A "row" is like a slice of bread. Imagine that your slice of bread has, say, 12 tubes running along it, or "12 tubes all lined up in a row".
If you put two slices of bread together, you'd have a two-row core. If you put 3 slices of bread together, it'd be a 3-row core.
We'll assume a two-row core in the following example of "pass".
As described above, a single-pass core will have the water flowing down all 24 tubes (two slices of 12 tubes) from one end to the other in a single pass.
A two-pass core will have the water flow down 12 tubes, being 6 tubes on one half of the slice (row), multiplied by two slices (rows). Goes to the other end, gets mixed in a tank, and up the other 12 tubes. Inlet and outlet will therefore be at the same end.
A triple pass would be an S-shaped path. Goes in, down 8 tubes on one side, up the middle 8 tubes, then back down to the 8 tubes on the other side. Inlet and outlet would therefore be at opposite ends.
|