Design and Numerical and Experimental Investigation of Pre-Swirl Stators PSS

This paper describes a CFD based approach to the design of a Pre-Swirl Stator (PSS) to be used as Energy Saving Device (ESD) on a retrofit chemical tanker. The designed PSS is shown to deliver 4% power savings at vessel selfpropulsion condition through a relevant speed range in full scale. This is close to the maximum gain statistically achievable with this type of ESD, under comparable propeller loading. Analysis of velocity and kinetic energy fields is presented to explain the mechanisms behind power saving. An extensive experimental program, including flow field measurements without and with ESD, is conducted to provide additional validation material on the present ship and to verify the ESD performance.