Originally Posted by Jumbo Driver
Quote:
Originally Posted by bsieker
Countercurrent flow heat exchangers are much more efficient than parallel flow designs.
Why is this?
Basic thermodynamics, really.
Ideally, a countercurrent flow HE can make the "hot" fluid (oil) at its exit almost as cold as the "cold" fluid (fuel) at its inlet (when it is coldest).
Ideally, a parallel flow HE can make the "hot" fluid (oil) at its outlet only almost as cold as the "cold" fluid (fuel) at its outlet (when it is warmest).
Originally Posted by Dak Man
Also, it is normal practice to arrange the flow path so that the hottest oil is cooled by the coldest fuel.
Is this not the opposite of bsieker's assertion ?
It is. And I think Dak Man might have been momentarily confused when he wrote it.
Because what he said also means that the hottest fuel would be used to cool the coldest oil, which would be inefficient.
Bernd