二零二三年 优质公开课TechnicalUpgradeandRetrofitofhullandpropellor.pptx

IMO Model Course 4.05Energy Efficient Operation of ShipsLecture 4-2:Technical Upgrade and RetrofitHangzhou, China 8 to 9 December 2016Dr Zabi BazariEnergy and Emissions SolutionsLondon, UK OverviewThere are a number of technologies that could be used on existing ships in order to reduce their hydrodynamic performance.This is referred to as “technology upgrade”.A number of such technologies are reviewed in this section. Devices forward of propeller - DuctsA number of designs exists:Wake field equalisation: The installed duct provides a more uniform wake field for the propeller.Reduction of propeller hub vortex: An improved flow behind the duct significantly reduces the propeller hub vortex.More suitable for the larger ships and hull forms.Mewis ductWake equalizing duct Devices forward of propeller – Pre-swirl statorEnhanced propeller efficiency via fitting of the bladed stators on the hull immediately forward of the propeller. The stator fins adjusts the flow into propeller as the same happens in in normal pumps with guide vanes. A gain of 4% in propulsion power is claimed. As with the ducts, the device is especially suitable for the larger ships and hull forms.Its first installation on a 320,000 DWT VLCC has resulted in a 4% reduction in fuel consumption with more installations afterwards.DSME system [SPPA] Propeller Boss Cap Fins (PBCF)Propeller has some flow losses that is recovered by PBCF.PBCF eliminates or reduces the hub vortices generated. As a result, PBCF can play an important role in reducing propeller generated noise and vibration.It is suitable for slow speed vessel. PBCF boost propulsive efficiency by about 5% and ship fuel efficiency by about 2%.PBCF can be retrofitted easily to an existing ship. Fathom Rolls Royce PROMASIntegrated propeller and rudder units An integrated system of propeller and rudder from fluid flow points of views.The effect of these units has been reasonably well documented in tests on models and in full-scale trials. A reduction o