A 'meandrop' Method For The Characterisation Of A Sprinkler Spray In A Two-phase Cfd-particle Tracking Model - An Improved Alternative To The 'superdrop' Method.

The 'superdrop' method, which characterises a sprinkler as a statistical representation of a number of real drops, has been revisited. The intensive experimental data of a Wormald 'A' culp sprinkler in the pendant position has been used for its development, optimisation and evaluation. An alternative 'meandrop' method, which characterises the sprinkler spray by a simplified representation of the drop-diameter histogram associated with each emission sector of the spray, has been proposed to rectify the limitations associated with the need to use statistical distributions and weighting adjustment methods in the superdrop method. The superdrop and meandrop methods for characterising the sprinkler have been impleme~ited in the two-phase multi-cell zone sprinkler model SPLASH and the two-phase CFD JASMINESPARTA sprinkler model. The sensitivity of the predicted heat transfer on the spray to the number of superdrops or meandrops released per emission sector, and the effect of the sprinkler on the buoyant hot smoke layer due to a fire in an enclosure have been examined.