Measurement Method And Experimental Study On Thermal Diffusivity Of Carbon Fibers

Carbon fibers have been applied in various industries due to their excellent properties. Therefore, to study the thermal performance of carbon fibers are importance and difficulty. It has been difficult and challenging to determine the thermal properties of an individual carbon fiber because of its small diameter (10μm). Fourier’s Law and other traditional heat transfer theory are no longer applicable. In this paper micron material thermal diffusivity measurement method was analyzed using transient electric theory model. At the same time the corresponding experimental measurement system was establishedthe. Thermal diffusivity of carbon fibers was measured.Using finite element software, the temperature distribution, temperature rise and thermal equilibrium state of carbon fibers during the dynamic thermal process were studied. Simulation results show that temperature distribution along the axial is parabolic. The temperature which from the center to the both ends is falling. The change in temperature along the radial is small. It can be approximately considered uniform. The heat transfer model which was approximation into one dimensional model was correct. The simulations about the temperature rise and thermal equilibrium time agree well with the theoretic calculations. The reliability of the test structure was confirmed.The transient electro-thermal technique experiment platform was set. The vacuum chamber can effectively avoid the influence of convection heat transfer in ambient air. The reliability of the system was proved by measuring the standard platinum wire. Then two kinds of carbon fiber were measured at room temperature.Experimental repeatability of measurement results are good. The results show that carbon fiber 1 and 2 were close to the test results.To study the influence of the temperature on carbon fibers, the current values were increased form 0.6 mA to 3.8 mA. Through the results we know that the thermal diffusivity and thermal conductivity increases with the rise of temperature.