Want to use a vertical dead leg to lose temperature.

[WrTexas]

I want to measure a liquid below a vertical dead head nozzle. The liquid comes in at 645'F into the vessel. The temperature at the instrument on top of the dead leg zozzle must not exceed 400'F. Assuming a 316SS schedule 40 3 inch uninsulated pipe, how tall would it need to be? How do I calculate?

 

[racookpe1978]

Er, start with your heat transfer problem requirements. (Hint, read the books; draw your problem.

State your assumptions: Air temperature, thermal input from the sun, wind speeds.
Look at the books, find your heat transfer coefficients for your geometry. (Hint: Dead head means no flow, why would the dead head leg not ultimately cool down to air temperature?)
What are the pipe OD, wall thickness, ID, thermal properties?
No flow = What is the inside (fluid to pipe wall) thermal transfer coefficient, and how does that change with temperature up the pipe?
What is the linear (pipe bottom to pipe top) heat transfer amounts?
What is the outside (pipe wall to atmosphere) heat transfer coefficients at each temperature range from bottom to top?

What is the combination of the above?

(No homework in this forum.)

I do want to see how your are going to hold that long, skinny, thin-walled SS316 3 inch pipe vertically in the air though.