A system for turbulent concentration measurements

Publisher Website
Google Scholar
Abstract
A system is described for measuring instantaneous concentration values in turbulent flow, when the levels of concentration are too low for conventional laboratory techniques to be used. The system is designed for use in the wind tunnel modelling of atmospheric dispersion. It consists of a small sampling valve, placed in the wind tunnel at the required measuring position, which injects samples of tunnel air into a carrier line of gas flowing to a flame ionisation detector. The low dispersive properties of laminar pipe flow are utilised in passing the sample to the flame ionisation detector. Tests show the system to be capable of measuring down to 1 ppm by volume of trace gas (propane) in air, with a 2 mm diameter sample volume and a 10 m carrier line, at a sampling rate of 2 s-1.