Hydrodynamics Simulations and Analyses of a Fluid Lubricated Screw-Nut Pair

Abstract

A new method is proposed to solve the hydrodynamics performances of a fluid lubricated screw-nut pair using FLUENT. Before the simulations, the Computational Fluid Dynamics (CFD) model of the gap flow field is built, based on some approximation rules. During the simulations, the dynamic mesh technology is employed to realize the real-time update of the grids of the computational domain. For a given velocity perturbation, the stiffness and damping coefficients of the system are solved using the finite difference method, and the influences of the perturbations on the system are compared among different ranges. With the fluid–solid interaction and the real-time restriction of the restrictors considered, the system is solved under different loading conditions. A more accurate solution method for the dynamic stiffness and damping coefficients is provided, and the dynamics characteristics of the system after loading are analyzed. On this basis, a qualitative and quantitative comparison is carried out between the method based on the simplified Reynolds equation and the proposed method in this paper, showing the latter superiorities in illustrating the field. A general understanding of the dynamics properties under different loading conditions of the system is obtained through this research, providing a basis for the precision control of the system in the future research.

Keywords

• fluid lubricated screw-nut pair
• stiffness and damping coefficients
• finite difference method
• dynamic mesh technology
• fluid–solid interaction