Isentropic exponent and specific heat ratio 3

[fifaln]

Hi all,
That's a small question but really make me confused in the control valve calculation.
Could "isentropic exponent" be treated same as "specific heat ratio" in control vavle calculation?

Thanks

 

[mbeychok]

fifaln:

I suspect that you are talking about the "isentropic expansion factor" which is a synonym for "specific heat ratio" ... in other words, they are the same thing.

You might be interested in reading this article in the online Citizendium encyclopedia:

http://en.citizendium.org/wiki/Specific_heat_ratio

Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

[fifaln]

mbeychok:

Thank you for your reply. Now, I got the idea that for the ideal gas, they are same thing,right?

 

[jack256]

This basic thermo stuff can be found in SVNA or Kyle, whichever one you used for undergrad.

 

[sailoday28]

fifaln (Electrical) Yes,right, for the ideal gas, they are the same thing.

 

[mbeychok]

sailoday28:

mbeychok (Chemical) 23 Mar 09 14:31
fifaln:

I suspect that you are talking about the "isentropic expansion factor" which is a synonym for "specific heat ratio" ... in other words, they are the same thing.

Thanks for agreeing with me, that is very kind of you.


Milton Beychok
(Visit me at www.air-dispersion.com)
.

 

[hacksaw]

that is for an ideal but not a perfect gas, in other words idealized non-ideality...

 

[sailoday28]

hacksaw (Mechanical)Both ideal and perfect gas have an equation of state pv=RT. For this equation of state, specific heat ratio, and isentropic expansion factor are equivalent.
Note that for pv=RT, the difference of specific heats is easily shown to be, Cp - Cv =R

 

[hacksaw]

perfect, or is it an ideal respomnse, i think i'll go sailing...