Variable Core Heat Exchanger Flow Control
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Solution Overview
Problem
Heat exchangers in aircraft applications face challenges in efficiently managing heat transfer rates and pressure loss across different operational modes, such as take-off and cruising speeds, due to the limitations of existing designs.
Innovation Solution
A heat exchanger design featuring a core with two layers, where the first layer has a higher heat transfer rate and the second layer has lower pressure loss, coupled with a flow control mechanism within the headers that can direct fluid flow through either or both layers, optimizing heat exchange based on operational demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-layer heat exchanger design is used, then the structure is simple, but it cannot simultaneously achieve high heat transfer rate and low pressure loss across different operational modes
Solution Approach 1:
The heat exchanger core is divided into two distinct layers: a first layer with passages configured for high heat transfer rate and a second layer with passages configured for low pressure loss. This segmentation allows the system to address different operational requirements in different layers, enabling adaptability to various flight conditions without requiring a completely different heat exchanger design for each mode.
Solution Approach 2:
The patent incorporates flow control mechanisms (valves) that dynamically redirect fluid flow between the first and second layers based on operational demands. During high-demand operations (e.g., take-off), the system can direct more flow through the first layer for maximum heat transfer. During lower-demand operations (e.g., cruising), flow can be redirected to the second layer to minimize pressure loss, providing dynamic adaptation to changing conditions.
2Productivity
If fluid flow is directed through the first layer for high heat transfer rate, then heat exchange efficiency improves, but pressure loss increases
Solution Approach 1:
The flow control valves enable dynamic adjustment of fluid distribution between layers. The system can optimize the balance between heat transfer rate and pressure loss by adjusting valve positions based on real-time operational requirements, allowing the heat exchanger to adapt its performance characteristics to match current flight conditions.
Solution Approach 2:
The patent changes the flow distribution parameter between layers to optimize performance. By adjusting the proportion of fluid directed through each layer, the system can shift between prioritizing heat transfer rate (more flow through first layer) and minimizing pressure loss (more flow through second layer), effectively managing the trade-off between these two parameters.
3Loss of energy
If fluid flow is directed through the second layer for low pressure loss, then pressure loss decreases, but heat transfer rate reduces
Solution Approach 1:
The flow control mechanisms enable the system to dynamically switch between prioritizing pressure loss reduction and prioritizing heat transfer rate based on operational mode. During cruising conditions where pressure loss is more critical, the valves redirect flow to the second layer. During high-demand conditions where heat transfer is paramount, flow is redirected to the first layer.
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 exchange efficiency by directing fluid flow through the high-rate layer during high-demand operations and the low-pressure layer during lower-demand operations, thereby optimizing performance across varying aircraft conditions.
Implementation Method 1
Heat exchangers are often used to transfer heat between two fluids
Implementation Method 2
a flow control mechanism within the plenum that can direct fluid flow through either or both layers
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
A heat exchanger (10) includes a core (12). The core includes a first layer (22) and a second layer(42). The first layer includes a first plurality of fluid inlets (24). The second layer includes a second plurality of fluid inlets (44). The heat exchanger also includes a fluid header (60) attached to the core adjacent the first plurality of fluid inlets and the second plurality of fluid inlets. The fluid header (60) includes an inlet (62), an outlet (66), a plenum (64) between the inlet and the outlet, and a flow control mechanism (68) within the plenum (84). The flow control mechanism selectively directs fluid through the first plurality of fluid inlets, through the second plurality of fluid inlets, or through both the first plurality of fluid inlets and the second plurality of fluid inlets.