CFD-based design and experimental verification of energy saving solutions for the STREAMLINE tanker
Dr. Francesco Salvatore, M. Falchi, CNR-INSEAN - Italian Ship Model Basin, Italy; R. Bensow, Chalmers University, Sweden; T. Bugalski, CTO, Poland; G. B. Deng, P. Queutey, CNRS-ECN, France; E. J. Foeth, MARIN, The Netherlands; D. Hafermann, HSVA, Germany; T. Rung, TUHH, Germany
The reduction of fuel consumption of marine vessels is nowadays motivated by both economic and environmental considerations. The convergence of these two sometimes conflicting interests yields a strong impulse to explore the feasibility of (quasi-)zero emission vessels in the (near?) future and, in parallel on a shorter timescale, to demonstrate the economic profitability of retrofit-solutions for a better hydrodynamic efficiency of existing vessels. The development of advanced Computational Fluid Dynamics (CFD) and numerical optimization models for the analysis and design of energy saving solutions has been one of the main objectives of the STREAMLINE Project, a large collaborative R&D initiative funded by the European Union under the Seventh Framework Programme. The four year project coordinated by Rolls-Royce ended in February 2014. In parallel with activities addressing radically new propulsive concepts, a specific focus was dedicated in the project to investigate the capability of computational models to design propulsion layouts with enhanced hydrodynamics with respect to the state-of-art. Design and optimization studies considered as a common baseline a 7000 DWT single-screw vessel representative of small-size short-shipping vessels populating European sea routes. Identified by project partners, this configuration has rapidly imposed as an interesting case study (the “STREAMLINE Tanker”) taken as benchmark in other EU-funded R&D projects. Energy saving solutions for the STREAMLINE Tanker addressed in the project included a completely re-designed hull aftbody and propeller as well as a variety of retrofit-type studies:
1. One optimised procelle
2. Two optimised rudders
3. Three alternative inflow improving devices.
In parallel to CFD studies, an extensive experimental work was performed to characterise the hydrodynamic performance of the original model and of all the retrofitted configurations. Ship hydrodynamic performance results from model tests and predicted at design stage were compared. At the Workshop, an overview of results from computational and experimental studies will be presented. Considering obvious time and budget limitations within the project, the final aim of the work was not to deliver actual drawings of devices to be installed on an existing ship. The objective was rather to analyse the capability of CFD-based tools to correctly describe and predict the mechanisms through which energy savings can be achieved by hull retrofits. Achievements in this area at the end of the project will be discussed through examples.