Performance Model for Ultimate Heat Spray Ponds

Abstract

A mathematical model for the performance of spray ponds is developed using a detailed computational approach. The model considers heat transfer and evaporation from individual droplets of sprayed water and the pond surface, and drift loss from the sprays. Modification of the temperature and humidity of the surrounding air is taken into account in calculating heat and mass transport from the sprays. Flow of air through the spray field is considered to be either driven by the ambient wind, or by natural convection. Relationships for heat and mass transfer from the drops are derived from the empirical studies of Ranz and Marshall. Numerical experiments demonstrate that simplified models can still be useful for spray pond performance assessments. The models are validated with data on several industrial and nuclear power plant spray ponds, and with data from an extensively instrumented, experimental spray pond. Results of the validation studies demonstrate generally good agreement. These models are used in a complex methodology for predicting the performance of spray ponds used for nuclear power plant service, although it is not limited to this application. A companion paper describes the overall assessment methodology.