Future Outlook of Artificial Cavity Application for Reducing Hydrodynamic Resistance of Containerships

Abstract

Absolute commitment to reduce the impact of greenhouse gas emissions while increasing fuel efficiency and power density requires further enhancement of prime mover characteristics and special coatings, but mostly requires compliance with EEDI (energy efficiency design index) measures. For the container shipping industry this represents significant increases in fuel costs that can be mitigated above all by reduction of power demand, that is, of ship frictional resistance. In this respect, this paper discusses advantages attainable by application of the ACS (air cavity system) technology on the basis of recent KSRC (Krylov State Research Centre) studies. Savings in operating costs yielded by the enhanced propulsion performance for ships fitted with this system are illustrated by a case study of a containership.

Potential Energy Savings of Air Lubrication Technology on Merchant Ships

“…According to the sea-trial results for a cruise ship from Foreship (Pavlov et al, 2020), a relatively small tendency of net power saving due to air bubbles according to ALS onoff was seen for Beaufort scale 6 and above compared to less than Beaufort scale 4. According to the model test of a tanker by Borusevich et al (2017), as the sea-state (ss) increased, cavity instability due to waves occurred in PCDR. As a result, the power saving efficiency of the air cavity system dropped by 20% in ss5, 40% in ss6, and 90% in ss7, and was hardly functional above.…”

“…7(c) shows the results of PCDR analysis of two container ships. As shown in the figure, it was not possible to collect the power consumption of the compressor according to speed from the relevant research (Borusevich et al, 2017;Pavlov et al, 2020), they were compared in terms of power saving by ALS, without correcting for compressor power. Looking at the predicted results, it can be seen that it is in quite good agreement with the results of two ships within the computable area.…”