On Sun, Nov 20, 2011 at 3:12 AM, Jouni Valkonen <jounivalko...@gmail.com>wrote:
> Joshua refering to wikipaedia: "The quality of steam can be quantitatively > described by steam quality (steam dryness), the proportion of saturated > steam in a saturated water/steam mixture. [4] i.e., a steam quality of 0 > indicates 100% water while a steam quality of 1 (or 100%) indicates 100% > steam." > > This says that steam quality is referring to _saturated_ steam/water > mixture. This _saturated_ mixture however cannot exist in arbitrary > proportions in normal pressure and in closed container, but it is always > ca. 99-98%. (>95% to be in safe side). This is because surface tension and > pressure gredients in liquid. > > > and a lot of other stuff that didn't make sense, or was wrong. This should be simple. If you pass water through a device that transfers heat to it, then the output must consist of liquid water, steam, or a mixture of the two. After enough time, equilibrium is established, so the output mass flow rate equals the input mass flow rate. Then the ratio of the steam to water is determined completely by the amount of power transferred to the fluid, and the pressure inside the conduit. To the extent that the power of the device can be varied continuously, any ratio of vapor to liquid is possible (at any pressure). For goodness sakes, we all agree that pure water is possible, and everyone is claiming pure steam is possible. You have to get from one to the other. The only constraint is that the mixture has to be at the boiling point for the local pressure (that's what saturated steam means), unless the quality is zero or 100%. I don't care if you don't want to call the ratio of this mixture "steam quality", but that's what it's called in the literature. Whether the mixture is single phase liquid, bubbly (low quality), slug, churn, wispy, annular, mist (high quality), or single phase vapor, the ratio of steam mass to total mass is always referred to as the quality, and it varies continuously between 0 and 100% in experiments at all kinds of pressures. Look it up. I gave the reference. So, let's just call it the steam ratio if you prefer. All I'm arguing is that from the measurements presented, we don't know the steam ratio, or the nature of the mixture, and the measurements are consistent with a very low steam ratio, and therefore with power output of 70 kW. Considerations of thermal mass, time, and the coincidence of 107 ecats turning on simultaneously, make 70 kW vastly more likely than 470 kW.
