Double-Flow Heat Exchanger with Separated Fin Paths
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Solution Overview
Problem
Existing heat exchangers in turbomachines face challenges in optimizing thermal performance while minimizing mechanical energy losses, particularly due to the disruption of air flow and increased cooling requirements with higher rotational speeds and powers.
Innovation Solution
A heat exchanger design featuring two separate air flows that circulate without crossing, with fins and distribution means to guide and separate the air flows, utilizing additive manufacturing for a compact and efficient structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If SACOC heat exchangers are used to cool oil with secondary air flow, then cooling performance is improved, but pressure losses in secondary vein increase and aerothermal performance decreases
Solution Approach 1:
The heat exchanger is divided into two separate sections: a first section with first fins for the first air flow, and a second section with second fins for the second air flow. The distribution means separate the air flows so that each section handles only its designated flow, preventing flow interference and reducing pressure losses while maintaining cooling effectiveness.
Solution Approach 2:
Distribution means are introduced as intermediary structures between the two air flow paths. These distribution means guide and separate the first and second air flows, ensuring they do not cross or interfere with each other, thereby maintaining efficient flow patterns and reducing energy losses.
2Temperature
If fins are added to increase contact surface with air flow, then heat exchange capability is improved, but drag and mechanical energy losses increase
Solution Approach 1:
The fins are segmented into two distinct groups (first fins and second fins) corresponding to the two separate air flows. Each fin group is optimized for its specific flow, allowing efficient heat exchange without creating excessive drag on the overall air flow system. The separation prevents the fins from interfering with each other's flow paths.
Solution Approach 2:
Different regions of the heat exchanger are optimized locally: the first section with first fins is optimized for the first air flow pattern, and the second section with second fins is optimized for the second air flow pattern. This local optimization ensures maximum heat exchange efficiency in each region while minimizing drag effects.
3Productivity
If cooling requirements increase with higher rotational speeds, then thermal performance demand increases, but available cooling capacity becomes insufficient
Solution Approach 1:
The heat exchanger is designed to handle multiple air flows simultaneously (first air flow and second air flow) through separate sections. This multi-functional design allows the system to provide adequate cooling capacity even as cooling requirements increase with higher rotational speeds, because both air flows contribute to the overall cooling capability without interfering with each other.
Solution Approach 2:
The heat exchanger utilizes spatial separation by creating two distinct flow paths in different dimensional spaces. The first air flow passes through the first section while the second air flow passes through the second section, allowing the system to scale cooling capacity by utilizing additional spatial dimensions rather than increasing load on a single flow path.
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
Enhances thermal performance and reduces mechanical energy losses by optimizing air flow paths, minimizing drag, and improving cooling efficiency.
Implementation Method 1
a heat exchanger for a turbomachine... intended to cool a fluid... circulating a first air flow... circulating a second air flow... thermal performance is increased since the second air flow replaces the first air flow that has already passed through the first fins
Implementation Method 2
use the secondary air flow to cool the oil circulating in the turbomachine. These heat exchangers are in the form of a metal surface part allowing the passage of oil in machined channels. The secondary air flow is guided along fins carried by this surface part and whose role is to increase the contact surface with the secondary air flow and to extract calories
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a heat exchanger (21) comprising a support wall (22) and a first plurality of fins (23) that each stand proud from an outer surface (24) of the support wall (22) and are designed to have a first air flow pass over them. According to the invention, the heat exchanger comprises, downstream of the first plurality of fins (23), a second plurality of fins (25) that each stand proud from the outer surface (24) of the support wall (22), the first and second pluralities of fins (23, 25) being separated by distribution means (26) which are configured in such a way that the first air flow flows outside the second plurality of fins (25) and a second air flow flowing outside the first plurality of fins passes through the second plurality of fins (25).