Vu Phi's work at UCI's Combustion Laboratory fostered his interest in combustion technology and instilled a desire to pursue a career in this field. Vu's research focuses on a project being sponsored by the Kaiser Marquardt Corporation. Vu found his experience with the Mars Ascent project to be extremely exciting because of the uncertainties of the project. He commented that his favorite experience was working with the laser sheet and watching the spray scattering on it. Vu also gained skills and knowledge about the tools and equipment with which he worked. Vu recommends that everyone take advantage of research in order to see textbook concepts "in action."

Low temperature (-40 °C) storable liquid propellant was considered as the propulsion source by the NASA Jet Propulsion Laboratory (JPL) to return samples from the planet Mars. The propellant combination selected was Monomethylhydrazine (MMH) fuels and Mixed Oxides of Nitrogen (MON) 25 oxidizers. Different sized doublet injectors were used to inject the two liquids. In this study, the basic properties of the sprays were characterized under cold flow test conditions, thereby allowing direct comparison of the results to corresponding hot fire tests. The strategy involved the use of simulants that met a variety of constraints. The characterization consisted of visualization for a variety of geometric and operational conditions. Once these results were reviewed, a reduced set of conditions was identified for a more detailed investigation using Planar Laser Induced Fluorescence (PLIF). The visualization results demonstrated the effects of the impingement angles, O/F ratio, and the liquid properties associated with the two temperatures (25 °C and -40 °C). The visualization indicated that greater impingement angles improved dispersion. Optimal performance was indicated at O/F ratios between 2 and 3 for the -40 °C case and at O/F ratios between 1 and 2 for the 25 °C cases. The PLIF results were obtained for four select cases at O/F ratios of 1.6, 2.0, 2.53, and 2.8. The case that demonstrated superior mixing and performance for the -40 °C case occurred at O/F = 2.0 (corresponded to Re ratio of 6.35).

Scott Samuelsen Henry Samueli School of Engineering

This research is at the leading edge of liquid-fueled rocket technology. The technological challenges of space exploration are requiring creative solutions and the latest in laser diagnostics to overcome the key hurdles. Liquid fuels provide the attribute of flexibility over solid fuels, but demand new solutions for chamber injection if proposed interplanetary mission scenarios are to be successfully met. These results allow the design of optimized fuel/oxidant injectors, and form the foundation for the next generation "smart spray system" techology that will be required to support the demands of future space exploration. Vu Phi's efforts are recognized as contributing to the research projects of the Combustion Laboratory at UCI.