Development of Embedded Vascular Networks in FRP for Active/Passive Thermal Management.

摘要

The increasing use of strong, lightweight composite materials in primary structural components within aerospace promises to substantially reduce aircraft non-payload weight, thereby improving fuel consumption and operating profitability. Weight reduction through use of polymer based composites for propulsion system components, however, can prove challenging due to the fact that the maximum operating temperature for a fiber-reinforced polymer composite is constrained by the glass transition temperature, Tg, typically in the range 100 Degrees C - 200 Degrees C. This study sets out to investigate how the degradation of CFRP can be mitigated at raised temperature by applying a system of active cooling. Integration of vascular networks capable of cooling the host FRP component has been studied via a series of long te rm exposure, mechanical testing to measure the effect on interlaminar shear strength and fracture toughness. Results show that active cool ing can realize significant reductions (50- 70 Degrees C) in temperature compared to the operating environment (150 Degrees C), resulting in prolonged service performance. In parallel, a numerical model has been developed to evaluate performance to predict the temperature distribution in a thin flat plate that is subjected to a hot external air flow and is actively cooled by an internal vasculature and an external cool film. This thin plate test model offers a good first approximation to heat transfer properties for a gas turbine compressor blade. The vascular network topology in a structural component requires careful consideration to balance thermal efficiency between the vascular and film cooling effects. Experimental work is included which attempts to validate this numerical model, and indicates that this approach shows significant promise.