(114e) Hydrogen Car Fill-up Modeling

When filling up the tank of a hydrogen car from a hydrogen supply station, the pressure inside of the car's vessel will increase as well as the temperature. However, that temperature could rise to a potential hazardous level and explode. Thus, it is necessary to understand the behavior of hydrogen in the filling system in order to operate it at safe and optimal conditions. The filling system analyzed consists of a car tank with a side hose that is connected to the supply line by a valve. The model considers hydrogen to be a non ideal gas described by the Redlich-Kwong state equation. The flow of hydrogen into the car tank is modeled by two ordinary differential equations (mass balance and energy balance), and two algebraic equations (state equation and Joule-Thompson effect at valve) which constitute a differential algebraic equation (DAE) problem. This mathematical model is solved by coupling a typical fourth order Runge-Kutta with a Newton-Raphson Method for systems of nonlinear equations since the two algebraic equations cannot be solve analytically. The hydrogen behavior obtained from the model is then compared with experimental data to prove its validity.