Dual optical fibre measurements of the particle concentration in gas/solid flows

Abstract

Numerous optical probe designs to measure particle volume fraction have been proposed in the literature. Unfortunately, almost all of them suffer from an ill-defined measurement volume, poor sensitivity or require frequent and tedious calibration. We propose an improvement in the design of a dual optical fibre probe. It has a well-defined measuring volume and a near-linear sensitivity. A general calibration theory for optical fibre probes is also proposed. The design and the theory have been tested in a simple experimental set-up with encouraging results.