Pre-Swirl Duct of Fuel Oil Saving Device Design and Analysis for Ship

Abstract

Recently, with oil price jumping and environmental issues, Green ship is paid deep attention to by ship owner, operator, builder, class and government. Fuel efficiency and reduction of CO 2 emissions are expected to have a strong influence on the design and operation of merchant ships. Many ship owners and operators are seeking the more economic method by the best operating route and the application of reliable and effective energy saving devices. With the Energy Efficiency Design Index (EEDI) in 2013 attention will more than ever be focused at achieving maximum fuel economy in the hydrodynamic design of hull forms, their appendages and propellers. IMO requirements for CO 2 emission for ships will now be implemented for vessels ordered from 1st January 2013. So far, a lot of new idea and patents have been proposed, tested, claimed and applied for various kinds of ship type. This paper shows numerical and experimental work related to a study on a energy saving devices particularly for fuller ship such as merchant vessel of Tanker and Bulker. From the bare hull wake measurements, typical upper/lower asymmetry of hull wake at the propeller disk was found. The pre-swirl duct have been designed and reviewed to recover the loss of propeller running in that condition. The general function of the pre-swirl duct was set to work against this asymmetry of wake and generate pre-swirled flow into the propeller against the propeller rotating direction.

Maneuverability Performance of a KRISO Container Ship (KCS) with a Bulb-Type Wavy Twisted Rudder and Asymmetric Pre-Swirl Stator

“…The propulsion efficiency of a combination of ESDs was evaluated i study [9], in which APSS+FSR and APSS+WTR_Bulb improved the propulsi by 4% and 5.4%, respectively. Figure 3 shows the flow field analyzed usin 1.017 LPP (Length between Perpendiculars) position of the rudder (just beh der) for each case [9]. The port-to-starboard axial velocity balance improv APSS and a higher tangential velocity was recovered compared with the case The FSR and WTR_Bulb profiles and principal dimensions are presented in Figure 2 and Table 3, respectively.…”

“…The FSR, which is the reference for comparing the research results, has the same specifications as the semi-spade rudder provided by KRISO, and the skeg part attached to the hull is filled. The propulsion efficiency of a combination of ESDs was evaluated in a previous study [9], in which APSS+FSR and APSS+WTR_Bulb improved the propulsion efficiency by 4% and 5.4%, respectively. Figure 3 shows the flow field analyzed using CFD at the 1.017 LPP (Length between Perpendiculars) position of the rudder (just behind the rudder) for each case [9].…”

“…In addition, the wavy twisted rudder has better maneuverability than the conventional twisted rudder, whereas its efficiency is similar or slightly lower. The wavy rudder has been improved by aligning the wavy configuration to improve the propulsion performance as well as the maneuverability [8,9].…”

“…The wake flow on the port and starboard sides varies depending on the direction of rotation of the propeller and the upward flow of the stern. Therefore, an asymmetry in the number of blades (three blades on the port side and one blade on the starboard side) is introduced, which has several advantages [9,[16][17][18]. In this study, the effect of an APSS with rudders on maneuverability was evaluated.…”

“…The aim of this study is to determine the effect of ESDs (APSS and bulb) on maneuverability when the newly developed wavy rudder [9] was used. The experiments in this study were conducted in a towing tank at Pusan National University.…”