| Liquefied Natural Gas ship(hereinafter referred to as LNG ship)is a ship specially used to transport liquefied natural gas.During the operation of LNG ship,the liquid cargo containment system is an important structure to ensure its safety,efficiency and economy.Due to the particularity of the cargo,the huge temperature difference between the inside and outside of the cargo tank will cause the heat of the environment to continuously flow into the tank,causing the loss of evaporation of the cargo and increasing the pressure of the cargo tank and threatening the navigation safety of the ship.In addition,the special installation platform for the enclosure system is the key structure to ensure the smooth construction of the LNG ship,and the research on the Mark-? type LNG ship installation platform and its enclosure system is basically blank in China.Therefore,studying the structural strength of the installation platform of such LNG ships and the thermal insulation performance and evaporation rate of the enclosure system at low temperatures are of great significance for the design and construction of real ships.In this paper,the Mark-? LNG ship simulation cabin enclosure system(hereinafter referred to as the simulation cabin)with a volume of 130m3 and the installation platform are the research objects.The thermal insulation performance of the simulation cabin at low temperature and the structural strength of its dedicated installation platform were developed.The series of theoretical and experimental research can be summarized as follows:(1)Design the low-temperature test plan of the simulation cabin,select the equipment and instruments used in the test,and introduce the data acquisition system and the test process.Refer to the test process to reasonably design the installation position of the sensor and the test piping system.According to the difference between the simulated cabin and the actual ship,the theoretical correction formula of the evaporation rate is obtained,which provides a basis for the correction of the evaporation rate;(2)Perform low-temperature performance tests on the simulation cabin,and obtain the temperature distribution of the insulation layer during the pre-cooling process of the simulation cabin and the liquid cargo evaporation data at the rated charging rate.And use the evaporation rate correction formula to convert the testevaporation into an evaporation rate and then modify it to obtain the evaporation rate of the actual ship.Verify the thermal insulation performance of the liquid cargo containment system of the simulated tank through the temperature distribution of the pre-cooling situation and the corrected evaporation rate data;(3)Using the finite element software Ansys Fluent as a tool,the calculation models were established respectively,and the temperature change and evaporation rate of the simulation cabin during the low temperature test pre-cooling process were simulated and simulated,and the temperature distribution of the insulation layer during the pre-cooling process and The numerical solution of the evaporation rate of the simulation cabin,and the comparison and analysis of the calculation results and the test results,to verify the applicability of the finite element method for the study of such problems;(4)According to the structural characteristics and installation requirements of the simulation cabin enclosure system,design a set of installation platform structure that can meet the requirements of use.Using the finite element software Ansys Workbench as a tool,a three-dimensional model was established,buckling strength analysis was performed on various typical working conditions,and the strength of the installation platform components under different working conditions was checked.The strength test was carried out on the typical telescopic beam system of the installation platform,and the deformation and stress values ? ? were measured under normal working conditions,and compared with the calculation results under the same working conditions. |
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