Double Pipe Heat Exchanger Groove Design
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Solution Overview
Problem
Conventional double pipe heat exchangers face issues with reduced heat exchange efficiency due to incomplete fluid flow rates and difficulties in accurate coupling and airtight sealing, particularly caused by the protrusion of helical grooves and challenges in welding processes.
Innovation Solution
The design incorporates spiral-shaped first grooves and U-shaped second grooves on the inner pipe's outer surface, along with temporary fastening portions and pressing grooves in the outer pipe to enhance fluid flow rates, ensure accurate alignment, and achieve airtight sealing through rolling processing and welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a helical groove is formed at the outer circumferential surface of the inner pipe to enable heat exchange, then heat exchange operation occurs between fluids at different temperatures, but the protrusion between grooves contacts the outer pipe inner surface reducing flow rate and heat exchange area
Solution Approach 1:
The single continuous helical groove is segmented into multiple discrete grooves arranged in a spiral pattern. This segmentation prevents the protrusion between grooves from contacting the outer pipe, maintaining flow rate while preserving heat exchange surface area. The grooves are distributed around the circumference rather than forming one continuous helix.
Solution Approach 2:
The groove arrangement transitions from a two-dimensional helical path to a three-dimensional spiral distribution around the pipe circumference. By adding the circumferential dimension to the groove layout, the design maintains adequate spacing between groove protrusions and the outer pipe while preserving heat exchange effectiveness.
2Ease of manufacture
If the inner pipe is inserted into the outer pipe for coupling, then assembly is simplified, but movement occurs during additional processes preventing accurate coupling at the intended location
Solution Approach 1:
A temporary fastening portion is formed on the outer pipe before the inner pipe is inserted. This preliminary structure prevents movement of the inner pipe during subsequent welding or sealing processes, ensuring accurate coupling location while maintaining the simplicity of the insertion-based assembly approach.
Solution Approach 2:
The temporary fastening portion acts as an intermediary element between the inner and outer pipes during the assembly process. It provides temporary constraint to prevent movement, allowing precise positioning, and can be removed or integrated afterward, enabling both easy assembly and precise coupling.
3Reliability
If welding process is used to couple the inner pipe to the outer pipe, then airtightness is attempted, but sufficient airtightness cannot be maintained at the coupling portion
Solution Approach 1:
The welding process is replaced with a mechanical pressing groove mechanism. The pressing groove is formed by rolling or pressing the outer pipe surface against the inner pipe, creating a mechanical interference fit that provides both coupling and airtight sealing without the complexity and reliability issues of welding in tight spaces.
Solution Approach 2:
The coupling method transitions from thermal joining (welding) to mechanical joining (pressing/rolling). By changing the physical parameter of the joining process from temperature-based to force-based, the solution achieves reliable airtightness while simplifying the manufacturing process for curved surface coupling.
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 increases the heat exchange area, improves fluid flow rates, ensures accurate coupling, and secures sufficient airtightness between the inner and outer pipes, thereby enhancing heat exchange efficiency and maintaining mechanical sealing.
Implementation Method 1
a plurality of first grooves formed in a spiral shape in a lengthwise direction at an outer circumferential surface of the inner pipe to enable the second flow channel to have at least partially a spiral shape
Implementation Method 2
forming a pressing groove at each reduced pipe portion of the outer pipe into which the inner pipe is inserted and coupling the inner pipe to the pressing groove
Implementation Method 3
enables a heat exchange between a fluid flowing in an outer pipe and a fluid flowing in an inner pipe
Implementation Method 4
a heat exchange between a high temperature fluid and a low temperature fluid
Data Source
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AI summary
A double pipe heat exchanger and a method of manufacturing the same are provided. The double pipe heat exchanger including an outer pipe and an inner pipe having a first flow channel therein and having an outer diameter smaller than an inner diameter of the outer pipe and inserted into the outer pipe to form a second flow channel between the inner pipe and the outer pipe includes a plurality of first grooves formed in a spiral shape in a lengthwise direction at an outer circumferential surface of the inner pipe to enable the second flow channel to have at least partially a spiral shape and at least one second groove each formed in a portion between two first grooves adjacent to an outer circumferential surface of the inner pipe and formed along the first groove.