Numerical and experimental study of a HVAC wall diffuser

Publication date: October 2014
Source:Building and Environment, Volume 80
Author(s): J.J. Martinez-Almansa , A. Fernandez-Gutierrez , L. Parras , C. del Pino
In this paper we have developed a Micro/Macro Level Approach (MMLA) method to model a conventional diffuser. This procedure reduces the number of points in order to solve the airflow in a room. This can be seen as a numerical box method, and it provides a number of variables at the inlet of the room (outlet of the diffuser) which are difficult to obtain experimentally, e.g. turbulent properties. Flow visualizations have been carried out to determine the shape of the plume. These qualitative experimental data are also compared with numerical temperature fields for sufficiently high Reynolds numbers and give accurate results. In addition, we report the throw and drop of the diffuser for different flow rates. Finally, the pressure drop of the terminal device has been obtained experimentally, and it is also shown that numerical results can predict it accurately. A discussion of two different methods to compute the pressure drop is given, showing the differences in relation to the airflow characteristics near the outlet of the diffuser.