QUOTE(john rogers @ Oct 21 2006, 08:14 PM)
The problem with the dash 10 lines is the velocity of the oil is greater than the dash 12 and this causes a reduction of cooling in the cooler since the oil is moving along faster.
I understand the velocity difference between -10 versus -12. The greater the cross section, the lower the velocity of the fluid. Since friction is a function of velocity, -12 move more fluid for the same amount of work than -10. However, isn't it be the cross section of the cooler itself that determines the velocity at which fluid flows through it, and not the feed lines?