zamakaze
Chemical
- Sep 3, 2020
- 46
For heat exchangers in simulations, I have often seen that sometimes the UA value is often held constant. Like its taken from a max/design case and kept constant for other cases like turndown. However, is this truly the correct approach? Given that the overall heat transfer coefficient (U) is influenced by film coefficients (h), which themselves depend on Reynolds number and flow velocity, wouldn't operating the exchanger in turndown mode inherently alter the U value? Shouldn't we account for variations in U rather than assuming a fixed UA, especially at lower flow rates where changes in flow regime might impact heat transfer performance?