How do you explain this?
Ha! I did not recall any of that. Merciful amnesia perhaps. In any case, none of it made it into the Proceedings.
How do you explain this?
Ha! I did not recall any of that. Merciful amnesia perhaps. In any case, none of it made it into the Proceedings.
[...] In any case, the experimental evidence shows that Tin was asymptotically approaching Tamb. There is no possibility at all that this very specific trend can be induced by a heat flux emanating from the Ecat. It is the clear sign that the temperature of the water inside the tube is going to equalize the temperature of the surrounding ambient, and this can happen only if the water is still. This is the more simple, straightforward and congruent explanation.
I haven't still understood if you exclude it, and, in case, why, and which specific alternative explanation you propose.
I don't know whether there's "no possibility at all", but I'm afraid that there's not enough information in the report to confidently state that it certainly didn't.
Convection of the Lugano ECAT rib area
I updated the convective heat transfer coefficients on my Excel sheet for the Lugano dummy run recalculation
The Error is somewhat lower now, about 9.1 %
With that error I expect that if we consider that the temperatures where inflated, the error will be much lower and close to the zero percent.
Whatever the outcome will be, it seems that the correct calculation of the convective heat transfer of the ribbed area will be the factor that determines the correctness of the calculation.
That because even after correcting my heat transfer coefficients, there is still a large difference between the convective heat transfer of the ribbed area in my calculation and that of the Lugano report.
During the recalculation, looking at the contents of the Lugano report and consulting literature, new questions about the convective heat calculation of the rib area arose.
See below.
1. Area used for the calculation of the convective heat transfer
The Lugano report mentions 61 ribs for the finned area. (You realy can count 69 from the picture !)
Since we have 10 sections, each section then contains 6.1 ribs
The Lugano team calculated the area of the ribs as Af = 2x Pi x(Ra^2 - Rb^2), Ra being the diamer of tube + fins ( 12.3 mm) and Rb the diameter of the tube (10 mm).
This calculation gives an area of the fin of 3.22E-4 meter
For 6.1 fin per section the total fin area of a section becomes 6.1 x 3.22 E -4 = 1.96E-3 m^2
This is a large difference compared to the section fin area I calculated as being 2.63E-3 m^2 (34% more)
To make things worse, the Lugano team rounded the value of 6.1 ribs per section to 6 in their calculation of the convective heat transfer of a rib section which lowers the calulated heat transfer even more.
The Lugano team referred to the "Heat Transfer Handbook " For using this approximate formula for the rib area.
Indeed does that book use that formula and refers to another work for a more detailed explanation, the book "Extended surface heat transfer".
However I could not find that explanation in the last reference.
2. Fin spacing
Convective heat transfer from fins are normally calculated for one fin, For multiple fins you can multiply the convective heat transfer of one fin with the number of fins if the fins are widely spaced.
If the spacing gets closer the total convective heat transfer rises due to the effect of having more fins. That is until we arrive at the optimal spacing , where the total convective heat transfer will be at it's maximum. If from the optimal spacing you lower the distance between the fins even more, then the total convective heat transfer drops off from it's maximum, and quite rapidly.
Thus the convective heat transfer coefficient of multiple fins is not linear dependent on the number of fins, but also depends on the spacing and is quite non linear near the optimal spacing value.
For the Lugano ECAT I don't know what the value of the optimal spacing is and if the spacing of the fins is less, equal or grater then the optimal spacing.
Even if we know the value of the optimal spacing it will not give us the needed heat transfer coefficients for a recalculation.
The conclusion is that for an accurate Lugano dummy run recalculation we have to find out how to calculate the correct heat transfer coefficient of the finned area.
This means determining which area to use and also to find out if we need a correction for the used fin spacing.
It looks that that there is currently at least one option to calculate the proper heat transfer coefficients for the ribbed area.
That is to model a finned section and to simulate that section with CFD software.
My CFD software is too limited (restricted maximum number of finite elements I can use) to undertake that task.
Maybe I have to consider upgrading my license (Quite expensive).
I built a simple Lugano-esque dummy device in 5 days, most of which were curing time for the mold and cement, and tested it in a couple of hours.
Did you ever publish your measurements results of your replica ?
What where your conclusions ?
Did you ever publish your measurements results of your replica ?
What where your conclusions ?
Thanks for your hard work. I am currently in an area of very poor internet, and soon to be where there is none, so I will be brief.
I was mainly interested in building the IR emissivity tester to a reasonable level of ease of testing. The results are those for my plain cylinder that I have posted some info from previously, and several flat slabs. I will attempt a ribbed version some time later in the summer, and attempt to rent an IR camera with suitable abilities. I do have stored thermocouple data, pages of notes, etc., which I will compile now that I have fewer distractions in the evenings.
For the finned calculations, I don't think that I can help at present. I have been attempting to look up some better information and equations, but it is nearly impossible at present. I can barely read a page of the Forum once an hour, and sometimes barely post. Luckily the Forum software stores my posts so I can re-send until they go through.
It seems to me that the valley of the fins must convect much more poorly than the outer parts of the fins, due to the rarified air in that area, due to the increased heat and lesser air flow possible in that valley bottom region. So to some degree that surface area is not as efficient as the increase in physical area due to the ribs might suggest.
It seems to me that the valley of the fins must convect much more poorly than the outer parts of the fins, due to the rarified air in that area, due to the increased heat and lesser air flow possible in that valley bottom region. So to some degree that surface area is not as efficient as the increase in physical area due to the ribs might suggest.
That reason for a lower convection rate was also mentioned in literature as the reason for the total convective heat transfer dropping off below the optimum fin spacing.
If I remember well, you mentioned this before and you where right.
My plan now is to make a short ribbed section ( 5 cm) in CAD and import that in the CFD software I am using.
I can then estimate how much finite element sections I run short off.
Maybe I can then negotiate a deal with the CFD software vendor.
I had contact with them in the past and they where at that time willing to negotiate customized deals (eg lower price)
In the meantime I am open to any suggestions where to find literature on the effect of fin spacing which can give the answers we need.
To summarize my conclusion: The erroneous use of the IR camera emissivity function resulted in nearly doubling the numerical value of the true temperature, which results in nearly 4 times the calculated power compared to the real power emitted by the Lugano device, due to the T^{4 }relationship of temperature to radiant power. The ratio of false radiant output to real radiant output increases with the overall temperature, independent of the overall physical size or input power of the device measured, and is directly dependent of the emissivity delta between the real (high) and artificial (low) emissivity functions used for the IR camera, for any equivalent isothermal surface area. (IE: The addition of caps, rods, or other areas of cooler temperature compared to the maximum temperature zones reduce the combined apparent ratio of output to input, while for each individual area (segment) the ratio is directly dependent on the temperature and emissivity error delta only.) Additional areas of lower temperature obscure the T^{4 }inflation relationship when the total input and combined radiant output of several areas of significantly different temperature are compared. The inflated "COP" effect can be optimized by simplified architecture (one diameter, reduced non-radiant losses), higher (real) temperature, and increasing the delta between the (low) camera emissivity function and (high) real camera emissivity function. The general idea is to maximize the inflated T^{4 }power relative to the real T^{4 }power, resulting in the T^{4 } of the inflated temperature's numerical values to increase at an accelerated rate compared to those of the T^{4 }of the real temperature, as the real temperature increases, thereby systematically and logarithmicly increasing the numerical value of the apparent and false COP with increasing temperature. A false "COP" of 5 is achievable without much difficulty.
Thanks Alan,
The link is for longitudinal fins, not for anular fins.
Also the shape of the fins in the link is rectangular, not triangular as in the Lugano case.
So I don't think we can apply the numbers of the calculator to the Lugano case.
Ha! I did not recall any of that. Merciful amnesia perhaps.
Yes, most likely. It's probably a selective amnesia, triggered by topics connected to the Bologna demo (1). But don't worry, fortunately the Vortex mail-archive helps us to refresh our memory.
Btw, your reportage from ICCF16 is really very interesting. It shows that the results of the Bologna demo have been widely discussed between you, Melich and Storms, and considered "a definitive triumph" even in case "there was a only a tiny bit of steam".
Your reportage also mentions Test 1: "Levi remarked somewhere that he felt confident in the machine after the Dec. 16 test [Test 1] and also when he saw it run with no input, in heat after death." As you can see in this same thread, for some days I'm discussing with *can* on the interpretation of the few experimental evidences that appear in the calorimetric report, including the photo with temperature curves taken from a PC screen, mentioned also in this phrase of yours: "The data acquisition system failed, as noted by Levi in his report, which is why they had to use a photo of the screen."
Until now there are two possible interpretations (2). The one described in the official calorimetric report, which states that the Ecat produced almost 10 kW, initially with an input power of 1120 W, and, later, in self-sustaining mode during the last 15 minutes. My alternative explanation is that in the middle of the test the water flow has stopped. Well, since you have some experience in calorimetry and T-probes, can I ask you which one of these two interpretations appears more realistic to you, or if you have a third possible alternative to suggest?
You also wrote at the end of your reportage: "People such as Melich and Levi, who know the most about this machine, seem to have the highest confidence that it is real." These are very important opinions, considering that they both have a PhD in physics, and have long been teachers at high-level universities. In addition, the first is one of the maximum expert in LENR, while the second was a member of the American Skeptic Society, and was trained in LENR by one of the fathers of the Ni-H technology. They were probably the most talented and informed members of the two groups A and B (3) that in January 2011 collaborated in the drafting of the UniBo calorimetric report. So, I would ask you, could they have been cheated for so long by someone like Rossi on the calorimetric performances of an alleged LENR device?
(1) https://www.lenr-forum.com/for…D/?postID=30161#post30161
I don't know whether there's "no possibility at all", but I'm afraid that there's not enough information in the report to confidently state that it certainly didn't.
I wonder which kind of information would you have expected from a document where it is reported that "… the original data has been lost …".
Sorry, I have no more argument for you. If the temperature graph of the Decembre 16 test is not convincing enough for you, I'm afraid that I will not be able to find more convincing arguments for showing you the flaws present in the January 14, and February 10 tests.
Thank you for the all the nice graphs you have prepared following my indications.
To clarify the wording above: I did acknowledge that the trend in the graph could indeed be interpreted as the water flow getting interrupted and that there's not enough information in the report allowing to tell that it [the flow] didn't [get interrupted].
No need to shut the door angrily.
To clarify the wording above: I did acknowledge that the trend in the graph could indeed be interpreted as the water flow getting interrupted and that there's not enough information in the report allowing to tell that it [the flow] didn't [get interrupted].
No need to shut the door angrily.
Sorry, your wording was cryptic. I thought that "it didn't" meant "the report had not enough information for concluding that the flow stopped". Consequently, I was really discouraged, not angry at all.
However, if you acknowledge that in the December test the water was stopped, it also means that at least one of the testers was aware that the Ecat was unable to operate as claimed. Now, if you wish, we could go on with the subsequent tests.
QuoteTo summarize my conclusion: The erroneous use of the IR camera emissivity function resulted in nearly doubling the numerical value of the true temperature, which results in nearly 4 times the calculated power compared to the real power emitted by the Lugano device, due to the T^{4 }relationship of temperature to radiant power. The ratio of false radiant output to real radiant output increases with the overall temperature, independent of the overall physical size or input power of the device measured, and is directly dependent of the emissivity delta between the real (high) and artificial (low) emissivity functions used for the IR camera, for any equivalent isothermal surface area. (IE: The addition of caps, rods, or other areas of cooler temperature compared to the maximum temperature zones reduce the combined apparent ratio of output to input, while for each individual area (segment) the ratio is directly dependent on the temperature and emissivity error delta only.) Additional areas of lower temperature obscure the T^{4 }inflation relationship when the total input and combined radiant output of several areas of significantly different temperature are compared. The inflated "COP" effect can be optimized by simplified architecture (one diameter, reduced non-radiant losses), higher (real) temperature, and increasing the delta between the (low) camera emissivity function and (high) real camera emissivity function. The general idea is to maximize the inflated T^{4 }power relative to the real T^{4 }power, resulting in the T^{4 }of the inflated temperature's numerical values to increase at an accelerated rate compared to those of the T^{4 }of the real temperature, as the real temperature increases, thereby systematically and logarithmicly increasing the numerical value of the apparent and false COP with increasing temperature. A false "COP" of 5 is achievable without much difficulty.
Yes. Very very nice job.
But all of it would have been moot if only correct calibration with a reliably known power input to a blank reactor would have been performed at the time, over the entire relevant temperature range. Somehow, of all the renown scientists involved with Rossi, none seemed to know or care about the concept of calibration and blank runs. Truly strange.