Stack Heat Exchanger Protrusion Design to Reduce Stress Concentration
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Solution Overview
Problem
Conventional stack type heat exchangers have insufficient pressure withstanding strength against high-pressure refrigerants, leading to breakage and refrigerant leakage due to stress concentration on protrusions and joining portions.
Innovation Solution
Incorporating protrusions with thick structure portions on the side walls adjacent to the tank space in the heat exchanger plates, which are joined through brazing materials to enhance tensile strength and distribute stress effectively, thereby improving the pressure withstanding capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If protrusions are provided in the plates to improve pressure withstanding strength, then the pressure resistance improves, but tensile stress concentrates on the side wall portion of the protrusion causing breakage
Solution Approach 1:
The patent applies local quality by providing a thick structure portion specifically at the side wall portion of the protrusion adjacent to the tank space, while other parts of the plate maintain their original thickness. This localized thickening concentrates the structural reinforcement exactly where the tensile stress concentration occurs, resolving the contradiction between needing protrusions for pressure resistance and avoiding stress concentration-induced breakage.
2Strength
If the plate thickness is increased to improve pressure resistance, then the strength improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of uniformly increasing the plate thickness throughout, the patent applies local quality by providing the thick structure portion only at the specific location of the protrusion's side wall adjacent to the tank space. This selective local thickening achieves the necessary pressure resistance without the complexity and material cost of increasing overall plate thickness.
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
The solution significantly enhances the pressure withstanding strength of the heat exchanger by distributing stress and improving tensile strength, reducing the likelihood of breakage and refrigerant leakage.
Implementation Method 1
a part of the side wall portion adjacent to the tank space is connected to the second tube portion and joined to a part of the first tube portion through a brazing material
Data Source
AI summary
A stack type heat exchanger includes a plurality of first plates and a plurality of second plates. At least one of the respective first plates and the respective second plates has a protrusion protruding from a main body of the first plate or the second plate toward a first flow path, the protrusion being located at a peripheral portion of a tank space in the first flow path. The first plate and the second plate are joined to each other through the protrusion. The protrusion has a top portion and a side wall portion. A part of the side wall portion adjacent to the tank space has a thick structure portion, an entire thickness of the thick structure portion being thick in a direction perpendicular to the stacking direction.