Advanced Carbon-Based Fan Duct Heat Exchanger

High conductivity (Hi-K) Carbon foam and Carbon-Carbon (C-C) composites are light-weigh and offers the highest specific thermal conductivity (conductivity/ density) among various engineering materials. Carbon foam and C-C have been identified as ideal corematerials for medium to high temperature heat exchangers. However, Hi-K carbon foam is relatively brittle and exhibit low strength. In this proposal, a fan-duct surface-type heat exchanger using structurally enhanced carbon foam and Hi-K C-C heat transfersfins is proposed. The proposed design is relatively simple and maximizes the usage of state-of-the-art carbon foam and Hi-K C-C materials. A surface-type heat exchanger also offers significantly lower risk in manufacturing and in operation. In thisproposal, critical technical issues are identified and innovative design and process are proposed. Enhancements in both structural integrity and thermal conductance through interfaces will be investigated. Assuming a successful demonstration of theproposed technology, a highly efficient carbon-based heat exchanger can be designed and fabricated.A successful demonstration of a surface-type fan duct heat exchanger using structurally enhanced carbon foam and high conductivity C-C will lead us to many new applications. Since the proposed fan duct heat exchanger design concept may be converted into astandardized module, it can easily be scaled up with minimum modification to handle higher thermal load as required by larger military fan duct heat exchangers. Since the proposed design is relatively simple to fabricate, the production cost maybesignificantly reduced if volume requirement increase. A low-cost light-weigh high-performance heat exchanger can find many commercial applications in both aerospace and non-aerospace applications.