Element differential method for the multi-physics coupled contact analysis of high-temperature dynamic seal structure

High-temperature dynamic seals are the structures used to seal movable clearances in high-temperature environments. The essential components of these seals are the fiber-braided seal strips. When it is working, the strip is subjected to a transverse preload, decreasing its porosity and restricting gas flow to achieve sealing. To implement seal design, efficient numerical analysis is essential, which is supposed to involve the deformation, heat transfer, seepage, and the interactions among these physical processes. In this paper, a nonlinear thermal-mechanics-seepage coupled contact model is used to describe the seal strips with circular sections. An element differential scheme is proposed to solve the coupled governing equations, and an iterative procedure based on the element differential method (EDM) tracks the contact interfaces, which further determines the range of boundary conditions of other physical fields. The proposed method simplifies the computation by avoiding integral evaluations and reducing matrix density. Two examples are implemented to verify the correctness of the proposed scheme and to predict the variations in physical variables of the seal structures. Furthermore, a comparison between the EDM and finite element method results indicates that the EDM is more efficient because of fewer contact iterations and a sparser coefficient matrix.