A Shock-Tube Facility for Gas-Phase Chemical Kinetics Studies: Design, Validation, and Application for Methane Oxidation

High-temperature chemical-kinetics play an important role in the development of next-generation combustion systems. Toward this goal, a shock-tube facility capable of handling pressures up to 100 atm is constructed. It consists of an 8 m long driven section with an 18 cm internal diameter. The driver section measures 2.9 m in length, extendable to 6.5 m using a U-bend tube. The test section of the shock tube features eight optical windows, facilitating the application of multiple optical diagnostics. Shock-tube tests are performed to characterize the test time and non-·ideal pressure-rise phenomena. Typical test times are in the order of 3–4 ms, with longer durations of 21 ms achieved using tailoring techniques. To validate the shock-tube performance, ignition delay time measurements of stoichiometric methane/air mixtures are conducted, and the results show excellent agreement with literature data. Furthermore, experiments are conducted for stoichiometric methane/oxygen/argon mixtures to perform simultaneous carbon monoxide and carbon dioxide time-history measurements using laser absorption spectroscopy. These species time-history measurements show discrepancies with predictions from kinetics mechanisms, highlighting the need for such data for further mechanisms’ refinement. To the best of the authors’ knowledge, the present study reports the first CO₂ species time histories during methane oxidation behind reflected shock waves. The presented facility will be utilized in future chemical-kinetics studies, particularly for low-carbon and carbon-free fuels.