Joshua, and I think Abd, believe "...steam inside the conduit is always at 100% RH. Regardless of what fraction of the water is converted to steam. At 100C, the vapor pressure is 1 atm, and the steam pressure (also the partial pressure of the water vapor) is also 1 atm. Ergo, 100% RH.
I think the RH of the steam is 0% when it is fully dry just like the RH of fully dry air is 0%. You can correct me if I am wrong, but here is my reasoning: Dry steam is water in the form of a gas and only a gas. (I prefer the word gas over the word vapour because the meaning of water vapour is highly fluid in common paralance. Pun intended) Water can only exist as a gas if the atmospheric pressure drops considerably or if the temperature rises considerably or through combination of the two. Therefore at room temperature and pressure water does not exist as a gas, and the humidity of the air consists entirely of an extremely fine suspension of liquid water drops. Air at room temperature and pressure is free of water gas. When the relative humidity of the air (or some other gas) reaches 100% it can't hold any more liquid water drops. On the other hand my assertions about water gas are hard to reconcile with the phenomena of water evaporation so I may well be wrong! Harry > >From: Joshua Cude <[email protected]> >To: [email protected] >Sent: Thu, June 23, 2011 1:02:02 AM >Subject: Re: [Vo]:E-Cat vs. Water Heater for coffee/tea... > > > > >On Wed, Jun 22, 2011 at 11:14 PM, Mark Iverson <[email protected]> wrote: >Yes, as I've been trying to explain all along, once you get to 100%RH, all >remaining water will be >>in the form of liquid water because at the given temperature and pressure it >>is >>now saturated and >>can no longer support further water molecules as vapor. >> But steam inside the conduit is always at 100% RH. Regardless of what fraction of the water is converted to steam. At 100C, the vapor pressure is 1 atm, and the steam pressure (also the partial pressure of the water vapor) is also 1 atm. Ergo, 100% RH. >I've already answered your question as to HOW one can calculate that portion >that is liquid water... > No. You really haven't.
