Analysis of non-contact finger seal force based on deformation of the finger pad

Abstract

As a type of flexible seal, finger seal has attracted wide attention due to its low cost and leakage rate. Its potential in engineering applications has been demonstrated by numerous experiments. The deformation of the pad under load during the operation of non-contact finger seal is a critical factor that limits the performance. To investigate the change of the seal force of finger beams and pads, it has been focused on the non-contact finger seal, and the force on low-pressure finger beam has been simulated and analyzed. By differentiating the force acting on finger pad, the simulation on different regions of the finger pad has been considered. The seal force distribution coefficient has been introduced, the results are unified to obtain the final seal force, and its rationality is verified by comparing it with existing results. Subsequently, the relationship between pressure drop, eccentricity, rotor speed, friction coefficient, finger pad size, and finger seal force is explored. It has demonstrated that, at the same eccentricity, the seal force decreases as the pressure difference increases. A larger eccentricity leads to better seal performance. Additionally, it has been observed that the size of the finger pad affects seal force of the beam. Specifically, an increase in the axial dimension of the pad results in a larger force. Through the analysis of the resultant force on the rotor on the whole ring finger seal, the result is closer to the engineering project. The deformation of finger pad is studied, and the stress on pad is analyzed by analytical method, which lays a foundation for further study of finger seal performance.