Professor Paul Ewart: Publications

Time-resolved gas thermometry by Laser Induced Grating Spectroscopy with a high-repetition rate laser system

Experiments in Fluids Springer Verlag 58:7 (2017) 87

Authors:

Felix Förster, C Crua, Martin Davy, Paul Ewart

Abstract:

Thermometry using Laser Induced Grating Spectroscopy (LIGS) is reported using a high– repetition rate laser system, extending the technique to allow time–resolved measurements of gas dynamics. LIGS signals were generated using the second harmonic output at 532 nm of a commercially available high– repetition rate Nd:YAG laser with nitrogen dioxide as molecular seed. Measurements at rates up to 10 kHz were demonstrated under static cell conditions. Transient temperature changes of the same gas contained in a cell subjected to rapid compression by injection of gas were recorded at 1 kHz to derive the temperature evolution of the compressed gas showing temperature changes of 50 K on a time scale of 0.1 s with a measurement precision of 1.4 %. The data showed good agreement with an analytical thermodynamic model of the compression process.

High precision measurement of combustion parameters in flames and engines using Laser Induced Grating Scattering, LIGS

Optica Publishing Group (2017) eth2a.2

Authors:

A Luers, A-L Sahlberg, F Förster, C Willman, J Camm, R Stone, B Williams, P Ewart

Laser-based measurements of combustion engines – inside and outside

Optica Publishing Group (2017) ftu4e.3

Authors:

Paul Ewart, Benjamin AO Williams

Tomographic Infrared Multi-Mode Absorption Spectroscopy for spatially resolved multi-species detection

Optica Publishing Group (2017) em2b.3

Authors:

S O’Hagan, H Northern, J Dai, W Cai, P Ewart

Multi-mode absorption spectroscopy using a Quantum Cascade Laser for simultaneous detection of NO and H2O

Applied Physics B: Lasers and Optics Springer Verlag 122:8 (2016) 226

Authors:

Paul Ewart, S O'Hagan, T Pinto, GAD Ritchie

Abstract:

Detection of multiple transitions in NO and H2O using multi-mode absorption spectroscopy, MUMAS, with a quantum cascade laser, QCL, operating at 5.3 m at scan rates up to 10 kHz is reported. The linewidth of longitudinal modes of the QCL are derived from pressure-dependent fits to experimental MUMAS data. Variations in the spectral structure of the broadband, multi-mode, output of the commercially available QCL employed are analysed to provide accurate fits of modelled MUMAS signatures to the experimental data.

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