Heat transfer fin
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Solution Overview
Problem
Conventional heat exchangers with staggered heat transfer tubes experience inefficient heating due to repeated temperature rise and fall of the heat medium caused by alternating combustion exhaust gas and air flow, leading to suboptimal heat transfer.
Innovation Solution
A heat transfer fin design with heat-transfer-tube insertion holes aligned in a single stage, featuring downstream cut portions recessed toward the upstream side, downstream flanges, and alternately protruding first and second cut-and-raised pieces to promote turbulent flow and extended contact time with combustion exhaust gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heat transfer tubes are arranged in staggered stages in the direction of gas flow, then heat transfer efficiency is improved, but temperature fluctuations of the heat medium occur due to alternating combustion exhaust gas and air flow
Solution Approach 1:
The heat transfer tubes are segmented into multiple stages arranged in the gas flow direction, with each stage processing the heat medium sequentially. This segmentation allows the heat medium to progressively absorb heat while minimizing temperature fluctuations through the staged configuration.
Solution Approach 2:
Different regions of the heat transfer fin are given different functions: the upstream region handles combustion exhaust gas heating, while the downstream region handles combustion air heating. This local differentiation prevents mixed temperature effects on the heat medium.
2Duration of action of moving object
If downstream cut portions are recessed toward the upstream side, then contact time with combustion exhaust gas is extended, but device complexity increases
Solution Approach 1:
The downstream cut portions are formed with curved or recessed profiles instead of straight edges, creating a tapered configuration that naturally extends the gas flow path and contact time without requiring additional mechanical components.
Solution Approach 2:
The cut portions extend in the thickness direction of the heat transfer fin, creating a three-dimensional recessed structure that increases contact time through the fin's depth rather than requiring longer lateral paths.
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 design enhances heat transfer efficiency by reducing temperature fluctuations and promoting turbulent flow, ensuring consistent heating of the heat medium despite partial combustion conditions.
Implementation Method 1
combustion exhaust gas generated from a burner flows through a heat exchanger
Implementation Method 2
heat in the combustion exhaust gas to efficiently transfer to the heat medium flowing in the heat transfer tubes
Implementation Method 3
downstream cut portions recessed toward the upstream side, downstream flanges, and alternately protruding first and second cut-and-raised pieces to promote turbulent flow
Data Source
AI summary
A heat transfer fin (1) includes a plurality of heat-transfer-tube insertion holes (10) aligned in a single stage, a downstream cut portion (3) formed so as to be recessed toward an upstream side of a gas flow passage of combustion exhaust gas, a downstream flange (13) formed on a peripheral edge of the downstream cut portion (3) so as to protrude from one surface of the heat transfer fin (1), and a plurality of first protruding pieces (4a) (4b) (4c) formed between the heat-transfer-tube insertion hole (10) and the downstream flange (13) so as to protrude alternately from both surfaces of the heat transfer fin (1).