An Exploratory Study on the Working Principles of Energy Saving Devices (ESDs): PIV, CFD Investigations and ESD Design Guidelines

Abstract

A new Joint Industry Project (JIP) has been initiated recently by MARIN, called ESD-JILI ( ( ( (机理 机理 机理 机理) ) ) ), looking into the working principles and scale effects on Energy Saving Devices (ESDs). Three ESDs have been chosen for the investigations in the first phase. They were a preduct with a supporting stator in the duct, a pre-swirl stator with asymmetric blade design and Propeller Boss Cap Fins (PBCF). Measurements of forces and moments on all components of the ESDs have been carried out in selfpropulsion model tests with dedicated sensors. Particle Image Velocimetry (PIV) technique has been used in the investigation of the detailed flow around the ESDs. In order to investigate the scale effects in model tests, a fullscale wake field was approximated by a 'smart ship model'. Computational Fluid Dynamics (CFD) calculations were carried out both for designing the smart ship model and also for the detailed flow around the ESDs. Some findings and fundamental issues on scale-effects of the ESDs are addressed in this paper.

Experimental and numerical analyses of the hydrodynamic performance of propeller boss cap fins in a propeller-rudder system

“…The contours represent the axial velocity magnitude, and the vectors represent the velocity magnitude and the direction of the plane. Figure 11 shows that the velocity distribution changes significantly at the plane center, and the result is similar to the result obtained by PIV (Dang et al, 2011). Due to the installation of the PBCF, the axial and rotational velocity magnitude at the plane center reduces, and there is even a small amount of reverse rotation.…”

“…The measured increase of the propeller efficiency was from 1% to 1.5%. The Joint Industry Project (JIP; Dang et al, 2011) started by MARIN (Maritime Research Institute Netherlands) conducted a research on the flow field distribution and energy-saving mechanisms of PBCFs, and particle image velocimetry (PIV) was used in the experiment. The results showed that the velocity around the hub vortex decreases.…”

Numerical Simulation and Experimental Studies on Aft Hull Local Parameterized Non-Geosim Deformation for Correcting Scale Effects of Nominal Wake Field

“…It is always difficult to judge sea trial results because the efficiency gains by the ESDs are often in the same order of magnitude as the uncertainties of the sea trial measurements. In addition to this, the scale effects of the ESDs can be rather large, because most of the ESDs are fitted to a place in the boundary layer of the vessel which differs from that in model scale [7][8][9].…”

A non-geometrically similar model for predicting the wake field of full-scale ships

“…Di Felice (2004) and Felli et al (2006) had gotten the main characteristics of propeller flow field measurement in a large cavitation tunnel by particle image velocimetry (PIV). Dang et al (2012) performed PIV measurements of the local flow fields of a ship's hull and around its energy-saving appendages. There have been some efforts in measuring full scale wake, for example, in project EFFORT and DALIDA.…”