Instrumentation for the 1/20th scale Shuttle exhaust duct

Summary form only given. Space Shuttle launches at the Vandenberg Air Force Base require the exhaust gases from the main liquid propellant engines to pass through a complex three-dimensional duct. In the cases of a flight abort or a flight readiness firing, the shutdown of these engines would result in large quantities of hydrogen and entrained air entering the duct. An extensive program was conducted to develop a means for the safe disposal of the flammable mixtures. As part of this effort, a 1/20th scale version of the duct was built and used to characterize the fluid dynamic aspects of the flow. The data served as initial benchmarks in comparison with the computational models that eventually were to include the combustion kinetics. The authors describe the experimental techniques used and present representative results from both steady-state and transient tests