Nucleate Boiling and More, Subcooled

For the record, more sometime.  Left click to see the show.

Bunk from academia regarding nucleate boiling on small wires

Here is an "informative" link from the 1970's.

http://www.uh.edu/engines/BoilingFromSmallCylinders.pdf

I've copied the following and added some highlights (bold).

BOILING FROM SMALL CYLINDERS* 

NANIK BAKHRU IBM Corporation, Hopewell Junction, New York 12533, U.S.A .

and

.JOHN H. LIENHARD  Dept. of Mechanical Engineering, University of Kentucky, Lexington, Kentucky 40506, U.S.A.

(Received 27 Seprember 1971)

Abstract-Heat transfer is observed as a function of temperature on small horizontal wires in water and four organic liquids. When the wire radius is sufficiently small, the hydrodynamic transitions in the boiling curve disappear and the curve becomes monotonic. Three modes of heat removal are identified for the monotonic curve and described analytically: a natural convection mode, a mixed film boiling and natural convection mode, and a pure film boiling mode. Nucleate boiling does not occur on the small wires.

In the text you will find:

Since the wires would melt during atmospheric runs in water,  the water runs were all made at pressures in the neighborhood of 3 in. Hg abs.

It is absurd to operate at reduced pressure in order to avoid burnout.  Think about it.

Nucleate boiling was averted by operating at reduced pressure.  Burnout was avoided by limiting the maximum power.  Burnout could likewise have been avoided at atmospheric pressure.
  
Nucleate boiling will occur on the "small cylinders" at higher pressures. Below are four runs with 0.0003 inch platinum "cylinders" and nucleate boiling (phase change heat transfer) is evident.  Right click on "view image" to view the entire plots.  No, I give up.  Left click on the lower image to enlarge and to return here click on the reload (circular) arrow.

My 30 year anniversary UHI and the NRC Training Center (Simulator)

I knew how to operate; of course, I knew my stuff!

The caption below refers to a photograph from today's (May 5, 2010) NRC web page.

NRC Commissioner William Ostendorff (center) recently toured the agency’s Technical Training Center, established in 1980, in Chattanooga, Tenn. where nuclear plant simulators, like the one shown here, provide hands-on training for NRC engineers.
Of course, I wonder about the quality of that hands-on training for NRC engineers. Baker-Just and Cathcart-Pawel are alive and likely the 2200 Fahrenheit game is in the NRC's simulator.
The NRC engineers' time would be better spent in a study of PRM-50-93 and its associated public comments.

The above caption says the Technical Training Center was established during 1980. Following is my experience with that Center during 1984. Click to enlarge; your return arrow gets you back.

Here is more!

THURSDAY, AUGUST 16, 2012

UHI Ultra High Risk EPRI NSAC NRC Ohi

This is the third consecutive entry in my UHI series.   Here are three uploaded pages that document part of the turmoil that followed my October 3, 1984, memorandum, UHI-Ultra High Risk.    Click on the page to enlarge for easier reading and access to the right side that is partially obscured.

As I said in earlier, my October 3, 1984 memo let to a lot of turmoil.  The heat was on. I was fighting for survival, so I worked on the day after Thanksgiving and it was an advantage to have no others around.

The above memorandum was addressed to Lang who had been assigned to monitor (to control) the UHI investigations.  So, I worked within the system, and addressed all correspondence to Lang, but I worked independently. I stayed under control because I intended to continue working for EPRI, however, my above contact with the NRC Training Center was effective and there was no way that NSAC could reprimand me for pursuing that credible source even though it alarmed Rossin and very likely others.

Rossin was apparently concerned that Taylor would think Leyse was out of control, hence his note of 11/30 (1984) in which he stopped distribution to J. J. Taylor, the head of the EPRI Nuclear Power Division. 

I'll have further documentation of the very revealing UHI  turmoil that raged within NSAC and EPRI. Several outside organizations became involved including at least three within the NRC. The SANDIA National Laboratory was drawn into the turmoil as a consultant to the NRC.  The ACRS wrote a letter to the Commissioners of the NRC and I'll also post that later.  EPRI even hired an outplacement service, Ward Associates on the famous Sand Hill Road, and later you read how that action intensified the turmoil, although I believe it worked to my advantage.

And More.  It is a great 30th Anniversary!

TUESDAY, AUGUST 21, 2012

UHI Ultra High Risk, October 3, 1984: Inside Stuff, EPRI & NRC

This is my sixth consecutive entry that documents the turmoil that followed my memorandum, UHI Ultra High Risk, October 3, 1984.

This entry jumps ahead of a lot of documentation that I have and that I guess I'll have to place in book if I ever get around to writing that.  On November 7, 1984, Rossin and Breen told me my position was being eliminated, but that I'd have a few months to look for work elsewhere.  So, I looked elsewhere with no immediate success.  I talked to Jim Keppler of the NRC and showed him my memorandum, UHI Ultra High Risk, October 3, 1984, as part of several illustrations of my experience and capabilities.  Keppler asked if he could send this elsewhere in NRC and I agreed, however, I blanked out the source of the document as well as my name.

So, the following two pages are an interesting document that reveals very secret relationships between EPRI and the NRC that I was never aware of.  It also reveals turmoil.  I do not recall how I gained access to the following document; it most certainly was not sent to me.  I am inclined to doubt that Rossin was aware of it, but I do not know that.  I suspect that Layman and Lang were not aware that my position had been eliminated.  On the other hand, 
Rossin may have encouraged this documentation in order to justify getting rid of Leyse. Click to enlarge and back arrow to return.

I'm certainly pleased that EPRI (Layman and Lang) documented the above. This is a clear report of a basically secret set of arrangements between EPRI and the NRC and I suspect that those have continued in various forms over the years and are really intense in today's post-Fukushima world. 

The second page is "interesting" as it describes the "running around" in generating a response to Keppler.  The very last paragraph is also revealing as EPRI apologizes to the NRC for my contact with Keppler.  Well, it is a fact that I was never a party to contacts with the NRC regarding our analyses of operating experience at nuclear power plants.  It is also a fact that others who analyzed operating experience were not very adept at that work.

More later.

5th International Conference on Boiling Heat Transfer Montego Bay, Jamaica, May 4-8, 2003

 5th International Conference on Boiling Heat Transfer
Montego Bay, Jamaica, May 4-8, 2003

IMAGINE EXPLORE DISCOVER INVENT

WHY NOT?

Auracher Nukiyama Boiling Analysis

Here is reference that may be useful.
http://www.jsme.or.jp/ted/NewsLetter42/Auracher_J.pdf

http://www.jsme.or.jp/ted/NewsLetter42/Auracher_J.pdf

Some Remarks on the Nukiyama Curve
Hein Auracher
Professor, Dr.−Ing.
Institut für Energietechnik
Techniche Universität Berlin
auracher@iet.tu-berlin.de

It was about 70 years ago when Shiro Nukiyama published his pioneering paper on “Maximum and Minimum Values of Heat Q Transmitted from Metal to Boiling Water under Atmospheric Pressure” [1]. A milestone at the beginning of a long way towards the “truth” in boiling heat transfer. Numerous researchers
discovered a lot on this way but the more we find out the more difficult it becomes to really understand this extremely complex process.

Basically Nukiyama’s boiling curve has never been disputed. Only specific aspects were and are subject of studies or disagreements. The shape of the boiling curve, for instance, is still a subject of discussions in terms of its behavior in the transition region, its change in a transient situation with respect to the steady-state case, its dependence on contaminations on the heating surface etc. 

The shape of the boiling curve and its change under
different system conditions is, of course, a result of different boiling mechanisms and their change. Since pure empirism can never solve such problems, several physical models for the different boiling modes have been developed. We should trust these models only after experimental verification. Moreover, due to the improvement of our experimental techniques and also of the mathematical tools in recent years, older and relative simple models can now be improved and new ones can be developed.

The present report makes some remarks on the aspects mentioned above. Of course not comprehensive and – subject of excuse – focused mainly on our own work. It is just meant as a small tribute to Nukiyama’s pioneering work. Those who need a sort of survey on new developments may look into the “Proceedings of the 5th Int. Boiling Heat Transfer Conf. in Jamaica, May 2003”. A selection of the papers presented there will soon be published in the “International Journal of Heat and Fluid Flow”.

HYSTERESES ALONG THE NUKIYAMA CURVE
No contradiction exists about a hysteresis in the region of nucleation incipience (see Fig. 1). In contrast, in transition boiling and for steady-state conditions a hysteresis was postulated [2] consisting of a transitional nucleate boiling–and a film boiling–branch, both overlapping with respect to the heat flux. However, if a precise temperature control system [3] is available and with a clean heating surface, boiling curves even for liquids with large contact angles (water) show no hysteresis regardless in which direction they are measured: stepwise from
film to nucleate boiling or vice versa. In contrast, if surface contamination is involved, boiling curves are not reproducible. Each test run, even under carefully established steady- state conditions, results in a shift of the curve already at a minimal change of the deposit [3,4].
log
CHF
MHF
surface
evaporation
nucleate
boiling
transition
boiling
film
boiling
incipience of
nucleation
∆T = TW - Tsat
q
heat
flux
wall superheat
B
A
A
B
Fig. 1: The Nukiyama curve.

The boiling curve behavior log
changes under transient conditions,
even on clean surfaces. Recently it
was argued that “how the unsteady
process influences the hysteresis is not
cleared, yet” [5]. Objection! It is, as
shown by systematic experiments in
[6]. There, measurements with
controlled heating and cooling rates
were carried out, of course, by taking
into account the “coupling problem
[5]” between heater and fluid which
requires the solution of an inverse heat
conduction problem. One typical
result is shown in Fig. 2: The

steady-state curve was measured with 

JSME TED Newsletter, No.41, 2003

Upton Sinclair Wisdom

"It is difficult to get a man to understand something, when his salary depends upon his not understanding it."