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Hello John, Water behaves as a high voltage dielectric for only very short intervals (microseconds or less). This property allows ultra-pure, filtered and degassed water to be used as a high k (k ~80) self-healing dielectric for low impedance transmission lines and capacitors in high energy pulsed power work. The presence of gas bubbles on the surface of the metal electrodes will significantly reduce the breakdown voltage. The presence of soluble ionic contaminants are OK (as long as gas bubbles are not generated through electrolysis) since the applied voltage stress is evenly distributed through the solution. In fact, high energy high voltage water resistors are sometimes made with plastic tubing. Pure copper electrodes are used at each end, and the tubing is filled with water that's been doped with a small amount of copper sulphate. Generally speaking, the presence of suspended dirt or dust will significantly degrade the breakdown voltage of the any dielectric liquid, including water. I'm not aware of specific models or that predict the effects of suspended imurities in water. All of the water breakdown models that I've seen assume pure, clean DI water. In your experiment were you applying a high voltage pulse, or were you using 60 Hz or DC? Also, if you apply a relatively high current through an electrolyte, you may can create arcing at the interface between the water solution and the electrodes. Under the right conditions, you can create an underwater arc (plasma) at the electrode interface. Best regards, -- Bert --
: In my experiment,i found the electric conductivity of water affects the
: breakdown voltage so much.Other contanminants such as gas bubbles,solid
: particles also have significant influence on the break down of water.I want
: to
: know how the conductivity affect the break down of the water
: solution?especially why?(possible theories?or where can find relevant
: information?)
: In addition, I am still wondering,how the electric conductivity of water
: affect the breakdown of the water-air mixture and also
: water-solid(particles)-air(bubbles) mixture? Is there a modle to determine
: detailed influence?
: thank you so much!
:
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