Experimental characterization of the aeraulic behaviour of centrifugal fans in specific functioning modes and numerical comparisons with the SYLVIA code

The purpose of this paper is to present results obtained in the frame of the VentilSTAR program. This program has been carried out to perfect the modelling of fans in the SYLVIA code, developed by the French Institute for Radiological Protection and Nuclear Safety (IRSN) notably to simulate airflows in ventilation systems. The aeraulic behaviour of fans in normal functioning is well-known, but specific functioning modes could occur when fans are submitted to severe aeraulic conditions due to incidental or accidental cases. These modes correspond to turbine and reverse modes when negative values are reached for total head and airflow rate, respectively. For some ventilation modes, the fans can be stopped. To model these modes, transient behaviour during starting and stopping operations, as well as the behaviour of a stopped fan, must also be known. Thus, the objectives of the VentilSTAR program are to experimentally characterize the aeraulic behaviour of fans in these modes, to compare results with the numerical results of the SYLVIA code, and to propose improvements of the modelling of fans if needed.