Key Design Elements of a Radio-Acoustic-Sounding System for Industrial Applications

This article discusses compact radio-acoustic-sounding systems (RASSs) for industrial applications. The electromagnetic-acoustic interaction enables to measure temperatures of gases without contact and spatially resolved. For this purpose, the speed of a modulated sound pulse, travelling through the gas with a velocity proportional to the temperature, is determined with a Doppler radar. The optimum sound pulse´s in terms of its frequency is discussed. The so called Bragg condition is essential to obtain sufficient receive power. The two most important conditions for an optimal Bragg reflection are the tuning of the wavelengths and an optimal collocation of the sources. These conditions are calculated numerically and verified with real-world measurement data. One purpose of this paper is to summarize physical effects that are key elements to the function of the RASS.