Improvement of mooring tests of main engine running to fixed pitch propeller

Abstract

The most important stage in vessel’s construction is acceptance tests. By testing the main power plant of the vessel the design solutions adopted to ensure stable operation of the main engine and the propeller are checked. Such a check of the main engine according to design characteristics at the quay wall can significantly reduce sea trials cost. In practice, the peculiarities of the propeller operation at zero free-flow velocity at the quay wall limit the operating modes of the main power plant and the possibilities of mooring tests. There are considered the traditional and innovative simulation methods and tools used in mooring tests. The methods allow unloading the engine in terms of torque bringing its operation mode closer to the design parameters. An urgent scientific and technical problem has been solved to reduce the mechanical stress of the main engine, which operates according to the mooring characteristic on a fixed pitch propeller. The factors influencing the value of the resistance moment of the propeller at a zero vector of the incident flow are determined. Possible directions for improving the acceptance tests of the main power plant by supplying an additional environment, i.e. air to the suction surface of the propeller blade, are substantiated. In the complex of computational fluid dynamics, a computational model of a fixed pitch propeller has been created. The amount of air required to change the propeller operating mode has been estimated. Resistance moment of the propeller for various methods of air supply to the propeller has been analyzed. Additional means of controlling the main engine operating mode at the stages of the ship's life cycle are proposed.