Multi-Phase Modeling of Rainbird Water Injection

During the launch of the Space Shuttle several water suppression systems were used. These consist of the crest water nozzles mounted on the apex of the flame defector, Ignition Overpressure (IOP) water nozzles placed around the exhaust hole, and rainbird water nozzles installed above the launch deck (Figure 1). The rainbird water is specifically designed to suppress launch acoustics that can reflect from the flat surfaces of the deck. The Shuttle rainbirds were located on the North deck of the mobile launcher platform and were activated at T-0, so they didn’t really pose a threat to Shuttle. For the new Space Launch System (SLS) vehicle the operation is similar, regardless of the new mobile launcher and new engine configurations. The goal of the rainbird nozzle system remains the same, which is sound suppression (SS), and the rocket engines still cannot get wet. However, the rearrangement of the rainbird water system for the SLS mobile launcher, as shown in Figure 2, locates the rainbirds closer to the first-stage rocket engines, which are positioned above the exhaust hole and not shown in the Figure. The close proximity of the rainbird nozzle system could potentially cause vehicle wetting during liftoff. This study is to complement the one-dimensional projectile calculation by considering the VOF multiphase. The objective of this study is to determine if the Shuttle-heritage rainbird system can be used for the SLS without water splashing on its rocket engines.