Effect of reinforcement structure on thermal properties of carbon-carbon exit cone composites

Three kind of carbon fiber preforms, carbon cloth ply preform (P preform), needled caborn cloth perform (N preform) and carbon fiber weaving preform (W preform), are investigated for three kind of carbon-carbon composites (C/C), P-C/C, N-C/C, W-C/C, which are used for nozzle exit cone, as well as the influence of reinforcement structure on thermal proper-lies of three C/C are also studied. It is found that thermal capability of the three C/C are close and all increase with increasing testing temperature. The anisotropy degree of reinforcement has a large influence on thermal conductivity of the three C/C, the thermal conductivity of the three C/C in X-Y direction is larger than that in Z direction, among which the thermal conductivity of P-C/C in X-Y direction is more than 10 times of that in Z direction, N-C/C has minimum thermal conductivity in two direction and low anisotropy degree in structure, the thermal conductivity value of W-C/C has remarkable difference in two direction, and is lower than P-C/C in Z direction, while larger than N-C/C in Z direction. The thermal expansion coefficient (CTE) of three C/C display large anisotropy, which is characterized by parameters of the ratio of CTE-in Z direction and in XY direction (ZCTE/XYCTE), the ratio of three C/C all decrease with increasing testing temperature, the ratio of P-C/C has maximum value of 340, the ratio of W-C/C is far lower than that of P-C/C, and the ratio value of N-C/C is minimum.