Diverging Tertiary-Vein Heat Exchanger for Axial Turbomachines
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Solution Overview
Problem
Existing turbomachines face performance penalties and efficiency losses due to the placement of heat exchangers in the secondary flow, which disrupt thrust and cause aerodynamic disturbances, and are vulnerable to foreign object impacts.
Innovation Solution
An axial turbomachine design with a heat exchanger positioned in the tertiary flow vein, utilizing diverging heat exchange surfaces and structural arms to facilitate cooling while minimizing aerodynamic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat exchanger is placed in the secondary flow downstream of the fan, then the oil cooling function is achieved, but the thrust force is slowed down and aerodynamic disturbances occur
Solution Approach 1:
The air flow is segmented into multiple veins (secondary flow, tertiary flow, and other flow paths) through separation nozzles. The heat exchanger is specifically placed in the tertiary flow vein rather than the secondary flow, dividing the cooling function from the main thrust generation path to avoid aerodynamic interference while maintaining cooling effectiveness.
Solution Approach 2:
A third flow path (tertiary flow) is introduced as an intermediary between the fan and the heat exchanger. This intermediary flow vein allows the heat exchanger to be positioned without directly blocking the main secondary flow that generates thrust, thus mediating between the cooling requirement and the thrust requirement.
2Temperature
If a heat exchanger is placed in the secondary flow, then oil cooling is provided, but aerodynamic disturbances and vibrations occur
Solution Approach 1:
The flow is segmented into separate veins using separation nozzles, with the heat exchanger isolated in the tertiary flow vein. This segmentation prevents the heat exchanger from directly interfering with the main secondary flow, eliminating aerodynamic disturbances and vibrations while maintaining the cooling function.
3Temperature
If a heat exchanger is placed upstream of the turbomachine, then cooling is provided, but foreign body impact risk increases
Solution Approach 1:
The heat exchanger is extracted from the vulnerable upstream position and relocated to the tertiary flow vein downstream of the fan. This extraction removes the heat exchanger from the high-risk zone where foreign bodies could impact, while the tertiary flow path provides adequate cooling capability.
4Temperature
If a bulky heat exchanger is used for effective cooling, then cooling efficiency is improved, but the impact on engine efficiency increases
Solution Approach 1:
The heat exchanger is positioned in the tertiary flow vein where the air flow has specific characteristics (lower velocity, appropriate temperature). This local positioning allows the use of a more compact heat exchanger design that achieves effective cooling without the bulk required in high-velocity secondary flow, thus minimizing impact on engine efficiency.
Solution Approach 2:
The flow parameters (velocity, temperature, pressure) in the tertiary flow vein are different from the secondary flow. By utilizing these parameter changes, the heat exchanger can be designed with smaller dimensions while maintaining cooling effectiveness, reducing the penalty on engine efficiency.
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 solution ensures efficient cooling with less bulky exchangers, reducing engine efficiency hindrance and gas emissions by using cold, slow-moving air, thus optimizing thrust and reducing carbon dioxide emissions.
Implementation Method 1
an air/oil type heat exchanger arranged in the tertiary flow vein and comprising heat exchange surfaces with air and oil passages extending in said tertiary flow vein
Data Source
AI summary
An axial turbomachine including a first separation nozzle capable of separating an incoming air flow into a radially internal air flow and a radially external air flow, called secondary flow; a second separation nozzle capable of separating the radially internal air flow into a primary f flow and a tertiary flow, said tertiary flow being in a tertiary flow vein radially external to said flow primary; and an air/oil type heat exchanger disposed in the tertiary flow stream and including heat exchange surfaces with air and oil passages extending in said tertiary flow stream; and structural arms extending radially through the tertiary flow vein. Each structural arm has in the tertiary flow vein a cross section with a downstream portion having a width decreasing towards the downstream, the heat exchanger being adjacent to said downstream portions of the structural arms.