An experimental investigation of angled sight flame detectors with 850nm photodiode sensor. Development of experimental equipment
Abstract
This thesis describes an experimental investigation of applying photodiodes as sensors inside flame detectors exposed to laminar, transient and turbulent gas explosions, and reflecting environment of various degrees. Small-scale and large-scale experiments have been carried out, in a 0.135m^3 apparatus and a 50m^3 vessel, respectively, with vented premixed gas explosions. The experimental approach of small-scale is transferable to that of large- scale experiments. Experiments with mixtures of propane/air and methane/air with different fuel-air ratios were carried out. High-speed cameras recorded the flame front propagations. The time of arrival detected by the flame sensors, in combination with the high-speed videos, made it possible to validate the functionality of the detectors. Three different optical detectors were investigated, two in small-scale and one in large-scale explosions. A total of 99 tests were carried out, 80 in small scale and 19 in large scale. The data and experience acquired through tests and optimization in small-scale experiments were used to develop flame detectors for the large-scale experiments. The developed detectors were tested and optimized in a 50m^3 test vessel.