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A Fabric Composite Radiation Heat Transfer Study has been conducted to determine the effective emissivities of specific fabric composite materials. The weave of the fabric and the high strength capability of the individual fiber in combination with the thermal conductivity and chemical stability of specific metallic liner, result in a very efficient light weight heat rejection system. Primary investigation included aluminum, copper, stainless steel and titanium as liner materials, and three different ceramic fabrics - Astroquartz II (a trademark of JPS Co., Slater, SC), Nextel (a trademark of 3M Co., St. Paul, MN) and Nicalon (a trademark of The Nippon Carbon Co., Japan). Experiments showed that fabric composite materials have significantly higher effective emissivities than the bare metallic liner materials. Aluminum and Astroquartz II combination and aluminum and Nextel combination appeared to be the most promising among the tested samples. To simulate deep space the experiment was performed in vacuum where coolant fluid was cirulated at about -10°C. The effective emissivity measurements were conducted at 376 K, 521 K and 573 K. Also high temperature effective emissivity measurements need to be performed. / Graduation date: 1993

Composites, though used in a variety of applications from chairs and office supplies to structures of U.S. Navy ships and aircrafts, are not all designed to hold up to extreme heat flux and high temperature. Fiber-reinforced polymeric composites (FRPC) have been proven to provide the much needed physical and mechanical properties under fire exposure. FRPC notable features are its combination of high specific tensile strength, low weight, along with good corrosion and fatigue resistance. However FRPC are susceptible to thermal degradation and decomposition, which yields flammable gas, and are thus highly combustible. This property restricts polymeric material usage. This study developed a numerical model that simulated the degradation rate and temperature profiles of a fiber-reinforced polyester resin composite exposed to a constant heat flux and hydrocarbon fire in a cone calorimeter. A numerical model is an essential tool because it gives the composite designer the ability to predict results in a time and cost efficient manner. The goal of this thesis is to develop a numerical model to simulate a zonal-layer polyester resin and fiberglass mat composite and then validate the model with experimental results from a cone calorimeter. By inputting the thermal properties of the layered composite of alternating polymer and polymer-infused glass fiber mat layers, the numerical model is one step closer to representing the experimental data from the cone calorimeter test. The final results are achieved through adding a simulated heat flux from the pilot ignition of the degraded gas of the polyester resin. The results can be coupled into a mechanical model, which may be separately constructed for future study on the mechanical strength of composites under fire conditions.