Quasi-One-Dimensional Modeling of an Adiabatic-Compression Preheated Ludwieg Tube

Abstract

A novel hypersonic facility is proposed that will reproduce the high pressures and temperatures necessary for the accurate simulation of hypersonic flight conditions. It will provide sufficient test times for investigating unsteady, transient flow effects while maintaining high flow quality due to the absence of vitiation contaminants and shocks in the generating flow. An electrically preheated Ludwieg tube provides the initial means of heating while the piston-compression is used to further increase the pressure and temperature. Preliminary constraints on the design space for optimal operation are presented through the method of characteristics (MOC). Further characterization is performed with quasi-one-dimensional Euler computations. The MOC approach shows the optimal operating condition constrains the compression ratio and Ludwieg tube to nozzle exit diameter ratio, assuming proper simulation of flight conditions. The unsteady Euler computations predict the presence of pressure oscillations generated during the piston-compression process. Methods are investigated to mitigate these oscillations.