Spiral single-rod double-channel experimental device and experimental method based on additive manufacturing

Abstract

The invention discloses a spiral single-rod double-channel experimental device and experimental method based on additive manufacturing, a spiral rod in the experimental device is processed by adopting an additive manufacturing technology, the inner surface and the outer surface of the spiral rod are both spiral surfaces, and a support ball on the outer surface of the spiral rod is used for forming radial support with a middle barrel. The pressure drop of the inner channel and the pressure drop of the outer channel are measured through the two pressure difference transmitters respectively, and then the volume flow ratio of the inner channel and the volume flow ratio of the outer channel and the Darcy friction resistance coefficient of the inner channel can be obtained through the experiment method. Experiments under different working conditions can be carried out by controlling the volume flow of the experiment loop and the temperature of the lower chamber. The experimental result of the invention can provide a basis for the design of the annular spiral nuclear fuel.

Description

Technical Field

[0001] The present invention relates to the technical field of experimental devices, and in particular to a spiral single-rod dual-channel experimental device and an experimental method based on additive manufacturing. Background Art

[0002] Compared with traditional rod-type nuclear fuel, spiral nuclear fuel can improve the core power density of lead-bismuth reactors and eliminate the positioning grid. Annular spiral fuel is developed on the basis of spiral fuel. This type of fuel can achieve double-sided cooling, improve heat transfer efficiency and reactor thermal power density. Annular spiral fuel includes inner and outer channels. The flow distribution of inner and outer channels affects fuel cooling and temperature distribution. It is necessary to study the flow distribution characteristics of the inner and outer channels of annular spiral fuel. Existing flow distribution characteristic experiments use transparent fluids (such as water) as experimental media. Based on particle image velocimetry technology, the flow rates of the inner and outer channels can be obtained respectively. However, lead-bismuth alloy is an opaque fluid with high operating temperature, which is difficult to measure using traditional methods. In addition, both the inner and outer channels are spiral surfaces, which are difficult to manufacture using traditional machining methods. Therefore, for annular spiral fuel, it is necessary to propose a new manufacturing method and inner and outer channel flow measurement method. Summary of the invention

[0003] In order to overcome the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a spiral single-rod dual-channel experimental device and experimental method based on additive manufacturing, and the spiral rod is manufactured by using additive manufacturing technology. On the basis of the existing experimental results of the flow characteristics of the spiral single rod, the friction pressure drop of the inner channel and the outer channel of the spiral single rod is measured, and the volume flow rate ratio of the inner channel to the outer channel can be obtained.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A spiral single-rod dual-channel experimental device based on additive manufacturing, the experimental device comprises an assembled spiral rod 1, an upper chamber 2, an upper chamber temperature measuring component 3, an upper flange 4, an outer channel low-pressure end temperature measuring component 5, an outer channel low-pressure end pressure leading component 6, an outer channel high-pressure end temperature measuring component 7, an outer channel high-pressure end pressure leading component 8, a lower flange 9, a lower chamber temperature measuring component 10, a lower chamber 11, a middle cylinder 12, an inner channel high-pressure end pressure leading component 13, an inner channel high-pressure end temperature measuring component 14, an inner channel low-pressure end pressure leading component 15, an inner channel low-pressure end temperature measuring component 16, an outer channel pressure differential transmitter 17 and an inner channel pressure differential transmitter 18; the middle cylinder 12 is located in the middle of the experimental device, the upper chamber 2 is located at the upper part of the middle cylinder 12, the lower chamber 11 is located at the lower part of the middle cylinder 12, the upper chamber 2 and the middle cylinder 12 are connected by an upper flange 4, and the lower chamber 11 and the middle cylinder 12 are connected by a lower flange 9; the outer channel low-pressure end pressure-leading assembly 6, the outer channel high-pressure end pressure-leading assembly 8, the inner channel high-pressure end pressure-leading assembly 13 and the inner channel low-pressure end pressure-leading assembly 15 are located on the side of the middle cylinder 12 and connected to the middle cylinder 12 vertical welding connection; the outer channel low-pressure end pressure-leading assembly 6 is located on the upper part of the outer channel high-pressure end pressure-leading assembly 8, the inner channel low-pressure end pressure-leading assembly 15 is located on the upper part of the inner channel high-pressure end pressure-leading assembly 13, the outer channel low-pressure end temperature-measuring assembly 5, the outer channel high-pressure end temperature-measuring assembly 7, the inner channel high-pressure end temperature-measuring assembly 14 and the inner channel low-pressure end temperature-measuring assembly 16 are respectively located on the sides of the outer channel low-pressure end pressure-leading assembly 6, the outer channel high-pressure end pressure-leading assembly 8, the inner channel high-pressure end pressure-leading assembly 13 and the inner channel low-pressure end pressure-leading assembly 15; the outer channel low-pressure end pressure-leading assembly The pressure-leading assembly 6 and the inner channel low-pressure end pressure-leading assembly 15 are located at the same height section of the middle cylinder 12, and the outer channel high-pressure end pressure-leading assembly 8 and the inner channel high-pressure end pressure-leading assembly 13 are located at the same height section of the middle cylinder 12; the outer channel differential pressure transmitter 17 adopts flanges to connect the outer channel low-pressure end pressure-leading assembly 6 and the outer channel high-pressure end pressure-leading assembly 8 respectively, and the inner channel differential pressure transmitter 18 adopts flanges to connect the inner channel high-pressure end pressure-leading assembly 13 and the inner channel low-pressure end pressure-leading assembly 15 respectively; during the experiment, the upper chamber 2 and the lower chamber 11 are connected to the experimental circuit;

[0006] The assembly spiral rod 1 comprises a first spiral rod 1-1, a second spiral rod 1-2 and a third spiral rod 1-3 of a hollow structure, wherein the first spiral rod 1-1, the second spiral rod 1-2 and the third spiral rod 1-3 are located at the upper, middle and lower parts of the inner side of the middle cylinder 12, the bottom end of the first spiral rod 1-1 and the top end of the second spiral rod 1-2 are welded and connected, and the bottom end of the second spiral rod 1-2 and the top end of the third spiral rod 1-3 are welded and connected; an outer channel is formed between the outer surface of the assembly spiral rod 1 and the inner surface of the middle cylinder 12, the hollow interior of the assembly spiral rod 1 is an inner channel, and the outer channel and the inner channel contain a lead-bismuth alloy medium;

[0007] The first spiral rod 1-1, the second spiral rod 1-2 and the third spiral rod 1-3 are all processed by additive manufacturing technology, and the inner and outer surfaces are spiral surfaces; the first spiral rod 1-1 is provided with an inner channel low-pressure pressure port 1-1-1 and a first spiral rod support ball 1-1-2 by additive manufacturing technology, the inner channel low-pressure pressure port 1-1-1 is located at the same height section of the inner channel low-pressure end pressure-leading assembly 15, the inner channel low-pressure end pressure-leading assembly 15 measures the pressure of the inner channel of the first spiral rod 1-1 through the inner channel low-pressure pressure port 1-1-1, the first spiral rod support ball 1-1-2 is located at the top of the first spiral rod 1-1, and the first spiral rod support ball 1-1-2 forms a support with the inner surface of the middle cylinder 12; the second spiral rod 1-1 is provided with an inner channel low-pressure pressure port 1-1-1 and a first spiral rod support ball 1-1-2 is provided with a first spiral rod support ball 1-1-2 and a first spiral rod support ball 1-1-2 are provided with a first spiral rod support ball 1-1-2; the second spiral rod 1-1 is provided with an inner channel low-pressure pressure port 1-1-1 and a first spiral rod support ball 1-1-2 are provided with a first spiral rod support ball 1-1-2 ... An inner channel high pressure taking port 1-2-1 is opened on the rod 1-2 by using additive manufacturing technology, and a second spiral rod supporting ball 1-2-2 is set. The inner channel high pressure taking port 1-2-1 is located at the same height section as the inner channel high pressure end pressure drawing assembly 13. The inner channel high pressure end pressure drawing assembly 13 measures the pressure of the inner channel of the second spiral rod 1-2 through the inner channel high pressure taking port 1-2-1. The second spiral rod supporting ball 1-2-2 is located in the middle of the second spiral rod 1-2, and the second spiral rod supporting ball 1-2-2 forms a support with the inner surface of the middle cylinder 12; the third spiral rod supporting ball 1-3-1 is set on the third spiral rod 1-2 by using additive manufacturing technology, and the third spiral rod supporting ball 1-3-1 forms a support with the inner surface of the middle cylinder 12.

[0008] The first spiral rod 1-1, the second spiral rod 1-2 and the third spiral rod 1-3 are all made of additively manufactured 316L stainless steel material.

[0009] The first spiral rod supporting ball 1 - 1 - 2 and the third spiral rod supporting ball 1 - 3 - 1 are welded to the inner surface of the middle cylinder 12 .

[0010] The outer channel differential pressure transmitter 17 measures the friction pressure drop of the outer channel, and the inner channel differential pressure transmitter 18 measures the friction pressure drop of the inner channel.

[0011] The experimental method of the spiral single-rod dual-channel experimental device based on additive manufacturing is achieved by the following steps:

[0012] Step 1: Connect the upper chamber 2 and the lower chamber 11 of the experimental device to the pipe of the experimental circuit, and conduct the experiment after testing the air tightness of the experimental circuit;

[0013] Step 2: Conduct spiral single-rod dual-channel flow distribution characteristic experiment:

[0014] Step 1: Adjust the electromagnetic pump current to obtain the total flow rate of the specified experimental circuit;

[0015] Step 2: Adjust the power of the heating section of the experimental circuit, and stop heating after the temperature of the lower chamber 11 of the spiral single-rod dual-channel experimental device reaches the specified temperature;

[0016] The third step is to control the heating power of the heating wire in the experimental circuit to ensure that the temperature deviation between the upper chamber 2 and the lower chamber 11 of the spiral single-rod dual-channel experimental device is less than 1.5°C;

[0017] Step 4: Record the inner channel pressure difference Δp1 and the outer channel pressure difference Δp2 under the specified flow condition for no less than 60 seconds;

[0018] Step 5: Stop the electromagnetic pump and record the inner channel pressure difference Δp3 and the outer channel pressure difference Δp4 under static conditions of the lead-bismuth medium;

[0019] Step 6, repeat steps 1 to 5 to obtain experimental data under different flow rates and inlet temperatures;

[0020] Step 7: Process the experimental data:

[0021] The external channel volume flow rate Q is calculated using the following formula: V2 :

[0022] Q V2 =u2A f2 (1)

[0023] Where: u2 is the average velocity of the fluid in the outer channel, m / s;

[0024] A f2 is the fluid flow cross-sectional area of ​​the outer channel, m 2 ;

[0025] According to the reading of the external channel differential pressure transmitter 17, u2 can be obtained:

[0026]

[0027] ρ is the density of the fluid, kg / m 3 ;

[0028] l2 is the vertical position difference between the outer channel low-pressure end pressure-leading assembly 6 and the outer channel high-pressure end pressure-leading assembly 8, m;

[0029] f2 is the known Darcy friction coefficient of the outer channel;

[0030] The inner channel volume flow Q is obtained based on the total volume flow of the experimental loop and the volume flow of the outer channel. V1 , the volume flow ratio of the inner channel to the outer channel

[0031] Q V1 =Q V -Q V2(3)

[0032]

[0033] The Darcy friction coefficient f1 of the inner channel can be calculated according to the reading of the inner channel differential pressure transmitter 18:

[0034]

[0035] Where: D h1 is the hydraulic diameter of the inner channel, m;

[0036] A f1 is the fluid flow cross-sectional area of ​​the inner channel, m;

[0037] Δp1 and Δp2 are the readings of the inner channel differential pressure transmitter 18 under the moving condition and the stationary condition, i.e., the inner channel differential pressure, Pa;

[0038] ρ is the density of the fluid, kg / m 3 ;

[0039] l is the vertical position difference between the inner channel low-pressure end pressure-leading assembly 15 and the inner channel high-pressure end pressure-leading assembly 13, m.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] 1. The spiral rod of the experimental device of the present invention adopts additive manufacturing technology, which can realize the manufacturing of complex structures, including the spiral surface of the supporting ball and the inner channel. Compared with the traditional experimental device, its manufacturing cost is low and the processing accuracy is high.

[0042] 2. Since the lead-bismuth alloy is opaque and has a high temperature, it is difficult to use particle image velocimetry to obtain the volume flow ratio of the inner and outer channels. The present invention only measures the pressure difference between the inner and outer channels, does not involve complex measuring equipment, and the experimental method used can relatively simply obtain the flow distribution ratio of the inner channel and the outer channel.

[0043] 3. The experimental method of the present invention can eliminate the influence of the gravity pressure difference at different temperatures, thereby obtaining more accurate experimental results. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the front view structure of the single-rod dual-channel experimental device of the present invention.

[0045] Figure 2 It is a schematic diagram of the top view structure of the single-rod dual-channel experimental device of the present invention.

[0046] Figure 3 It is a schematic diagram of the assembled spiral rod structure of the single-rod dual-channel experimental device of the present invention.

[0047] Figure 4 It is a schematic diagram of the first spiral rod structure of the single-rod dual-channel experimental device of the present invention.

[0048] Figure 5 It is a schematic diagram of the second spiral rod structure of the single-rod dual-channel experimental device of the present invention.

[0049] Figure 6 It is a schematic diagram of the third spiral rod structure of the single-rod dual-channel experimental device of the present invention.

[0050] Figure 7a and Figure 7b The graphs show the variation of Darcy friction coefficient along the flow direction in the inner channel and the outer channel respectively. DETAILED DESCRIPTION

[0051] The present invention provides a spiral single-rod dual-channel experimental device based on additive manufacturing, which will now be described in further detail in conjunction with the accompanying drawings.

[0052] like Figure 1 and Figure 2As shown, the spiral single-rod dual-channel experimental device based on additive manufacturing of the present invention includes an assembled spiral rod 1, an upper chamber 2, an upper chamber temperature measuring component 3, an upper flange 4, an outer channel low-pressure end temperature measuring component 5, an outer channel low-pressure end pressure leading component 6, an outer channel high-pressure end temperature measuring component 7, an outer channel high-pressure end pressure leading component 8, a lower flange 9, a lower chamber temperature measuring component 10, a lower chamber 11, a middle cylinder 12, an inner channel high-pressure end pressure leading component 13, an inner channel high-pressure end temperature measuring component 14, an inner channel low-pressure end pressure leading component 15, and an inner channel low-pressure end temperature measuring component 16, an outer channel pressure differential transmitter 17 and an inner channel pressure differential transmitter 18; the middle cylinder 12 is located in the middle of the experimental device, the upper chamber 2 is located at the upper part of the middle cylinder 12, the lower chamber 11 is located at the lower part of the middle cylinder 12, the upper chamber 2 and the middle cylinder 12 are connected by an upper flange 4, and the lower chamber 11 and the middle cylinder 12 are connected by a lower flange 9; the outer channel low-pressure end pressure-leading assembly 6, the outer channel high-pressure end pressure-leading assembly 8, the inner channel high-pressure end pressure-leading assembly 13 and the inner channel low-pressure end pressure-leading assembly 15 are located on the side of the middle cylinder 12 and connected to the middle cylinder 12 vertical welding connection; the outer channel low-pressure end pressure-leading assembly 6 is located on the upper part of the outer channel high-pressure end pressure-leading assembly 8, the inner channel low-pressure end pressure-leading assembly 15 is located on the upper part of the inner channel high-pressure end pressure-leading assembly 13, the outer channel low-pressure end temperature-measuring assembly 5, the outer channel high-pressure end temperature-measuring assembly 7, the inner channel high-pressure end temperature-measuring assembly 14 and the inner channel low-pressure end temperature-measuring assembly 16 are respectively located on the sides of the outer channel low-pressure end pressure-leading assembly 6, the outer channel high-pressure end pressure-leading assembly 8, the inner channel high-pressure end pressure-leading assembly 13 and the inner channel low-pressure end pressure-leading assembly 15; the outer channel low-pressure end pressure-leading assembly The pressure assembly 6 and the inner channel low-pressure end pressure leading assembly 15 are located at the same height section of the middle cylinder 12, and the outer channel high-pressure end pressure leading assembly 8 and the inner channel high-pressure end pressure leading assembly 13 are located at the same height section of the middle cylinder 12; the outer channel differential pressure transmitter 17 adopts flanges to connect the outer channel low-pressure end pressure leading assembly 6 and the outer channel high-pressure end pressure leading assembly 8 respectively, and the inner channel differential pressure transmitter 18 adopts flanges to connect the inner channel high-pressure end pressure leading assembly 13 and the inner channel low-pressure end pressure leading assembly 15 respectively; during the experiment, the upper chamber 2 and the lower chamber 11 are connected to the experimental circuit.

[0053] like Figure 3 As shown, the assembled spiral rod 1 includes a first spiral rod 1-1, a second spiral rod 1-2 and a third spiral rod 1-3 with a hollow structure. The first spiral rod 1-1, the second spiral rod 1-2 and the third spiral rod 1-3 are located at the upper, middle and lower parts of the inner side of the middle cylinder 12. The bottom end of the first spiral rod 1-1 and the top end of the second spiral rod 1-2 are welded and connected, and the bottom end of the second spiral rod 1-2 and the top end of the third spiral rod 1-3 are welded and connected; an outer channel is formed between the outer surface of the assembled spiral rod 1 and the inner surface of the middle cylinder 12, and the hollow interior of the assembled spiral rod 1 is an inner channel, and the outer channel and the inner channel are lead-bismuth alloy media.

[0054] like Figure 4 , Figure 5 and Figure 6 As shown, the first spiral rod 1-1, the second spiral rod 1-2 and the third spiral rod 1-3 are all processed by additive manufacturing technology, and the inner and outer surfaces are spiral surfaces; the first spiral rod 1-1 is opened with additive manufacturing technology to open an inner channel low-pressure pressure port 1-1-1 and set a first spiral rod support ball 1-1-2, the inner channel low-pressure pressure port 1-1-1 is located at the same height section of the inner channel low-pressure end pressure-leading assembly 15, the inner channel low-pressure end pressure-leading assembly 15 measures the pressure of the inner channel of the first spiral rod 1-1 through the inner channel low-pressure pressure port 1-1-1, the first spiral rod support ball 1-1-2 is located at the top of the first spiral rod 1-1, and the first spiral rod support ball 1-1-2 forms a support with the inner surface of the middle cylinder 12; the second spiral rod 1-1 is opened to open an inner channel low-pressure pressure port 1-1-1 and set a first spiral rod support ball 1- ... An inner channel high pressure taking port 1-2-1 is opened on the spiral rod 1-2 by using additive manufacturing technology, and a second spiral rod supporting ball 1-2-2 is set. The inner channel high pressure taking port 1-2-1 is located at the same height section as the inner channel high pressure end pressure drawing assembly 13. The inner channel high pressure end pressure drawing assembly 13 measures the pressure in the inner channel of the second spiral rod 1-2 through the inner channel high pressure taking port 1-2-1. The second spiral rod supporting ball 1-2-2 is located in the middle of the second spiral rod 1-2, and the second spiral rod supporting ball 1-2-2 forms a support with the inner surface of the middle cylinder 12; the third spiral rod supporting ball 1-3-1 is set on the third spiral rod 1-2 by using additive manufacturing technology, and the third spiral rod supporting ball 1-3-1 forms a support with the inner surface of the middle cylinder 12.

[0055] As a preferred embodiment of the present invention, the first spiral rod 1-1, the second spiral rod 1-2 and the third spiral rod 1-3 are all made of additively manufactured 316L stainless steel material, which has low processing cost. In addition, the additive manufacturing technology using this material is relatively mature and has higher manufacturing precision.

[0056] As a preferred embodiment of the present invention, the lengths of the first spiral rod 1-1, the second spiral rod 1-2 and the third spiral rod 1-3 are 400 mm respectively. This design length meets the upper limit of the product length of most additive manufacturing machine tools and can control the processing cost.

[0057] As a preferred embodiment of the present invention, the first spiral rod support ball 1-1-2 and the third spiral rod support ball 1-3-1 are welded to the inner surface of the middle cylinder 12. This design can fix the spiral rod and reduce the impact on the flow field.

[0058] The outer channel differential pressure transmitter 17 measures the friction pressure drop of the outer channel, and the inner channel differential pressure transmitter 18 measures the friction pressure drop of the inner channel.

[0059] The experimental method of the spiral single-rod dual-channel experimental device based on additive manufacturing is achieved by the following steps:

[0060] Step 1: Connect the upper chamber 2 and the lower chamber 11 of the experimental device to the pipe of the experimental circuit, and conduct the experiment after testing the air tightness of the experimental circuit;

[0061] Step 2: Conduct spiral single-rod dual-channel flow distribution characteristic experiment:

[0062] Step 1: Adjust the electromagnetic pump current to obtain the total flow rate of the specified experimental circuit;

[0063] Step 2: Adjust the power of the heating section of the experimental circuit, and stop heating after the temperature of the lower chamber 11 of the spiral single-rod dual-channel experimental device reaches the specified temperature;

[0064] The third step is to control the heating power of the heating wire in the experimental circuit to ensure that the temperature deviation between the upper chamber 2 and the lower chamber 11 of the spiral single-rod dual-channel experimental device is less than 1.5°C;

[0065] Step 4: Record the inner channel pressure difference Δp1 and the outer channel pressure difference Δp2 under the specified flow condition for no less than 60 seconds;

[0066] Step 5: Stop the electromagnetic pump and record the inner channel pressure difference Δp3 and the outer channel pressure difference Δp4 under static conditions of the lead-bismuth medium;

[0067] Step 6, repeat steps 1 to 5 to obtain experimental data under different flow rates and inlet temperatures;

[0068] Step 7: Process the experimental data:

[0069] The external channel volume flow rate Q is calculated using the following formula: V2 :

[0070] Q V2 =u2A f2 (1)

[0071] Where: u2 is the average velocity of the fluid in the outer channel, m / s;

[0072] A f2 is the fluid flow cross-sectional area of ​​the outer channel, m 2 ;

[0073] According to the reading of the external channel differential pressure transmitter 17, u2 can be obtained:

[0074]

[0075] ρ is the density of the fluid, kg / m 3 ;

[0076] l2 is the vertical position difference between the outer channel low-pressure end pressure-leading assembly 6 and the outer channel high-pressure end pressure-leading assembly 8, m;

[0077] f2 is the known Darcy friction coefficient of the outer channel;

[0078] The inner channel volume flow Q is obtained based on the total volume flow of the experimental loop and the volume flow of the outer channel. V1 , the volume flow ratio of the inner channel to the outer channel

[0079] Q V1 =Q V -Q V2 (3)

[0080]

[0081] The Darcy friction coefficient f1 of the inner channel can be calculated according to the reading of the inner channel differential pressure transmitter 18:

[0082]

[0083] Where: D h1 is the hydraulic diameter of the inner channel, m;

[0084] A f1 is the fluid flow cross-sectional area of ​​the inner channel, m;

[0085] Δp1 and Δp2 are the readings of the inner channel differential pressure transmitter 18 under the moving condition and the stationary condition, i.e., the inner channel differential pressure, Pa;

[0086] ρ is the density of the fluid, kg / m 3 ;

[0087] l is the vertical position difference between the inner channel low-pressure end pressure-leading assembly 15 and the inner channel high-pressure end pressure-leading assembly 13, m.

[0088] The numerical simulation results of the spiral single-rod dual-channel experimental device are obtained by using mature numerical calculation tools, the variation law of the Darcy friction coefficient of the inner channel and the outer channel along the flow direction (z direction) is calculated, and the pressure measurement position is determined to ensure the accuracy of the experimental measurement results of the present invention.

[0089] like Figure 7a and Figure 7b As shown in Figure 2, when z ≥ 400 mm, the fluctuation of Darcy friction coefficient decreases, so at 400

Claims

1. A spiral single-rod dual-channel experimental device based on additive manufacturing, characterized by: The experimental device comprises an assembled spiral rod (1), an upper chamber (2), an upper chamber temperature measuring component (3), an upper flange (4), an outer channel low-pressure end temperature measuring component (5), an outer channel low-pressure end pressure leading component (6), an outer channel high-pressure end temperature measuring component (7), an outer channel high-pressure end pressure leading component (8), a lower flange (9), a lower chamber temperature measuring component (10), a lower chamber (11), a middle cylinder (12), an inner channel high-pressure end pressure leading component (13), an inner channel high-pressure end temperature measuring component (14), an inner channel low-pressure end pressure leading component (15), an inner channel low-pressure end temperature measuring component (16), an outer channel differential pressure transmitter (1 7) and an inner channel pressure differential transmitter (18); the middle cylinder (12) is located in the middle of the experimental device, the upper chamber (2) is located in the upper part of the middle cylinder (12), the lower chamber (11) is located in the lower part of the middle cylinder (12), the upper chamber (2) and the middle cylinder (12) are connected through an upper flange (4), and the lower chamber (11) and the middle cylinder (12) are connected through a lower flange (9); the outer channel low-pressure end pressure leading assembly (6), the outer channel high-pressure end pressure leading assembly (8), the inner channel high-pressure end pressure leading assembly (13) and the inner channel low-pressure end pressure leading assembly (15) are located on the side of the middle cylinder (12) and connected to the middle cylinder (12). ) are vertically welded and connected; the outer channel low-pressure end pressure-leading assembly (6) is located on the upper part of the outer channel high-pressure end pressure-leading assembly (8), the inner channel low-pressure end pressure-leading assembly (15) is located on the upper part of the inner channel high-pressure end pressure-leading assembly (13), the outer channel low-pressure end temperature-measuring assembly (5), the outer channel high-pressure end temperature-measuring assembly (7), the inner channel high-pressure end temperature-measuring assembly (14) and the inner channel low-pressure end temperature-measuring assembly (16) are respectively located on the sides of the outer channel low-pressure end pressure-leading assembly (6), the outer channel high-pressure end pressure-leading assembly (8), the inner channel high-pressure end pressure-leading assembly (13) and the inner channel low-pressure end pressure-leading assembly (15); the outer channel low-pressure end pressure-leading assembly (6) and the inner channel low-pressure end pressure-leading assembly (15) are located at the same height section of the middle cylinder (12), and the outer channel high-pressure end pressure-leading assembly (8) and the inner channel high-pressure end pressure-leading assembly (13) are located at the same height section of the middle cylinder (12); the outer channel differential pressure transmitter (17) is respectively connected to the outer channel low-pressure end pressure-leading assembly (6) and the outer channel high-pressure end pressure-leading assembly (8) by flanges, and the inner channel differential pressure transmitter (18) is respectively connected to the inner channel high-pressure end pressure-leading assembly (13) and the inner channel low-pressure end pressure-leading assembly (15) by flanges; during the experiment, the upper chamber (2) and the lower chamber (11) are both connected to the experimental circuit; The assembled spiral rod (1) comprises a first spiral rod (1-1), a second spiral rod (1-2) and a third spiral rod (1-3) of a hollow structure. The first spiral rod (1-1), the second spiral rod (1-2) and the third spiral rod (1-3) are located at the upper part, the middle part and the lower part of the inner side of the middle cylinder (12). The bottom end of the first spiral rod (1-1) and the top end of the second spiral rod (1-2) are welded and connected, and the bottom end of the second spiral rod (1-2) and the top end of the third spiral rod (1-3) are welded and connected. An outer channel is formed between the outer surface of the assembled spiral rod (1) and the inner surface of the middle cylinder (12). The hollow interior of the assembled spiral rod (1) is an inner channel. The outer channel and the inner channel contain a lead-bismuth alloy medium. The first spiral rod (1-1), the second spiral rod (1-2) and the third spiral rod (1-3) are all processed by additive manufacturing technology, and both the inner surface and the outer surface are spiral surfaces; the first spiral rod (1-1) is provided with an inner channel low-pressure tapping port (1-1-1) and a first spiral rod support ball (1-1-2) by additive manufacturing technology; the inner channel low-pressure tapping port (1-1-1) is located at the same height section as the inner channel low-pressure end pressure-guiding assembly (15); the inner channel low-pressure end pressure-guiding assembly (15) measures the pressure of the inner channel of the first spiral rod (1-1) through the inner channel low-pressure tapping port (1-1-1); the first spiral rod support ball (1-1-2) is located at the top end of the first spiral rod (1-1); the first spiral rod support ball (1-1-2) and the inner surface of the middle cylinder (12) form a support; the second spiral rod An inner channel high pressure tapping port (1-2-1) is opened on the inner channel (1-2) by using additive manufacturing technology and a second spiral rod support ball (1-2-2) is arranged. The inner channel high pressure tapping port (1-2-1) is located at the same height section as the inner channel high pressure end pressure drawing assembly (13). The inner channel high pressure end pressure drawing assembly (13) measures the pressure of the inner channel of the second spiral rod (1-2) through the inner channel high pressure tapping port (1-2-1). The second spiral rod support ball (1-2-2) is located in the middle of the second spiral rod (1-2). The second spiral rod support ball (1-2-2) forms a support with the inner surface of the middle cylinder (12). The third spiral rod support ball (1-3-1) is arranged on the third spiral rod (1-2) by using additive manufacturing technology. The third spiral rod support ball (1-3-1) forms a support with the inner surface of the middle cylinder (12).

2. The spiral single-rod dual-channel experimental device based on additive manufacturing according to claim 1, characterized in that: The first spiral rod (1-1), the second spiral rod (1-2) and the third spiral rod (1-3) are all made of additively manufactured 316L stainless steel material.

3. The spiral single-rod dual-channel experimental device based on additive manufacturing according to claim 1, characterized in that: The first spiral rod supporting ball (1-1-2) and the third spiral rod supporting ball (1-3-1) are welded to the inner surface of the middle cylinder (12).

4. The spiral single-rod dual-channel experimental device based on additive manufacturing according to claim 1, characterized in that: The outer channel differential pressure transmitter (17) measures the friction pressure drop of the outer channel, and the inner channel differential pressure transmitter (18) measures the friction pressure drop of the inner channel.

5. The experimental method of the spiral single-rod dual-channel experimental device based on additive manufacturing according to any one of claims 1 to 4, characterized in that: The method is achieved by the following steps: Step 1: Connect the upper chamber (2) and the lower chamber (11) of the experimental device to the pipe of the experimental circuit, and conduct the experiment after testing the air tightness of the experimental circuit; Step 2: Conduct spiral single-rod dual-channel flow distribution characteristic experiment: Step 1: Adjust the electromagnetic pump current to obtain the total flow rate of the specified experimental circuit; Step 2: adjusting the power of the heating section of the experimental circuit, and stopping heating after the temperature of the lower chamber (11) of the spiral single-rod dual-channel experimental device reaches a specified temperature; The third step is to control the heating power of the heating wire in the experimental circuit to ensure that the temperature deviation between the upper chamber (2) and the lower chamber (11) of the spiral single-rod dual-channel experimental device is less than 1.5°C; Step 4: Record the inner channel pressure difference Δp1 and the outer channel pressure difference Δp2 under the specified flow condition for no less than 60 seconds; Step 5: Stop the electromagnetic pump and record the inner channel pressure difference Δp3 and the outer channel pressure difference Δp4 under static conditions of the lead-bismuth medium; Step 6, repeat steps 1 to 5 to obtain experimental data under different flow rates and inlet temperatures; Step 7: Process the experimental data: The external channel volume flow rate Q is calculated using the following formula: V2 : Q V2 =u2A f2 (1) Where: u2 is the average velocity of the fluid in the outer channel, m / s; A f2 is the fluid flow cross-sectional area of ​​the outer channel, m 2 ; According to the reading of the external channel differential pressure transmitter (17), u2 can be obtained: Where: D h2 is the hydraulic diameter of the external channel, m; Δp2 and Δp4 are the readings of the external channel differential pressure transmitter (17) under operating and static conditions, i.e., the external channel differential pressure, Pa; ρ is the density of the fluid, kg / m 3 ; l2 is the vertical position difference between the outer channel low-pressure end pressure-leading assembly (6) and the outer channel high-pressure end pressure-leading assembly (8), m; f2 is the known Darcy friction coefficient of the outer channel; The inner channel volume flow Q is obtained based on the total volume flow of the experimental loop and the volume flow of the outer channel. V1 , the volume flow ratio of the inner channel to the outer channel Q V1 =Q V -Q V2 (3) The Darcy friction coefficient f1 of the inner channel can be calculated based on the reading of the inner channel differential pressure transmitter (18): Where: D h1 is the hydraulic diameter of the inner channel, m; A f1 is the fluid flow cross-sectional area of ​​the inner channel, m; Δp1 and Δp2 are the readings of the inner channel differential pressure transmitter (18) under the moving condition and the static condition, i.e., the inner channel differential pressure, Pa; ρ is the density of the fluid, kg / m 3 ; l is the vertical position difference between the inner channel low-pressure end pressure-leading assembly (15) and the inner channel high-pressure end pressure-leading assembly (13), m.

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