Evaluation of Heater Temperature to Detect Gases in a Flowing Fluid

摘要

In this contribution the behavior of a calorimetric flow sensor was investigated, at which only therntemperature of the heater is evaluated. A time-dependent excitation (f = 1 Hz) was applied to thernheating element with a constant power amplitude. The influence of different gases and flow velocitiesrnon the heater temperature were observed. Measurements and simulations were carried outrnin no-flow condition and in flowing fluids in order to obtain the restrictions regarding to a simultaneousrndetection of flow speed and gas type. A simultaneous measurement of flow velocity and gas type wasrnpossible, however certain conditions had to be respected, e.g. a high difference in thermal conductivityrnwhich is predetermined by the flow speed range.