Mechanisms Controlling Non-Steady Plume-Wall Interactions in Rocket Launch-Tubes (Gas, Fluid Dynamics, Rocket Systems, Base Flows, Supersonic Flows)

235 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.The mechanisms controlling the interactions between base flow induced irreversibilities with downstream effective critical flow conditions within rocket launch tubes due to friction and/or cross-sectional obstruction are studied here in detail. The analytical treatment by the flow component approach using one- and two-dimensional techniques is corroborated by a comprehensive experimental program.A full qualitative understanding of the very complex interactions of non-steady processes is attained by delineating the controlling mechanisms such as fluidic mass entrainment in the base region, mass storage, shock wave development and kinematics, and shock wave interactions with the wake. Due to the multi-dimensional nature of the flow, the flow component approach helps provide satisfactory results.Diagnostic experiments have been conducted by means of the water table analogy and supersonic air flows to help determine parametric ranges producing unsteady behavior as well as to gain a deeper insight into the controlling processes. The details of fast pressure transients have been recorded and subsequently analyzed with respect to their quasi-periodical characteristics. Futhermore, details of base pressure reduction and rise times along with wave travel times have been recorded to obtain pressure and time scales for comparison with the analytical model. Computer programs have been developed in support of data acquisition, reduction, and analysis.Comparison of analytical and experimental results shows reasonable agreement with respect to prediction of non-steady performance windows, component verification, and mechanisms. However, the comparison points to difficulties in assessing development thresholds for moving wave systems. Consequently, differences between theoretical and experimental cycle periods and their causes need further investigation.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD