Acoustic gas temperature measurement

The acoustic gas temperature measurement , also known as sound pyrometry , is a non-contact measurement method based on the temperature dependence of the speed of sound .

The acoustic gas temperature measurement is mostly used in power plants to measure the temperature in the boiler and to optimize combustion or to control flue gas denitrification systems .

functionality

A transmitter sends a sound signal generated by compressed air, which is in the frequency range between 200 and 3000 Hz. The runtime of the signal is measured until it arrives at the receiver. Since the speed of sound depends on the temperature in a known way, the temperature of the path between the transmitter and receiver can be determined mathematically in this way. If several paths that cross each other and are located in different planes are measured, a graphic representation of the temperature distribution in the boiler can be generated.

The following applies to the speed of sound c: with the adiabatic coefficient , the general gas constant R, the molar mass M and the gas temperature T. Although and M are not known exactly in practice, the inaccuracy of the measurement is in the range of 1%. ${\displaystyle c={\sqrt {\frac {\kappa RT}{M}}}}$ ${\displaystyle \kappa }$ ${\displaystyle \kappa }$

Web links

Acoustic gas temperature measurement (manufacturer's website from Bonnenberg und Drescher GmbH)

Individual evidence

1. ↑ ^{a b} M. Deuster: Measuring high gas temperatures without contact at the speed of sound. (pdf; 195 kB) Retrieved September 23, 2009 .