You are wrong about the re-radiation. That is because at the temperatures I did this calculation
The method you are using is erroneous.
The accepted method is to calculate Q12 using A2,A1,E1,E2
Using this method I get a wall temperature of around 40-42C for 300W output from the reactor
In addition your calculations of box temperature based on Stefan's Law are erroneous
For instance if the reactor/box configuration is idealized as concentric cylinders
the power output assuming the ambient is 80C is 352W
but when the reflected heat from the box is accounted for the
net power output is only 215 W.
The actual net radiant power from the reactor when the shape factors are included is something like 150W.
Anyways, the exact composition of the heater sheath should be determined
It is enclosed.in a sheath.. appears to be 316ss from posts so far
18.8,2 Cr Ni Mo... similar to the reactor wall
to be confirmed.
forced convection from foil depends on foil - air
forced convection from reactor surface depends on reactor - air
please note that the air temperature varies significantly throughout the air stream
from high near the reactor wall to lower near the calorimeter wall.
and that the convective HTC varies greatly with airspeed
which is variable (0-2 m/s) throughout the entire box.
which makes any calculation with convective HTCs difficult
and therefore any calculation of the temperatures based on textbook generalised assumptions
are extremely prone to assumption error
THHnew..
if one reads a standard engineering textbook on heat transfer
it will state that the actual HT , both radiative and convective
depends greatly on the details of geometry.
In addition your calculations of box temperature based on Stefan's Law are
erroneous. If you do not take into account the reradiated radiation from the
calorimeter boxwalls you get a calorimeter box temperature of 80C..
if you do take into account the reradiated radiation you get a significantly lower
box wall temperature
Even though the +80C figure depends on power and is very rough, my contention that radiation dominates forced convection in determining calorimeter heat loss remains correct enough even for any inner foil uplift > 20C, supposing exit air uplift is +10C.
I'm glad your comment here is not personal
It never was.
Your contention is erroneous
not very rough.
calculations a long time ago based on R value
Please restate these calculations and show how convection has been accounted for
remembering that the reality is that
The convective heat transfer btw thw reactor and the calorimeter is in two parts..
1)btw the reactor and the airstream
2)and btw the airstream and the calorimeter wall
I need is the (textbook) assumption that forced convection cooling is roughly proportional to temperature delta, and the (proven from insulation R value) fact that the inner insulation surface is a lot hotter than the forced air, to make my point that heat loss from enclosure is roughly proportional to radiation power.
Your understanding of the complexity of heat transfer is poor
which heat transfer textbook are you quoting..
your calculations without convective heat transfer are erroneous,
Try this for a start
then I will stop posting here for at least 12 months.
I will miss your input...
ah Yet another swan song..possibly
I'd also like to point out that multiple impolite and personalised posts .. emotional bias etc
You are the one personalising
When I say you have poor knowledge of heat transfer it is not personal.
You cannot model heat transfer by radiation only. .. it is obvious.
You have not shown any mathematical calculation that takes convection into account.
when convection is the major heat transfer
until you do
your calculations based on radiation only are erroneous.
You are saying we really can't know what the emissivity is on the inside and that it changes depending on the hypothesized Ni metal hydride (actually deuteride) on the inside.
Not exactly..we don't know.
There is some evidence to suggest that the 316 ss surface gets microcracks in hydrogen atmosphere.
316ss is 18,8,2 Cr,Ni,Mo which gives ~72 Fe as balance.
The'hydride, deuteride??is of unknown chemistry.. and what austenitic phases do at 500+C with hydrogen is unknown.
But probably the reactor/heater 316ss has a different surface from non hydrogen conditions( whether reducing or oxidising)
which affects emissivity among other things
Paradigmoia prompted this discussion by asserting that the heater would fail early..
Which may be a useful. comment.. because the reactor wall itself may be part of the mechanism
I assume that Mizuno has not experienced early heater failure due to high temperature..
perhaps Jed could confirm
Babble on.
That's all I have to say!
Another ad hominem.
Is there a technical comment from Bang 99?
God Bless
Get a real life, RB!
So does Bang99 have a technical comment
Is it richtig to model heat transfer by radiation only when convection is more predominant?
I have objected to your latest ad hominem statement
If you want to start another topic
called defend THHnew please do
there are multiple other anonymous persona ... perhaps paid trolls perhaps unpaid trolls who will
Because Mizuno devotes 90% of his upcoming paper to it?
This is a half truth.
Which upcoming paper?
there are two
1. Excess heat
2, Increased heat
http://lenr-canr.org/acrobat/MizunoTexcessheata.pdf
http://lenr-canr.org/acrobat/MizunoTincreasede.pdf
the most recent being
Increased heat which is about R20.
Is there any reason to replicate R19 over R20?
R20 gave a 300% increase in measurable delta T for the
active reactor versus the calibration reactor
What did R19 give? 50%???
And THHnew says replicate R19??? because Mizuno wrote about it in a paper.
THHNew has a bad habit of writing half truths
IMHO both of these bad habits are made worse by an adversarial approach here where you see me as your enemy.
Your opinion is your opinion.
THHnew is the one personalizing here
THHNew has a bad habit of doing this
which calculation show was not true.
Did the calculation measure the temperature to show it was not true?
Please use a different tense.
Your calculation is erroneous.
You have misunderstood the point of the radiation calcs
No I haven't. You cannot use T4 radiative ht dependency alone to model the heat transfer when 60- 90 %
of the heat transfer btw the reactor and the outside is caused by forced turbulent convection
radiation is a lesser heat transfer mode.
You have to take into account convective heat transfer otherwise your conclusions about
insulator wall temperature based on radiative heat transfer only will be erroneous.
If that is not obvious to you ....it shows how limited is your understanding of
heat transfer..
If your source is better please cite it so I can use that data.
The problem with "use that data." using any current data is that the atmosphere inside the reactor.. is hydrogen.
and specifically deuterium
We don't know what the emissivity is after reaction with deuterium at 500C.
0.2,0.4,0.6,0.8?
It is known that hydride formation in austenitic stainless steels will modify the surface greatly.
" these hydrides form a hard and brittle surface layer, several mu m thick with numerous microcracks,
and it is probable that these hydride phases play an important role during stress corrosion cracking (SCC) of austenitic stainless steels."
The emissivity and surface condition of 316 ss under these special R20 conditions
should be the subject of further research.
For those doing replication a cursory examination of the 'shininess' of the heater surface
before and after would be a good thing to to do.
But for replicators
The fact that Mizuno is doing many hour long multiple experiments shows that
the postulated early failure of the heater due to too high temperature is not occurring.
. But I'm not confident at all in that hope.
But you cannot quantify your lack of hope...its one of those vague TTHnew feelings.
Your attempts to quantify and model the reactor transfer by T4 so far have been ridiculously amateur. Not analytic
but showing ignorance of the complexity of heat transfer. No wonder you found a missing 60W in the heat transfer.
You have entirely underestimated the importance of convective heat transfer,
"I have done an analytic calculation. Showing that the T^4 term, when used to determine radiation between two surfaces
makes radiation much larger at higher temps.
The goal is to replicate R20 according
to the dishwashing manual
Build as close to the the calorimeter
airbox dimensions as possible
build the reactor cylinder to the dimensions given.
use a similar airflowrate.
Try 50W calibration.
This should give an approx. 3C temp diff,
If not adjust the airflowrate until it does.
Then try the 50W active reactor.
This should give ~12 C temp diff
According to the graph
Why are you even bothering with R19.
Don't give us vague reasons.
The specified heater has a steel sheath, so quite similar in emissivity to that of a steel tube used to contain it.
The emissivity of the stainless sheath increases with temperature .. the available data suggests ..
so an estimated sheath temperature of 700 C for a reactor inner surface T of 370C and
RT emissivity of 0.2 may be excessive
For an emissivity of 0.6 , Stefan' s Law gives a sheath temp. of only 530C for a sheath SA of 0.006
and radiated power of 50W.
https://www.engineeringtoolbox…-heat-transfer-d_431.html
the T^4 term dominates so temperature varies relatively little with the other variables.
Not true
The temperature varies greatly with emissivity
Mizuno is better than this one, because Mizuno is available to help you
and for electrochemical cells
I am sure that Dr Michael Staker is available to help
within his busy academic schedule
Scout's honour
Perhaps google's attempts are as good as the best in the field so far
Perhaps google's attempts are NOT as good as the best in the field so far
Especially since they appear not to have consulted with the best in the field
Nothing published yet.
But for sure they spent $10 million
" Turbulent flow does not have a flat velocity flow across the middle 3/5"
Whereas poor behavior seems to stick and be recycled forever!
The continual use of the terms fringe science and pseudoscience with regard to LENR is poor behaviour,
Especially when TTHnew often misconstrues what is written as conventional science in an egregious manner
As with
The neutron proton mass difference is significant to six significant figures
when Stephan Durr's research shows that it is only accurate to two significant figures.
https://pdfs.semanticscholar.o…632-1745062307.1563745632
Is there a simple way to describe with few parameters the dynamic properties of a calorimeter and the reactor ?
No,
The convective transfer btw the reactor and the moving airstream and the moving airstream and the calorimeter wall
is extremely difficult to model..
The airstream is laminar and turbulent at different positions
and this situation changes as the reactor heats up
Therefore the heat transfer coefficients are very difficult to predict.
the difference btw laminar and very turbulent HTCs can be a hundred fold.
the air velocities in the region btw the reactor
vary btw ... near zero.. at the corners and up to 2-3 m/s
