Mixture flow analysers for mixtures consist- - ing partly of a liquid phase and partly of

摘要

A light system projects a beam of light, i.e. visible or invisible radiation, onto a window. The latter and its mounting are such that changes in the optical properties, reflective and refractive, of the flow (including skin flow) in the vicinity of the window control the extent of the light reflected by the window. Provision is made for detecting this and for analysing devices to indicate the value of the changes in the extent of the light reflected. An example of application is detecting the formation of ice on aircraft wings.