Correlations of Fuel and Helium Flow for Holes with Very Small Leak Rates

The relationship between the leak rate of hydrocarbons (HC) and helium through small channels is being evaluated. Measurements of the flow of HC down micro-channels through walls are compared with theoretical models. It is shown that a realistic model for fuel micro-leaks is that of a channel with length/diameter >> 1. HC flow through such channels is shown to be laminar for driving pressures of at least 3 kPa. These results may be used to provide upper bounds for fuel loss estimates using helium leak detection techniques.