Integrated Design And Calculation Method Based On Strong Dynamic Load Of The Partially Submerged Propeller

The conventional propeller is prone to the problems of hydrodynamic degradation and surface erosion caused by cavitation on high-speed ships,and the partially submerged propeller propulsion is one type of the main ways to solve this problem.However,due to the strong dynamic loads caused by the working mode of circulating water in and out of the blades of the partially submerged propeller,which has an important impact on the strength and fatigue life of the blades and the driving device.In this paper,the strong dynamic load of partially submerged propeller was studied,and the numerical calculation method and test measurement method of dynamic load were established;the dynamic load characteristics and structural strength of partially submerged propeller propulsion were systematically analyzed,and strength calibration criteria were put forward;the integrated design platform of partially submerged propeller propulsion was developed,and the dynamic load prediction and integrated design calculation method of partially submerged propeller were verified by practical application.In this paper,the research content are mainly as follows:(1)Aiming at the complex gas-liquid two-phase flow around the partially submerged propeller,the meshing strategy around the blade,wake zone and free surface was studied,and the applicability of turbulence model and the factors affecting the prediction accuracy of near-wall turbulence were analyzed.And thus,the numerical calculation method of the complex flows around the partially submerged propeller was established,which provided the technical method for obtaining the strong dynamic load of the partially submerged propeller.(2)The experimental research on six-component force measurement of the partially submerged propeller model was carried out,and the six-component dynamic load data processing and analysis method under the multi-coordinate system was formed;by using the stress-strain method and the fluctuating pressure method of oil cylinder,the bench test technique for dynamic load of full-scale partially submerged propeller was established;and thus the correlation between the model scale and the full scale of the dynamic load of the partially submerged propeller was revealed,which provides a verification method for the numerical calculation method.(3)The research on the influence of strong dynamic load of partially submerged propeller on the strength characteristics of propeller blade and its driving device was carried out,which broke through the load transfer and decomposition technology of the node of each component of the partially submerged propeller propulsion,and established the evaluation and calculation method of the static strength and fatigue life of the partially submerged propeller and its driving device,the relationship between the fatigue life and the static strength was analyzed through serial calculation,determined the safety factor of partially submerged propeller and its core components,and put forward the strength calibration criterion of partially submerged propeller propulsion.(4)Through the parametric influence research of partially submerged propeller,the digital atlas of hydrodynamic performance was established,and combined with the load distribution function and strength checking method of driving device,the integrated design flow of partially submerged propeller propulsion was formed;the integrated design platform of partially submerged propeller was developed,and the serial design of digital prototype of partially submerged propeller was completed,which provided design method for practical engineering application.(5)Based on the land performance test and the comprehensive performance test of the real ship,the test verification system of the partially submerged propeller propulsion was proposed,which supported the establishment of the industry standard of the partially submerged propeller propulsion.And finally,the reliability and practicability of the integrated design calculation method for the partially submerged propeller propulsion were verified by engineering application and ship test.This research basically solves the problems of lack of safety and reliability evaluation method and insufficient verification in the design of partially submerged propeller propulsion,and provides an effective integrated design method and verification system for the conceptual design and product development of partially submerged propeller propulsion.