Investigation on the thermal performance of a novel spray tower with upward spraying and downward gas flow

This paper presents the design and evaluation of a novel spray tower which called the reversibly used cooling tower with upward spraying and downward gas flow (RUCT-UD). Unlike conventional spray towers, RUCT-UD has no high-resistance drift eliminator and no restriction on the minimum droplet diameter, which gives it the potential to achieve better performance of heat and mass transfer and particle scavenging. A mathematical model was developed and validated by field experiments. This model is highly efficient in calculation due to the simultaneous consideration of rising and falling droplets. Using the model, the heat and mass transfer characteristics were investigated by a parametric study, which provides a theoretical basis for the tower design. After that, the performance of RUCT-UD was compared with that of other spray-type RUCTs. Results show that RUCT-UD is 45% shorter than RUCT-UU (the reversibly used cooling tower with upward spraying and upward gas flow) and RUCT-DU (the reversibly used cooling tower with downward spraying and upward gas flow), meanwhile it could realize a high thermal performance like RUCT-UU. The particle collection efficiency of PM2.5 for RUCT-UD is 75.9%, which is higher than that of RUCT-UU (48.9%) and that of RUCT-DU (61.1%). The configuration of the proposed RUCT-UD might be applied to other spray towers for the performance improvement.