Simulation of the transient response of limiting current oxygen sensor

The transient response of the limiting current oxygen sensors following step changes in gas composition has been simulated by assuming a Knudsen diffusion of the gases in the diffusion barrier. The simulation results showed that the expression of the stable state current had the same form as that deduced from stable state model. The response time values in the simulation results were independent of the oxygen molar fractions (X1, X2), the operation pressure (P) and the effective cross section area of the diffusion barrier (S × θ), but decreased with the pore radius (r) in the diffusion barrier and the operation temperature (T), and increased with the effective diffusion barrier length (L × τ). The simulation results were compared with some experimental measurements on our designed amperometric sensors.