Thermal Property Determination of Laminar-Flowing Fluids Utilizing the Frequency Response of a Calorimetric Flow Sensor
Sprache des Titels:
Englisch
Original Buchtitel:
Proc. IEEE Sensors Conference 2008, Lecce, Italy
Original Kurzfassung:
We demonstrate that the thermal conductivity and
diffusivity of fluids can be measured independently of their
motion state utilizing a micromachined calorimetric sensor. The
sensor membrane bears a heating resistor and two symmetrically
arranged thermistors. By immersing the sensor into the laminarflowing
sample fluid and applying an AC heating current,
the frequency response of the thermistor temperatures can be
exploited to evaluate the thermal properties of the fluid. We
developed a novel analytical model to describe the conductive
transfer in the micromachined sensor as well as the fully
conjugated heat transfer in the fluid. The validity of this model
was confirmed experimentally by a practical example using
nitrogen as fluid flowing through a rectangular flow channel.
Based on these results, a thermal parameter extraction procedure
can be deduced. Moreover, with known thermal parameters, the
arrangement can also be used for flow measurements.
Forschungs-