Date: Thu Nov 9 17:52:14 2006

Author: Wallin, Stephen R

Subject: Re: Cycling heat engine with sensors

Post:
..temperature measuring possibilities:
1) Via conductivity in a fine thermistor type hair wire?
2) Temperature sensing laser near an absorption spectral feature?
3) Does a gas have any blackbody feature to be of use? Perhaps with CO2
or other gas, non-transparent to IR?

Stephen

-----Original Message-----
From: tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On
Behalf Of Charles R. Card
Sent: Thursday, November 09, 2006 3:04 PM
To: tap-l@lists.ncsu.edu
Subject: Re: [tap-l] Cycling heat engine with sensors

Hi,

We use the older-style Leybold Stirling engine that is vertically
constructed. We measure pressure with a Vernier gas pressure sensor and

enclosed volume by attaching a small rod to the working piston on one
end
and to a slide-wire potentiometer on the other end. The output voltages
of
the potentiometer and the pressure sensor are both fed into a Vernier
LabPro
data acquisition system by which they are calibrated and analyzed using
Graphical Analysis. The present pressure sensor doesn't have rapid
enough
response and tends to obscure the isochoric sections of the Stirling
cycle.

Does anyone have a recommendation for a rapid sampling pressure sensor
that
ranges from 100 to 300 kPa?

Urs, would you tell me more about your laser distance sensor?

Thanks,


Charles R. Card, Sr. Scientific Assistant
Dept. of Physics and Astronomy
Box 3055, University of Victoria
Victoria, BC V8W 3P6 Canada

ph: 250 721 7730
fax: 250 721 7715
----- Original Message -----
From: "Urs Lauterburg"
To:
Sent: Thursday, November 09, 2006 12:17 PM
Subject: Re: [tap-l] Cycling heat engine with sensors


> Wallin, Stephen wrote on Tue, 7 Nov 2006:
>>Does anyone know of a working cyclic heat engine/refrigerator with
>>pressure, volume, and temperature sensors. By changing cam timing
which
>>could also control access to reservoirs, then you could have semi-
>>adiabats, isovolumetric, isotherms, isobarometric. ~Stephen
>
> Stephen,
>
> We draw a pV-diagram with a transparent stirling engine made of glass
much
> like this one:
>
>
http://www.phywe.de/e_frames.php?ref=main&reftxt=1800005&refnav1=0&refna
v2=10&reffach=son&txtnr=1100038&prodnr=2000006
>
> It's a neat little engine that shows all the mechanical components and

> reservoirs clearly. I have a small pressure gauge to measure the
momentary
> pressure and I trace the volume by monitoring the movement of the
working
> piston with a small and accurate laser distance sensor. The device
draws a
> nice pV-diagram of the cycles, free running as well as under load.
This is
> one demo I prefer to show the parameters with a simple oscilloscope
set to
> the XY-mode, although I guess it could be scaled and plotted with
LabVIEW
> as well.
>
> I imagine temperature measurements to be difficult because you need a
> temperature sensor that reacts very quickly. Maybe the new type remote

> infrared sensors would do the job but then again I don't know how fast

> their sampling rates are. I understand that you could do a lot of
what
> you want with this device from Leybold Didactic from germany:
>
> http://www.leybold-didactic.com/phk/produkte.asp
>
> I hope this helps.
>
> Happy demonstrating physics
>
> Urs
>
> Us Lauterburg
> Physics demonstrator
> Physikalisches Institut
> University of Bern
> Switzerland




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