A high-pressure-resistant underwater carrier shell cooler and a cooling method

Abstract

This invention discloses a high-pressure resistant hull cooler and cooling method for an underwater vehicle, comprising a cooling core and pressing plates at both ends thereof. The cooling core includes a plurality of sequentially sealed and stacked cooling plates. The cooling plates are hollow structures designed to be fitted onto a supercritical carbon dioxide Brayton cycle system. At least one side of each cooling plate has a cooling channel arranged circumferentially along the cooling plate, forming a circulation path with the heat source of the supercritical carbon dioxide Brayton cycle system.

Description

Technical Field

[0001] This invention relates to the field of heat exchange technology, specifically to a high-pressure resistant shell cooler and cooling method for an underwater transport vehicle. Background Technology

[0002] Compared to the steam Rankine cycle, the supercritical carbon dioxide Brayton cycle boasts lower compression power consumption, a more compact structure, and higher efficiency, making it a promising candidate for development in Generation IV nuclear reactors, fossil fuel power generation, and ship propulsion systems. It has garnered widespread global attention in recent years. With ongoing exploration of the ocean, current lithium-ion battery technology is insufficient to support the long-term operation of underwater platforms. Therefore, the application of the supercritical carbon dioxide Brayton cycle to underwater platforms is an inevitable trend. The stable ocean environment provides excellent natural cooling for underwater platforms. By designing the platform's outer shell as a cooler, seawater can be eliminated, significantly reducing the space required for the propulsion system and improving safety. However, limited platform space, the enormous cooling demands of the system, and the limited usable area of ​​the cooler shell necessitate highly compact cooler equipment with high heat exchange efficiency, capable of withstanding the high pressure of deep water and the working fluid to ensure safety.

[0003] Traditional underwater platform hull steam coolers involve cutting grooves along the entire axial direction of the hull, then brazing metal plates to the cut hull. The grooves and welded plates form the cooler's flow channels. Depending on the cutting trajectory, these channels are typically straight or spiral, offering limited improvement in heat transfer capacity. The top and bottom ends of the hull serve as the inlet and outlet for the entire heat exchanger. However, this cutting method results in relatively rough flow channels, making it difficult to guarantee compactness and quality. Furthermore, the brazed flow channels have low pressure resistance, failing to meet the high parameters of supercritical carbon dioxide Brayton cycle systems, thus reducing safety. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a high-pressure resistant shell cooler and cooling method for underwater vehicles. The cooler has a compact structure and high cooling efficiency, enabling rapid cooling of underwater supercritical carbon dioxide Brayton cycle systems at the 100kW level.

[0005] This invention is achieved through the following technical solution:

[0006] A high-pressure resistant shell cooler for an underwater vehicle includes a cooling core and pressure plates pressed at both ends thereon. The cooling core includes a plurality of cooling plates that are sequentially sealed and stacked.

[0007] The cooling plate has a hollow structure and is used to be fitted onto the shell of the supercritical carbon dioxide Brayton cycle system. At least one side of the cooling plate is provided with a cooling channel, which is arranged circumferentially along the cooling plate. The cooling channel forms a circulation path with the heat source of the supercritical carbon dioxide Brayton cycle system.

[0008] Preferably, the sidewall of the cooling plate is provided with multiple cooling channels, which are evenly distributed around the circumference, and a flow divider is provided between two adjacent cooling channels.

[0009] Preferably, the connection between the flow divider and the cooling channel is rounded.

[0010] Preferably, the working fluid in the two adjacent cooling channels flows in opposite directions.

[0011] Preferably, the cooling channel has turbulence-inducing structures on both sides.

[0012] The preferred flow path of the cooling channel is a direct flow channel, a Z-shaped flow channel, or an S-shaped flow channel.

[0013] Preferably, the cross-section of the cooling channel can be rectangular, semi-circular, or elliptical.

[0014] Preferably, the cooling plate is annular, and the outlet and inlet of the cooling channel are located on the inner ring wall of the annulus.

[0015] The preferred materials for the plates are stainless steel, aluminum alloy, titanium alloy, and copper alloy.

[0016] A cooling method for a high-pressure resistant shell cooler for an underwater vehicle, wherein the working fluid of the supercritical carbon dioxide Brayton cycle system enters the cooling channels of each cooling plate through the inlet of each cooling channel, and the working fluid exchanges heat with the seawater outside the cooling plate in the cooling channel to cool down. The cooled working fluid enters the supercritical carbon dioxide Brayton cycle system through the outlet of each cooling channel and circulates.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] This invention provides a high-pressure resistant shell cooler for underwater vehicles, which uses multiple cooling plates stacked sequentially to form the entire cooling core. Multiple cooling channels are evenly distributed around the sidewalls of each cooling plate and circulate with the heat source of a supercritical carbon dioxide Brayton cycle system. The working fluid of the heat source exchanges heat with seawater radially as it passes through the cooling channels, thus utilizing seawater for cooling. No external cold source is required. Furthermore, this cooler has advantages such as high heat transfer efficiency, compact size, high temperature and high pressure resistance, and low leakage, and can meet the cooling requirements of the supercritical carbon dioxide Brayton cycle system of underwater platforms. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the cooler of the present invention;

[0020] Figure 2 for Figure 1 Enlarged view of the intercooler inlet area;

[0021] Figure 3 This is an exploded view of the cooler of the present invention;

[0022] Figure 4 This is a plan view of the cooling plate of the present invention;

[0023] Figure 5 for Figure 4 Enlarged view of the cooling channels in the cooling plate.

[0024] In the diagram: 1-Upper pressure plate, 2-Cooling plate, 3-Flow channel inlet, 4-Lower pressure plate, 5-Flow channel outlet, 6-Outer pressure-bearing layer, 7-Cooling flow channel, 8-Inner pressure-bearing layer, 9-Turbulence structure, 10-Flow divider, 11-Flow guiding area. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings. These descriptions are intended to explain the invention and not to limit it.

[0026] See Figure 1-5 A high-pressure resistant shell cooler for an underwater vehicle includes a cooling core and pressure plates pressed at both ends thereon. The cooling core includes a plurality of cooling plates that are sequentially sealed and stacked.

[0027] The cooling plate 2 has a hollow structure and is used to be fitted onto the supercritical carbon dioxide Brayton cycle system. At least one side of the cooling plate is provided with a cooling channel 7, which is arranged circumferentially along the cooling plate. The cooling channel forms a circulation path with the heat source of the supercritical carbon dioxide Brayton cycle system.

[0028] Cooling plate 2 is a ring-shaped plate, the inner diameter of which matches the outer diameter of the shell of the supercritical carbon dioxide Brayton cycle system, so that the cooling core can be fitted onto the shell and fixed. Cooling channel 7 is a notched ring structure, and is concentrically arranged with cooling plate 2. The two sides of the ring notch form channel inlet 3 and channel outlet 5. Channel inlet 3 and channel outlet 5 are respectively connected to the outlet and inlet of the shell of the supercritical carbon dioxide Brayton cycle system. During operation, the working fluid of the supercritical carbon dioxide Brayton cycle system enters the cooling channel 7 through channel inlet 3. After the working fluid exchanges heat with the seawater outside the cooling core and is cooled down, it enters the supercritical carbon dioxide Brayton cycle system through channel outlet 5 and circulates, thereby realizing the cooling of the supercritical carbon dioxide Brayton cycle system.

[0029] The cooling channels 7 are multiple, each being an arc-shaped structure of a certain length, located in the middle of the cooling plate. These channels are evenly distributed along the central circumference of the cooling plate. A flow-dividing baffle 10 is installed between adjacent cooling channels 7. The connection between the flow-dividing baffle 10 and the channel is rounded to form a guiding zone, preventing dead zones and reducing the flow resistance of the working fluid. The cooling channels 7 form an outer pressure-bearing layer 6 with the outer side of the cooling plate, and an inner pressure-bearing layer 8 with the inner side of the cooling plate. By using flow-dividing baffles, the circumference of the heat exchange surface is divided into multiple heat exchange zones, reducing the high Reynolds number caused by the large mass flow rate of a single channel. Simultaneously, the shortened channel length helps reduce pressure drop, indirectly improving the system's operating efficiency.

[0030] The cooling channel cross-section can be rectangular, semi-circular, or elliptical. The flow path of the cooling channel can be a direct flow channel, a Z-shaped flow channel, or an S-shaped flow channel, which increases the optimization space for heat transfer and flow resistance and can meet the design requirements of multiple heat exchange conditions. The working fluid of two adjacent cooling channels flows in opposite directions and enters the supercritical carbon dioxide Brayton cycle system after merging. The cooling channels are etched by PCHE or mechanical machining, which results in higher precision in the cross-sectional shape of the channels and controllable roughness, making the flow rate and heat transfer of each channel more uniform.

[0031] In this embodiment, two semi-circular cooling channels 7 are provided on one side of the cooling plate, and the two cooling channels are symmetrically arranged radially. The thickness of the plate is 1-4 mm. The cooling plate 2 is made of stainless steel, aluminum alloy, copper alloy or titanium alloy, with high welding quality and able to withstand seawater and carbon dioxide environments.

[0032] The two clamping plates are circular ring structures, namely the upper clamping plate 1 and the lower clamping plate 4. The upper clamping plate 1 and the lower clamping plate 4 are located on both sides of the cooling core. The two adjacent cooling plates are processed by vacuum diffusion welding. The whole machine can achieve 95% of the strength of the base material and can withstand the high pressure of deep water and working fluid. The flow channel has small deformation during welding and low working fluid leakage.

[0033] Example 1

[0034] A high-pressure resistant shell cooler for an underwater vehicle includes multiple stacked cooling plates 2 and clamping plates at both ends. Each cooling plate 2 has two semi-circular cooling channels on the same side. All cooling plates are annular and arranged in parallel. They are solid-phase connected by vacuum diffusion welding to form a ring-shaped cooling core. The cooling channels are processed by PCHE, resulting in high precision and high processing efficiency. All cooling plates are formed into a ring shape by vacuum diffusion welding, resulting in a cooling core with small deformation, high strength, and low leakage.

[0035] The cooler is integrally mounted on the shell of the supercritical carbon dioxide Brayton cycle system of the underwater platform. The inlet and outlet of the cooling channel 7 are connected to the outlet and inlet of the shell, respectively, thus connecting the cooler to the entire underwater platform. The core has upper clamping plates 1 and lower clamping plates 4 at both ends, which have a certain thickness to ensure the strength of the entire core and facilitate welding of the shell cooler to other shell sections.

[0036] refer to Figure 3 The cooler plates of this invention are annular with a thickness of 1-4 mm. The outer pressure-bearing layer 6 of the cooler plates isolates the seawater outside the cooler from the supercritical carbon dioxide inside the cooler. Simultaneously, the outer pressure-bearing layer 6 transfers heat to the seawater to achieve cooling. The innermost side of the cooler plates is an inner pressure-bearing layer 8, ensuring the strength of the core. The two cooling fluids are separated by a flow divider 10, dividing the circumference of the heat exchange area into two halves. The flow rate of the working fluid in each channel is reduced by half, reducing pressure loss. Simultaneously, the channel length is reduced, further lowering flow resistance, allowing for more efficient utilization of the heat exchange area of ​​each plate. To enhance the heat transfer coefficient on the carbon dioxide side, a Z-shaped structure 9 is provided on the inner wall of the channel, with an angle of 5-45°, arranged periodically according to the central angle of the plate's annulus. After the heat exchange of the working fluid is completed, the working fluid flows to the cooler outlet 5. Through the guiding effect of the flow divider, it flows out from the inside of the annular cooling core and enters the supercritical carbon dioxide Brayton cycle system. The flow divider and the flow guiding area of ​​the flow channel are designed with rounded corners of 0.5 to 5 mm to prevent dead zones from being generated during the flow of the working fluid and reduce resistance loss.

[0037] The cooling method for a high-pressure resistant shell cooler for an underwater transport vehicle provided by the present invention is described in detail below, including the following steps:

[0038] Step 1: Install the shell cooler on the shell of the supercritical carbon dioxide Brayton cycle system of the underwater transport vehicle, and connect the cooling channel inlet of each cooling plate to the working fluid outlet of the shell, and connect the cooling channel outlet to the working fluid inlet of the shell.

[0039] Step 2: The supercritical carbon dioxide working fluid flows into the cooler from the inlet on the inner wall of the annular cooler core, is split once by several cooling plates, and then flows evenly into two cooling channels through the splitting baffles of each cooling plate.

[0040] Step 3: Supercritical carbon dioxide flows in opposite directions along the two cooling channels of each cooling plate. During the flow of supercritical carbon dioxide working fluid, the seawater outside the cooler undergoes convective heat exchange through the outer pressure layer. After cooling, it enters the supercritical carbon dioxide Brayton cycle system through the outlet of the cooling plate and circulates back and forth.

[0041] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A high-pressure resistant shell cooler for underwater transport vehicles, characterized in that, It includes a cooling core and pressure plates pressed at both ends thereon. The cooling core includes a plurality of cooling plates (2) that are sequentially sealed and stacked. The cooling plate (2) is a hollow structure and is used to be fitted onto the shell of the supercritical carbon dioxide Brayton cycle system. At least one side of the cooling plate is provided with a cooling channel (7). The cooling channel is arranged circumferentially along the cooling plate and forms a circulation path with the heat source of the supercritical carbon dioxide Brayton cycle system. The cooling plate (2) has multiple cooling channels on its side wall. The multiple cooling channels are evenly distributed around the circumference, and a flow divider (10) is provided between two adjacent cooling channels.

2. The high-pressure resistant shell cooler for an underwater transport vehicle according to claim 1, characterized in that, The connection between the flow divider (10) and the cooling channel is rounded.

3. The high-pressure resistant shell cooler for an underwater transport vehicle according to claim 1, characterized in that, The working fluid in the two adjacent cooling channels flows in opposite directions.

4. A high-pressure resistant shell cooler for an underwater transport vehicle according to claim 1, characterized in that, The cooling channel has turbulence structures on both sides.

5. A high-pressure resistant shell cooler for an underwater transport vehicle according to claim 4, characterized in that, The flow path of the cooling channel is a direct flow channel, a Z-shaped flow channel, or an S-shaped flow channel.

6. A high-pressure resistant shell cooler for an underwater transport vehicle according to claim 1, characterized in that, The cross-section of the cooling channel is rectangular, semi-circular, or elliptical.

7. A high-pressure resistant shell cooler for underwater transport vehicles according to claim 1, characterized in that, The cooling plate is annular, and the outlet and inlet of the cooling channel are located on the inner ring wall of the annulus.

8. A high-pressure resistant shell cooler for an underwater transport vehicle according to claim 1, characterized in that, The plates are made of stainless steel, aluminum alloy, titanium alloy, and copper alloy.

9. A cooling method for a high-pressure resistant shell cooler for an underwater transport vehicle according to any one of claims 1-8, characterized in that, The working fluid of the supercritical carbon dioxide Brayton cycle system enters the cooling channels of each cooling plate through the inlet of each cooling channel. The working fluid exchanges heat with the seawater outside the cooling plate in the cooling channels to cool down. The cooled working fluid enters the supercritical carbon dioxide Brayton cycle system through the outlet of each cooling channel and circulates.

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