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Offshore Drilling and Production Platforms/Units
Published in Sukumar Laik, Offshore Petroleum Drilling and Production, 2018
In a ducted propeller, the open propeller is placed in a specially shaped housing called a duct. This thruster is illustrated in Figure 3.96. The primary reason for adding the ducting to the open propeller is to increase its efficiency or thrust output per unit horsepower. The increase in efficiency can be as much as 20% at the low speeds used during dynamic positioning.
Hydrodynamic loads and wake dynamics of ducted propeller in oblique flow conditions
Published in Ships and Offshore Structures, 2020
Jie Gong, Chun-yu Guo, Nhan Phan-Thien, Boo Cheong Khoo
Ducted propeller has the advantages of excellent maneuverability and high efficiency under heavy load conditions. Owing to the complexity of the operating environment and/or maneuvering commands, the ducted propeller is often found working in a state of off-design scenario (Dubbioso et al. 2013). For example, several ducted propellers are the main components of the dynamic positioning (DP) system for an offshore platform, and they frequently need to adjust the thrust direction during maneuvering operation just to keep the platform in the designated area (Carlton 2012). The motion of the platform or the actual sea conditions (waves, wind or current) may lead to a lateral flow and thus increase the non-uniformity of propeller’s inflow. The unsteady and asymmetric inflow causes unbalanced loads on the blades, resulting in the thrust reduction, stronger vibrations and potential structural damage to the propulsion system (Gaggero et al. 2014). Thus, it is evident that a deeper understanding of the ducted propeller behaviour in oblique flow could pave the way for improving the strategy for DP algorithms. Additionally, the analysis of the essential wake features in off-design condition benefits the interpretation of the varied hydrodynamic loads’ characteristics.
A critical review of different works on marine propellers over the last three decades
Published in Ships and Offshore Structures, 2023
Pritam Majumder, Subhendu Maity
There are various types of propellers with different purposes such as high loading cargo shipping propeller, general transport ship propeller, low noise producing propeller, ducted propeller, rim driven propeller and so on. In this section, different types of propellers with the proper purpose of application will be discussed in detail (Tables 1 and 2).