Subsea Heat Exchanger Pipe with Internal Thermal Element
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Solution Overview
Problem
Subsea electronic systems face inefficiencies in heat transfer due to the limited cooling performance of natural convection, requiring large heat exchanger sizes and risking galvanic corrosion, with existing solutions being cumbersome and prone to leaks.
Innovation Solution
A heat exchanging arrangement featuring a pipe with a heat exchanging element internally, where the element is shrink-fitted or secured using an expansion tool to ensure efficient thermal contact and reduce the number of pipes, using materials resistant to seawater corrosion and galvanic corrosion, and incorporating fins for enhanced heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a tube bundle heat exchanger with thick tubes is used, then the structural strength is improved, but the oil wetted surface area becomes small and heat transfer efficiency deteriorates
Solution Approach 1:
The heat exchanger is divided into multiple individual tubes instead of a single thick tube bundle. This segmentation increases the total surface area available for heat transfer while maintaining structural integrity through distributed support. Each tube can be optimized for both strength and heat transfer performance independently.
Solution Approach 2:
The invention transitions from a two-dimensional surface heat transfer approach to a three-dimensional volumetric heat transfer approach by incorporating internal fins or corrugations within the tubes. This creates additional heat transfer surfaces inside the tubes, effectively increasing the oil wetted surface area without increasing the external tube dimensions.
2Reliability
If the number of pipes is increased to improve heat transfer, then heat transfer efficiency is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Multiple heat transfer functions are merged into a single integrated tube structure. The tube combines external seawater heat transfer, internal dielectric fluid heat transfer, and internal fin surfaces into one component, eliminating the need for separate tube bundles and reducing overall system complexity.
Solution Approach 2:
The tube structure serves multiple functions simultaneously: it provides structural support, acts as a heat transfer conduit for both seawater and dielectric fluid, and incorporates internal surfaces for enhanced heat transfer. This multi-functionality reduces the number of separate components needed.
3Strength
If individual tube welding is used to assemble the heat exchanger, then structural integrity is improved, but manufacturing time increases and leakage risk increases
Solution Approach 1:
Multiple tube connections are merged into a single integrated manifold structure. Instead of welding individual tubes to multiple connection points, the design uses a unified manifold that connects all tubes in fewer welding locations, reducing both manufacturing time and leakage risk while maintaining structural integrity.
Solution Approach 2:
A manifold serves as an intermediary component that simplifies the connection between multiple tubes and the external piping system. The manifold provides standardized connection points and distributes flow evenly, reducing the complexity of individual tube connections and minimizing welding requirements.
4Reliability
If aluminum heat exchanger components are used, then heat transfer efficiency is improved, but galvanic corrosion occurs when combined with steel enclosure
Solution Approach 1:
The heat exchanger components are made from the same material (steel or stainless steel) as the enclosure, creating material homogeneity throughout the system. This eliminates the dissimilar metal contact that causes galvanic corrosion while maintaining effective heat transfer through optimized tube geometry and internal surfaces.
Solution Approach 2:
The invention uses composite or coated steel structures that combine the corrosion resistance of stainless steel with the heat transfer properties of aluminum-like surfaces. This may involve aluminum coatings on steel substrates or steel alloys that provide both structural integrity and thermal performance without galvanic corrosion issues.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances heat transfer efficiency, reduces system weight and complexity, improves reliability, and simplifies maintenance by minimizing welds and allowing easier cleaning, while avoiding galvanic corrosion.
Implementation Method 1
heat from the flowing coolant is transferred to the tubes and then to the external environment
Implementation Method 2
Due to the relatively low cooling performance of natural convection cooling
Data Source
AI summary
A heat exchanging arrangement for a subsea electronic system, the heat exchanging arrangement including: at least one pipe having an external surface; and at least one heat exchanging element arranged inside the at least one pipe and defining at least one internal passage for conducting a dielectric fluid through the at least one pipe; wherein the at least one heat exchanging element is arranged to press laterally outwards against an internal surface of the at least one pipe to establish a heat transfer bond between the at least one heat exchanging element and the at least one pipe. A subsea electronic system including the heat exchanging arrangement is also provided.