Stepped-Port Heat Exchanger Case for Higher Rigidity
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Solution Overview
Problem
Heat exchangers with rectangular casings face challenges in maintaining rigidity due to the formation of inlet and outlet ports in the side wall, which can lead to deformation during manufacturing or use, compromising space utilization efficiency.
Innovation Solution
A heat exchanger design featuring a stacked body with alternating fluid passages, a tubular rectangular case, and a base plate, incorporating stepped parts around inflow and outflow ports to enhance rigidity, and enlarged internal spaces to improve flow passage and reduce stress concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If inlet and outlet ports are formed in the side wall part of a rectangular-shaped case, then space utilization efficiency is improved and the heat exchanger can be flattened, but the rigidity of the case decreases and deformation may occur
Solution Approach 1:
The case is designed with non-uniform wall thickness: the flat surface part has a first thickness while the stepped part has a second thickness greater than the first. This local variation in thickness provides structural reinforcement at the port location without increasing the overall size of the case, thereby maintaining space utilization efficiency while improving rigidity locally where stress concentration would occur
Solution Approach 2:
The design transitions from a two-dimensional flat wall to a three-dimensional stepped structure by adding a thickness dimension at the stepped part. This dimensional change creates a reinforced zone that resists deformation while maintaining the compact rectangular footprint of the case
2Strength
If pipes are attached to the case by brazing with larger diameter to lower flow path resistance, then joint strength increases, but stress concentration at the attachment base increases and may cause deformation
Solution Approach 1:
The stepped part provides localized structural reinforcement at the pipe attachment location. The increased thickness at this specific zone distributes the stress from larger diameter pipes over a greater area, preventing stress concentration and deformation while allowing the use of larger pipes for reduced flow resistance
Solution Approach 2:
The stepped structure acts as a pre-designed stress distribution zone that cushions the concentration of forces at the pipe attachment point. By anticipating the stress concentration problem, the design incorporates the thicker stepped part in advance to prevent deformation before it occurs
Data Source
AI summary
A heat exchanger is disclosed. The heat exchanger includes a stacked body including multiple plates stacked to form a flow passage for a first fluid and a flow passage for a second fluid alternately in the stacking direction. A bottomed tubular and rectangular parallelepiped shaped case houses the stacked body and is open on one side in the stacking direction. A base plate is provided on an open side of the case. The case has an inflow port and an outflow port through which the first fluid passes in a flat surface part of a side wall part that extends in the stacking direction, and a stepped part formed around the inflow port or the outflow port.