ASTM A-335 Grade P11 thermal conductivity?
ASTM A-335 Grade P11 thermal conductivity?
(OP)
I found a calculator online (http://www.hrsgdesign.com/page5_6.htm) that claims to calculate the tube wall temperature. I believe this would give me an idea of the superheater tube wall temperature, given the process steam temperature at the superheater outlet. If so, I need to know the thermal conductivity of ASTM A335 Gr. P11, but I can not find this information online. Can anyone help?
Thanks in advance.
Thanks in advance.
---
Scott Stamey
Project Engineer
CPM, Inc.
www.cpm-inc.com





RE: ASTM A-335 Grade P11 thermal conductivity?
You'll find the info you're looking for in II-D, table TE-1. For a 1¼Cr-½Mo-Si material you're in material group 1 which has mean coeff's of thermal expansion (10E-6*in/in/°F)in going from 70°F to the indicated temp of:
6.4 at 70°F
6.5 at 100
linear 'till
7.3 at 500
7.3 at 550
7.4 at 600
linear 'till
7.9 at 850
7.9 at 900
8.0 at 950
8.1 at 1000
8.1 at 1050
8.2 at 1100
8.3 at 1200
8.4 at 1250
8.4 at 1300
jt
RE: ASTM A-335 Grade P11 thermal conductivity?
I forgot to mention that I don't think you'll find that varying the conductivity will have much impact on your calc's. The heat transfer equation is most likely bottlenecked by convection/radiation on the outside or convection on the inside. Try running the calc's with conductivities of 1 and 10 and see what happens to your results.
jt
RE: ASTM A-335 Grade P11 thermal conductivity?
RE: ASTM A-335 Grade P11 thermal conductivity?
Conductivity is in table TCD of II-D, material group C, and varies from 23.5 at 70°F to 21 at 800°F to 15.1 at 1500°F. That's BTU/(hr*ft*°F). So vary the conductivity from 10 to 100 and see what happens.
jt