Research On Ballast Water Allocation Optimization For Pump And Gravity Self-flow Combined Ballast System Of Floating Cranes

The floating crane is one of the key equipments for rescue,salvage,large-scale offshore projects and deep sea operation.Ballast systems and their ballast water allocation are the key issues in determining the efficiency and safety of offshore operations.With the development of large-scale,automatic and intelligent floating cranes,it is difficult for manual experience to meet the demand of ballast water allocation for safety and high efficiency.Therefore,efficient and automatic ballast system has become an urgent need.This paper analyzes the typical working conditions and operating characteristics of the full-revolving floating cranes during the construction process,and establishes the optimization model and efficient solution algorithm of the ballasting time based on the ballast pump and gravity self-flow combined ballast system.The main research contents include:First,the working principle and operation flow of the ballast system based on the combined ballast system are analyzed.Based on the hydrostatics and optimization theories,the optimization model with the ballast water high efficiency allocation for floating cranes based on combined ballast system is built.The minimum total ballasting time is set as optimization objective.The ballast water height is set as optimization variable.The balance and stability of the hull is set as constraint condition in the ballasting process.This model provides decision model support for efficient and automatic allocation of ballast water.Second,because the ballasting process is the Markov process,the dynamic programming optimization model is established,which divide the ballasting process into multiple stages based on crane turning angle to solve the optimal ballasting process.Furthermore,the flow of the algorithm is given,which is the basis of the solution.The analysis of a numerical simulation case shows that the ballasting time of the combined ballast system is reduced by 41.2%compared with the ballast pump system.Third,based on the established ballast water allocation optimization model of the combined ballast system,the design scheme of the ballast water allocation system and its ballast water allocation pipeline system for the floating crane is proposed.The design scheme includes valve control system,pipeline flow-rate monitoring system,ballast water pump system and pipeline system layout design,which provide technical support for the automation of floating crane ballast system.This paper can provide theoretical and technical supports for selecting the optimal ballast water allocation scheme based on combined ballast system during the construction process and building the automatic ballast system to realize the dynamic ballasting computer control for large ships,which can improve the working efficiency and reduce the energy consumption of floating cranes.