Numerical modelling of the solid- and fluid dynamic phenomena controlling the ring plate valve motion and tumbling

The reciprocating compressor is a vital component in refrigeration systems, and the compressor valves are
key for the compressor performance. In the present work, we have developed and employed a coupled
simulation strategy using computational fluid dynamics (CFD) and finite element modeling (FEM) to account
for the physical phenomena that control the ring plate valve dynamics. The discharge valve of an ammonia
compressor is considered, and the detailed geometry is included. We study the different variations in the
compressor configuration that can cause unsteady valve motion with rotation and tumbling of the ring. It is
found that both pressure inhomogeneity in the discharge chamber as well as spring non-uniformity can
initiate the valve rotation. The gas flow during rotation has the possibility to amplify the rotation and increase
the impact speed of the ring plate edge. We discuss the consequences of this for the efficiency and reliability
of the system.
Keywords: Reciprocating Compressor, Ring Plate Valves, Valve Dynamics, CFD, FEM, Experiments