mean metal temperature of tubesheet

in tubesheet design, one should have to consider mean metal temperature of tubesheet. in pv elite, inputs are for mean metal temperature at rim, shell metal temperature at tubesheet & channel metal temperature at tubesheet.
however in TEMA, calculations are only for untubed & tubed portion of tubesheet.
i m a little confused that what should be the inputs for PVELITE as it has a major effect on thickness of tubesheet

Dear as1893,


The inputs for mean metal temperature at tubesheet rim, shell metal temperature at tubesheet & channel metal temperature at tubesheet are required for ASME UHX Calculations. (Refer UHX 13.8)

It has no relation with TEMA Calculations.

And regarding its effect on tubesheet thickness, It can not be generalised.

thanks purav
m agreed wid u
but can u please tell me that how to calculate those mean metal temperature values as per UHX

This mean metal temperature is the highest temperature on the particular side we will take, these are used to calculate Ts*, Tt* & Tr.

can u give exact formulas to calculate the values of Ts*, Tt* & Tr.

You can get some of these temperatures from process design. So, check with your process engineer. For other temperatures you have to use your (or process engineer's) best judgment.

Remember this is the temperature of the metal and not the process liquid. So, it depends upon the heat transfer between process liquid and the metal.

TEMA has some formula for computing the metal temperatures of tubes and shell. You can also refer to it.