Seminar: State-Resolved Chemical Kinetics Measurements for Hypersonic and Atmospheric Entry Flows - Feb. 17
Jesse Steicher
Research Scientist, Stanford University
Monday, Feb. 17 | 10 a.m. | AERO 114
Abstract: The design of next-generation, high-speed flight vehicles requires a combination of robust flow simulations and low-uncertainty ground test data. Although high-fidelity modeling advancements have improved flow simulations, experimental ground testing has lacked the required measurement sensitivity for model validation, especially at high temperatures. Significant progress in sensitive optical diagnostic techniques, coupled with the expansion of nation-wide ground test facilities, now offers renewed interest and opportunities to advance ground test measurements.Ìý
Recent experimental studies – leveraging quantum-state-specific laser absorption diagnostics – enable measurements of many high-temperature air species, including molecular oxygen (O2), nitric oxide (NO), molecular nitrogen (N2) using CO as a tracer, atomic oxygen (O), and atomic nitrogen (N). These quantum-state-specific time-histories have been used to infer internal energy excitation and chemical reaction rates for important nonequilibrium processes for shock-heated air with the necessary sensitivity for model validation.
Experiments performed in shock tubes probe temperatures from 2,000 - 14,000 K and pressures from 0.022 - 1.524 atm, extending to higher temperatures than any past studies. The resulting quantum-state-specific time-histories were used to isolate key reaction rates in high-temperature nonequilibrium in air. Extension of this measurement technique can apply similar methods to study nonequilibrium relevant to entry to other planetary atmospheres, ablation chemistry, and ionized flows, extending validation data to a wider range of flow conditions and design considerations.
Bio: Jesse Streicher is a research scientist from Prof. Ron Hanson's shock tube laboratory at Stanford University. He graduated with his PhD in 2022, and his postdoctoral research has advanced new techniques for measuring very high vibrational states and high-temperature reaction rates. His research has developed new laser absorption diagnostics for Stanford and the NASA Ames electric arc shock tube (EAST) and inferred time-histories and reaction rates at the extreme conditions relevant to hypersonic and atmospheric entry flows.