Gallium-water-air intelligent heat exchanger

Abstract

The present invention relates to a gallium-water-air intelligent heat exchanger, which includes a tube side and a shell side that exchanges heat with the tube side. The shell side includes two medium circuits, namely a first circuit and a second circuit, and the first circuit and the second circuit are arranged in parallel. The first circuit and the second circuit are used to form four different medium combinations to exchange heat with the tube-side medium at different temperature levels respectively. The four different medium combinations are as follows: a first medium is introduced into the first circuit and no medium is introduced into the second circuit; a first medium is introduced into the first circuit and a second medium is introduced into the second circuit; the first medium is introduced into both the first circuit and the second circuit; the second medium is introduced into both the first circuit and the second circuit. The structure of the shell side includes two circuits to realize four medium combinations, so as to meet the heat exchange with the tube-side medium at different temperature levels. By reasonably configuring the types of media and the flow rate of the tube-side medium, the heat exchange effect can be maximally improved and the heat exchange efficiency can be enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and in particular to a gallium-water-air intelligent heat exchanger. Background Art

[0002] There are many existing heat exchanger structures. According to the heat transfer principle, they can be divided into shell-and-tube heat exchangers, regenerative heat exchangers, fluid-connected indirect heat exchangers, direct contact heat exchangers, and compound heat exchangers. According to their uses, they can be divided into heaters, preheaters, superheaters, and evaporators. Currently, most heat exchanger structures require the use of two heat transfer media for heat exchange. The main disadvantage is that it has limitations for the medium on the side with a large temperature change range: for example, if the temperature of the heat-releasing side medium decreases and the heat-absorbing side medium still operates under the original conditions, it will lead to a decrease in heat exchange efficiency and excessive heat exchange resulting in energy waste. Therefore, it is necessary to design a heat exchanger suitable for the change of medium temperature levels to improve efficiency and energy utilization rate. Summary of the Invention

[0003] In view of the deficiencies of the prior art, the present invention provides a gallium-water-air intelligent heat exchanger, which rationally configures heat transfer media through multi-loop settings to improve the heat exchange efficiency for media with different temperature levels.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A gallium-water-air intelligent heat exchanger includes a tube side and a shell side that exchanges heat with the tube side. The shell side includes two medium loops, namely a first loop and a second loop, and the first loop and the second loop are arranged in parallel.

[0006] The first loop and the second loop are used to form four different medium combinations to respectively exchange heat with the tube-side media of different temperature levels. The four different medium combinations are respectively:

[0007] The first medium is introduced into the first loop and no medium is introduced into the second loop;

[0008] The first medium is introduced into the first loop and the second medium is introduced into the second loop;

[0009] The first medium is introduced into both the first loop and the second loop;

[0010] The second medium is introduced into both the first loop and the second loop;

[0011] The tube side includes a tube bundle formed by arranging a number of single tubes. The single tubes are divided into three categories: those that exchange heat with the first loop, those that exchange heat with the second loop, and those that exchange heat with both the first loop and the second loop.

[0012] A further technical solution is:

[0013] It further includes a control system, and the control system includes:

[0014] A temperature sensor, which is arranged on the tube side and is used to monitor the medium temperature on the tube side;

[0015] A central processing unit module, which is used to control the types and flow rates of the media introduced into the primary loop and the secondary loop according to the medium temperature on the tube side;

[0016] An electromagnetic valve, which is arranged on the tube side and is used to adjust the medium flow rate of each single tube under the control of the central processing unit module according to the medium temperature on the tube side and the types and flow rates of the media in the primary loop and the secondary loop.

[0017] The secondary loop includes a main path and an auxiliary path with opposite flow directions, and the flow path length of the main path is greater than that of the auxiliary path; the medium flow direction of the main path is countercurrent to that of the primary loop, and the medium flow direction of the primary loop is countercurrent or concurrent with that of the tube side.

[0018] A flow splitting valve is arranged at the inlet of the secondary loop, and it is used to split the medium into the main path and the auxiliary path.

[0019] The structure of the shell side includes an outer shell body, an inner shell body is arranged inside the outer shell body, the primary loop is formed inside the inner shell body, and the secondary loop is formed between the outer shell body and the inner shell body; the inlet and outlet of the primary loop are arranged on the inner shell body, and the inlet and outlet of the secondary loop are arranged on the outer shell body.

[0020] The flow channels of the primary loop and the secondary loop form a continuous bending structure with concave and convex correspondences.

[0021] The tube bundle penetrates through the outer shell body and the inner shell body, and both ends of the tube bundle are connected to the tube sheet by a fixed tube sheet and a floating head tube sheet respectively; a floating head is connected to one end of the floating head tube sheet.

[0022] A material interface is arranged at the end of the single tube, and it is used to add nanoparticles into the tube to form nanofluid for the medium on the tube side.

[0023] The medium on the tube side is liquid gallium used as a coolant for a nuclear reactor; the first medium is normal temperature water, and the second medium is pressurized air with a pressure range of 0.5 Mpa to 5.0 Mpa.

[0024] The cross-section of the single tube is circular, square, annular or triangular, rib plates are arranged on the inner wall or outer wall of the tube, and an anti-corrosion coating is arranged on the outer wall of the tube; the single tube is a silver-plated copper tube, a carbon steel tube or a graphene nanotube.

[0025] The beneficial effects of the present invention are as follows:

[0026] Four medium combinations are realized on the shell side to meet the heat exchange with the tube-side media at different temperature levels. By reasonably configuring the types of media and the flow rates of the tube-side media, the heat exchange efficiency and effect can be maximally improved. The primary and secondary circuits are set on the shell side to give full play to the inlet-end effect of convective heat transfer and further improve the heat exchange performance. Brief Description of the Drawings

[0027] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0028] Figure 2 It is a schematic diagram of the shell-side structure of the present invention.

[0029] In the figure: 1, tube-side inlet; 2, primary circuit inlet; 3, primary circuit outlet; 4, tube-side outlet; 5, flow-dividing valve; 6, inner shell; 7, fixed tube sheet; 8, primary circuit; 9, outer shell; 10, floating head; 11, floating tube sheet; 12, tube box; 13, single tube; 14, secondary circuit; 141, main path; 142, secondary path; 19, secondary circuit inlet; 20, secondary circuit outlet; 21, partition. Detailed Embodiments

[0030] The following describes the detailed embodiments of the present invention with reference to the accompanying drawings.

[0031] As Figure 1 shown, a gallium-water-air intelligent heat exchanger of the present application includes a tube side and a shell side that exchanges heat with the tube side. The shell side includes two medium circuits, namely a primary circuit 14 and a secondary circuit 8, and the primary circuit 14 and the secondary circuit 8 are arranged in parallel;

[0032] The primary circuit 8 and the secondary circuit 14 are used to form four different medium combinations to exchange heat with the tube-side media at different temperature levels respectively. The four different medium combinations are respectively:

[0033] The first medium is introduced into the primary circuit 8 and no medium is introduced into the secondary circuit 14;

[0034] The first medium is introduced into the primary circuit 8 and the second medium is introduced into the secondary circuit 14;

[0035] The first medium is introduced into both the primary circuit 8 and the secondary circuit 14;

[0036] The second medium is introduced into both the primary circuit 8 and the secondary circuit 14;

[0037] The tube side includes a tube bundle formed by arranging a number of single tubes 13. The single tubes 13 are divided into three categories: those that exchange heat with the primary circuit 8, those that exchange heat with the secondary circuit 14, and those that exchange heat with both the primary circuit 8 and the secondary circuit 14.

[0038] It further includes a control system, and the control system includes:

[0039] A temperature sensor, which is arranged on the tube side and is used to monitor the medium temperature on the tube side;

[0040] A central processing unit module, which is used to control the types and flow rates of the media introduced into the primary loop 8 and the secondary loop 14 according to the medium temperature on the tube side;

[0041] An electromagnetic valve, which is arranged on the tube side and is used to adjust the medium flow rate of each single tube 13 under the control of the central processing unit module according to the medium temperature on the tube side and the types and flow rates of the media in the primary loop 8 and the secondary loop 14.

[0042] As Figure 1 shown, the specific structure on the shell side includes a shell body 9. An inner shell body 6 is arranged inside the shell body 9. The primary loop 8 is formed inside the inner shell body 6, and the secondary loop 14 is formed between the shell body and the inner shell body 6;

[0043] As Figure 2 shown, the inlet and outlet of the secondary loop 14 are arranged on the inner shell body: the primary loop inlet 2 and the primary loop outlet 3; the inlet and outlet of the secondary loop 14 are arranged on the shell body 9: the secondary loop inlet 19 and the secondary loop outlet 20.

[0044] Figure 2 The bold part in

[0045] is the structure of the primary loop 8 surrounded by the inner shell body 6. The solid arrow indicates the flow direction of the primary loop medium, and the dashed arrow indicates the flow direction of the secondary loop medium.

[0046] Among them, the flow direction of the primary loop 8 and the medium on the tube side is countercurrent or cocurrent;

[0047] Specifically, the secondary loop inlet 19 is arranged at the position of 1 / 3 to 1 / 4 of the entire secondary loop flow length, so that the flow length of the main path 141 is greater than that of the auxiliary path 142;

[0048] Specifically, the flow channels of the primary loop 8 and the secondary loop 14 form a continuous bending structure with concave and convex correspondence.

[0049] Specifically, baffles 21 are arranged in the flow channels of the primary loop 8 and the secondary loop 14 for guiding the medium to flow along an S-shaped bending path.

[0050] As Figure 1As shown, a tube bundle composed of multiple single tubes 13 arranged runs through the outer shell 9 and the inner shell 6. Both ends of the tube bundle are respectively connected to the tube boxes 12 through the fixed tube sheets 7 and the floating head tube sheets 11. One end of the floating head tube sheet 11 is connected with a floating head 10, and the floating head 10 is used to take out the tube bundle from the shell through the floating head tube sheet 11.

[0051] For a gallium-water-air intelligent heat exchanger of the present application, the medium on the tube side is liquid gallium used as a coolant for a nuclear reactor; the first medium is normal temperature water, and the second medium is pressurized air with a pressure range of 0.5 Mpa to 5.0 Mpa.

[0052] In existing fast neutron reactors, sodium is often used as a coolant. Compared with sodium and lead, gallium has a larger temperature difference between its melting point and boiling point, a higher density, and conducts more heat per unit volume. At the same time, gallium does not react with water, providing more security. Therefore, gallium has higher superiority as a cooling working medium.

[0053] Although water has a relatively narrow working range, it has a large specific heat capacity and can absorb a large amount of heat within the same working range, thereby increasing the heat transfer per unit volume and the heat transfer efficiency. When used in a small reactor, especially a mobile small reactor, water is convenient to obtain and has a low price, so it is used as a heat transfer working medium. Liquid gallium has a relatively high density, about 6.093 g / cm3. The relatively large densities of the two working media can significantly reduce the pipe diameter size while absorbing more heat, reducing the consumption of pipe materials. Gallium is in a liquid state at 29.76 °C, and its boiling point is 2403 °C. Water is in a liquid state at 0 °C to 100 °C under standard atmospheric pressure. Therefore, it is applicable to heat exchangers with a temperature range of 30 °C to 200 °C.

[0054] The above four medium combinations are specifically applicable to 4 heat transfer methods:

[0055] Method 1: The primary circuit 8 uses water as the medium, and the secondary circuit 14 is empty. It is applicable under general conditions, for example, when the temperature of the liquid gallium in the tube bundle is not higher than 1000 K.

[0056] Method 2: The primary circuit 8 uses water as the medium, and the secondary circuit 14 is pressurized air. Since this method enhances heat transfer, it is applicable to heat transfer under the condition that the temperature of liquid gallium is 1000 K - 1100 K, and is applicable when the water source is limited.

[0057] Method 3: Both the primary circuit 8 and the secondary circuit 14 use water as the medium. At this time, it is applicable when the nuclear reactor is in a full-power state, the temperature of liquid gallium is 1100 K - 1300 K, and is applicable when the water source is sufficient.

[0058] Method 4: Both the primary and secondary circuits are pressurized air, which is applicable to situations with relatively low heat transfer requirements, such as when the temperature of liquid gallium is lower than 500 K during startup. At the same time, it is applicable to situations where the water source is short or as an emergency heat transfer method in case of sudden water cut-off.

[0059] During the heat exchange process, as Figure 1 shown, a part of the single tube 13 is completely in the secondary circuit 14, a part is completely in the primary circuit 8, and most of it is in both the primary circuit 8 and the secondary circuit 14 at the same time. For example, in the first heat exchange mode, the single tube 13 in the secondary circuit 14 does not exchange heat, the single tube 13 in the primary circuit 8 exchanges heat completely, and the single tube 13 in both the primary and secondary circuits exchanges heat partially. For the single tube 13 that is not completely in the primary circuit 8, a solenoid valve is used to change the flow rate to achieve stable heat exchange, and the single tube 13 not in the primary circuit 8 is closed. This heat exchange structure realizes flexible heat exchange. Moreover, the setting of the secondary circuit can share the heat exchange load of the primary circuit under transient conditions during high-temperature heat exchange, so that the final temperature will not be too high, improving safety.

[0060] The purpose of setting the main and auxiliary circuits in the secondary circuit is as follows: The main circuit 141 of the secondary circuit flows in the opposite direction to the primary circuit 8 for heat exchange in a countercurrent manner, while the auxiliary circuit 142 flows in a manner countercurrent to the tube side to reduce the flow rate for auxiliary heat exchange. The structures of the main and auxiliary circuits give full play to the entrance effect (two entrance effects), improving the heat exchange effect. In addition, the inlet positions of the main and auxiliary circuits are in the middle position, and the medium flow path is reasonably distributed.

[0061] The main and auxiliary circuits can be rotated to be opened and closed according to the temperature. Under steady state, when the outlet temperature of the primary circuit is too high, the auxiliary circuit can be allowed to participate in heat exchange, and the flow rate can also be appropriately adjusted by the flow control valve to achieve stability.

[0062] Specifically, the temperature sensor transmits the temperature data to the central processing unit module. After the data collected by the computer is processed by the artificial intelligence algorithm, the opening degree of the solenoid valve on the tube side is controlled in real time to control the flow rate of liquid gallium and the switching of the corresponding valves on the external pipeline, realizing different medium combinations to achieve heat exchange of liquid gallium at corresponding temperature levels.

[0063] The end of the single tube 13 is provided with a material interface, which is used to add materials into the tube to increase the disturbance of the medium on the tube side.

[0064] Specifically, by adding nanoparticles into the single tube 13, gallium forms nanofluid. The nanoparticles enhance the heat transfer ability of gallium through disturbance. The nanoparticles can be selected as CuO, Al2O3, Zn, etc. The particle shapes can be selected as oval, square, round, etc. The diameter of the nanoparticles can be selected from 10nm to 50nm.

[0065] Specifically, the cross-section of the single tube 13 forming the tube bundle is circular, square, annular or triangular, with rib plates provided on the inner or outer wall of the tube, and an anti-corrosion coating provided on the outer wall of the tube.

[0066] Specifically, the inner diameter of the single tube 13 is 30 mm to 35 mm, the length of the shell is 1200 mm to 2800 mm, the inner diameter of the shell is 200 to 350 mm, and the wall thickness is 2 mm to 6 mm. The pipe diameters of the inlet and outlet nozzles of the shell side are 60 to 120 mm.

[0067] Specifically, to ensure the heat exchange effect, no fins are added to the inlet section of the single tube 13 due to the inlet section effect, and fins are added in the middle and tail parts. The working fluid velocity in the middle part is relatively high. Therefore, the fins from the middle to the tail are arranged in a way that the fin density gradually decreases, so as to ensure a better heat exchange effect. The fin structure is straight fin, cylindrical fin or ring fin, etc. The fin length can be 50 mm to 100 mm, and the thickness can be 10 mm to 30 mm.

[0068] Specifically, the single tube is a silver-plated copper tube, a carbon steel tube or a graphene nanotube, etc. The shell can be made of materials such as 06Cr17Ni12Mo2, TP347H / HFG, Super304H, XA704, NF709, etc., which have both excellent high-temperature strength and corrosion resistance.

[0069] This application uses liquid metal gallium, liquid water and air as working media. Liquid gallium has a high latent heat of vaporization, so it has a high heat flux density heat transfer even at a small temperature difference, thus improving the efficiency of the heat exchanger. At the same time, gallium is liquid at 29.76 °C, ensuring its fluidity in the pipeline. Both gallium and water have good thermal stability and high density, ensuring the stability, safety and compactness of the device. And in some cases, air can be used and pressurized for combined heat exchange or emergency treatment, reflecting the flexibility and double insurance characteristics in actual operation. The wide temperature range of liquid gallium and its very low vapor pressure make it suitable for a variety of systems. Therefore, the gallium-water-air heat exchanger of this application has good prospects in the energy field. At the same time, through AI intelligent learning, the main parameters of the working fluid in the pipe are controlled. The gallium-water-air heat exchanger can meet the working requirements of the conventional heat exchanger of the mobile small reactor under the complex alternating high heat flux density heat load field with difficulty. Through different combinations of flowing media, it can adapt to the working temperature requirements of liquid gallium, and through the control system, the switching of different medium combinations is realized to adjust the heat exchange effect, ensuring the high efficiency and safety of heat exchange. It has good prospects in small reactors, especially mobile reactors, as well as in the integration of military and civilian applications.

Claims

1. A gallium-water-air intelligent heat exchanger, comprising a tube side and a shell side that exchanges heat with the tube side, characterized in that The shell side includes two medium circuits, namely the primary circuit and the secondary circuit, which are arranged in parallel; The primary circuit and the secondary circuit are used to form four different medium combinations to exchange heat with the tube side medium at different temperature levels respectively. The four different medium combinations are as follows: The first medium is introduced into the primary circuit and no medium is introduced into the secondary circuit; The first medium is introduced into the primary circuit and the second medium is introduced into the secondary circuit; The first medium is introduced into both the primary circuit and the secondary circuit; The second medium is introduced into both the primary circuit and the secondary circuit; The tube side includes a tube bundle arranged by several single tubes. The single tubes are divided into three categories: exchanging heat with the primary circuit, exchanging heat with the secondary circuit, and exchanging heat with both the primary circuit and the secondary circuit simultaneously.

2. The gallium-water-air intelligent heat exchanger according to claim 1, characterized in that It also includes a control system, and the control system includes: A temperature sensor, which is arranged on the tube side and is used to monitor the medium temperature on the tube side; A central processing unit module, which is used to control the types and flow rates of the media introduced into the primary circuit and the secondary circuit according to the medium temperature on the tube side; A solenoid valve, which is arranged on the tube side and is used to adjust the medium flow rate of each single tube under the control of the central processing unit module according to the medium temperature on the tube side and the types and flow rates of the media in the primary circuit and the secondary circuit.

3. The gallium-water-air intelligent heat exchanger according to claim 1, characterized in that The secondary circuit includes a main path and a bypass with opposite flow directions. The flow length of the main path is greater than that of the bypass; the flow direction of the main path and the primary circuit is countercurrent, and the flow direction of the primary circuit and the tube side medium is countercurrent or concurrent.

4. The gallium-water-air intelligent heat exchanger according to claim 3, characterized in that A flow splitting valve is arranged at the inlet of the secondary circuit, which is used to split the medium into the main path and the bypass.

5. The gallium-water-air intelligent heat exchanger according to claim 1, characterized in that The structure of the shell side includes an outer shell. An inner shell is arranged inside the outer shell. The primary circuit is formed inside the inner shell, and the secondary circuit is formed between the outer shell and the inner shell; the inlet and outlet of the primary circuit are arranged on the inner shell, and the inlet and outlet of the secondary circuit are arranged on the outer shell.

6. The gallium-water-air intelligent heat exchanger according to claim 5, characterized in that The flow channels of the primary circuit and the secondary circuit form a continuous bending structure with concave and convex correspondence.

7. The gallium-water-air intelligent heat exchanger according to claim 5, characterized in that The tube bundle penetrates through the outer shell and the inner shell. Both ends of the tube bundle are connected to the tube box through a fixed tube sheet and a floating head tube sheet respectively; a floating head is connected to one end of the floating head tube sheet.

8. The gallium-water-air intelligent heat exchanger according to claim 7, characterized in that A material interface is arranged at the end of the single tube, which is used to add nanoparticles into the tube to form nanofluid for the tube side medium.

9. The gallium-water-air intelligent heat exchanger according to claim 1, characterized in that The medium on the tube side is liquid gallium used as a coolant for a nuclear reactor; the first medium is normal temperature water, and the second medium is pressurized air with a pressure range of 0.5 Mpa to 5.0 Mpa.

10. The gallium-water-air intelligent heat exchanger according to claim 1, characterized in that The cross-section of the single tube is circular, square, annular or triangular. Rib plates are arranged on the inner wall or outer wall of the tube, and an anti-corrosion coating is arranged on the outer wall of the tube; the single tube is a silver-plated copper tube, a carbon steel tube or a graphene nanotube.

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