Research On The Cargo Hold Anti-Sloshing System And Its Effect For The Liquefiable Cargo Carrier

Liquefiable cargo refers to solid granular cargo containing a certain amount of fine particles and moisture.In the process of maritime transportation,the Liquefiable cargo are easy to be affected by external forces and become fluid,which leads to the reduction of the deviation and stability of the cargo,and even causes the capsizing accident of the carrier,resulting in huge losses.In order to avoid this kind of accident,the way to control the water content of cargo is generally adopted at home and abroad.However,this method has some limitations due to the complex properties of cargo and imprecise moisture content measurement.Therefore,in order to solve the shortage of existing equipment and facilities,this thesis proposes a set of anti-sloshing system in cargo hold of a liquefiable cargo carrier.The anti-sloshing system prevents the cargo from large deviation by restraining the cargo on both sides of the baffles.In this thesis,the design,effect and optimization of the anti-sloshing system are studied from the aspects of model test and numerical simulation.In terms of model test,since it is difficult to carry out practical application test of the anti-sloshing system in the cargo hold of a cargo transport ship in a fluid state,a prototype model of the anti-sloshing system is manufactured in this thesis to verify the effectiveness of the anti-sloshing effect of the system through laboratory model test.The anti-sloshing system prototype is mainly composed of control cabinet,simulation cargo hold,anti-sloshing baffles,motor lifting module,hydraulic push rod,pressure sensor and so on.In order not to affect the cargo handling operation,the baffles can be retracted and retracted.At the same time,a series of replaceable baffles were designed during the machining process of the prototype,so as to explore the influence of different sizes on the anti-sloshing effect of the system and improve the system design.Considering the influence of baffles size,the prototype test of anti-sloshing system is carried out by using indoor swing platform.The results show that the system can effectively restrain the large movement of cargo in the cargo hold and reduce the forces at different positions of bulkhead caused by cargo movement.In addition,when the length of the baffles reaches l=0.4L,the system has a more obvious inhibition effect on cargo migration movement,which further confirms the importance of the design of the size of the baffles on the anti-sloshing effect of the system.In terms of numerical simulation,by comparing the cargo center of gravity offset and the cargo hold force,this thesis analyzes the effect of anti-sloshing baffles and explores the optimal baffles scheme,so as to improve the design of anti-sloshing system of cargo hold of a cargo transport carrier in fluid state.In this thesis,the discrete element software is used for numerical simulation,and 106 groups of working conditions are designed.Factors such as the installation height,size design and layout of the partition are considered.The installation position of the baffles is designed in four different heights with a gradient of20 mm,including above,above and below the surface of the cargo;Dimension design around length,width and area;The layout takes into account the schemes of single baffles and modular baffles.Taking laterite nickel ore with water content of 40% as an example,the following conclusions are drawn from the numerical simulation: under the action of a single baffles,when the height of the anti-sloshing baffles is near the surface of the cargo,the cargo’s center of gravity offset is smaller.Compared with the unimpeded sloshing system,the anti-sloshing system can reduce the cargo center of gravity offset by about24.74%.Meanwhile,under the same area,the anti-sloshing effect of modular baffles is better than that of a single baffles,and there is a long and wide combination(l=0.26 L,b=0.46B),which makes the anti-sloshing effect the best,and the maximum offset of the center of gravity of cargo in the slosh direction is reduced by about 30.76%.