A prototype acoustic gas sensor based on attenuation

Acoustic attenuation provides the potential to identify and quantify gases in a mixture. We present results for a prototype attenuation gas sensor for binary gas mixtures. Tests are performed in a pressurized test cell between 0.2 and 32atm to accommodate the main molecular relaxation processes. Attenuation measurements using the 215-kHz sensor and a multiseparation, multifrequency research system both generally match theoretical predictions for mixtures of CO2 and CH4 with 2% air. As the pressure in the test cell increases, the standard deviation of sensor measurements typically decreases as a result of the larger gas acoustic impedance.