Energy analysis of spray flash evaporation from superheated upward jets

Abstract

Flash evaporation is widely used in desalination technologies. The flash evaporation from upward and downward jets shows different characteristics. To study the upward flash evaporation, a model based upon droplet analysis is developed. The present model takes the droplet motion, droplet size variation and droplet temperature into consideration. The model is validated against the corresponding experimental results from previous literature and the calculated results from the model coincide with the experimental results. The dimensionless temperature profiles of the upward and downward flash evaporation are compared. Employing this model, the influences of the injection pressure, evaporation chamber pressure and flow velocity on the energy utilization efficiency and spray flash speed are investigated. The critical time and critical distance are also compared and analyzed.