An experimentally validated mathematical and CFD model of a supply air window: Forced and natural flow

Computational Fluid Dynamics (CFD) has been used, with considerable success, in modelling the physics in supply air windows. In this research, a comprehensive three-dimensional CFD model is proposed. Under the conditions investigated, the temperature rise and heat gain ranged from 6 K to 24 K and 23.45 W/m2 to 96.34 W/m2, respectively. The temperature rise and heat gain were higher in the natural flow case than in the forced flow cases. The models were experimentally validated in terms of velocity field, flow field and temperature rise. The velocity field was measured using Laser Doppler Velocimetry (LDV) and the overall flow field was captured using smoke for flow visualisation. Qualitatively, the CFD predictions are in good agreement with experiment. Quantitatively, there is noticeable error between experiment and CFD. The average error between CFD and experiment is: 3.46 K for temperature values at the outlet, 35% for axial velocities in the cavity and 44% for turbulence intensity in the cavity. The results indicate that good agreement could be obtained, between experiment and CFD, if the LDV seeding issues are resolved and a turbulence model that is capable of resolving anisotropic turbulence and transition is used.

► First LDV velocity and turbulence measurements in a supply air window to date.
► Flow visualisation of flow field in supply air window for natural and forced flow.
► 3D mathematical and CFD model of a supply air window for both natural and forced flow.
► Incorporated solar model to predict effect of solar radiation in supply air windows.
► Fan-induced swirl and buoyancy via temperature dependent fluid properties included.