Application of the thermal wave resonator cavity sensor to the measurementof the thermal diffusivity in air contaminated with vapours of different liquid hydrocarbons

A measuring device based in thermal wave interference in a cavity is descri bed. It was tested measuring the air thermal diffusivity with good accuracy . The device is further applied to the measurement of the thermal diffusivi ty of air mixed with the vapors of liquid hydrocarbons of the paraffin fami ly (n-pentane, n-hexane and n-heptane). Our results illustrate how the diff usion of their vapors in air can be monitored by a simple method and how th e thermal properties (i.e. the thermal diffusivity) of the gas mixture chan ge as a result of this mechanism. Based in the former results a device suit able for in field measurements is predicted.