Numerical Evaluation of Exit Air of outdoor unit of Split-type Air-conditioner and Study the Grille Effect on the Exit Air Throw Distance and the flow Rate

Investigation of the air-flow in outdoor-unit of air-conditioner and study the effect of grille on exit hot air-flow characteristics has a great importance, especially in apartment complexes. In this research, the effect of two types of industrial grille (circular and square) and a suggested grille (designed with symmetrical NACA-0012 cross-section to guide the flow in desired direction) on air-throw distance and flow rate have been investigated. Numerical evaluations of flow behavior include geometrical modeling, grid generation, and flow solution within the computational domain. Flow simulation within the fan has been made using the multiple reference frame (MRF) and also the realizable kԑ turbulence model. For outdoor-unit with a circular grille, comparison between numerical and experimental results of three high-speed averages show 6.24 percent difference in exit flow rate. Results show that the grille of air outlet window reduces the exhaust air flow rate, increases the propeller’s rear pressure, and increases the number of vortices. Beside, from the non-dimensional aerodynamic performance and also air-throw distance point of view, the proposed grille, and circular grille respectively have the best performance.