Dual-probe 1-d hybrid fs/ps rotational CARS for simultaneous single-shot temperature, pressure, and O2/N2 measurements

TL;DR

This paper introduces a dual-probe 1-d hybrid fs/ps rotational CARS technique for simultaneous, high-accuracy measurements of temperature, pressure, and O2/N2 ratios in gas diagnostics, capable of resolving single-shot gradients in various flow conditions.

Contribution

It presents a novel dual-probe HRCARS method that enables simultaneous time and frequency-domain measurements with high accuracy and resolution for gas-phase diagnostics.

Findings

Achieved pressure measurement accuracy below 1%.

Resolved 1-d pressure gradients in laminar and turbulent flows.

Demonstrated single-shot measurement capability for dynamic pressure gradients.

Abstract

We employ dual-probe 1-d fs/ps hybrid rotational coherent anti-Stokes Raman spectroscopy to investigate simultaneous temperature, pressure, and O2/N2 measurements for gas-phase diagnostics. The dual-probe HRCARS technique allows for simultaneous measurements from the time and frequency-domain. A novel approach for measuring pressure, which offers high accuracy (<1%) and precision (0.42%) is presented. The technique is first demonstrated in a chamber for a range of pressures (1-1.5 bar). This technique shows an impressive capability of resolving 1-d pressure gradients arising from a N2 jet impinging on a surface, both in laminar and turbulent conditions. The technique is shown to be capable of resolving single-shot pressure gradients (0.04 bar/mm) originating from kinetic energy conversion to pressure, and resolves characteristic O2/N2 structures from laminar and turbulent mixing.