Heat transfer problem in pipesim

[amanx]

Dear All,
Ied mubarak for all of you..

For pipeline heat transfer, Some client provide ambient temperature (lets say 50 C) and temperature at burial depth (lets say 35C at 1 m depth).
In heat transfer tab of the flowline/pipline I do as follows:
a. set 50C as ambient temperature, set the wind velocity, and set 1 m burial depth and its soil conductivity.
b. set 35C as ambient temperature, set 0 m/h for the wind velocity and 0 m burial depth.
However both result may yield different arrival temperature (for identical input value)..
Which one of these approach should be followed?
Do you have any suggestion to input heat transfer for pipeline at 35 C at 1 , deepth?

Thank you in advance...

[kkhan]

Dear Imanx,
Eid Mubarak.

From my experience, it is better to take ambient temperature 50 oC with burial depth of 1 m. I have performed numerious calculations for flowline simulations and have always used higher side temperature. I know that using low temperature will result in high liquid holdup thus being conservative but it is practicle appraoch.

[thaihy]

Heat transfer problem is always a challenge matter of pipeline simulation, especially as dealing with high viscosity fluid while Re and Nu number have their huge impact on force and natural convection heat transfer. Please be noted that there is only one heat transfer method (nature or force i can not exactly remember) taken into account. If arrival temp. is critical issue, OLGA is expected to proceed.

[asozhyan]

Dear
Unfortunately this disadvantage is the same for both olga and pipesim. At depth below frost/throw depth soil temperature is constant during day and isn't affected by temperature changes. But this value is constant for a season (e.g. 35C for summer). At burial depth less than this depth the arrival temperature will be at least/at most equal to this temperature. There is no absolute way to how to simulate this with olga or pipesim. You should compare with actual data.