Influence of gaseous species transport on the response of solid state gas sensors within enclosures

The filling of a measurement chamber for gas sensor characterization, with CO diluted in air by the flow-through method is simulated by using a general-purpose CFD code. Numerical data allow to follow the time evolution of CO concentration at any point inside the chamber, thus representing an helpful tool for designing effective test chambers and for interpreting experimental electrical data. In particular, it is shown that CO concentration over the sensor surface increases with time quite slowly, even if the air–CO jet impinges on the device from a short distance. In addition, a comparison of numerical results with experimental data is presented and discussed.