Hypersonic Leading Edge Cooling via Porous Phase-Change
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Solution Overview
Problem
High-speed vehicles, particularly hypersonic aircraft, face thermal management issues due to extreme heat loads at leading edges, leading to component degradation and failure, with existing cooling methods like transpiration cooling increasing weight and volume through the use of expendable fluids.
Innovation Solution
A leading edge assembly with a porous section and a coolant supply structure that distributes coolant through a tapered outer wall, featuring distinct porous regions with varying permeability and pressure zones to enhance cooling, and a method to adjust internal pressure in response to changing conditions for efficient thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If transpiration cooling is used to cool the leading edge, then cooling effectiveness is improved, but weight and volume increase due to expendable cooling fluid and supporting hardware
Solution Approach 1:
The leading edge structure itself serves as the cooling system through its porous walls that allow coolant passage. The structure cools itself by utilizing the thermal properties of the porous material and the phase change of the coolant, eliminating the need for separate cooling hardware and reducing overall vehicle weight.
Solution Approach 2:
The leading edge incorporates a porous wall structure that allows coolant to permeate through it. This porous configuration provides large surface area for heat transfer while maintaining structural integrity, enabling effective cooling without requiring thick walls or additional cooling components that would increase weight.
2Temperature
If transpiration cooling is used to cool the leading edge, then cooling effectiveness is improved, but volume increases due to storage tanks and piping
Solution Approach 1:
The cooling system is merged with the leading edge structural component itself. The porous walls of the leading edge serve dual purposes: maintaining aerodynamic shape and providing coolant passage. This integration eliminates separate storage tanks and piping, significantly reducing the volume occupied by cooling hardware.
Solution Approach 2:
The leading edge structure performs multiple functions simultaneously: it provides aerodynamic shaping, structural support, and thermal management. The porous walls enable the same component to serve as both the vehicle's structural element and its cooling system, eliminating the need for dedicated cooling infrastructure.
3Temperature
If coolant is pressurized to distribute through porous section, then cooling distribution is improved, but energy consumption increases
Solution Approach 1:
The coolant utilizes phase change (evaporation) as it passes through the porous section to absorb heat from the leading edge. This phase transition provides natural cooling without requiring high pressurization, as the phase change itself drives the cooling process and reduces the energy needed for pump operation.
Solution Approach 2:
The system replaces mechanical pressurization with thermal-driven flow. The temperature gradient and phase change of the coolant create natural pressure differentials that drive coolant through the porous structure, reducing or eliminating the need for high-power pumps and associated energy consumption.
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 effectively mitigates thermal loading on hypersonic vehicle leading edges by efficiently distributing coolant and managing pressure, reducing weight and volume requirements while maintaining structural integrity and improving high-temperature durability.
Implementation Method 1
the porous section comprising a first porous region and a second porous region; a coolant supply structure defining a first supply flowpath extending to the first porous region and a second supply flowpath extending from the first supply flowpath at a location upstream of the first porous region to the second porous region
Implementation Method 2
a coolant supply for providing a flow of a coolant through the coolant supply structure and through the porous section to cool the outer wall
Implementation Method 3
an internal pressure, P1, of the coolant in the first porous region is higher than an internal pressure, P2, of the coolant in the second porous region
Data Source
AI summary
A hypersonic aircraft includes one or more leading edge assemblies that are designed to manage thermal loads experienced at the leading edges during high speed or hypersonic operation. Specifically, the leading edge assemblies may include an outer wall tapered to a leading edge or stagnation point. The outer wall may define a vapor chamber and a capillary structure within the vapor chamber for circulating a working fluid in either liquid or vapor form to cool the leading edge. In addition, a dual-modal cooling structure can enhance heat transfer from the outer wall at the leading edge to the outer wall within the condenser section of the vapor chamber.