Development of an Energy Efficient Stern Flap for Improved EEDI of a Typical High speed Displacement Vessel

  • Y. Hemanth Kumar Indian Institute of Technology Madras, Chennai - 600 036
  • R. Vijaya Kumar Indian Institute of Technology Madras, Chennai - 600 036
Keywords: Energy efficiency design index, Energy saving device, Exhaust emissions, Stern flap

Abstract

The surge in maritime trade is leading to large scale deployment of high-speed displacement ships by all nations. Cargo vessels are designed for a voyage in pre-determined routes at consistent speeds. On the other hand, high-speed displacement vessel engines designed with a capability to cater for top speeds are under-utilised during their normal course of operation. This sub-optimal utilisation impacts efficiency and increases emissions. In this study, a most favourable stern flap is designed for reducing the energy efficiency design index of a typical high-speed displacement vessel with a slender hull. CFD simulations and experimental model testing were conducted for 12 different stern flap configurations for determining most favourable flap design in the Froude no of 0.17-0.48. Performance of the most favourable stern flap was established by calculating, energy efficiency design index (EEDI) and fuel consumption based on typical operating profile. NOx, VOC and PM emissions were estimated in with and without flap condition. Studies demonstrated that the stern flap reduced effective power demand, average fuel consumption and emissions by about 8 per cent, which when considered for the ship’s operating life cycle, are significant. The most favourable stern flap reduced EEDI by 3.74 units and 1.98 units as compared to the bare hull condition and the required EEDI respectively, thereby demonstrating that EEDI could be used as an index to indicate stern flap efficiency.

Author Biographies

Y. Hemanth Kumar, Indian Institute of Technology Madras, Chennai - 600 036

Lt Cdr Hemanth Kumar obtained BTech in Naval Architecture & Shipbuilding from Cochin University of Science and Technology. He has subsequently completed Diploma in Naval Construction at IIT Delhi. He is presently serving as a commissioned officer in the Indian Navy and is pursuing research at IIT Madras in the field of Ship Hydrodynamics with respect to application of stern flap technology in the hydrodynamic drag reduction of ships.

R. Vijaya Kumar, Indian Institute of Technology Madras, Chennai - 600 036

Cdr (Dr) R. Vijayakumar (Retd.) is a PhD from Indian Institute of Technology Delhi. He is presently working as an Associate Professor at Department of Ocean Engineering at Indian Institute of Technology, Madras. He has published 27 paper in refereed journals and conference. His fields of interest include warship design, submarine design, ship hydrodynamics, ship dynamics and computational fluid dynamics, green ship technologies and autonomous under water vehicles.

Published
2020-02-10
How to Cite
Kumar, Y. H., & Kumar, R. V. (2020). Development of an Energy Efficient Stern Flap for Improved EEDI of a Typical High speed Displacement Vessel. Defence Science Journal, 70(1), 95-102. https://doi.org/10.14429/dsj.70.14669
Section
Naval Systems