REFLECTOR: Advance Turbine Power ne Innodyn
Richard Riley
richard at riley.net
Sun Oct 10 22:35:37 CDT 2004
At 07:43 PM 10/10/04, you wrote:
>The universal gas law is P V = n R T. We are looking at a change in
>temperature due to a change in pressure and volume, so R, the universal gas
>constant, and n, the amount of gas involved, can be dropped out. We then
>see that the product of pressure and volume is directly proportional to the
>absolute temperature, assuming heat leaking out of the system is small
>(which is reasonable because compression is very rapid). We certainly
>expect a significant reduction in volume with the 3.5 times increase in
>pressure, so the increase in absolute temperature will be much less than the
>compression ratio.
>
>If we assume an initial temperature of 80 degrees F (about 540 degrees
>Rankine), an increase to 750 degrees F (about 1210 R) would be a factor of
>2.2. This would imply a change in volume of only 2.2/3.5 = 0.63 would be
>associated with the 3.5 times increase in pressure, which seems
>unreasonable. I think the temperature difference is probably overstated, as
>Richard implied.
Thanks, Keith.
I got a courtesy "C" in thermodynamics. And they gave me that 'cause I was
the only theater major to have ever taken it as an elective, not because I
understood enthalpy.
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