Numerical Investigation of The Effect Of Geometries with Different Cross Section Expansion on The Flow in An Empty Cell with An Anemostat Type Diffuser Designed For Air Conditioning Power Plants

The output cross-sectional area of the fans used in the air conditioning power plants is smaller than the cross-sectional area of cells, which are located after the fan, such as heating/cooling batteries, silencer, filter, mixing chamber or heat recovery. In order for the air conditioning power plant to operate efficiently, the air that the fan blows must spread to the next cell with the lowest possible pressure drop and homogeneous velocity distribution. Diffusers are used to spread air from a small to a larger cross-sectional area. In this study, both the structure of the sudden section expansion in the empty cell and the effect of the diffuser structure used in the inlet section have been numerically investigated to provide a homogeneous distribution of air at shorter distance in the empty cell. Five different geometries (sudden section expansion with square geometry, section expansion with cut geometry from 45° on both sides, section expansion with cut geometry from 45° on four sides, section expansion with cut geometry from 15° on both sides, section expansion with cut geometry from 15° on four sides) have been created to determine the effect on flow of the structure of the section expansion of the empty cell. Flat (pyramid height = 0 mm) and pyramid (pyramid height = 30, 60 mm) shaped anemostat type diffusers have been used as the diffuser structure. The effect of five different cross section expansions where anemostat type diffuser is used at three different heights with 80° wing angle on the pressure drop and the velocity distribution in the empty cell has been investigated numerically. As a result of this study, the lowest pressure drop has been obtained in the empty cell with a section expansion with cut geometry from 45° on four sides, and it has also been determined that the pressure drop reduces with increasing the height of the diffuser pyramid. The homogeneous airflow in the empty cell with a section expansion with cut geometry from 45° on four sides has been found at h = 0 and 30 mm pyramid heights in the anemostat type diffusers at the 80° wing angle.