MERM App.24F air table

[dpolet]

I found App24F and direct isentropical equation will generate different results. Which one will be used? For example, Linderburg 500 practice problem 29-1. I get result of 1319R using equation. the solution is 1375R using air table. Did I do anything wrong? Thanks.

 

[ongreystreet]

Lindeburg provides the solutions, don't over think it.

 

[CRNewsom]

Did you account for the change in density of the gas? For liquids, this may be negligible, but not for air.

 

[dpolet]

Here is the detailed data

Air expands isentropically from point 1 to point 2

P1=200 psia T1=1960R

P2=50 psia T2=?

using the equation of isentropical process

(P2/P1)=(T2/T1)^(k/k-1)

k=1.4 for air. T2 can be calculated to 1319R

Did I do anything wrong on this calculation? Thank you.

 

[CRNewsom]

I can't see any errors in your calculation. Check on PPI's website for the errata for your edition and printing of the book. A search of the first printing of the 12th edition yielded many results.