NCEES 2008 # 129

tmacier · Sep 16, 2010

Working thru problem 129 in the NCEES 2008 study guide.

I must be missing were they obtain 1335.2 BTU/lbm from.

Any guidance would be appreciated.

Thanks

Tim

tmacier · Sep 18, 2010

tmacier said:
Working thru problem 129 in the NCEES 2008 study guide.I must be missing were they obtain 1335.2 BTU/lbm from.

Any guidance would be appreciated.

Thanks

Tim

Anyone? Is the 1335 incorrect?

navyasw02 · Sep 18, 2010

1335 is correct. App 24.C superheated steam table at 14.696psi at 600F h= 1335.3

tmacier · Sep 19, 2010

THanks - got it-

I appreciate your response - for some foolish reason I could not find that!

MetsFan · Apr 12, 2012

Sorry for bumping such an old thread, but how can you use the h values at 14.7psia? Is it because they withdraw the product at ATM? If they hadn't mentioned that, how would you find the resulting temperature/pressure of the mixture?

Thanks!

Outlaw44 · Apr 12, 2012

MetsFan said:
Sorry for bumping such an old thread, but how can you use the h values at 14.7psia? Is it because they withdraw the product at ATM? If they hadn't mentioned that, how would you find the resulting temperature/pressure of the mixture?

Thanks!

Yes, you use the h values at ATM in the quality equation because they say it's withdrawn at that pressure. To find the quality, you'd have to know the temp or pressure so you can use the hf and hfg at that point from the steam tables.