Planar Fluorescence Imaging and Three-Dimensional Reconstructions of Capsule Reaction-Control-System Jets

PLIF Study of Mars Science Laboratory Capsule Reaction Control System Jets

“…The use of a 3.8 times larger mixing chamber compared to a prior Orion Crew Exploration Vehicle (CEV) RCS jet test 14 produced a more constant NO composition during the runs. Mixing of the NO and N 2 was enhanced by flowing the input gas into the plenum through a cylindrical tube having dozens of holes around the circumference and down the 10.4-in length of the tube.…”

“…For the flow visualization data presented in this paper, the same cameras, excitation schemes, etc., were used as in past work, 14 except that higher efficiency filters (Layertec GmbH, Germany, <1% transmission at 226 nm and >80% transmission at 235-280 nm) were used to transmit the LIF signal while rejecting the laser scatter. The fluorescence was imaged onto a gated, intensified CCD at a viewing angle normal to the laser sheet.…”

“…This study builds on the expertise gained in using nitric-oxide planar laser-induced fluorescence (NO PLIF) to study a similar capsule-type flow in support of the Orion crew module (OCM). 14,15 Similar to MSL, OCM also uses RCS jets to steer the vehicle during entry. In this study, a series of NO PLIF images are obtained through the translation of a laser sheet across the flow field and analyzed with the Virtual Diagnostics Interface (ViDI) method to visualize the RCS jet and MSL wake flow structures.…”

MHz-Rate NO PLIF Imaging in a Mach 10 Hypersonic Wind Tunnel

“…The NO was injected at a low flow rate, resulting in local seed mole fraction of ~1-2%, assuming the gas mixes uniformly with the boundary layer fluid. More details about the NO seeding can be found in references [8][9][10]. To facilitate measurement in the 31" wind tunnel, the laser/OPO optical system was mounted on a portable, 3' x 8' optical table.…”

“…This paper builds upon the recent results of Danehy, et al [8][9][10] by demonstrating, for the first time, the ability to capture sequences of 10 -20 NO PLIF visualization images at frame rates as high as 1 MHz. Such a system provides the potential to visualize and quantify highspeed hypersonic flow phenomena to reduce error margins of codes used to design the hypersonic vehicles.…”