Research on the LNG Carrier Tank’s Thermal Transfer and Stress Finite Element Analysis
|School||Wuhan University of Technology|
|Course||Design and manufacture of ships and marine structures|
|Keywords||LNG carrier finite element analysis thermal transfer thermal stress Ansys software|
Natural gas is a very important resource, it clean-burning, pollution of small, usually low-cost production and delivery. It will become the world’s main source of energy in the future because of enormous reserves.The growing LNG trade makes the delivery of LNG has become urgent problems at present, LNG carrier is the most effective way for natural gas transport over ocean. So, the construction quantity and transport frequency of LNG carrier are increasing. In order to make sure the economy and security of LNG during transport, which requires tanks maintained at-163℃for a long time. LNG carrier should withstand a long time under low-temperature source which may cause thermal stress, to ensure that the hull structure have no damage, such as bending or cracking problems. Therefore, analysis the thermal transfer and thermal stress of LNG carrier, to ensure compliance with strength requirements and their safety during transport have great significance and value.This paper first introduces the background and significance about thermal stress analysis of LNG carrier, reviewed the research on this issue both at home and abroad. Briefly introduce the nature and characteristics of natural gas. Reviewed the tank systems and insulation systems of LNG carriers, which include construction methods and construction materials, analyzed and compared the different types of LNG carriers. Then, we carried out a more detailed introduction on the thermal transfer and thermal stress problems of the basic concepts and calculation principles, and a detailed derivation calculus about finite element method of the thermal stress analysis has been made. The article also introduce the use of finite element calculation method to calculus the thermal transfer and thermal stress analysis of LNG carrier tank and the application of ANSYS finite element. Analysis is based on 147000m~3 membrane type LNG carrier, using large-scale general-purpose finite analysis software ANSYS to calculate and thermal analysis in case of full load. Researched the effects of thermal stress on LNG carrier tanks strength and some conclusions are obtained: (1) when Invar membrane wall of the main screen damaged, the temperature distribution of tank can not meet the requirements of LNG evaporation rate less than 0.15%; (2) Temperature gradient is directly proportional to thermal stress (3) Deck, floor and other components subject are impacted temperature load should be appropriate toplate thickening.In this paper, the research work on the membrane type LNG carrier design and analysis of full load with a reference value.