🚀 go-pugleaf

In article <1993Jan5.050543.28601@cis.ohio-state.edu> rubin@clam.cis.ohio-state.edu (Daniel Rubin) writes:

>   Hmmm...  You cannot get the probe any cooler than the temperature of the 
>   air flowing around it no matter how fast the air is flowing!  If anything
>   the friction of the air moving across the sensor would heat it up.  Now if
>   it is wet then the air will aid to evaporate the water on the sensor which
>   takes heat of evaporation from the sensor thereby lowering it's temperature.
>   Dry air flow around the sensor will not provide false readings unless 
>   excessive friction is created!  

Yes, but one should be careful not to put the sensor in a place where
the air flow causes pressure changes. If, for example, air is rapidly
compressed, the pressure rises and the temperature rises due to
constant thermal energy it has (adiabatic prosess). 
If the sensor is uncorrectly placed, it may happen that the indicated
temperature if a function of the speed of the vehicle!

>	 - Dan

Heke

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Heikki Paananen                           heke@stekt.oulu.fi
The University of Oulu                     
Department of electrical engineering    
Finland
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