A fixed-grid frost formation model is presented. In constrast to the previous studies, the present work accounts for a unified domain composed by both frost that is being formed due to phase changes under a saturation state and free humid air. Moreover, a porous treatment is given to the frost structure in which advective terms are taken into account as well as variable thermophysical properties. A 2D numerical test consisting on a duct flow with a cooled lower boundary is performed. Aspects related to the rate of growth as well as to the implemented finite volume approach have been analysed, proving the method to
be a valid candidate to simulate the free-air-frost coupled problem.
The aim of this paper is to present the numerical resolution of suction muffler configurations (by means of a tridimensional, unstructured, parallel and object oriented CFD&HT TermoFluids code (Lehmkuhl, et al. 2007) specially adapted to low Mach models (Lopez et al. 2012), coupled with the numerical resolution of the whole compressor domain (by means of a modular, unstructured and object oriented NEST-compressors tool (Damle et al. 2011) to simulate the thermal and fluid dynamic behavior of hermetic reciprocating compressors). The numerical results aim to evaluate the influence of the suction muffler geometry on the mass flow rate and compressor efficiency performance, while considering the whole compressor working conditions in a coupling manner. In that sense, the CFD&HT resolution of the muffler is obtained with boundary conditions obtained from the numerical simulation of the rest of the hermetic reciprocating compressor. The use of Large Eddy Simulation (LES) models for the turbulent suction muffler analysis; the adaptation of Low Mach formulation avoiding the full incompressible numerical problem, and the coupling of a numerical simulation model of the whole compressor as boundary conditions, are the important updated numerical aspects presented in this paper.