Laser Velocimetry in Semi-Industrial NaturalGas, Oil and Coal Flames by Means of a Water-Cooled LDV Probe

A water-cooled jacket enclosing a small fiber-optics LOA probe has been designed to perform laser velocimetry measurements in semi-industrial scale flames. The paper presents details of the probe design for front optics cooling and prevention of window contamination. Experiment sin natural gas, heavy fuel oil and coal flames have demonstrated fast and reliable operation. Laser velocimetry measurements are performed with the same speed as standard suction pyrometry. Operation for long periods in high temperature flames with high particle loading showed no heating of the LOV optics and no fouling of the front window. The effects of the probe intrusiveness and probe purge flow on the measurements accuracy were assessed and shown to be minor, provided that the measurement volume is located at least one and a half probe diameter from the probe tip.