Project Description

In 2028, NASA’s Dragonfly mission to Titan will launch and embark upon a six year journey to Titan where it will conduct unprecedented research regarding the origin of life in our universe. However, before such research can begin, Dragonfly must survive hypersonic entry into Titan’s atmosphere which will expose the vehicle to intense radiative heat transfer from the high-temperature (up to 10,000+ K) non-equilibrium gases behind the resulting shock waves. The bulk of the radiation is known to be produced by electronically excited cyano radicals (CN) which emit ultraviolet, visible, and infrared photons. Since 2020, the Goldenstein Group at Purdue has developed cutting edge laser diagnostics to measure CN and its distribution across quantum states to improve our understanding of non-equilibrium chemical kinetics and radiative heat transfer that occur at conditions relevant to atmospheric entry into Titan. This project seeks to significantly advance our understanding of the non-equilibrium spectroscopy and chemical kinetics of gaseous species produced behind strong shock waves in surrogate Titan atmosphere. This will be achieved through the use of high-speed ultraviolet and near-infrared absorption and emission spectroscopy diagnostics, shock tube and HYPULSE shock tunnel experiments, and chemical kinetics models.  

Start Date

Spring 2025

Postdoc Qualifications

Qualified candidates must have experience with at least one of the following: laser absorption spectroscopy, emission spectroscopy, shock tube experiments. A background in studying high-temperature reacting flows or non-equilibrium flows is also strongly preferred. 

Co-advisors

Professor Chris Goldenstein, School of Mechanical Engineering, csgoldenstein@purdue.edu, www.GoldensteinGroup.com
Professor Joe Jewell, School of Aeronautics and Astronautics, jsjewell@purdue.edu, https://engineering.purdue.edu/AAE/people/ptProfile?resource_id=221718 

Bibliography

1. V. Radhakrishna, R. J. Tancin, and C. S. Goldenstein, Characterization of non-Boltzmann CN X2Σ+ behind shock waves in CH4-N2 via broadband ultraviolet femtosecond absorption spectroscopy, The Journal of Chemical Physics, 159 (2023) 044308 doi.org/10.1063/5.0150382

2. V. Radhakrishna, R. J. Tancin, and C. S. Goldenstein, Broadband ultrafast-laser-absorption imaging in the ultraviolet for spatiotemporally resolved measurements of temperature and CN, Applied Physics Letters, 121 (2022) 031105, doi.org/10.1063/5.0103087

3. J. L. Vera, V. Radhakrishna, C. J. Schwartz, and C. S. Goldenstein, A 100 kHz TDLAS diagnostic for characterizing non-equilibrium CN formed behind strong shock waves in N2-CH4 mixtures, AIAA Aviation 2023 Forum, San Diego, CA, AIAA 2023-4383 (2023) doi.org/10.2514/6.2023-4383

4. G. C. Mathews, M. G. Blaisdell, A. I. Lemcherfi, C. D. Slabaugh, and C. S. Goldenstein, High-bandwidth absorption-spectroscopy measurements of temperature, pressure, CO, and H2O in the annulus of a rotating detonation rocket engine, Applied Physics B, 127 (2021), doi.org/10.1007/s00340-021-07703-9

5. J. J. Gilvey, M. D. Ruesch, K. A. Daniel, C. R. Downing, K. P. Lynch, J. L. Wagner, and C. S. Goldenstein, Quantum-cascade-laser-absorption-spectroscopy diagnostic for temperature, pressure, and NO X2Π1/2 at 500 kHz in shock-heated air at elevated pressures, Applied Optics, 62 (2023) A12-A24, doi.org/10.1364/AO.464623