Partial pressure gradients due to temperature gradients in a mixture of reactive gases

Partial pressure gradients due to temperature gradients in a mixture of reactive gases, limit the possible use of sensors. Problems arise when a partial pressure sensor is subjected to a temperature, different from that of the sample. A model is proposed that allows the calculation of the partial pressure distributions in a temperature gradient. Experiments conducted using O2, H2, and H2O in Ar confirm the predictions. It is shown how to relate the sensor’s reading to the parameter of interest. It is also concluded that in certain cases it is advisable to deliberately add a reactive gas, as this facilitates the interpretation of the measurements.