| According to the Paris Agreement,the United Nations Environment programme requires that global carbon emissions must be reduced by 7.6% per year from 2020 to2030,otherwise the incidence and damage rate of climate induced natural disasters will increase significantly.Reducing ship energy consumption,improving energy utilization rate and reducing carbon emissions is an important development direction and research goal of the ship industry.With the application of composite propeller more and more widely,the energy saving and emission reduction of composite propeller has become the focus and difficulty of current research.Propeller rudder matching is an easy energy saving measure.The designability of composite materials and propeller rudder matching provide more research space for energy-saving and emission reduction design of composite propellers.Aiming at the nonlinearity of the composite propeller-rudder system,this paper presents the fluid-structure interaction control equation and corresponding numerical method of the composite propeller-rudder system,studies the characteristics and matching problem of the propeller-rudder system,realizes the pushover performance optimization under all working conditions combined with the pre deformation design and material design,and carries out the lightweight of the composite propeller by using the sandwich structure combined with the pre deformation design,the energy saving optimization effect is further improved.The main work of this paper is as follows:Based on the nonlinear problem of composite material and propeller-rudder interaction,a fluid-structure interaction control equation of composite propeller-rudder system is proposed,and a numerical simulation method of fluid-structure interaction of composite propeller-rudder system based on RANS equation combined with finite element method is established.The convergence and numerical results of the hydrodynamic performance of the propeller-rudder system and the bending and torsion deformation of the composite structure are verified.By comparing with the experimental results,the feasibility of the fluid-structure interaction numerical method proposed in this paper is verified.Based on the deformation characteristics of composite propeller and the interaction between propeller and rudder,the difference between composite propeller-rudder system,single composite propeller system and rigid metal propeller-rudder system is described.The propulsive performance and structural response of the composite propeller-rudder system are calculated,and the effects of rudder interference on the propulsion performance,pressure distribution,wake distribution,bending and torsion deformation and blade strength of the composite propeller are analyzed.By comparing the composite propeller-rudder system and rigid metal propeller-rudder system,the influence of rudder interference on composite propeller and rigid metal propeller and the difference between them are analyzed.Based on the influence of rudder on the distribution of wake flow field,the effect of propeller-rudder relative position on propulsion performance and structural response is discussed.According to the deformation characteristics of composite propeller,an optimization scheme of "high efficiency,low deformation" is proposed to improve the propulsion efficiency and enhance the service life of composite propeller blade,and the optimal propeller-rudder relative position is selected.Based on the purpose of energy saving and emission reduction and improving the efficiency of main engine,the effects of ply scheme and material properties on propulsion performance,structural response and rudder interference of composite propeller-rudder system were studied.An optimization scheme to improve the propulsive performance of composite propeller-rudder system under all working conditions is established.The propulsive efficiency of composite propeller-rudder system under design condition is improved by pre deformation design method.Based on propeller theory,a scheme to improve the propulsion efficiency of composite propeller-rudder system under off design condition is proposed by optimizing the best ply scheme or material properties,and the optimal layout is selected The layer scheme and material properties can improve the propulsion efficiency of the whole working condition.Compared with the experimental results,the feasibility of the proposed optimization scheme is verified.Based on the characteristics of light weight and high strength of sandwich structure,the performance of composite propeller-rudder system with sandwich structure was studied.In this paper,a numerical simulation method of fluid-structure interaction for sandwich composite propeller-rudder system is established.The accuracy of the numerical method is verified by comparing with the experimental results.The effects of the sandwich structure on the propulsion performance,bending and torsion deformation,as well as the natural frequencies of dry and wet modes of the composite propeller-rudder system are analyzed.The influence of different panel thickness and core material on the performance of composite propeller-rudder system is discussed,which provides a theoretical basis for the structural design of sandwich composite propeller.Based on the influence of sandwich structure on propulsion performance,the propulsive performance of composite propeller-rudder system with sandwich structure was improved through pre deformation design.The blade deformation of sandwich structure and solid structure composite propeller and the propulsion efficiency of non design working condition after pre deformation design were compared,and the propulsion efficiency of off design condition after blade deformation and pre deformation design was explored It provides more research space for improving the propulsion efficiency of composite propeller under all working conditions... |
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