On Fri, Jul 15, 2011 at 1:21 PM, Mark Iverson <[email protected]> wrote:
> ** > JC stated: > "...and the heated walls are at a higher temperature. So, it must get > hotter." > > What makes you think that the walls of the vertical section (i.e., the > 'chimney') are at a higher temperature than the walls of the horizontal > section that has water at a much lower temperature entering, and the liquid > water has a MUCH larger specific heat than the vapor in the chimney? > I was not talking about the walls of the chimney. I was talking about the walls of the ecat, which is presumably the only source of heat inside the contraption. If the ecat is vaporizing all the water, then before it leaves the ecat, the water is in the gas phase. If the ecat power significantly exceeds the power needed to vaporize all the water (17 kW vs 12 kW), then the steam will have to pass by the hot walls of the ecat in the gas phase, and it will therefore get hotter. If it doesn't get hot enough to remove the additional 5 kW, then the ecat will have to get hotter causing the water vaporize earlier, giving the steam more time and hotter walls to take the heat from. This process continues until either the steam *does* remove the 5 kW, or the ecat melts. > The majority of the heat from the exterior heater around the reactor > section willl be flowing back towards the cooler section where the cold > water is entering... that is where the largest delta-T is. > The hypothetical 17 kW comes from inside the ecat. And anyway, once there is enough heat to vaporize all the water, the heat will have to flow into the steam or get hotter itself.
