A nice little open sourced paper on "Sloshing."

[NNadir]

I always like to hear about things at which I never spent much time - or any time - thinking, and to learn more about them.

Recently my son - on his spring break - visited one of the last independent bookstores of which I am aware, and came across a book in the Engineering section called "Sloshing." He found the title amusing and told me about it.

He didn't buy it, but its appearance in an engineering section led me to realize that, "Of course, there is a physics of sloshing."

Late in life, I've become more and more interested in fluid dynamics owing to a growing interest in the behavior of liquid metal nuclear fuels, eutectics of the low melting metals plutonium and neptunium, generally are very dense liquids.

Anyone who has ever handled a large flask of mercury or elemental bromine, can get a quick feel for the potential of forces involved in sloshing. Liquid plutonium is more dense than liquid mercury. The density of mercury is about 13.5 grams/ml; liquid plutonium, depending on temperature, as a density of between 16.0 and 16.7 grams/ml. (cf. L. J. WITTENBERG, D. OFTE, and W. G. ROHR, Properties of Liquid Plutonium (Nuclear Applications Volume 3, 1967 - Issue 9 pp 550-555.)

In addition, I favor liquid metal reactor coolants consisting largely - or entirely - of lead, a very dense metal.

The physics of these liquid metal materials have implications for the strength of materials with which they interact, in particular in events like earthquakes, so it's a very important topic.

Anyway, it's a topic into which I will look further, and a quick Google Scholar search - the way I always begin exposure to a new topic led me to this link to an open sourced paper: Sloshing (Faltensen, O.M. FFALTINSEN. Sloshing. Advances in Mechanics, 2017, 47: 201701)

(There's Japanese text but the paper is in English.)

It has interesting little bits like considering what liquids do in outer space where there is no gravity.

Cool, I think.

If interested, enjoy.

I hope you're having a pleasant Weekend.

[mr_lebowski]

1. Check your first character there in subject line mate :)

Hope you are having a good weekend as well, my most-scholarly DU cohort

[NNadir]

2. Thanks. Done.

[keithbvadu2]

3. I never knew about liquid lead as a coolant for nuclear reactors.

I never knew about liquid lead as a coolant for nuclear reactors.

It must take quite a system to pump it around for heat exchange.

[NNadir]

4. It is generally utilized as "LBE" - lead bismuth eutectic. It was used mostly in Soviet era...

...submarines.

Historically, these reactors were subject to significant corrosion and embrittlement but 316 steel is resistant to lead and seems to be at least one solution to this historic problem.

New classes of materials, in particular the MAX phases which exhibit properties of both ceramics and metals and are machinable, offer additional utility with respect to corrosion, as do other options.

The design of lead cooled reactors mostly relies on convective motion, not pumps.

This paper on the subject is open sourced: Turbulent Heat Flux and Temperature Variance Dissipation Rate in Natural Convection in Lead Bismuth

(I. Otić & G. Grötzbach, NUCLEAR SCIENCE AND ENGINEERING: 155, 489–496, 2007)

There are a wide array of other lead alloys that have extremely interesting properties for use in nuclear reactors. Lead forms an interesting set of salts in which it is present as a polyatomic anion with alkali metals. Some of these have remarkable thermal properties and offer a number of chemical features that may prove useful for reactions like water splitting.

Other alloys also offer related opportunities.

The relatively low boiling point of lead at reduced pressure affords an opportunity for passive heat removal, along with convection and thermal conductivity. The metal has a very high heat of vaporization.

Lead has a huge advantage over liquid sodium inasmuch as it does not have an explosive decomposition reaction with water.

A pure lead coolant will slowly be transmuted into LBE owing to the capture of neutrons by lead-208, leading to the formation of lead-209 which decays into non-radioactive bismuth. However there is a limit to how much bismuth can accumulate, since bismuth can capture a neutron, be transmuted into polonium-210, which in turn decays to lead-206 by alpha decay.

In CANDLE type reactors, designed to operate without refueling for decades, the lead 206 so formed can collect neutrons until it again forms bismuth in a cyclical series of nuclear reactions that generate helium.

[keithbvadu2]

6. Thanks. More theory than I know but I catch the generics of your explanation.

Thanks. More theory than I know but I catch the generics of your explanation.

[eppur_se_muova]

5. Sloshing was a big deal in early liquid-fuel rocket design.

Baffles in the fuel and LOX tanks help prevent the buildup of resonances excited by the vibration of launch. Seems to be routine design now.

Oh, and if the engine is one that needs to restart, you gotta do something about where that fuel sloshes in zero-g ...

[NNadir]

7. Yes, I saw that mentioned in the paper. I never thought much about it before now.

Of course, once the rocket fires in zero g, there is acceleration which should clarify the issue, at least until the acceleration stops.

An interesting point!