Design and calibration of a CO(sub 2)-laser nephelometer to measure the radiative properties of coal particles

摘要

In is paper, we will discuss the design and calibration of a CO(sub 2)-laser nephelometer for angular light scattering measurements to determine the effective radiative properties of pulverized-coal particles in a non-flame, planar system in-situ. A nephelometer is an instrument used for angular detection of scattered light incident on a cloud of particles. Its essential elements include a collimated light source and an arm which houses light collection optics and detectors. The arm can be rotated to record the angular scattered intensity distribution. A major problem when conducting experiments of this nature is that the intensity of the scattered light by pulverized-coal particles at angles other than the forward scattering direction can be as much as two to three orders of magnitude lower than the intensity at angles close to theta = O(sup o). This effect is more pronounced for larger size parameters. In order to have sufficiently strong signals at a wide range of angles, a 50 watt CO(sub 2)-laser operating at 10.6 mum is used in the experiments. (ERA citation 19:020680)