Transformer Tank Cooling Oil Round vs. Rectangular

[Mandrill22]

Oil filled transformer tanks are mostly rectangular, with small bend radii on the corners. The function of the oil is to cool the active part of the transformer. I think that either making the tank elliptical, or increasing the bend radii greatly, would improve the cooling properties of the oil. I would think the fluid being more evenly distributed would distribute the heat more evenly. Am I correct? If I am, how would I go about proving it with formulas? Would that increase or decrease the price? I would think it's less material, lower cost.

 

[bimr]

Transformer oil is also used to insulate, suppress corona discharge and arcing, as well as serving as the coolant.

 

[hydtools]

If you go to the extreme as approaching a cylinder, the surface area is reduced. Would that not lead to lower cooling capacity?

Ted

 

[KevinNZ]

If you are looking to reduce dead spots in the tank, then looking at the location of the inlet and outlet nozzles may be a more cost effective place to start.

 

[Compositepro]

Your logic is flawed. A rectangular tank has more surface area than a round one of equivalent volume. Oil inside the tank flows due to natural convection from top to bottom at the walls.

 

[LittleInch]

mandrill,

The function of the oil system is to cool the transformer, however the function of the tank in most ONAN transformers is simply to act as an expansion tank and to hold a reserve of oil in case of a small leak. It is not there to provide cooling - this is done from the finned pipes on the outside.

It is what is called the "conservator" on this diagram.

This one has a round tank as do many others.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Mandrill22]

Thanks for all of the replies. The oil is also there to cool and our transformers don't have pipes for the oil.

The capacity would be lower, but I would think the improvement in convection would improve temp rise, no?

 

[LittleInch]

Well include a drawing or picture then we know what you're talking about.

Adding some fins would be much better and more effective if indeed the tank is used for cooling.

I don't understand how increasing the radii "improves the cooling properties of the oil".

Care to explain your thinking a bit more?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[IRstuff]

increasing the CORNER radii, which puts the corner metal closer to the transformer itself

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

faq731-376 forum1529 Entire Forum list

http://www.eng-tips.com/forumlist.cfm

 

[hydtools]

Has anyone looked at the heat flow impedance of the relatively stagnant oil film/layer on the inside wall surface? It is suprisingly high. Lacking any means to scrub that layer to improve heat transfer, the sensible alternative is to increase surface area, not decrease it.

Ted