Analysis Of The Coupled Heat Transfer In Fiber Material Using The Lattice Boltzmann Method

Carbon fiber composite material has excellent thermal and mechanical properties, it is widely used in spacecraft thermal protection fields. Under high temperature conditions, there are thermal radiation heat transfer process and heat transfer process inside the material. Among others, some of the attributes of the LBM which make it an attractive method are clear physics, simple coding, suitable for a parallel architecture adaptable to complex geometry and ease in implementation of the boundary conditions. LBM has been applied to solve different class of heat transfer problems involving thermal radiation.Based on the lattice Boltzmann method, this article simulates heat conduction,radiation and radiation-conduction thermal coupling for three typical structures of carbon fiber composite materials, for three-dimensional weave four-step molding 3D woven carbon fiber structure, bevel interlock knitting 2.5 D molded carbon fiber structure and plain woven carbon fabric lamination molding 2 D braided carbon fiber structure, the main contents include:(1) For different weave carbon fiber composite structure, based on lattice Boltzmann method, establish phonon transport model for heat conduction and photon radiation transfer model for heat radiation. Program conduction, radiation and radiation- thermally coupled heat transfer process in Fortran, and select the appropriate object to verify the reliability of the program,(2) Analyze the influence of carbon fiber composite weave structure on anisotropic thermal conductivity. For three typical woven structure, calculated the anisotropic thermal conductivity of different thickness material at temperature from 773 K to 1773 K, and analyze the influence of temperature, weave structure and geometry on its thermal performance,(3) When only considering the radiative heat flux, calculated equivalent thermal conductivity of three structures under large scale conditions. Analyze the influence of temperature, weave structure and geometry on heat flux and the equivalent thermal conductivity,(4) Calculated the equivalent heat transfer performance parameter of three structures under the coupled thermal radiation heat transfer, and compared with the heat transfer performance parameters of pure heat conduction. Analysis the influence of radiation heat flux on heat transfer properties of carbon fiber composite material.The study found that the temperature, thickness and woven structure all have a significant effect on the heat transfer properties of carbon fiber composites. At low temperatures, the equivalent heat transfer performance under radiation have little different with the same performance under pure conduction,but as the temperature rises, the equivalent heat transfer performance parameter value is gradually higher than the value of pure heat conduction, providing design reference for the engineering application.