Evaluation of the Transient Thermal Performance of a Graphite Foam/Phase Change Material Composite

The thermal transient response of graphite foam infiltrated with paraffin wax as a thermal protection composite was investigated. Graphite foam is a rigid open-celled porous carbon material that exhibits high thermal conductivity along the ligaments. To increase the ability of graphite foam to store heat energy, it was infiltrated with a phase change material, paraffin wax. Filling the foam with a phase change material (PCM) creates a composite that transfers heat through an interconnected network of ligaments to a large surface area of PCM for absorption. Foams were made at various pressures to understand the effect of porosity, which also controls infiltrated wax fraction, on the thermal performance of the composite. The foam samples were infiltrated with paraffin wax and tested using a constant temperature heat source. The transient response was recorded for each sample. The results indicate that a compromise exists between the heat absorption rate and the time available for protection. A simulation was also developed and agreed well with the experimental data.