Experimental Perfect-Gas Study of Expansion-Tube Flow Characteristics

摘要

Results of an experimental investigation of expansion-tube flow characteristics performed with helium test gas and acceleration gas are presented. The use of helium, which behaves ideally for the conditions encountered in this study, elimi¬nates complex real-gas chemistry in the comparison of measured and predicted flow quantities. The driver gas was unheated helium at a nominal pressure of 33 MN/m. The quiescent test-gas pressure and quiescent acceleration-gas pressure were varied from 0.7 to 50 kN/m2 and from 2.5 to 53 N/m2, respectively. The effects of tube-wall boundary-layer growth and finite secondary-diaphragm opening time were examined through the variation of the quiescent gas pressures and secondary-diaphragm thick¬ness. Optimum operating conditions for helium test gas were also defined.