Target variables Sample Clauses
Target variables. The target variables are the most relevant variables for each phenomenon that will be considered for the comparison between simulations results and experimental data. Those target variables should be outputs of simulations. For each phenomenon, main and specific parameters permit to understand the physics behind the phenomenon. Those target variables can show the evolution of the parameter in space or/and in time. All of those target variables are given in function of the different means and techniques of measures currently available and in function of the experiments/experimental measures from the validation model database.
3.2.1 Release and mixing of gaseous hydrogen, including permeation Table 3- Target variables for release and mixing of gaseous hydrogen Direct target variable Derived target variable Comments erisatio n of the leak- source Pressure and temperature inside the hydrogen storage This will permit to calculate the flow rate and affect flow rate and temperature of released vessel and in the pipe hydrogen. If the pressure into the vessel is superior to 70b the law of perfect gases is not applicable Flow rate (mass / volume) From the flow rate, the velocity can be calculated if the diameter (and density) is known Pressure and Temperature dynamics in the nozzle exit Difference in temperature of released hydrogen and surrounding air in enclosure could affect mixing, e.g. for blowdown releases when temperature of gas in the nozzle exit is relevant. Jet/Plume Hydrogen concentration dynamics For all variables, the values could be provided both in the jet and/or outside the jet areas. (distribution in space and time) Size of jet; Length, distance to the LFL and UFL Mass and volume of hydrogen in flammable envelope Derived from the concentration distribution field. Can give an idea of the total quantity of hydrogen released Velocity flow field in the jet, at the nozzle (distribution in space and time) Turbulent fluctuation velocity Should include the turbulence intensity u’ and length scale Lt (Turbulent flows only) Visualisation of jet shape Schlieren and BOS techniques of visualisation of changes in gas density are useful for validation, e.g. for transition of momentum-dominated jet to buoyance-controlled. Dispersion Hydrogen concentration dynamics Concentration field In order to describe the transitory regime, steady regime and the transition Gradient of concentration Flow Rate Average velocity Residual turbulence Pressure dynamics into the enclo...