Leading-Edge Heat Pipe Wick Structure for Hypersonic Heat Flux
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Solution Overview
Problem
Current leading-edge heat pipes for hypersonic vehicles are limited by their geometry, which restricts their performance and operational envelope, making it challenging to manage high heat fluxes effectively and achieve faster, more maneuverable, and longer-range hypersonic flight.
Innovation Solution
A leading-edge heat pipe design featuring a porous wick with a bimodal pore distribution and a phase-change heat-transfer material, integrated within a thin, oxidation-resistant aeroshell, allowing for efficient heat rejection and capable of handling high heat fluxes up to 1000 W/cm2 or greater.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the leading edge operates at higher temperatures to increase heat rejection through radiative emissive cooling, then heat rejection capability is improved, but material stability and structural integrity deteriorate
Solution Approach 1:
A porous wick structure filled with phase-change material serves as an intermediary thermal management system between the heat-generating leading edge and the external environment. The phase-change material absorbs excess heat through phase transition, preventing direct thermal exposure of structural materials while enabling controlled heat rejection
Solution Approach 2:
The invention utilizes phase-change material that transitions between solid and liquid states to absorb and store thermal energy. This phase transition mechanism enables the system to handle high heat fluxes by converting thermal energy into latent heat of fusion, thereby protecting structural materials from overheating
2Stress or pressure
If heat is spread over a larger area for radiative emissive cooling, then heat flux density is reduced, but the ability to spread heat fast enough to remove heat from the leading edge deteriorates
Solution Approach 1:
The invention replaces conventional conduction-based heat spreading mechanisms with phase-change-based thermal transport. The phase-change material rapidly absorbs and redistributes heat through phase transition, achieving both high heat spreading speed and effective heat flux management without relying solely on thermal conduction
Solution Approach 2:
The system changes the thermal parameters of the leading edge by introducing phase-change material that dynamically adjusts heat absorption and storage capabilities. This parameter change enables the system to rapidly respond to high heat flux conditions while maintaining acceptable heat flux density through the wick structure
3Ease of manufacture
If conventional heat pipe geometries are used, then manufacturing is simplified, but performance and operational envelope are restricted
Solution Approach 1:
The invention employs a porous wick structure that can be manufactured using additive manufacturing techniques. This porous material provides both structural support and capillary action for phase-change material transport, enabling complex geometries that adapt to various leading edge configurations while maintaining manufacturability through modern fabrication methods
Solution Approach 2:
The heat pipe system utilizes composite construction combining porous wick material, phase-change material, and structural envelope. This composite approach enables tailored properties that balance manufacturing considerations with enhanced performance and adaptability for different hypersonic flight regimes
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
Enables faster speeds, enhanced maneuverability, and longer ranges by effectively managing high heat fluxes, reducing material deformation, and maintaining structural integrity under extreme conditions.
Implementation Method 1
a porous wick with a bimodal pore distribution
Implementation Method 2
a phase-change heat-transfer material contained within the porous wick
Implementation Method 3
an envelope fabricated from a shell material, wherein the envelope includes at least one edge with a radius of curvature of less than 3 mm
Data Source
AI summary
Some variations provide a leading-edge heat pipe comprising: (a) an envelope fabricated from a shell material, wherein the envelope includes at least one edge with a radius of curvature of less than 3 mm, and wherein the envelope includes, or is in thermal communication with, at least one heat-rejection surface; (b) a porous wick fabricated from a ceramic or metallic wick material, wherein the porous wick is configured within a first portion of the interior cavity, wherein at least a portion of the porous wick is adjacent to the inner surface, and wherein the porous wick has a bimodal pore distribution comprising an average capillary-pore size from 0.2 microns to 200 microns and an average high-flow pore size from 100 microns to 2 millimeters (the average high-flow pore size is greater than the average capillary-pore size); and (c) a phase-change heat-transfer material contained within the porous wick.