how to calculate static voltage of fluid flowing through pipes or hydraulic hoses ??

[dipakpunde]

Dear friends,

i need to calculate the static voltage or charge fluid flowing through hydraulic hoses.

i know basic formula V=IR and V=E/Q
E= ENERGY
Q=CHARGE

how to relate I and R to flow rate, density, length and diameters of hose.

study based on flow rate, density, length and diameters of hose.

please suggest me if you have any suggestion.

Regards`,
Dipak

 

[IRstuff]

Looks calculation difficult to do, but there seems to be lots of literature on the web:

http://pall.tekgroup.com/pdf/10005/IFPE-Static_charge.pdf

https://www.stle.org/assets/document/Generation_of_Static_Electricity.pdf

http://www.tandfonline.com/doi/abs/10.1080/05698190591002195#.U_oepcVdUQo

http://www.machinerylubrication.com/Read/828/electrostatic-charge-generation

http://www.wolfsonelectrostatics.com/01_hazards/pdfs/guidanceforplantengineers-staticelectricity.pdf

https://www.google.com/url?sa=t&rct...=Otu-Y4ZB6SUlXBvPMcccXw&bvm=bv.73612305,d.b2U

TTFN
faq731-376

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[dipakpunde]

Thank you for your replay.

however i want the some physical formula to related flow rate, density, length and diameters of hose.

my requriement is static voltage is not exceed than 250 volts, need to prove by calculation.

I got below formula

V=E/Q
E= ENERGY E = wp/γ + wz + wv2/2g

Q=CHARGE Q= AREA*VELOCITY

Regards,
Dipak

 

[rb1957]

can you explain some of the energy terms ? the 3rd term is obviously kinetic energy ("w" is weight density by the look of it)

btw, A*V = volume flow rate, not "CHARGE Q" ... in my limited understanding

Quando Omni Flunkus Moritati

 

[drawoh]

dipakpunde,

Are you trying to do fluid mechanics or electronics? If you need an analogy to understand something, you don't understand it.

--
JHG

 

[WKTaylor]

dipakpunde...

What is the ultimate purpose for this investigation?

Was this due to possible conductivity issues affecting some sort of precision in-system measurement?

I have asked several aerospace hydraulics systems experts around here what the purpose for this analysis could be... and they have all given me the "Whaaaaat???” followed by “Whhyyyy???" return questions. Fire-explosion, stray current arcing, arc-induced corrosion/pitting, electrical/electronic component failures [valves, pressure sensors, etc] due to arcing, etc… were all discussed. NO KNOWN problem’s in acft or missiles.

NOTE. Commercial aircraft usually have Phos-ester hydraulic fluids; while Military acft [my world] have synthetic hydrocarbon. General aviation still tends to pure hydrocarbon fluids.

Except for wire-braided flex hoses [Teflon lined], the vast majority of an aero-hydraulic system in an aircraft is metallic tubing, fittings, valves, etc that MUST be grounded to the aircraft. Any static charge will rapidly bleed away.

The primary problem with hydraulic system fire/explosion is high-compression of entrapped air [N2/O2/Ar2, etc] with flammable fluid [IE: dieseling effect]... which is the reason systems must be purged/filled with dry nitrogen.


Regards, Wil Taylor

Trust Me! I'm an engineer!

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

Unfortunately, in science what You 'believe' is irrelevant – "Orion"

 

[dipakpunde]

Thank you for your replays.

My requirement is "Nonmetallic plumbing installations shall be so designed that the static voltage generated by fluid flow will not exceed 350 volts at any point outside the pipes, tubes, or hoses.”

I need to prove analytical calculations it will not exceed than 350 volts.
(Equation in the form of hose dia, viscosity, length of hose and surface roughness of hose)

 

[MikeHalloran]

I'm sure we are all very curious about the origin of the stated requirement, which I personally have never encountered in random exposure to hydraulic system design over the past fifty years or so. ... which is why we're all saying "Huh?" or equivalent. Please educate us about the world in which your pursuit actually makes sense.

If I'm understanding the implied problem correctly, the parameters you have mentioned should allow you to estimate the current produced by physically moving whatever electrons are present in the fluid.
... but just like in a Van De Graaf generator, the voltage produced should be limited only by electrical leakage and the physical spacing of whatever metallic components contact the fluid and act as terminations for the ultimate flashover that must dump the accumulated charge.



Mike Halloran
Pembroke Pines, FL, USA

 

[dipakpunde]

Mike,

Thank you for your replay.

We need to find static voltage, however if we could predict electricity generated by fluid that is best for me.
Length of hose is 35 foot.
Inside diameter is .500 inch.
Application is aerospace fuel.

Regards,
Dipak

 

[Compositepro]

You cannot calculate what you seek, because there are so many random factors, like atmospheric humidity, for example. Humidity will change resistance of any polymer.
On the other hand, it is relative simple to apply measures to assure that static is not a problem, like a grounded spiral wire in the hose wall, conductive additives in the polymer. Certified fuel transfer hoses are readily available.

 

[WKTaylor]

dipakpunde... only comments I have seen in tech-lit/specs...

SAE AIR81 Importance of Physical and Chemical Properties of Aircraft Hydraulic Fluids

3.13 Electrical Conductivity
The electrical conductivity of a fluid should be stated in the fluid descriptive data as a function of temperature. While not of
general importance in system or component design, it is important for specific applications including wet solenoids, wet
cooling coils for electric motor driven pumps and hydraulically powered emergency generators. See ASTM D 2624 and
ASTM D 4308.

ASTM D2624 Standard Test Methods for Electrical Conductivity of Aviation and Distillate Fuels
ASTM D4308 Standard Test Method for Electrical Conductivity of Liquid Hydrocarbons by Precision Meter

Regards, Wil Taylor

Trust Me! I'm an engineer!

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

Unfortunately, in science what You 'believe' is irrelevant – "Orion"

 

[loki3000]

I'm sure we are all very curious about the origin of the stated requirement, which I personally have never encountered in random exposure to hydraulic system design over the past fifty years or so.

google it, it's nasa standard.
the author should leave the calculation to someone else though, as he doesn't appear to have the faintest idea what he's doing.

 

[WKTaylor]

loki3000... soooo You think this is a space application?

Regards, Wil Taylor

Trust Me! I'm an engineer!

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

Unfortunately, in science what You 'believe' is irrelevant – "Orion"