Abstract A model providing detailed description of the trajectory and the internal composition of firefighting hose streams in air quiescent conditions is presented. The proposed model is based on a 1D Eulerian approach over the stream’s trajectory path, allowing for simultaneous multi-phase description of the fire stream (water-core phase, spray phase and air phase), including air entrainment, jet break-up, spray generation and multi-dispersion. A series of 6 large nozzle streams were studied experimentally. Predicted and measured stream trajectories were compared using Mean Absolute Percentage Deviation (MAPD) and Maximum Absolute Error (MAE) performance criteria. Among the 6 tests, a MAPD peak value of 4.6 and MAE of 17?cm were found, showing a good agreement with experimental measurements. Internal composition of a fire stream was studied numerically. Results suggested a predominance of water-core phase initially, accounting 50 of the fire stream’s mass just before its break-up. In contrast, an increasingly leading role of air phase through the trajectory path was found, accounting 90 of the fire stream’s mass at ground level. In addition, results suggested that 49 of the injected water flow was evacuated from the stream consequence of the progressive generation of the spray along the trajectory.
展开▼
