Extension of the Steady Flow Duration of a Ludwieg Tube Using a Reservoir-Orifice Method : Part 1. Case of Orifices with Fixed Opening Area

A reservoir-orifice method has been used to extend the steady flow duration of a Ludwieg tube. The unsteady expansion waves generated by the opening of a valve or a diaphragm interact with the orifice plate which separates the reservoir gas from the supply tube gas. The interaction process is investigated, and the conditions when compression, Mach, or expansion waves will be reflected from the orifice are clarified. During the interaction process above mentioned, the flow from the reservoir is necessarily choked at the orifice. Therefore, it would be impossible to reflect only Mach waves throughout the process of the interaction. The reservoir-orifice method is more effective when a quick-opening valve is employed instead of a diaphragm, and the extended flow duration amounts to about 20 to 50 percent of that of the conventional Ludwieg tube.