Fluids in Shell and Tube Side

http://cr4.globalspec.com/thread/35656/Heat-exchangers

Well, the answers to the questions you have asked can be quite varied and therefore very many. However, here is my attempt at providing answers:

Hotter Fluid in Tubes:
Thermodynamic Efficiency Analysis of the Thought-Experiment Carnot Cycle described by the Heat Exchanger usually shows that hot fluid in tube has relatively higher efficiency: Then, of course, the relative size of the cooling fluid in the shell also gives much larger Cold Temperature Reservoir;

High Pressure Fluid in Tubes:
Flow-rate is usually much higher in the Tubes than in the Shell so high pressure should remove the need for possible deployment of a pump to further drive the fluid through at a high flowrate in the Tubes;

Corrosive fluid in Tubes:
Containment of material failure is easier managed with corrosive fluid in the Tubes than in the Shell;

Dirty Fluid in Tubes:
Fouling is a problem in heat transfer and Tube-side cleaning is easier than Shell-side cleaning as there is smaller surface area in Tube-side than in Shell-side, besides the flowrate is higher in the Tube, so fouling occurs only over a longer time span with dirty fluids in the Tubes than it would otherwise if dirty fluid were in the Shell-side.

These are just my thoughts but i suppose that others might have more; as I said earlier the explanations can be quite varied and so be quite many as well.

There is another aspect what you have to consider.

Usually the tubes are expanded into the tube sheets.

The higher pressure on shell side will act against the expansion, as will the higher temperature.

The tubes are more easily manufactured to be of corrosion resistant by selecting SS or similar material. However the shell are bound to have weld joints which may be more readily attacked by the chemicals

The tubes are more often than not made finned and that will attract the contaminants.

BTW- the Lube Oil System for our equipment are the reverse.

The hot oil, at higher pressure are fed to the shell side and the cold water to the tubes . Of course no contaminants (cooler is placed after filter)

So noted; thank you.

Singlaatul, plesae also note the additions

That was a good explanation, can you please put some light on Lube oil system where the reverse is true...it would be great help...

I would speculate that the higher viscosity of the Lube Oil is the factor, given that the flow area in the Shell-side is more than in the Tube-side. Depending on the characteristics of the viscosity the Shell-side may allow easier flow than the Tube-side: A shear thinning fluid could still be put in the Tube-side, however, a shear thickening fluid would have to be in the Shell-side.

But lets wait for sb to comment on this.

Yeah i am sure the higher viscocity will be one of the critrea, but i am sure there would also be another explainantion too...i.e related to it's connection with filter????

Thax a lot...it was really useful information.