Determination of the thermal conductivity of gases under flow conditions

This contribution presents a calorimetric flow sensor that is capable of determining the thermal conductivity (k) regardless of the flow conditions. The sensor can also measure the flow rate (Q) provided that the volumetric heat capacity (ρc_p) or the thermal diffusivity (α=k/(ρc_p)) of the flowing gas is known. No additional sensors or bypass channels are needed. The measuring principle relies on using high frequency heat generation (200 Hz). The thermal conductivity of several common gases is measured.