Thermal Management of Hypersonic Leading Edges via Integrated Liquid Metal Heat Pipe through Finite Element Analysis

Extreme hypersonic thermal conditions require advanced innovations to push the boundary of powered flight. To combat the damaging heat buildup on hypersonic leading edges, integrated liquid metal heat pipes have been proposed as a potential solution. Heat pipes, if successfully integrated, can spread and dissipate heat along trailing edges of aircraft with low maintenance and no additional power. Moreso, the aerothermal loading responsible for the high temperatures is the very phenomenon powering the heat removal. The heat pipe acts as an energy spreader, taking heat from blunt edges, dissipating it along the body to create an isothermal high temperature over a large surface, and finally using radiation as means of the heat removal. Heat pipes may seem like a straightforward solution, but problems arise during manufacturing, testing, and integration. This thesis presents a new method of prototyping integrated heat pipes using commercial finite element analysis (FEA) software to accurately predict thermal behavior and properties without the need for manufacturing test samples. Using representative thermal conductivities of the constituent heat pipe parts, a three-dimensional finite element simulation is performed to provide thermal and structural results at steady state condition. This method allows for rapid prototyping to test new structures, materials, flight conditions, and more. In addition to the presented simulation method, design considerations and results are given for integrated heat pipe length, leading edge radius, casing thickness, material selection, flight conditions, and finally an optimal design based on the key result parameters. A benefit of using three-dimensional modeling software is the ability to view results anywhere on the model which may be of interest. Through this process, the methodology presented in this thesis aims to further the understanding of integrated liquid metal heat pipes in hypersonic and other extreme thermal applications. Key findings include: iso-thermalization of nose cone structure with embedded heat pipe as well as temperature and thermally induced stress reduction below the yield limit. Additionally, increasing heat pipe length, decreasing wall thickness, and increasing leading-edge radius are found to effectively reduce temperature rise and induced stress. Although, these design suggestions may be compromised by cost, manufacturing, and other considerations.