> Horace Heffner ----- Original Message ----- > On this we may disagree significantly. Take a look at the photos > kindly provided by Enzo: > > http://www.redmatica.com/media/Thermo1.jpg > http://www.redmatica.com/media/Thermo2.jpg > > The central brass fitting is very thick. Given the hose ID is about > 1.5 cm I would guess over a cm thick. It appears the thermocouple was > placed not far from it. > > The intermediate section looks to be at least 0.75 cm thick > > From the location of the tape, and the protruding thermocouple, in: > > http://www.redmatica.com/media/Thermo2.jpg > > it looks like the thermocouple may have been taped to the > intermediate section and oriented axially toward the large steel nut.
I'm not vested in the dimensions. Taking the tube as 0.75 cm thick, and the distance from the center-line as 2.5 cm I calculate the temperature error (100C to 30C) as 16 C --- and the 2-resistor and 20-resistor triangular mesh agree to 0.7 This is VERY worrisome. > This is essentially the same method I posted earlier, except I did > not calculate an analog to current. We're using the same equations, but you were (I think) using the observed temperature difference to calculate R, and I am using the dimensions to calculate R and from that, the temperature difference. This analysis presumes that there is similar coupling of heat from the two streams. On the output (water) side the coupling is from water to brass, which is efficient. On the input (steam) side we have an unknown selection of any/all a) Superheated 120C (1 bar) steam (efficient) b) 100C (1 bar) or 120C (2 bar) vapour (inefficient) c) 100C (1 bar) or 120C (2 bar) fluid (efficient) which have a different "coupling coefficient" to brass (I can't think of the technical term),which limits the heat transfer from one side to the other. In a circuit simulation like Spice I could use a current source (= heat) rather than a voltage source (= temperature). In the absence of any new information (eCat flow) I'm inclined to go with the output from Lewan's Sept experiment -- 50% vapour, 50% fluid -- supported by your slug hypothesis -- which means that the coupling is the same on both sides (water-to-brass) and the resistor-model is valid. The specific heat (if needed) can be modeled with capacitors, but I'm only considering the DC solution. Rossi put the "cold" thermistor as far from the heat exchanger as it could go, and the "hot" thermistor very close to the steam inlet. Carelessness (or couldn't-care-less-ness)? Or ..... ? I have to say that my trust level is decreasing. [ This was posted while doing three things at once ... (Rossi's gum-chewing?) ... so I hope it's what I meant. ]
