Fluid-Structure Interaction of a Reed Type Valve Subjected to Piston Displacement

In the field of reciprocating compressors, the developing of reed type valves is a challenging task. The understanding of the fluid flow behaviour through the valve reed is essential to improve the valve design. Hence, this work attempts the dynamic simulation of this fluid-structure interaction (FSI) problem, taking into account valve movement due to piston displacement. In this work attends the in-house implemented CFD&HT and moving mesh coupled code TermoFluids [1]. The CFD&HT solver consists of a three-dimensional explicit finite volume fractional-step algorithm formulated in a second-order, conservative and collocated unstructured grid arrangement. The turbulence is modelled by means of large-eddy simulation. The moving mesh technique is based on a radial basis function interpolation method, which allows the dynamic deformation of the mesh according to the displacement of the valve [2,3]. The CFD&HT and moving mesh coupling is built by the space conservation law. The newly implemented FSI global solver is based on a partitioned coupled algorithm in which the dynamic action of the valve is modelled through a specific law based on modal analysis of valve reed theory [4]. In contrast to conventional CSD solvers, this alternative performs a fast prediction of the structure displacement. As a preliminary approach, a simplified geometry of an axial hole plus a rectangular diffuser with a piston based inlet condition is considered. An immersed body procedure is used to simulate solid parts inside the domain and, particularly, to reproduce the bottom and inlet boundaries. This strategy has been enhanced with respect to previous studies [5]; thus, the flow phenomena is now better captured specially when the opening of the valve is narrow. As an addition, a parametric study will be carried out in order to analyse the influence of the valve thickness. REFERENCES [1] O. Lehmkuhl, R. Borrell, C.D. Pérez-Segarra, M. Soria, A. Oliva. TermoFluids: A new parallel unstructured CFD code for the simulation of turbulent industrial problems on low cost PC Cluster, Parallel Computational Fluid Dynamics 2007, Vol. 67, pp. 275-282, 2009. [2] O. Estruch, O. Lehmkuhl, R. Borrell, C.D. Pérez-Segarra, A. Oliva. A parallel radial basis function interpolation method for unstructured dynamics meshes, Computer and Fluids, 80:44-54, 2013. [3] O. Estruch, O. Lehmkuhl, R. Borrell, C.D. Pérez-Segarra. Large-eddy simulation of turbulent dynamics fluid-structure interaction, 7th International Synopsium on Turbulence, Heat and Mass Transfer, Palermo, 2012. [4] W. Soedel. Mechanics, simulation and design of compressor valves, gas passages and pulsation mufflers, Purdue University Short Courses, IN, USA, 1992. [5] O. Estruch, O. Lehmkuhl, J. Rigola, A. Oliva and C.D. Pérez-Segarra. Transient and dynamic numerical simulation of the fluid flow through valves based on large eddy simulation models, 8th International Conference on Compressors and their Systems, London, 2013