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Updated: Jun 28, 2025

A Uniaxial Compression Experiment with CO2-Bearing Coal Using a Visualized and Constant-Volume Gas-Solid Coupling Test System
Published on: June 12, 2019
Laboratory study of rotationally inelastic collisions of CO2 at low temperatures
C Álvarez1, G Tejeda1, J M Fernández1
1Laboratory of Molecular Fluid Dynamics, Instituto de Estructura de la Materia IEM-CSIC, C/Serrano 121, 28006 Madrid, Spain.
Abstract:
The rotational relaxation of CO2 by inelastic collisions has been studied in three supersonic jets. The jets were probed by means of Raman spectroscopy with high spectral and spatial resolutions, measuring the rotational populations and the total number density. The time evolution of the rotational populations was analyzed by means of a kinetic master equation, with the help of the energy-corrected sudden power law to relate the numerous state-to-state rate (STS rates) coefficients. In the thermal range investigated, 60-260 K, the STS rates decrease with increasing temperature and with increasing change in the rotational quantum number. Other quantities of interest for fluid dynamics, such as the rotational collision number, the relaxation cross section, and the bulk viscosity, have been derived from the STS rates.
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