The article discusses the problems of flow condition modelling on real object as well as its reduced model while using similarity theory. Similarity criteria and model flow laws are derived by means of dimensional analysis. Presented is the computation of flow through the tunnel and its reduced model as well as the applied numerical methods.

The article presents the results of a numerical analysis of the flow conditions in the air distribution element in a combined refrigerator and freezer. A numerical analysis was carried out using the boundary conditions identified through an experiment. The article includes an analysis of the impact of the mesh type and the used turbulence models on the profile of the air flow velocity in the outlet openings of the used distribution element. The required ratio of the volumetric flow rates of the air absorbed by the fan, for the smaller to the larger outlet openings, should be 1:2.2. This air distribution ratio was monitored using three turbulence models: the SST model, the k- model and the RNG model, and two types of elements: tetrahedron and hexahedron, or combinations thereof. The obtained results were used as the basis for a modification of the geometry of the distribution element itself, and a concurrent modification of the size of the gap between the impeller and the internal space of the device.