Hollow cone water sprays are used in many humidifying, cooling and scrubbing applications. For predicting the heat and mass transfer in these spray-air flow systems a two-dimensional numerical model simulating the conservation of mass, momentum and energy of air, and water, were developed. Model inputs include drop size distribution and velocities at nozzle spray angle; inlet air DBT and humidity ratio. The set of conservation equations are time marched numerically and conditions at various downstream locations are computed. Experimental data were obtained on a horizontal once through wind tunnel at three air Velocities with each nozzle at three pressures in parallel flow configuration. Nozzles of 3.2 and 4.8 mm outlet diameter were used. Drop diameter at break-up was measured from still photographs of the spray and these data were used in the model. Predictions of air condition at wind tunnel outlet for. given input conditions agree well with experimental data. (C) 1997 Elsevier Science Ltd.