I have a shell and tube heat exchanger (1-1 pass ). It has shell of 250 mm ID and tubes of 50 mm ID (# 19). Length is 500 mm.

I want to know the time-constant for this heat-exchanger (approx. )

I also want to know how to determine the final time-value to carry out transient- simulation in CFD (as more time than its time-constant becomes computationally heavy).

thankl you.