Numerical simulation on leakage and dispersion from onboard hydrogen storage cylinders with high pressure in indoor environment
Combined one model of virtual nozzle with the other dynamics model of leakage from high-pressure vessels,a calculation method for leakage parameters has been developed for high-pressure hydrogen cylinders in order to ascertain hydrogen enriched in indoor garages during hydrogen leakage from the vessels in hydrogen-powered vehicles.In addition,some changes of parameters like pressure and leakage rate with volume of 120 L and storage pressure of 70 MPa were cal-culated using the Matlab during the leakage.They were served as boundary conditions projected in the Fluent numerical simulator.Finally,the numerical model on hydrogen leakage and dispersion from onboard hydrogen storage cylinders with high pressure was established to simulate hydrogen concentration in indoor environment for the cylinders with different size of leakage hole,vehicle parking location and flow regime at the hole.Results show that(i)the indoor combustible hydro-gen cloud may reach the peak bulk and then decrease gradually in the leakage process.The larger the hole's diameter,the heavier the hydrogen capacity,and the longer the aggregation time;(ii)when this leakage in the garage corner,the average concentration of hydrogen cloud is the highest whereas the capacity is the smallest;(iii)when hydrogen at the leakage hole is dominated by buoyancy,it may disperse along the ceiling in the arched shape,which is favorable for the arrangement of both hydrogen sensors and leakage source.When hydrogen is dominated by momentum,its bulk is the heaviest,and large amount of hydrogen may gather underneath vehicle chassis.
High-pressure hydrogenHydrogen storage cylinderLeakage and diffusionNumerical simulationHydrogen
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