Imaging of carbon monoxide distributions around igniting n-heptane droplets after excitation with a quantum cascade laser at 4.6 μm

摘要

Carbon monoxide distributions around igniting n-heptane droplets were determined using absorption measurements. The emission of a quantum cascade laser at 4.6 μm was shaped to a parallel laser beam using a lens. For detection, a plane through the droplet, perpendicular to the laser beam was imaged onto the focal plane array of a mid-infrared camera. For background suppression a long-pass filter was mounted in the detection ray path. To estimate the detection sensitivity of the set-up, CO absorption in a reference cell was measured. In addition, CO transmission spectra were calculated for different temperatures based on HITRAN 2000 catalogue.