Compressors

Simulation of reciprocating compressors

The simulation of a reciprocating compressor is addressed considering it as a thermal and fluid-dynamic system.
This allows employing a parallel partitioned coupled approach: several components conforming the compressor-system
are identified and modeled separately. By coupling these models any compressor configuration can be simulated.

Fig. 1: The compressor is a complex physical system involving several phenomena at a time.
Fig. 2: Sketch of the conceptual abstraction of a particular reciprocating compressor.
In this way, each compressor component can be modeled in the proper level of detail. Latest efforts in this research line have been focused on the coupling of zero and one-dimensional models and CFD&HT models. Certain parts of the compressor can be solved by CFD&HT models, while other parts can be solved by models with less computational expenses. This is essential to make an efficient use of the computational resources when we are studing specific parts of the fluid flow or we expetimentate with complex geometries under the influence of the compression mechanism.

Fig. 3: Pressure-volume, relative suction valve displacement, chamber pressure and crank angle evolution during one cycle of the simulation (Tevap=-10ºC).

Fig.4 : Evolution of the temperature contour map during the first steps of the simulation. Use of a Low-Mach based CFD&HT model, solving turbulence with LES model using a Variational Multiscale.

 

Fig. 5: Fluid flow though a valve reed. Use of a explicit fractional step CFD&HT model. LES have been performed using the wall-adapting local-eddy viscosity model (WALE).