Loop heat pipe reactor heat exchange system with ejector

Abstract

The invention discloses a loop heat pipe reactor heat exchange system with an ejector, and belongs to the technical field of nuclear energy system heat exchange. The system comprises a reactor, a heat exchanger, an ejector, a steam inlet valve, a liquid inlet valve and a liquid return pipe, a saturated liquid outlet of the reactor is connected with a liquid inlet of the ejector through the heat exchanger and the liquid inlet valve, the heat exchanger is connected with the reactor through a loop heat pipe, and heat generated by the reactor is transmitted; a saturated steam outlet of the reactor is connected with a steam inlet of the ejector through a loop heat pipe and a steam inlet valve; an outlet of the ejector is connected with a reactor inlet through a liquid return pipe; efficient heat transfer without pump driving is achieved through phase change circulation of a working medium. The ejector adopts a Laval nozzle to accelerate a high-temperature working medium, a low-pressure area is formed in a mixing chamber to drive a low-temperature working medium to be sucked, the pressure of the working medium is increased through a diffuser pipe, and circulation stability is maintained. The system abandons a traditional mechanical pump, drives circulation through a heat pipe, and has the advantages of simple structure, reliable operation, flexible arrangement and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear energy system heat exchange, and in particular relates to a loop heat pipe reactor heat exchange system with an ejector. Background Art

[0002] In the field of nuclear energy technology, the efficiency and reliability of heat exchange systems are directly related to reactor safety and economic viability. While traditional nuclear reactor heat exchange systems have achieved commercial application, their technical bottlenecks are becoming increasingly prominent in miniaturized, modular, and high-safety scenarios. Traditional systems require multiple main circulation pumps to drive the working fluid. For example, the AP1000 pressurized water reactor design typically includes more than three main pumps, whose total power consumption accounts for 10%-15% of the total plant auxiliary system energy consumption. While these systems have achieved commercial application, they face significant bottlenecks in miniaturized, modular, and high-safety scenarios. The need for multiple main pumps to maintain working fluid flow complicates the system and increases its size. For example, the AP1000 main pumps, with a diameter exceeding three meters and a weight of hundreds of tons, make them difficult to accommodate within the space constraints of small nuclear reactors.

[0003] At the same time, vibration and noise issues from mechanical pumps affect system stability, and long-term operation can easily lead to faults such as bearing wear and seal leakage, increasing maintenance frequency and costs. In industrial circulation systems, mechanical pumps serve as core drive components. The vibrations they generate during operation are transmitted to the entire system framework through rigid connection structures, causing resonance. This mechanical degradation reduces the system's thermal efficiency. Furthermore, noise pollution from the pump body can have a serious impact on the operating environment, requiring the addition of silencers and vibration isolation systems, increasing maintenance costs throughout the entire lifecycle. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, the present invention aims to provide a loop heat pipe reactor heat exchange system with an ejector, aiming to address the technical challenges of efficient and safe heat exchange in small nuclear reactors. By combining an ejector with a loop heat pipe, the present invention achieves pumpless working fluid circulation and heat transfer. The system controls working fluid flow and heat removal via liquid and steam inlet valves, ensuring stable operation. The present invention is particularly suitable for small nuclear reactor scenarios, offering advantages such as simple structure, reliable operation, and flexible layout.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A loop heat pipe reactor heat exchange system with an ejector comprises an ejector 1, a heat exchanger 2, a reactor 3, a steam inlet valve 4, a liquid inlet valve 5 and a liquid return pipe 6; the saturated liquid outlet of the reactor 3 is connected to the liquid inlet of the ejector 1 via the heat exchanger 2 and the liquid inlet valve 5, the heat exchanger 2 and the reactor 3 are connected via a loop heat pipe to transfer heat generated by the reactor; the saturated steam outlet of the reactor 3 is connected to the steam inlet of the ejector 1 via the loop heat pipe and the steam inlet valve 4; the outlet of the ejector 1 is connected to the inlet of the reactor 3 via the liquid return pipe 6; the saturated liquid working medium in the reactor 3 is cooled by the heat exchanger 2 and outputs heat energy to the outside, then enters the ejector 1 via the liquid inlet valve 5; the saturated steam working medium in the reactor 3 enters the ejector 1 via the steam inlet valve 4, ejecting the liquid from the liquid inlet valve 5, and the two are mixed and returned to the reactor via the liquid return pipe 6.

[0007] The ejector 1 includes a nozzle 11, a mixing chamber 12, a throat 13 and a diffuser 14 connected in sequence, wherein the nozzle 11 adopts a Laval nozzle structure; the ejector 1 uses the dynamic characteristics of the working fluid to achieve self-driven circulation without the need for an external power source; the high-temperature and high-pressure gaseous working fluid from the reactor 3 enters the ejector 1 through the steam inlet valve 4 and is accelerated by the nozzle 11, forming a low-pressure zone in the mixing chamber 12; this low-pressure zone absorbs the low-temperature and low-pressure liquid working fluid that enters the ejector 1 through the liquid inlet valve 5 through the pressure difference; the two working fluids in different states are fully mixed in the mixing chamber 12 to promote the exchange of momentum and heat energy; the mixed working fluid then enters the diffuser 13, the flow rate gradually decreases and the pressure gradually increases, and finally returns to the reactor 3 through the return pipe 6 in a high-temperature and high-pressure state, completing the entire circulation process.

[0008] The working medium in the reactor 3 is liquid metal.

[0009] The loop heat pipe is made of stainless steel or copper alloy.

[0010] The working fluid temperature in the system ranges from 400°C to 800°C, and the working pressure ranges from 0.5MPa to 3MPa.

[0011] In order to break through the bottleneck of circulation stagnation of traditional heat pipes under thermal load fluctuation scenarios, the present invention introduces an ejector to construct a power-energy integrated circuit. The ejector drives the fluid circulation through the Venturi effect: at the power level, the Laval nozzle accelerates the high-temperature and high-pressure working fluid to supersonic speed, forming a low-pressure area in the mixing chamber, and drives the suction of low-temperature working fluid through the pressure gradient to increase the pressure of the mixed flow; at the thermodynamic level, the diffuser reduces the irreversible loss of the system and improves the overall thermal efficiency. The loop heat pipe realizes pump-free driven circulation through the phase change of the working fluid. Its core advantages are reflected in passive safety characteristics and efficient heat transfer capabilities. By relying on pressure difference to drive the working fluid, the risk of system failure caused by pump group failure is completely avoided. Compared with the existing technology, the present invention has the following advantages:

[0012] (1) Simplified structure: The system consists of an ejector, heat exchanger, reactor, steam inlet valve, liquid inlet valve, and liquid return pipe, eliminating the traditional mechanical pump structure. This design not only reduces system complexity and manufacturing costs, but also avoids potential failures caused by wear of moving parts.

[0013] (2) Operational reliability: Based on the principle of self-driven circulation, the ejector directly uses the pressure potential energy generated by the phase change of the reactor working fluid to realize the working fluid circulation, completely eliminating the dependence on external power, effectively preventing the occurrence of circulation interruption due to power equipment failure, and improving the system operation reliability.

[0014] (3) Flexible layout: The connection between the various components of the system is achieved through loop heat pipes, which have low processing difficulty and can be flexibly arranged according to the spatial layout and actual needs of the small nuclear energy system, with strong adaptability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a system diagram of the present invention.

[0016] Figure 2 Schematic diagram of the injector. DETAILED DESCRIPTION

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 As shown, the present invention's loop heat pipe reactor heat exchange system with an ejector achieves heat transfer through a phase-change cycle of the working fluid. During system operation, the circulating working fluid follows the following path and undergoes phase changes: Starting from reactor 3, a portion of the working fluid flows sequentially through heat exchanger 2, liquid inlet valve 5, and then into ejector 1. Another portion, saturated steam, enters ejector 1 through steam inlet valve 4, ejecting liquid from liquid inlet valve 5. The two components then mix and return to reactor 3 through liquid return pipe 6.

[0019] In this invention, the reactor 3 provides heat, and the heat exchanger 2 releases it, forming an energy loop. The ejector 1 drives the working fluid to circulate, forming a power loop. Heat is transferred within the loop heat pipe, with the ejector 1 maintaining the continuity of heat transfer, forming a closed energy circulation loop.

[0020] Reactor 3 acts as a heat source, providing stable heat to the system and evaporating the working fluid. The working fluid can be liquid metal, which has high thermal conductivity and good chemical stability. The loop heat pipe can be made of stainless steel or copper alloy, which has good thermal conductivity and corrosion resistance and good compatibility with the working fluid. The loop heat pipe connects reactor 3, heat exchanger 2, and ejector 1 in sequence, forming a closed loop and providing a channel for the working fluid to circulate. The system operating conditions are: the working fluid temperature range is 400°C to 800°C, the operating pressure range is 0.5MPa to 3MPa, and the working fluid charge is accurately calculated based on the system heat load and the loop heat pipe volume.

[0021] like Figure 2 As shown, the ejector 1 is located within the loop heat pipe's circulation circuit and comprises a nozzle 11, a mixing chamber 12, a throat 13, and a diffuser 14. The nozzle 11 utilizes a Laval nozzle structure. The ejector 1 utilizes the dynamic characteristics of the working fluid to achieve a self-driven circulation, eliminating the need for an external power source. The specific operating principle is as follows: High-temperature, high-pressure gaseous working fluid from the reactor 3 enters the ejector 1 through the steam inlet valve 4 and is accelerated by the nozzle 11, forming a low-pressure zone within the mixing chamber 12. This low-pressure zone, through a pressure differential, draws in low-temperature, low-pressure liquid working fluid that enters the ejector 1 through the liquid inlet valve 5. The two working fluids in different states mix thoroughly within the mixing chamber 12, promoting efficient exchange of momentum and thermal energy. The mixed working fluid then enters the diffuser 14, where the flow rate gradually decreases and the pressure gradually increases. It ultimately returns to the reactor 3 through the return pipe 6 at a high temperature and high pressure, completing the entire circulation process. The ejector 1 accelerates the gaseous working fluid to supersonic speeds through its convergent-then-divergent geometry. During this process, the static pressure energy of the working fluid is converted into dynamic pressure energy, which increases significantly, providing a pressure gradient for the subsequent injection process. The supersonic working fluid forms a negative pressure zone in the mixing chamber 12, and the low-temperature, low-pressure two-phase working fluid from the heat exchanger 2 is injected through the pressure difference.

Claims

1. A loop heat pipe reactor heat exchange system with an ejector, characterized in that: The invention comprises an ejector (1), a heat exchanger (2), a reactor (3), a steam inlet valve (4), a liquid inlet valve (5) and a liquid return pipe (6); the saturated liquid outlet of the reactor (3) is connected to the liquid inlet of the ejector (1) through the heat exchanger (2) and the liquid inlet valve (5); the heat exchanger (2) and the reactor (3) are connected through a loop heat pipe to transfer heat generated by the reactor; the saturated steam outlet of the reactor (3) is connected to the steam inlet of the ejector (1) through the loop heat pipe and the steam inlet valve (4); the outlet of the ejector (1) is connected to the inlet of the reactor (3) through the liquid return pipe (6); The saturated liquid working medium in the reactor (3) is cooled by the heat exchanger (2) and outputs heat energy to the outside before entering the ejector (1) through the liquid inlet valve (5); the saturated steam working medium in the reactor (3) enters the ejector (1) through the steam inlet valve (4), ejects the liquid from the liquid inlet valve (5), and the two are mixed and returned to the reactor through the liquid return pipe (6).

2. The loop heat pipe reactor heat exchange system with an ejector according to claim 1, characterized in that: The ejector (1) comprises a nozzle (11), a mixing chamber (12), a throat (13) and a diffuser (14) connected in sequence, wherein the nozzle (11) adopts a Laval nozzle structure; the ejector (1) realizes a self-driven cycle by utilizing the dynamic characteristics of the working medium, without the need for an external power source; the high-temperature and high-pressure gaseous working medium from the reactor (3) enters the ejector (1) through the steam inlet valve (4), and is accelerated by the nozzle (11), forming a low-pressure zone in the mixing chamber (12); the low-pressure zone absorbs the low-temperature and low-pressure liquid working medium entering the ejector (1) through the liquid inlet valve (5) through the pressure difference; the two working mediums in different states are fully mixed in the mixing chamber (12), promoting the exchange of momentum and heat energy; the mixed working medium then enters the diffuser (14), the flow rate gradually decreases and the pressure gradually increases, and finally returns to the reactor (3) through the return pipe (6) in a high-temperature and high-pressure state, completing the entire cycle process.

3. The loop heat pipe reactor heat exchange system with an ejector according to claim 1, characterized in that: The working medium in the reactor (3) is liquid metal.

4. The loop heat pipe reactor heat exchange system with an ejector according to claim 1, characterized in that: The loop heat pipe is made of stainless steel or copper alloy.

5. The loop heat pipe reactor heat exchange system with an ejector according to claim 1, characterized in that: The working fluid temperature in the system ranges from 400°C to 800°C, and the working pressure ranges from 0.5MPa to 3MPa.

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