B7.4 - On the conditions for the determination of the thermal properties of flowing gases by using oscillatory thermal excitation
- AMA Conferences 2015
2015-05-19 - 2015-05-21
- Proceedings SENSOR 2015
- B7 - Flow II
- D. Reyes-Romero - Innovative Sensor Technology IST AG, Ebnat-Kappel (Switzerland), G. Urban - University of Freiburg - IMTEK, Freiburg (Germany)
- 319 - 323
This contribution presents the necessary conditions for the determination of the thermal properties of a gas in a channel under flowing conditions. The measurement principle relies on the modulation of the penetration depth of harmonic thermal waves by means of the oscillation frequency. Harmonic waves produced on the wall of the flow channel are confined within flow boundary layer that forms over the surface of the channel’s wall. Simulations and experiments using gases show that thermal conductivity and the volumetric heat capacity can be determined under flow conditions if v/(Dw) < 1, where v is the average flow speed in the channel, w the frequency and D the channel diameter. This verifies the results reported in the literature for liquids only.