2-way FSI simulations on a shock absorber check valve

Sammanfattning: A component of a hydraulic shock absorber, a check valve, is analyzed using both numerical simulations as well as experimental testing. A uid-structure interaction (FSI) model is set up in ANSYSWorkbench and is validated through physical experiments - both steady state and transient. The uid eld is solved in ANSYS Fluent and the structural deformation is solved for in ANSYS Structural. The coupling is made using ANSYS System Coupling. The report covers the fundamentals of FSI analysis - methods of coupling uid and structure solution elds and methods for adapting the uid mesh to account for a changing geometry. A brief background on general moving/deforming mesh algorithms are presented but the emphasis lies on the methods available in ANSYS Fluent and how to apply these on the case of a shock absorber check valve. A moving/deforming mesh consisting of tetrahedral cells without ination layers on wall boundaries proves the most robust dynamic mesh setup. The exclusion of ination layers is shown to signicantly a ect the solution at low valve lift height. At full lift the exclusion of ination layers has no inuence on the solution. The check valve is 4-fold axisymmetric but is shown to exhibit asymmetrical displacement. This is due to an asymmetrical uid pressure distribution on the check valve. Steady state FSI simulations show satisfactory correlation to ow bench experiments at low ow rates. The opening pressure di erential of the check valve, determined by the spring preload, is accurately predicted by the FSI model. At flow rates above 10 l/min the di erential pressure is under predicted, due tosimplications to the computational domain. Transient simulations and experiments both show an oscillatory pressure di erentialacross the check valve as it opens, albeit with di erent frequencies.