Analysis of Properties of Thrust Bearing in Ship Propulsion System

Thrust bearing is a key component of the propulsion system of a ship. It transfers the propulsive forces from the propeller to the ship＇s hull, allowing the propeller to push the ship ahead. The performance of a thrust bearing pad is critical. When the thrust bearing becomes damaged, it can cause the ship to lose power and can also affect its operational safety. For this paper, the distribution of the pressure field of a thrust pad was calculated with numerical method, applying Reynolds equation. Thrust bearing properties for loads were analyzed, given variations in outlet thickness of the pad and variations between the load and the slope of the pad. It was noticed that the distribution of pressure was uneven. As a result, increases of both the outlet thickness and the slope coefficient of the pad were able to improve load beating capability.

Novel Ship Propulsion System

As the development tends towards high-speed, large-scale and high-power, power of the ship main engine becomes larger and larger. This make the engine design and cabin arrangement become more and more difficult. Ship maneuverability becomes bad. A new ship propulsion system, integrated hydraulic propulsion （IHP）, is put forward to meet the development of modem ship. Principle of IHP system is discussed. Working condition matching characteristic of IHP ship is studied based on its matching characteristic charts. According to their propulsion principle, dynamic mathematic models of IHP ship and direct propulsion （DP） ship are developed. These two models are verified by test sailing and test stand data. Based on the software Matlab/Simulink, comparison research between IHP ship and DP ship is conducted. The results show that cabin arrangement of IHP ship is very flexible, working condition matching characteristic of IHP ship is good, the ratio of power to weight of IHP ship is larger than DP ship, and maneuverability is excellent. IHP system is suitable for engineering ship, superpower ship and warship, etc.

Long-Term Performance Prediction of Oscillating Wings for Assisting Ship Propulsion at Actual Seas

In order to raise ship energy efficiency, the possibility of wave energy recovery by a pair of coil-spring connected oscillating wings for assisting ship propulsion in waves is investigated. A frequency domain hydrodynamic model based on potential theory is established to predict the effect of the oscillating wings on the ship in regular waves, in terms of reducing wave-added resistance and improving seakeeping performance. The proposed linear model is suitable for short-term prediction based on conventional spectral analysis techniques, thus making it possible to evalute the long-term performance of oscillating wings for assisting ship propulsion at actual seas based on wave statistics. A sample containership is adopted to study the performance of the proposed concept. The results show that the oscillating wings can effectively reduce the added resistance of the ship at actual seas. The feasibility of this green ship technology is proved.

RESEARCH ON WAKE ENERGY RECOVERY TECHNOLOGIES FOR A FISHING BOAT

Wake energy recovery of a ship’s propeller is an important research subject in ship propulsion field. Based on the study on the mechanism analysis and computation method of the hydrodynamic performance of the propeller-rudder-rudder bubble combination, computer simulation system was built and then used to design and simulate four kinds of rudder bubbles, then the model comparison tests with the original rudder was carried out and the sensible factors influencing the energy-saving effects of rudder bubble was also analyzed. On this basis, a further optimized design of the rudder bubble for a fishing boat was put forward, and comparison test on a real boat was then carried out. It is shown that the optimized rudder bubble design can effectively recover wake energy of ships and the rudder bubble installation features a simple operation and high cost-effectiveness, and the energy-saving effect of real boat test achieves 5.1%.