Experimental Study of Direct Contact Condensation of Steam on Water Droplets

Abstract

Air or water cooled condensers are used to reduce the moisture content of the air in some devices. Because of disadvantages of these systems such as long drying time, high energy and water consumption, it is required to find a new system for dehumidifying air. This paper represents an experimental study of drying air by injecting water spray into hot and humid air. Spray water is injected into the moist air, in the meantime interaction of subcooled water droplets with air direct contact condensation occurs. As a result of this phenomenon steam condenses on the surface of the droplets due to temperature of water droplets less than the dew point of air. As a consequence of condensation latent heat is released and it increases the water temperature. Experiments were carried out to investigate the effect of different parameters on the dehumidification process i.e., spray droplet diameter, spray water flow rate and spray nozzle configuration (parallel counter). In this investigation maximum dehumidification performance was obtained when air is supplied with higher relative humidity. It was observed that for a given spray configuration, increasing flow rate of water spray leads to higher reduction in humidity ratio of moist air. The effect of spray configuration was also analyzed and maximum decrease in humidity ratio was observed in counter-flow arrangement.