Heat Exchanger With Diffuser Channels for High-Velocity Cooling
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Solution Overview
Problem
Conventional heat exchangers for high-velocity fluids face challenges in integration due to large frontal surfaces, leading to increased aircraft displacement and pressure resistance, and require optimization for smaller space and improved heat transfer.
Innovation Solution
A heat exchanger design with a diffuser region in low-temperature channels and common walls with high-temperature channels for heat transfer, allowing for reduced installation space and efficient heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heat exchangers are arranged outside the engine with large frontal surfaces, then heat transfer efficiency is improved, but aircraft displacement cross-section increases and pressure resistance increases
Solution Approach 1:
The heat exchanger is merged with the engine structure by integrating it into the bypass flow path. The cooling air is taken from the engine bypass flow rather than requiring a separate external heat exchanger, thereby combining the propulsion system and cooling system into a single integrated structure that eliminates additional frontal surface area.
Solution Approach 2:
The bypass flow of the engine serves dual functions: it provides thrust as part of the propulsion system and simultaneously serves as the cooling medium for the heat exchanger. This multi-functionality eliminates the need for separate cooling air inlets and large external heat exchanger surfaces.
2Volume of stationary object
If heat exchanger is arranged in the bypass flow with high velocity, then installation space is reduced, but pressure losses increase
Solution Approach 1:
The heat exchanger is segmented into multiple channels (first cooling air channels and first exhaust gas channels) that are arranged in parallel. This segmentation allows the high-velocity bypass flow to be distributed across multiple pathways, reducing the velocity in each individual channel and thereby minimizing pressure losses while maintaining compact dimensions.
Solution Approach 2:
The heat exchanger channels are designed with locally optimized geometries including curved inlet sections and extended surface areas at specific locations. These local quality enhancements improve heat transfer efficiency in the compact structure without requiring high velocities throughout the entire flow path, thus reducing overall pressure losses.
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 design reduces pressure losses and minimizes installation space while enhancing heat transfer efficiency, suitable for high-velocity fluid cooling applications.
Implementation Method 1
the diffusor region and a first high-temperature channel of the high-temperature grille through which the hot fluid flows have at least one common wall for heat transfer
Implementation Method 2
a diffusor region to slow down incoming fluid is arranged in the at least one (preferably several) first low-temperature channel(s) of the low temperature grille through which the cooling fluid flows
Data Source
AI summary
The invention relates to a heat exchanger for cooling a hot fluid, namely an exhaust gas or a fuel-cell cooling fluid, by means of a cooling fluid which is at a lower temperature than the hot fluid and which has a high flow velocity, comprising a high-temperature grille for guiding the hot fluid and a low-temperature grille for guiding the cooling fluid. According to the invention, a heat exchanger which can improve a transfer of heat despite a high-velocity inflowing fluid and/or which can reduce the required installation space is created in that a diffuser region for decelerating the cooling fluid is arranged in at least one first low-temperature channel, through which the cooling fluid flows, of the low-temperature grille, and in that the diffuser region and a first high-temperature channel, through which the hot fluid flows, of the high-temperature grille have at least one shared wall for heat transfer.