Physical Properties Sea Water 1

[stanier]

What I am after are the parameters for waterhammer analysis with sea water as the fluid. I need a text, spreadsheet or mathcad model where the input is depth, salinity or ppm and depth. The output required is viscosity, density, vapour pressure and bulk modulus.

There must be a reference out there somewhere used by marine and offshore engineers when designing the rigs for waterhammer? I have been through Perry's and other text but cant find an algorithm.

 

[arto]

For water hammer in piping try the greer accumulator catalog:

http://www.parker.com/accumulator/cat/english/1630007.pdf

 

[wassermann]

Stanier,
hope I've understood your requirements. I'm in high pressure water hydraulics (presses etc.) so the contraints may be different. However, water hammer in hydraulics is known as Jougelsky shock and is given by:
Dp = v . Vs . r where
Dp = pressure rise due to sudden stopping of fluid flow (MPa)
v = Velocity of Fluid (m/s)
Vs = Velocity of Sound in Fluid (m/s)
r = Fluid Density (kg/m^3)
This formula is based on the conversion of the kinetic energy of the moving fluid into mechanical work and hence pressure.
There is little difference in this respect between fresh water and sea water.

 

[stanier]

Hi Wassermann,

I am fully conversant with the subject of waterhammer. I am seeking the properties of sea water as I like my software output to have as few errors as possible that a customer can have disquiet about. Simple things like density and viscosity are easily seized upon.

Once you lose credibility in the exactness of the simple things it becomes that much harder when one approximates the approach to the hard issues.

There appears to be little data readily available for sea water yet the worlds surface is 80% covered by it?

 

[wassermann]

INTERIM REPLY
Hello Stanier,
Sorry I missed the point and that this response has taken so long! Wasn't notified. You are quite right about the exactness of simple things; Lord Kelvin had something pithy to say about it.

I have asked some colleagues who worked on developing a sea water motor (using sea water as the medium and the lubricant) who were obliged not only to research the topic of sea water properties in depth (pun not intended) but also to conduct some of their own basic research, which surprised me at the time as, like you I thought almost everything was known about it. (It's 71% by the way) Factors such as bulk modulus (determining factor in water hammer calculation), surface tension and viscosity were primary concerns and they are looking through their records. They did mention one contact at CSIRO of all places:

http://www.marine.csiro.au/~morgan/seawater/

but I've checked this and the site is no longer supported. There's an email at this site:
majordomo@marine.csiro.au
which I haven't checked but I guess, being from Oz that you'll know them. I'll be in touch.

 

[wassermann]

Hi Stanier,
unfortunately my colleagues inform me this is proprietary information. Apparently someone paid a lot of money for what you want to know. If I think of another source I'll report it.

Brian Hollingworth
Hastec Engineering
Ontario
Canada
hastec.com

 

[stanier]

Hi Wasserman,

Thanks for your efforts. Guess I'll have to tell the client to stop pumping sea water because its such a rare commodity and no one knows anything about it!

You can share knowledge but you cant share wisdom. Using knowledge wisely separates engineers from the enthusiastic amateurs that burden our society

 

[Charlesi]

Have you tried the CRC hand book this has helped me in the past. Try the Handbook of Aqueous Solubility Data or the CRC Handbook of Chemistry and Physics

Hope this helps

 

[HamishMcTavish]

Found this on amazon but may not be detailed enough for you,

http://www.amazon.co.uk/exec/obidos...46961/sr=1-1/ref=sr_1_0_1/026-7385943-2978040

You could try searching texts on physical oceanography and following up the journal references

No more things should be presumed to exist than are absolutely necessary - William of Occam

 

[sjohnr]

I've just been through this. For the denisty you need the UNESCO International Equation of State (IES 80) as described in Fofonoff, JGR, Vol 90 No. C2, pp 3332-3342, March 20, 1985. There are a few web sites that have Java calculators for it. Here's one:

http://ioc.unesco.org/oceanteacher/...te/Sea Water Equation of State Calculator.htm

This spits out a few other parameters but I'm not sure whether they're useful to you.