Optimization of Lobed Perforated Panel Diffuser: Numerical Study of Orifice Geometry

Passive control of jet flows in order to enhance mixing and entrainment is of wide applicative interest. Our purpose is to develop new air diffusers for Heating Ventilating Air Conditioning systems, by using lobed diffusers, in order to ameliorate the users’ thermal comfort. For a lobed perforated panel as a diffuser (Meslem et al., 2010), the jet induction optimization will be made by means of optimizing elementary orifice geometry and by arrangement of the neighboring orifices on the perforated panel. An experimental and a numerical investigation using different turbulence models has been carried out over the flow field of turbulent twin cross-shaped jet, in a recent study (Meslem et al., 2011). In comparison to Particle Image Velocity measurements, it was shown that among the investigated viscous models, the SST k-w turbulence model is able to reproduce reasonably well ambient air induction, jets interaction and global expansion of the studied jets when the flow is resolved by numerical simulation through the lobed diffuser. In this study the SST k-w turbulence model is used for the numerical simulations of parallel cross-shaped jets, based on the previous experimental validation. This work is dedicated to the lobe shape effect on flow dynamics and induction performance of the twin cross-shaped jet. It was shown that the lobes with rounded peaks are more advantageous than the right angled lobes.