TY - JOUR 
A1 - Zamora Parra, Blas
AU - Sánchez Kaiser, Antonio
AU - Lucas Miralles, Manuel
AU - Ruiz Ramírez, Javier
T1 - Analysis of the air-water droplet motion through cooling tower drift eliminators, including comparative efficiency evaluations of several types of devices, by numerical investigation
Y1 - 2011
SN - 2172-0436
UR - http://hdl.handle.net/10317/2076
AB - Mist eliminators (also called droplet eliminators, droplet separators or demisters) are devices that can remove liquid droplets from a gas flow. The gas flow laden with droplets is forced to pass through different channels, changing direction in a repetitive manner. Wave-plate (or vane type) eliminator are widely employed in chemical and industrial processes involving gas and vapour flows where mist removal is necessary for several reasons. For instance, one of the most important objectives is to restrict pollutant emission into the environment, as in cooling towers applications. Wave-plate mist eliminators can operate in vertical and horizontal situations, but in both cases, the removal of liquid droplets occurs mainly by inertial impaction. In cooling towers, spraying water is distributed over a heat transfer surface across or through which a stream of air is passing. Thus, water droplets can be captured by the stream of air and they will be carried out of the system. This phenomenon is known as drift. In countries with warm climate, inside the cooling towers the conditions of high temperature and humidity can strongly induce the spreading of pathogens agents, especially the Legionella pneumophila. The main disadvantage of installing mist (i.e., drift) eliminators is an increased pressure loss of the airflow. High-pressure loss contributes to lower flow rate of air or higher engine power of the ventilators. This fact leads to obtain lower overall efficiency values for the air-conditioning systems. Since a lack of systematic studies on comparative evaluation of morphologically similar separators has been detected, the behaviour of four wave-type eliminators having a similar geometry is studied. Both droplet collection efficiency and the pressure drop coefficient are calculated. Special emphasis is made on the validation of the numerical model with results taken from the literature, the study of the effects of relevant parameters, and the achievement of a procedure to evaluate the overall efficiency of each regarded type of eliminator. The obtained results may contribute to improve the passive droplets restraint systems in mechanical cooling towers, increasing the overall operation of the cooling tower on one side, and lowering their environmental impact on the other.
KW - Mecánica de Fluidos
KW - Particle flows
KW - Droplets
KW - Drift eliminator
KW - Turbulence
KW - CFD
KW - Uncertainty analysis
LA - eng
PB - Universidad Politécnica de Cartagena
ER -