Thermophysical properties of hybrid silica phenolic ablative composite: Theoretical and experimental analysis

Abstract Silica phenolic ablative composites are used in many high‐temperature applications like rocket/missile solid motor nozzles, space re‐entry vehicles, and so forth. As ablative composite with lower thermal conductivity and density can save considerable cost, a hybrid silica phenolic ablative composite was developed by establishing a novel processing methodology using chopped silica fiber, phenolic resin, and hollow glass microsphere. The thermophysical properties of the developed hybrid composite are analyzed and established the scientific know‐how. The developed composites, with 36% lower density, displayed 50% lower thermal conductivity and 50% lower thermal diffusivity than standard silica phenolic composite. Since a proper thermal conductivity model for a three‐component composite with matrix, fiber, and hollow glass microsphere is not available, the most suitable model for the developed composite is established.