Jouni Valkonen <[email protected]> wrote: Water inflow rate was calibrated and it was 13 kg/h.
For this test? Where does it say that? Anyway, that comes to 3.6 g/s which is enough to sustain the highest power without having the reservoir run dry. It could be the reservoir was overflowing during most of the test. That would make no difference to the readings in the heat exchanger. The flow could be steam, or a mixture of steam and hot water; the heat exchanger will read it the same way. I think that Hefner said that there may be intermittent bursts of hot water entering the heat exchanger and this might explain some of the outlet thermocouple variations. I do not think so: 1. We have very few data points from the thermocouples. You would have to have readings taken every few seconds to see a momentary heat burst. 3. Hot water coming through the pipe would lower the temperature not raise it. 3. Putting the outlet thermocouple on the pipe is a good way to blur out momentary variations and heat bursts. It is a recommended technique. The NRL went to a lot of trouble to make sure their pipes are good heat sinks in their test bed system. However, I think installation instructions recommend you put the thermocouple about 2 feet from the boiler or heat exchanger on a straight segment of pipe. I read somewhere that you are supposed put at strap on pipe thermocouple about 2 feet away. I cannot find that document. I think that is what it said. If that is true, the readings may be a little bit high because of the steam pipe. As I said before, the thermal mass of the cooling water is so much larger than that of the steam that even if the thermocouple is picking up the average temperature right between them -- which is highly unlikely given its position -- the temperature would still be pretty close to the correct value. There are many strap on thermometers available that are intended to be used on the outside of pipes. This one is a general-purpose thermocouple. However, this technique will work fine as long as the thermocouple is wrapped in insulation. - Jed
