On Thu, Jul 14, 2011 at 10:30 AM, Abd ul-Rahman Lomax <a...@lomaxdesign.com>wrote:
> > In many discussions of this, it was assumed that the only issue was "steam > quality." If we were to assume very wet steam, say 20% by weight, we would > then be able to infer excess heat, assuming complete boiling (only merely > "wet"), of about 3.6 kW. This is why some think steam quality is a red > herring. > I agree with much of what you wrote, but not with this. Very wet steam is not 20% by weight (I assume you mean 20% liquid by weight); it is 90% or 99% liquid by weight. Steam that is 99% liquid by weight corresponds to "steam quality" of 1%, and is still 94% gas by volume (at atmospheric pressure). In the literature on two-phase flow, the charts show data with steam quality below 1%, so this is not just a hypothetical fluid, in spite of what Storms seems to think. Whether the fluid is mainly a gas with entrained microscopic droplets (wet steam or mist), or largely separated fluids, we don't know. Inside the chimney, it is certainly possible to arrange the conduits or design an atomizer to produce a mist with 99% liquid by mass, but it seems reasonable that in the hose, where the diameter is quite large, that some separation of the liquid and gas would occur (in addition to some condensation). But it is important to realize that even for a fraction of a per cent gas by mass, the liquid cannot flow through the hose in the ordinary sense, where it fills the hose. The volume of the gas exceeds the volume of the liquid when only a part in 1000 of the water is vaporized (by mass). That means it has to move through the hose faster, and the liquid has to get out of its way. For a larger tube, this sort of flow is usually annular or annular/mist, with a film of liquid flowing along the walls, and the gas/mist flowing along the center of the tube. > > If there is no excess heat, under these conditions, there might be a small > level of boiling, it's marginal and would depend on the exact power and the > accuracy of the flow rate. If there is some boiling, the water and steam > will be exiting the E-Cat at 100 C., as observed. However, at minimum > boiling, 2 ml/sec of water would be flowing out through the hose to the > drain. That water would be at the boiling point, it would be "steamy," i.e., > mist would rise from it, plus any actual steam would create some visible > steam flow. > I agree that 2 mL/s of water (liquid) would be flowing through the hose, but I think your description of it is not apt. If 1% of the liquid (by mass) were vaporized, then 94% of the fluid would be gas (by volume), and what you would see would be dominated by this steam. The much less voluminous water would come out as a mixture of mist and larger sputtered droplets. It's hard to think of it as flowing out steamily, when steam occupies 94% of the volume. > Would water flow be visible from the hose? In the Krivit video, Rossi holds > up the hose to drain it before pulling the end from the drain. If the hose > is 16 mm inside diameter, the hose capacity is 5 g/cm, or 500 grams per > meter. To fill a meter of hose would then require 250 seconds. Rossi empties > more than a meter of hose. There is plenty of time to show the end of the > hose with no visible water flow and some steam and/or mist exiting. > Right. The water doesn't have to fill the entire hose and reach the end before something happens though. It only has to block the hose before the more voluminous steam behind it will cause some sort of sputtering which might scald the holder of the hose. The time for such blockage presumably depends on how much of the hose is lying at the lowest point (on the floor). And of course, the hose probably wouldn't actually block completely. As the opening for the steam closed, you might expect the level of sputtering to increase gradually until some kind of equilibrium is reached. Rossi was clearly not interested in recording that on video. > > We do not know how much water is unvaporized, no evidence is visible or > asserted, only the conclusion of complete vaporization is asserted by Rossi > and some observers. > > Some have commented, including myself, that the design of the E-Cat leads > to a conclusion that it would be designed to "leak" unvaporized water, i.e., > the flow rate would be set such that the water would not entirely boil away, > because this would lead to reduced control of heat. Because of the technical > difficulty of attempting to set generated heat to *exactly* the level to > cause boiloff with a fixed flow rate, and because heating above boiling is > not observed, we can assume some (possibly small) level of overflow, runoff. > You just have to assume some (possibly small and possibly large) level of liquid inclusion in the fluid, whether as a mist, or a film on the wall of the hose, or some combination. I don't think "flow" or "runoff" is descriptive of the sputtered, misty, spray of liquid that seems likely to come out along with a much greater volume of steam.
