Heat pipe heat exchange device

Abstract

The embodiment of the present invention relates to the technical field of marine nuclear power systems, and provides a heat pipe heat exchange device. The heat pipe heat exchange device includes a heat exchange body, which includes multiple layers of base bodies that are sequentially connected, and each layer of the base body is provided with mounting holes for inserting heat pipes, and each mounting hole is provided with a heat transfer channel that penetrates the base body for the circulation of cooling medium around the base body, and the cross-sectional area of ​​the heat transfer channel gradually decreases from the innermost base body to the outermost base body of the heat exchange body. The heat pipe heat exchange device provided by the embodiment of the present invention exchanges heat with the heat pipe through the heat exchange body, and compared with the traditional heat pipe heat exchanger, the vibration and corrosion of the heat pipe caused by the direct flushing of the cooling medium on the heat pipe is avoided; by setting a heat transfer channel with a gradually decreasing cross-sectional area from the innermost base body to the outermost base body, the temperature distribution of the heat exchange body is uniform, and the stress damage of the heat exchange device caused by uneven thermal stress is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of marine nuclear power systems, and in particular to a heat pipe heat exchange device. Background Art

[0002] In marine nuclear power systems, heat pipes are usually used as a means of core heat removal using capillary force and passive heat transfer, that is, heat pipes are inserted into the solid core to form a heat pipe cooling reactor (referred to as: heat pipe reactor). This can eliminate moving parts such as the traditional primary circuit main pump, greatly simplify the core structure, and improve reliability. The heat pipe is divided into an evaporation section, an adiabatic section, and a condensation section. The evaporation section is located inside the core body, and the adiabatic section and the condensation section are outside the core.

[0003] In the prior art, heat pipe heat exchangers are usually set in the condensing section of the heat pipe, and the secondary circuit working fluid is used to directly flush the heat pipe surface to achieve cooling of the heat pipe and take away the heat of the heat pipe for subsequent work, but the heat exchange efficiency is not ideal. Therefore, in order to improve the heat exchange capacity, measures such as adding fins to the surface of the heat pipe are adopted to enhance the heat exchange, but this method cannot be directly applied to the heat pipe stack.

[0004] The main reason is that the outlet temperature of the heat pipe stack is usually above 600°C. If the power conversion system uses water as the working fluid, a phase change will occur in the heat exchanger, the volume of the working fluid will increase sharply, the flow rate will increase, and it will be more corrosive at high temperatures; if helium, supercritical carbon dioxide and other gas working fluids are used, their ultra-high flow rate will bring about flow-induced vibration of the heat pipe. The power conversion system operates for a long time in both cases, and there is a hidden danger of heat pipe damage. In addition, due to the uneven distribution of reactor power, the temperature of the cooling working fluid is also unevenly distributed, which not only causes working fluid flow loss, but also aggravates the vibration of the heat pipe. In addition, the drastic temperature rise conditions at the working fluid inlet and the strong heat exchange between the working fluid and the heat pipe will cause the temperature field inside the heat exchanger to be abnormally complex, resulting in uneven expansion of structural parts inside the heat pipe exchanger, resulting in different degrees of thermal stress and thermal damage. Summary of the invention

[0005] The embodiment of the present invention provides a heat pipe heat exchange device, which is used to solve the problem that the existing heat pipe heat exchange technology easily causes heat pipe vibration and thus leads to heat pipe damage.

[0006] An embodiment of the present invention provides a heat pipe heat exchange device, including a heat exchanger, wherein the heat exchanger includes multiple layers of substrates that are sequentially nested, each layer of the substrate is provided with mounting holes for inserting heat pipes, and each mounting hole is provided with a heat transfer channel that penetrates the substrate for the circulation of a cooling medium around the mounting hole, and the cross-sectional area of ​​the heat transfer channel gradually decreases from the innermost layer of the substrate to the outermost layer of the substrate of the heat exchanger.

[0007] Wherein, the cross-sectional area of ​​the heat transfer channel in the same base body gradually decreases in the direction extending from the center to the outside.

[0008] The distribution density of the heat transfer channels gradually decreases from the innermost matrix to the outermost matrix of the heat exchange body.

[0009] Wherein, the heat exchange body comprises an inner matrix and an outer matrix, and the outer matrix is ​​sleeved on the outer side of the inner matrix.

[0010] Wherein, the heat transfer channel in the inner matrix is ​​wavy along the flow direction of the cooling medium.

[0011] Wherein, the inner matrix is ​​made of titanium alloy, and the outer matrix is ​​made of stainless steel.

[0012] Wherein, six heat transfer channels are distributed around each of the mounting holes.

[0013] Wherein, the mounting hole is a blind hole.

[0014] Among them, an inlet distribution box is installed at the working fluid inlet end of the heat exchanger, and an outlet mixing box is installed at the working fluid outlet end of the heat exchanger. The inlet distribution box is provided with a working fluid inlet and a through hole. The through hole is used for the heat pipe to pass through and then be inserted into the installation hole. The outlet mixing box is provided with a working fluid outlet.

[0015] Wherein, the plurality of working medium inlets are evenly distributed on the side wall of the inlet distribution box, and the working medium outlet is arranged at the center of the end cover of the outlet mixing box.

[0016] The heat pipe heat exchange device provided in the embodiment of the present invention, on the one hand, provides mounting holes for installing heat pipes and heat transfer channels for circulating cooling medium in each layer of the substrate of the heat exchanger, so that the cooling medium flows only in the special heat transfer channel and exchanges heat with the heat pipe through the substrate. Compared with the traditional heat pipe heat exchanger, the vibration and corrosion of the heat pipe caused by the direct scouring of the heat pipe by the cooling medium are avoided. On the other hand, the problem of uneven temperature distribution of the heat exchanger is improved through the heat transfer channel with a gradually decreasing cross-sectional area from the innermost substrate to the outermost substrate, and stress damage of the heat exchange device caused by uneven thermal stress is avoided, thereby providing an effective and safe heat exchange interface for the heat exchange of the heat pipe stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the longitudinal cross-section structure of a heat pipe heat exchange device according to an embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of the installation structure of the heat pipe heat exchange device and the heat pipe stack according to an embodiment of the present invention;

[0020] Figure 3 It is an AA cross-sectional view of the heat pipe heat exchange device and the heat pipe after installation according to an embodiment of the present invention;

[0021] Figure 4 This is a BB cross-sectional view of the heat pipe heat exchange device and the heat pipe after installation according to an embodiment of the present invention.

[0022] In the figure: 1, heat exchanger; 10, mounting hole; 11, inner base; 110, first heat transfer channel; 12, outer base; 120, second heat transfer channel; 2, heat pipe stack; 3, heat pipe; 4, inlet distribution box; 41, working fluid inlet; 42, through hole; 5, outlet mixing box; 51, working fluid outlet. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "first" and "second" are for the purpose of clearly describing the numbering of product components and do not represent any substantial difference. The directions of "up", "down", "left" and "right" are all based on the directions shown in the accompanying drawings. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0025] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] like Figure 1The figure shows a schematic diagram of the longitudinal cross-section structure of a heat pipe heat exchange device according to an embodiment of the present invention. The heat pipe heat exchange device comprises a heat exchange body 1, which comprises a plurality of bases which are sequentially nested, and each layer of the base is provided with mounting holes 10 for inserting heat pipes, and each mounting hole 10 is provided with a heat transfer channel which penetrates the base for the circulation of the cooling medium around the mounting hole 10, and the cross-sectional area of ​​the heat transfer channel gradually decreases from the innermost base to the outermost base of the heat exchange body 1. The base may be a columnar structure such as a cylindrical structure, or may be other structures, which are not specifically limited in the embodiment of the present invention. When the base is a columnar structure, the axis of the mounting hole 10 is parallel to the central axis of the base. The heat pipe exchanges heat with the cooling medium through the base.

[0027] The arrangement of the mounting holes 10 is the same as the arrangement of the heat pipes on the corresponding heat pipe stack 2. For example, a conventional heat pipe stack is formed by alternately inserting heat pipes and fuel rods into the holes of a "honeycomb briquettes" structure, and the mounting holes 10 and the heat transfer channels are also arranged in a similar manner to the holes of the "honeycomb briquettes".

[0028] like Figure 2 The figure shows a schematic diagram of the installation structure of the heat pipe heat exchange device and the heat pipe stack according to an embodiment of the present invention. When in use, the heat pipe 3 is first inserted into the installation hole 10 and tightly combined with the installation hole 10, so that the heat of the heat pipe 3 can be transferred to the substrate. The heat pipe 3 takes out the heat from the heat pipe stack 2 and transfers the heat to each layer of the substrate by heat conduction. The cooling medium flows into the heat transfer channel from one end close to the heat pipe stack 2, absorbs the heat of the substrate when flowing through the heat transfer channel, and flows out from the other end, thereby realizing heat exchange between the heat pipe 3 and the cooling medium.

[0029] Due to the problem of uneven radial power distribution in the heat pipe stack 2, the temperature of the heat pipe 3 on the heat pipe stack 2 is distributed in a cosine curve, which causes the temperature of the heat exchanger 1 from the innermost substrate to the outermost substrate to be distributed in a corresponding curve. In the embodiment of the present invention, the cross-sectional area of ​​the heat transfer channel gradually decreases from the innermost substrate to the outermost substrate, and a larger heat exchange area, stronger heat exchange capacity and smaller flow resistance are obtained through a large diameter, and a larger flow rate is obtained through a small diameter, thereby improving the heat transfer coefficient. The flow rate and cooling load of the cooling medium in the heat exchanger 1 gradually decrease from the innermost substrate to the outermost substrate in a gradient manner, that is, the cooling medium with a large flow rate in the middle takes away more heat load, and the cooling medium with a small flow rate at the edge takes away a small amount of heat load, so that the heat exchanger 1 tends to have a more uniform temperature distribution from the innermost substrate to the outermost substrate, so that each layer of the substrate is subjected to a more uniform thermal stress, avoiding stress damage caused by uneven expansion of the heat exchanger 1, and improving the safety and reliability of the heat exchange device.

[0030] The heat pipe heat exchange device provided in the embodiment of the present invention, on the one hand, provides mounting holes 10 for mounting heat pipes 3 and heat transfer channels for cooling medium to flow in each layer of the substrate of the heat exchange body 1, so that the cooling medium flows only in the special heat transfer channel without direct contact with the heat pipe, and exchanges heat with the heat pipe 3 through the substrate. Compared with the traditional heat pipe heat exchanger, the vibration and corrosion of the heat pipe 3 caused by the direct scouring of the heat pipe 3 by the cooling medium are avoided; on the other hand, the problem of uneven temperature distribution of the heat exchange body 1 is improved through the heat transfer channel with a gradually decreasing cross-sectional area from the innermost substrate to the outermost substrate, and stress damage of the heat exchange device caused by uneven thermal stress is avoided, thereby providing an effective and safe heat exchange interface for the heat exchange of the heat pipe stack 2.

[0031] The cross-sectional area of ​​the heat transfer channel in the same substrate gradually decreases in the direction extending from the center to the outside, so that the heat exchange body 1 presents a more uniform temperature distribution in the direction extending from the center to the outside. For example, if the substrate is a cylindrical structure, the cross-sectional area of ​​the heat transfer channel inside it gradually decreases from the center to the outside in the radial direction of the substrate.

[0032] In the embodiment of the present invention, in order to further make the temperature of each layer of the substrate in the heat exchanger 1 uniform, the distribution density of the heat transfer channel in the heat exchanger 1 can also be gradually reduced from the innermost layer of the substrate to the outermost layer of the substrate, so that the substrate with a relatively high temperature has a relatively large heat exchange area, and the heat of the substrate with a relatively high temperature can be more effectively transferred to the cooling medium, so that the overall temperature distribution of the heat exchanger 1 is uniform.

[0033] like Figure 3 The figure shows the AA cross-sectional view of the heat pipe heat exchange device and the heat pipe after installation in the embodiment of the present invention. In the embodiment of the present invention, six heat transfer channels are distributed around each mounting hole 10. Of course, the number of heat transfer channels around the mounting hole 10 can be increased or decreased according to actual needs, and the embodiment of the present invention does not make specific limitations.

[0034] like Figure 1 As shown, the mounting hole 10 in the embodiment of the present invention is a blind hole, so that the heat pipe 3 does not contact the cooling medium outside the substrate after being installed in the mounting hole 10, thereby preventing the alkali metal-containing medium in the heat pipe 3 from leaking into the cooling medium, causing the cooling medium to damage components in the power generation device such as blades when performing work subsequently.

[0035] Considering that the temperature of each layer of the substrate is different, the expansion degree of each layer of the substrate is different. In the embodiment of the present invention, from the innermost substrate to the outermost substrate, the expansion coefficient is made of a material with a gradient decrease, so that the entire heat exchanger 1 shows a relatively uniform expansion from the inside to the outside. In addition, considering that the thermal stresses borne by the substrate at different temperatures are different, the inner substrate with a higher temperature is made of a material with relatively high mechanical strength to ensure the integrity and safety of the heat exchanger 1. For the outer substrate with a lower temperature, it is preferred to use a material with high thermal conductivity.

[0036] like Figure 3 As shown, in the embodiment of the present invention, the heat exchange body 1 includes two layers of substrates, namely an inner substrate 11 and an outer substrate 12, and the outer substrate 12 is sleeved on the outer side of the inner substrate 11. The inner substrate 11 is located in the high power area of ​​the heat pipe stack 2, and the outer substrate 12 is located in the low power area of ​​the heat pipe stack 2. A first heat transfer channel 110 is provided in the inner substrate 11, and a second heat transfer channel 120 is provided in the outer substrate 12. The cross-sectional area of ​​the first heat transfer channel 110 is greater than the cross-sectional area of ​​the second heat transfer channel 120. That is, the inner matrix 11 adopts a large-diameter heat transfer channel, and a large-flow cooling medium is used to take away more heat load in the inner matrix 11. At the same time, the large-diameter heat transfer channel can increase the heat exchange area of ​​the cooling medium, improve the heat exchange capacity of the cooling medium and reduce the flow resistance of the cooling medium; the outer matrix 12 adopts a small-diameter heat transfer channel, and a relatively low-flow cooling medium is used to take away less heat load in the outer matrix 12. At the same time, the small-diameter heat transfer channel can increase the flow rate of the cooling medium and obtain a higher heat transfer coefficient.

[0037] In the embodiment of the present invention, the temperature of the inner matrix 11 is high, the temperature change of the cooling medium from the inlet to the outlet of the heat transfer channel is large, and the expansion of the inner matrix 11 is large, so a titanium alloy material with a low expansion coefficient and high mechanical strength is used to limit its expansion and ensure high reliability. The temperature of the outer matrix 12 is low, the temperature change of the cooling medium from the inlet to the outlet of the heat transfer channel is relatively small, and the expansion of the outer matrix 12 is small, so a stainless steel material with high thermal conductivity is used. Thus, a heat exchanger 1 structure with an inner matrix 11 with less expansion and higher strength and an outer matrix 12 with more expansion but higher thermal conductivity is formed, which is more conducive to the heat pipe 3 transferring heat to the matrix and the cooling medium, and avoiding stress damage caused by uneven thermal stress of the inner and outer matrixes.

[0038] In an embodiment of the present invention, the heat transfer channel in the inner matrix 11 is wavy along the flow direction of the cooling medium. The contact area between the cooling medium and the inner matrix 11 in the high temperature zone is further increased, and the heat exchange capacity of the cooling medium is improved. The heat transfer channel in the outer matrix 12 is set as a straight channel to obtain a lower flow resistance of the cooling medium. Among them, the wavy heat transfer channel is symmetrically distributed around the center of the inner matrix 11. For example, when the inner matrix 11 is cylindrical, the wavy heat transfer channel in the inner matrix 11 is symmetrical with respect to the axis center of the inner matrix 11.

[0039] In the embodiment of the present invention, Figure 1 and Figure 2 As shown, the working medium inlet 41 end of the heat exchanger 1 is installed with an inlet distribution box 4, and the working medium outlet 51 end of the heat exchanger 1 is installed with an outlet mixing box 5. The inlet distribution box 4 is provided with a working medium inlet 41 and a through hole 42. The through hole 42 is used for the heat pipe 3 to pass through and then be inserted into the installation hole 10. The outlet mixing box 5 is provided with a working medium outlet 51. The cooling working medium enters the inlet distribution box 4 from the working medium inlet 41, and then enters the heat transfer channel to exchange heat with the heat pipe 3. After passing through the heat transfer channel, it enters the outlet mixing box 5 for mixing and is discharged from the working medium outlet 51 for subsequent work. Figure 4 The figure shows the BB cross-sectional view of the heat pipe heat exchange device and the heat pipe after installation according to the embodiment of the present invention.

[0040] Among them, the inlet distribution box 4 and the outlet mixing box 5 can be welded and fixed to the end surface of the heat exchanger 1 respectively, or can be fixed to the base body by sleeve connection, such as threaded sleeve connection, and ensure that the inlet distribution box 4 and the outlet mixing box 5 are sealed and connected to the base body.

[0041] In an embodiment of the present invention, a plurality of working fluid inlets 41 may be provided on the inlet distribution box 4, and the plurality of working fluid inlets 41 are evenly distributed on the side wall of the inlet distribution box 4, so that the cooling working fluid enters the inlet distribution box 4 from multiple directions at the same time, thereby evenly entering each heat transfer channel, and the working fluid outlet 51 is provided at the center of the end cover of the outlet mixing box 5.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A heat pipe heat exchange device, characterized in that: The heat exchanger comprises a plurality of bases which are sequentially connected, each base has a mounting hole for inserting a heat pipe, and each mounting hole has a heat transfer channel which penetrates the base for cooling medium to flow around the mounting hole, and the cross-sectional area of ​​the heat transfer channel gradually decreases from the innermost base to the outermost base of the heat exchanger; The heat exchange body comprises an inner matrix and an outer matrix, wherein the outer matrix is ​​sleeved on the outer side of the inner matrix; the heat transfer channel in the outer matrix is ​​a straight channel, and the heat transfer channel in the inner matrix is ​​wavy along the flow direction of the cooling medium.

2. The heat pipe heat exchange device according to claim 1, characterized in that: The cross-sectional area of ​​the heat transfer channel in the same base body gradually decreases in a direction extending from the center to the outside.

3. The heat pipe heat exchange device according to claim 1, characterized in that: The distribution density of the heat transfer channels gradually decreases from the innermost matrix to the outermost matrix of the heat exchange body.

4. The heat pipe heat exchange device according to claim 1, characterized in that: The inner matrix is ​​made of titanium alloy, and the outer matrix is ​​made of stainless steel.

5. The heat pipe heat exchange device according to any one of claims 1 to 4, characterized in that: Six heat transfer channels are distributed around each of the mounting holes.

6. The heat pipe heat exchange device according to any one of claims 1 to 4, characterized in that: The mounting hole is a blind hole.

7. The heat pipe heat exchange device according to claim 1, characterized in that: An inlet distribution box is installed at the working medium inlet end of the heat exchanger, and an outlet mixing box is installed at the working medium outlet end of the heat exchanger. The inlet distribution box is provided with a working medium inlet and a through hole, the through hole is used for the heat pipe to pass through and then be inserted into the installation hole, and the outlet mixing box is provided with a working medium outlet.

8. The heat pipe heat exchange device according to claim 7, characterized in that: The plurality of working medium inlets are evenly distributed on the side wall of the inlet distribution box, and the working medium outlet is arranged at the center of the end cover of the outlet mixing box.

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