Classification society ABS and owner and operator of LNG carriers GasLog LNG Services have completed a joint development project demonstrating a new approach to evaluating LNG boil-off rate (BOR).
“By expanding the application of computational fluid dynamics (CFD) analysis to simulate the LNG BOR in cargo tanks, owners are able to better predict boil-off gas and account for it in future designs and operations of LNG carriers,” Howard Fireman, ABS Chief Technology Officer, said.
LNG boil-off gas is the vapor phase of LNG carried in a cargo tank. Accurate assessment of the rate of LNG boil-off gas generation is said to be critical for the design of the cargo tank and the boil-off gas processing system.
To support the project, a CFD analysis procedure was developed modeling the physics of heat transfer, boiling, phase change and vapor flow. Extensive simulations were run on a representative LNG carrier and actual BOR measurements were taken to demonstrate the accuracy of the analysis results, according to ABS.
“By taking a collaborative approach with ABS on this project, we were able to demonstrate and prove the viability of CFD analysis to determine LNG BOR,” Vassilis Millas, GasLog FSRU Project Engineer, commented.
“Being able to predict BOR in various operating conditions will allow us to build efficiencies into future designs,” Millas added.