Saturation tower design for micro humid air turbine applications

The micro Humid Air Turbine (mHAT) has proven to have the highest potential of all mixed air/water micro Gas Turbines (mGTs). Turning a mGT into a mHAT however requires the installation of a saturation tower. Most common saturation towers use packing material to increase the contact area between compressed air and water. The packing material however causes a pressure drop, which has a severe negative effect on the mGT performance. To limit this pressure drop, we have developed a spray tower without packing that uses nozzles to inject water in the compressed air. In this paper, we propose a design for the
spray tower based on two-phase flow simulations. The two major constraints during the design were minimal pressure loss and tower size. A sensitivity analysis was performed in order to indicate the key parameters to obtain fully saturated air from the tower. Results of simulations showed that using a spray tower reduces the pressure losses significantly when compared to a classic saturation tower.
Sensitivity analysis showed that droplet diameter and injected water mass flow rate have the largest effect on the final size of the spray tower. Finally, a cross?current spray
tower design was proposed for a Turbec T100 mGT because the sensitivity analysis showed that cross?current droplets injection meets the design constraints best.