Is Convection Happening in our Surface Condensers?

Unless this is a sealed, batch process, there will be conduction, convection and radiation.

The movement of warm vapor from the "outside world" to the outer surface of the tubes is indeed convection, even if not in the most conventional of understandings. However, within the condenser, the dominant action of interest is conduction.

Convection is a combination of gravity driven fluid circulation and conduction. So I believe your debate will be settled by how these vapours move.

Conduction will remove heat from the vapour closest to the heat exchanger, that vapour will now be cooler than the surrounding vapour which will cause a convection current to flow in those vapours as they attempt to equalize temperatures and pressures in the vessel.

The cooler condensed molecules will transport through the vapour to the bottom of the vessel thus gaining some conducted heat from vapour in transit.

The movement of cooler product to the bottom of the vessel will cause displacement of warmer product to higher up, another one for convection.

The vapours will also experience conduction between individual molecules in contact.

So... Both conduction and convection will take place, with conduction probably being the major player.

@sealed condenser via which vacuum is created in a crystalliser (whose vapours travels inside condesner), condenser is joined by a vacuum pump (water ring type)

Thnx for the replies & I have come to some precise explanation do correct it if it appears wrong...

I can recall that if a test tube filled with water is heated from the top side convection not but conduction is the major heat transfer mode but if you heat the same test tube from below convection is the major player...

In the diagram I believe that the part above the tube carrying coolant suffers no convection (denser condensate travelling down will have no effect on vapour present here) but convection does occur in the portion below the coolant line as explained above that condensate falls down due to gravity & the vapours thus moves up to replace it...all in all conduction is the dominant transfer mode

I can't agree with your final comment there. If the denser concentrate is travelling down it is creating a difference in local pressure (negative in this case) and this must have a convection effect on the local vapour as it is forced to move in to take up the vacated space.

I would say this is both convection and conduction as it involves fluids for heat transfer. Remember when the is conduction of vapour, the volume that was occupied by steam/vapour reduces when steam/vapour converts to liquid. The reduction in volume thus creates vacuum which then allows steam/vapour to travel towards the tubes for more of conduction and convection process.

In my opinion, the creation of vacuum allows the steam/vapour to be closer to the tubes for better thermal convection, thermal gradient is thus also noticeable in situations like these.

Major heat transfer is conduction of heat through the tube walls (and any scale material on the inside of the tubes, along with any loose oxides of the tube on the outside). For new, undamaged tubes with no mineral scale on them, there is a specific U value for the type of metal, thickness, diameter, length, number of tubes, cold supply temperature, and the vacuum in the system (defines the condensation temperature). While there is some convection, the collapsing of vapor near the tube surfaces into liquid provides a driving force to flow vapor into the boudary layer. With most condensation processes, some of the condensation will occur in the zone just above the tube bundle. I suspect there is even a miniscule pressure differential from the condenser inlet (or turbine exhaust), to the tube bundle, although measurements of vacuum in these devices are either not set up to "see" this, or not sensitive enough to see it.

In steam power applications of this technology, it is important to monitor the "back-pressure" and ensure that the exhaust temperature of the steam turbine is appropriately high not to allow condensation to occur before steam exits the final stage of blades, otherwise there will impingement damage.