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.