Research On Ballast Water Allocation Optimization And Simulation Of Revolving Floating Cranes

With the vigorous development of marine resources around the world,the demand for offshore operations is increasing day by day.As the key equipment for offshore operations,crane ships play an important role in large-scale projects such as salvage,offshore oil development,offshore equipment installation and deep-sea engineering.With the increasing difficulty of offshore operations,crane ships are also developing in the direction of large-scale,complex and intelligent.In this paper,based on the analysis of the lifting operation process of large-scale full-slewing crane ship,the optimization model of ballast water allocation of full-slewing crane ship is established by considering the response time of valve and the flow time of ballast water in pipeline,which is solved by a practical example.Then,by building a simulation module,the floating state of crane ship during operation is analyzed and the matching strategy of crane and ballast water allocation is given.Finally,the feasibility of the optimization model and the accuracy of the simulation module are verified by experiments.The main research contents of this paper include:(1)Based on the theory of ship statics and optimization,the water level height of each ballast tank is taken as the optimization variable,the stability of the ship in lifting operation is taken as the constraint condition,and the filling time of ballast tank is taken as the constraint condition The corresponding operation time of the valve and the total time of the ballast water flowing in the pipeline were taken as the optimization objectives,and the optimization model of ballast water allocation for the full rotary crane ship was established,which laid a foundation for the design of the intelligent ballast water allocation scheme and the intelligent ballast system.(2)Aiming at the characteristics of large cranes,the Sequence Quadratic Program(SQP)method was used to solve the optimization model of allocation.Taking the ballast water allocation scheme of a crane ship with 25 ballast tanks as an example,the calculation results show that when the crane load is turned from the port side of the ship to 90,the flow direction of ballast water in the ship is from port to starboard,and later from stern to bow.Compared with the empirical scheme,when the ballast pump works at rated load,the ballast time is only 77% of the time required by the empirical scheme.(3)The simulation module is built based on Simulink,the simulation model is established,and the simulation analysis of the optimization scheme is carried out with the simulation case First of all,we simulated and analyzed the operation of the crane ship in the no-load state.It can be seen that the change of the ship’s trim is more obvious than that of the trim during the lifting operation.The change of the ship’s trim is small,and the allocation specification can be met without adding ballast water,so only the influence of the ship’s roll can be considered in the allocation process Secondly,the operation state when the ballast water is allocated in the crane is simulated and analyzed.By combining the operation state of the crane and the ballast pump,two matching strategies of the crane and the ballast pump are given to realize the matching and coordination of the crane and the ballast pump during the operation of the crane.(4)Finally,the ballast water allocation experiment of a full-rotation crane ship is carried out by using a real ship model,and the floating state of the ship in the empty tank state and the ballast water allocation state is measured.At the same time,combining with the simulation model,the feasibility of the operation of the crane ship in the waiting strategy is verified.