Heat transfer & fouling factors
 

I am currently simulating a system where a steam pipe is being used to heat a volume of fluid, a process intended to heat-sterilise the outer fluid. I want to consider the effect of fouling on the inner and outer surfaces of my steam pipe.

On the inner surface I expect there will be a layer of rust, on the outer side there may be a burned-on layer of the outer fluid (milk for instance).

The transfer of heat, and the surface temperatures on either side of the pipe, will depend upon the thickness and thermal properties of the two fouling layers.

Could someone please suggest a good reference that contains either useful information on fouling in general or, more specifically, appropriate coefficients to use in simulating fouling layers of different materials?

Re: Heat transfer & fouling factors
 

Any good heat-transfer reference book will have some information on fouling resistance, in the heat-exchanger section.

The fouling resistance is essentially the reciprocal of heat-transfer, placed in the overall heat-transfer coefficient - one for the inner surface & the other for the outer surface. They actually tend to dominate the heat-transfer coefficient in many cases, so be careful in their selection.

Bejan, Webb, Kuppan, Rohsenhow, Incropera are names that come to mind.

mw...

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Re: Heat transfer & fouling factors
 

Thanks for your reply momentum_waves.

I have already looked through some of the available literature on the subject of heat exchangers and there's some good info on fouling in general. My problem, however, is that I am trying to find some appropriate coefficients that could be used in my simulation.

The rig I am simulating must be maintained contaminant-free and is completely sealed. It is not possible to actually measure the properties of the fouling layer on the outer surface of the heat pipe. The geometry of the heat pipe also means that it's difficult to insert a probe or camera to study the insides of the heat pipe. There's no entrance or viewing portal to the steriliser so we can't even get a hand-wavey appreciation of the fouling layers.

If you can think of any way to circumvent these problems, or know of any relevant references, then I'd be very grateful. Dave

Re: Heat transfer & fouling factors
 

There is good CFD work done by Jun and Puri in this area (fouling of milk HE). look in the journal of food engineering, or get your hands on the first authors phd thesis. or http://www.abe.psu.edu/facstaff/puri.htm. i'm sure they encountered similar to what u are talkin about