The full simulation of rapid refueling of a Natural Gas Vehicle on-board cylinder

Abstract

The full simulation of the rapid refueling of a Natural Gas Vehicle (NGV) on-board cylinder is presented. The cylinder is fueled with Compressed Natural Gas (CNG). A concurrent simulation of the heat transfer and flow inside the cylinder and its wall is a troublesome work. It has not been investigated in antecedent researches. Rapid refueling may cause a surprising temperature rise, which has a significant effect on final conditions and may breach the safety standards. In this research, Firstly, based on a numerical simulation, an equation has been developed for foretelling heat transfer rate between in-cylinder flow and inner surface cylinder wall. Afterwards, a thermodynamic method has been developed for foretelling pressure and temperature variations inside the cylinder and transient wall temperature during the refueling. The method has been applied to types I and III on-board storage cylinders. The numerical results compare well with prior related experimented values. The results showed that a major portion of heat dissipation from the in-cylinder flow is reserved in the cylinder wall. It was also found that ambient temperature during refueling process has sizeable outcomes on refueling behavior in general and in particular on the final in-cylinder temperature and filled mass. The results are also presented and compared for adiabatic cylinders.