A design scheme of the direct air intake system of a large bulk carrier is proposed in order to reduce the energy consumption of the ship. The rationality of the design is analyzed by numerical simulation based on the computational fluid dynamics (CFD). And the application of the direct air intake system on the ship is also discussed. Theoretical analysis and ship trial show that the flow velocity in the intake duct is consistent with the designed flow velocity, and the total resistance of the direct intake system is much lower than the allowable limit value. The outboard air can be directly inhaled through the self-absorption capacity of the turbocharger, and the system design is reasonable. By applying this system, the fuel consumption of the main engine and auxiliary engine is reduced, the total energy consumption of the fan in the engine room is reduced by 50%, and the initial investment recovery cycle is short with reduced cost of ship operation.

The increasing popularity of polar shipping routes poses greater challenge to the marine cold protection technology. Considering the importance of the cold-proof design of the sea chest, the key requirements of the sea chest in the ice region in the relevant specifications of the classification society are introduced in order to ensure the stable operation of the ship in polar environment. The current cold protection technologies are classified and analyzed from the structural design, structural layout and auxiliary deicing according to the principles of different cold protection technologies. The application of the cold protection measures based on different technical principles in different design schemes are highlighted by comparing the characteristics of four cold protection design schemes. The unique technical key points of the cold protection design of the sea chest in the ice region are summarized. It can provide ideas for promoting the scientificity and rationality of the cold protection technology of the sea chest in the ice region in subsequent researches.