Theoretical research of power flow on ship shafting systems

Abstract

Ship shafting system is the indispensable component of a ship power plant. The primary function of a ship shafting system is to carry out energy transfer from marine engine to propeller, transmit axial thrust produced by the rotation of propeller to the hull, and drive the ship ahead. Vibrational power flow combines the effects of force and velocity amplitudes as well as the irrelative phase angle in a single quantity, and thus can better reflect the transmission of vibration energy between various sub-systems of an integrated structure. In this paper, the nonlinear and linear simplified physical model of shaft system is established. The control equations of hull-bearing-oil film-shafting systems are derived. Power flow transfer characteristics of the coupling model are analyzed. Condition monitoring theory of large ship propulsion shafting energy flow distribution is proposed to provide methods and technical supports for optimal design, installation, performance monitoring and maintenance of large ship propulsion shafting, which can also be provided as a reasonable basis for extending the service life of the ship.