Originally Posted by
aramis
If diffusion and dispersion weren’t important in refrigeration then absorption cooling wouldn’t exist!
Sounds he’s a smart guy!
If counterflow diffusion where impossible then how do you explain a fire? What is the mechanism that feeds low temperature low pressure oxygen into a high temperature and higher pressure area!
In air conditioning it is known that humidity travels counterflow in air.
What makes water from a leaking heat exchanger fill the whole inner volume of a system that is not working.
If you ever experienced refrigerant migration, these mechanisms are the ones that feed the oil with refrigerant vapor, without pressure differentials.
What you should be questioning is not that it seldom happens but if it happens in amounts large enough to be a problem in the system. I think that this is rare but it does happen.
What is not rare is that fluid flows produce all sorts of induced currents and low pressure zones like in a ventury or an eductor and these eddies may bring in air into the system.
Like you I try to keep an open mind and never say never!