Charging a Fluid


by AkInfinity
Tags: charging, fluid
AkInfinity
AkInfinity is offline
#1
Mar27-13, 11:14 AM
P: 33
Hello friends,

I am performing an experiment and need a charged fluid here are some questions I have, hopefully someone can help.

Can I create a charged fluid by taking distilled water, then adding NaCl (positive and negative charges), and then immersing the positive end of a voltage generator (set it to 5kiloVolts) in the fluid while grounding the negative end to ground and "extract electrons from fluid" (i guess in this case Cl-)" to make it positive?

If yes would it be better for me to ground the negative end of the voltage generator or not.

If no is there another way I can generate a charged fluid easier?

Secondly in order to maintain my fluid charged do i need to insulate it from air? Would it be easier to keep a positively charged fluid or negatively charged fluid?

Just to clarify by positive fluid i mean it has a positive net charge, like if i had pure water and put Ca+ in it so that the fluid is positively charged.

Thanks
Phys.Org News Partner Physics news on Phys.org
Physicists design quantum switches which can be activated by single photons
'Dressed' laser aimed at clouds may be key to inducing rain, lightning
Higher-order nonlinear optical processes observed using the SACLA X-ray free-electron laser
DrClaude
DrClaude is offline
#2
Mar28-13, 04:05 AM
Sci Advisor
PF Gold
DrClaude's Avatar
P: 1,111
Good luck with that! You will never be able to significantly charge a fluid.
AkInfinity
AkInfinity is offline
#3
Mar28-13, 08:48 AM
P: 33
Sup Claude,

What if instead I place an extensive amount of NaCl in an extensive amount of water, then stick both proves of the voltage generator in thus the cl- will go to one end and na+ to the other. then separate the two in the middle so taht on one side i have ca+ (positive charge) and on the other -cl fluid, and then separate it.

You guys think it will work then? I mean the body works wtih charged fluids out of neurons and in neurons.

DrClaude
DrClaude is offline
#4
Mar28-13, 09:04 AM
Sci Advisor
PF Gold
DrClaude's Avatar
P: 1,111

Charging a Fluid


Quote Quote by AkInfinity View Post
What if instead I place an extensive amount of NaCl in an extensive amount of water, then stick both proves of the voltage generator in thus the cl- will go to one end and na+ to the other. then separate the two in the middle so taht on one side i have ca+ (positive charge) and on the other -cl fluid, and then separate it.
Won't work either. The problem is that while you do get a layer of ions around an electrode, you get also another layer of counter ions around that first layer, such that the overall polarization is small.

Quote Quote by AkInfinity View Post
I mean the body works wtih charged fluids out of neurons and in neurons.
This is out of my depth, but I would be that there are counter ions nearby.
DrZoidberg
DrZoidberg is offline
#5
Mar28-13, 11:04 AM
P: 371
Salt water is a conductor. Any conductor can be charged. But the charge always moves to the surface. So all the excess ions will be at the surface of the water or the sides of the container.
However there may be a way to get some charge to stay dispersed throigh the water for a while if you use very pure water.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2845823/

Inside the body you have voltages across cell membranes. But the charge is not dispersed throughout the liquid. It's all at the surface of the membrane. The membrane in this case acts as a capacitor. The charge is created by ions passing through the membrane.
AkInfinity
AkInfinity is offline
#6
Mar28-13, 12:33 PM
P: 33
@DrClaude; Well here's what I'm thinking; If say one of your electrodes has positive charge and the other has negative charge it would only make sense that positive atoms and negative atoms would distribute untill for example the sodium "cancels" the negative field of the negative electrode so other sodiums are not attracted anymore. Thus if I am using very high voltage (10kV) I would expect that I would get a measurable separation. So where is it that your opinion differs from mine and why?

@drzoid Very good paper i def bokmarked it. Anyway you are right about charge storing on the outside of a conducting sphere, my goal is to have this charged fluid inside a balloon so even if the charge is resting on the surface (between water and balloon) it is okay. So do you think the double electrode idea and separating the fluid would work better or just to try to charge it wiht one electrode (i.e. suck electrons out).
DrZoidberg
DrZoidberg is offline
#7
Mar29-13, 06:00 AM
P: 371
I have to say I didn't read this paper completely before posting the link. After reading the discussion part at the end it seems to me that the experimenters didn't do their homework. What they got there is a simple electrochemical reaction. It's a form of concentration cell with different ph values at the electrodes. There was no charge stored in the water. And their comparison with the kelvin water dropper is completely inappropriate. In short, I should never have posted that link.

Anyway, charging your balloon should be easy. A spark can jump right through the latex skin. So just place the balloon on an insulating surface e.g. a plastic table, and bring a charged object close to the balloon so a spark can jump over.
DrClaude
DrClaude is offline
#8
Mar29-13, 08:00 AM
Sci Advisor
PF Gold
DrClaude's Avatar
P: 1,111
Quote Quote by DrZoidberg View Post
I have to say I didn't read this paper completely before posting the link. After reading the discussion part at the end it seems to me that the experimenters didn't do their homework. What they got there is a simple electrochemical reaction. It's a form of concentration cell with different ph values at the electrodes. There was no charge stored in the water. And their comparison with the kelvin water dropper is completely inappropriate. In short, I should never have posted that link.
Have a look also at DOI:10.1021/la900723t
DrClaude
DrClaude is offline
#9
Mar29-13, 08:08 AM
Sci Advisor
PF Gold
DrClaude's Avatar
P: 1,111
Quote Quote by AkInfinity View Post
If say one of your electrodes has positive charge and the other has negative charge it would only make sense that positive atoms and negative atoms would distribute untill for example the sodium "cancels" the negative field of the negative electrode so other sodiums are not attracted anymore.
You seem to think that you would have an area of ions around an electrode up to the point where the field of the electrode is cancelled out, but this is not what happens. I wasn't clear enough in what I wrote previously, but the layer I was mentioning is extremely thin, something like a monolayer. And behind that, you get counter ions. The total charge you would be able to get tiny.

Quote Quote by AkInfinity View Post
Thus if I am using very high voltage (10kV) I would expect that I would get a measurable separation.
Be sure you know what you are doing when working with such voltages. As DrZoidberg mentioned, salt water is a conductor.
AkInfinity
AkInfinity is offline
#10
Mar29-13, 02:16 PM
P: 33
@drZ; thanks; I will let you know how the experiment goes.

@drClaude; Thanks for your help too and appreciate you concern for me to be careful. I will I have worked with extremely high voltages and light extensively.


Register to reply

Related Discussions
Fluid Mechanics HW How pressure in a tank affects exit velocity of a fluid Engineering, Comp Sci, & Technology Homework 3
Super Capacitor Banks, Instant Charging, Inversion, Charging Battery Banks, Capacitor Electrical Engineering 6
Fluid mechanics. Plate pulled within viscous fluid. Introductory Physics Homework 1
Simple question about object submerged in a fluid (fluid Mechanics) Mechanical Engineering 1
Fluid dynamics - finding pressure for a rotating fluid Calculus & Beyond Homework 2