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CFD modelling of compressed hydrogen fuelling provides information on the hydrogen and tank structure temperature dynamics required for onboard storage tank design and fuelling protocol development. This study compares five turbulence models to develop a strategy for cost-effective CFD simulations of hydrogen fuelling while maintaining a simulation accuracy acceptable for engineering analysis: RANS models k-ε and RSM; hybrid models SAS and DES; and LES model. Simulations were validated against the fuelling experiment of a Type IV 29 L tank available in the literature. For RANS with wall functions and blended models with near-wall treatment, the simulated average hydrogen temperatures deviated from the experiment by 1–3% with CFL ≈ 1–3 and dimensionless wall distance y+ ≈ 50–500 in the tank. To provide a similar simulation accuracy, the LES modelling approach with near-wall treatment requires mesh with wall distance y+ ≈ 2–10 and demonstrates the best-resolved flow field with larger velocity and temperature gradients. LES simulation on this mesh, however, implies a ca. 60 times longer CPU time compared to the RANS modelling approach and 9 times longer compared to the hybrid models due to the time step limit enforced by the CFL ≈ 1.0 criteria. In all cases, the simulated pressure histories and inlet mass flow rates have a difference within 1% while the average heat fluxes and maximum hydrogen temperature show a difference within 10%. Compared to LES, the k-ε model tends to underestimate and DES tends to overestimate the temperature gradient inside the tank. The results of RSM and SAS are close to those of LES albeit of 8–9 times faster simulations. [ABSTRACT FROM AUTHOR]

A novel element for gas–liquid contact, a plate with rectangular windows was designed to enhance absorption process. Coexistence and interaction of wall‐bounded films and confined free films named as “twin‐liquid films” were observed on the plate. Volume of fluid (VOF) method was used to simulate its flow behavior. Flow phenomena such as flow around a step‐in, jet impingement, varicose waves, and sinuous waves were observed. Different from thin films flow on an unperforated plate, larger mean velocity, thinner film thickness, more intensive capillary waves, and stronger vorticity on the free surfaces were detected inside the window, and the disturbances could propagate over the whole plate. Three‐dimensional simulation results generally agreed with our experimental observations and further demonstrated complex wavy structures both inside and outside the window. The results would broaden traditional knowledge of liquid films flow and clarify the mechanism of mass transfer intensification for the plate with windows. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1458–1468, 2018 [ABSTRACT FROM AUTHOR]