Understanding Two-Pass Shell and Tube Heat Exchangers

[Janiceleong26]

Homework Statement

'A shell and tube exchanger is used to do heating, with single shell and 2 tube passes. There are 70 tubes each with an outside diameter of 25mm and length of each tube pass is 6m. '

I am wondering whether the 70 tubes are in between the 2 tube passes, or is it 1 tube pass contains 70 tubes?

Homework Equations

The Attempt at a Solution

 

[deuel18]

Its one huge shell that looks like a capsule with 70 tubes inside. But if u cut that capsule shell in middle, those 70 tubes would pass twice the cut.

 

[Janiceleong26]

I see. Meaning there will be a total of 140 tubes in the heat exchanger? But wouldn't that be 140 tube passes? I'm confused as to what is the difference between 'tube pass' and 'tube'

 

[Nidum]

A two pass heat exchanger has two sets of tubes . Working fluid first goes through one set of tubes then does a U turn and comes back through the other set of tubes . So the working fluid passes through the heat exchanger twice . Hence the description two pass .

 

[Janiceleong26]

A two pass heat exchanger has two sets of tubes . Working fluid first goes through one set of tubes then does a U turn and comes back through the other set of tubes . So the working fluid passes through the heat exchanger twice . Hence the description two pass .

Ok got it. Thanks!

 

[deuel18]

I see. Meaning there will be a total of 140 tubes in the heat exchanger? But wouldn't that be 140 tube passes? I'm confused as to what is the difference between 'tube pass' and 'tube'

U r correct if u cut the capsule shell u will see 140 tubes. The configuration is as what Nidum said, it makes a U turn. This is to increase effective area in which the two fluids interect.

A two pass heat exchanger has two sets of tubes . Working fluid first goes through one set of tubes then does a U turn and comes back through the other set of tubes . So the working fluid passes through the heat exchanger twice . Hence the description two pass .