidification section is monitored. In the experiment, the temperature of the horizontally arranged thermocouples reaches the solidification point. The time of solidification is used to determine the transient change of the solid-liquid interface in the horizontal direction. At the same time, the temperature of the vertically arranged thermocouples is used to determine the transient change of the solid-liquid interface in the vertical direction. The two are combined to obtain the transient distribution of the lead-bismuth solidified layer in the solidification section (2). After the temperature stabilizes for more than 2000s, the cooling water is stopped and the lead-bismuth in the circuit is drained to end the experiment. After the temperature of the experimental section drops to room temperature, the solidification section (2) is disassembled as a whole. Then the first screw (205) is removed and the cover plate (204) is taken off. The lead-bismuth solidified layer inside the solidification section (2) is photographed and recorded, and the spatial distribution and maximum thickness of the lead-bismuth solidified layer are measured.

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