Vapor pressure sucks.

[Ls7corvete]

Well I am testing flourinert in my pumpless system. Results are bad but lets move on past that.....

Anyways, I am getting alot of vapor bubbles building up in my block. Basically it is turning into a very very bad phase change system- the bubbles build up in the block until they block flow and the TEC goes into chernobyl mode. The problem is the coolant I am using is supposed to have a BP of 157c.

So two options going on here:

1.The vapor pressure of the liquid is 423pa, I am not sure if a high vapor pressure can lead to bubbles in a closed container or not.

2. This is not flourinert.

I am guessing #1 but not rulling out #2.

[Incoherent]

Originally Posted by Ls7corvete

2. This is not flourinert.

Any reason to suspect that? Where did you get it.

What kind of time frame are we talking here for the bubble formation? Seconds? minutes?, hours?

[LPorc]

Originally Posted by Ls7corvete

Anyways, I am getting alot of vapor bubbles building up in my block. Basically it is turning into a very very bad phase change system- the bubbles build up in the block until they block flow and the TEC goes into chernobyl mode. The problem is the coolant I am using is supposed to have a BP of 157c.

So two options going on here:

1.The vapor pressure of the liquid is 423pa, I am not sure if a high vapor pressure can lead to bubbles in a closed container or not.

2. This is not flourinert.

I am guessing #1 but not rulling out #2.

Well, bubbles will form when the vapor pressure of the heated liquid exceeds the pressure of the system. The boiling point. So, if bubbles are forming, something is boiling.

If your stuff is indeed what you think it is, I'd hazard a thought that perhaps something in your fill method has resulted in a low pressure, effectively lowering the boiling point. What method did you use to fill the device? I'd bet maybe you did something with boiling to force vapor to remove the air, and were left with a low pressure in the system when sealed and cooled.

I'd also consider contaminants, is your medium pure, or a mix? Maybe some other liquid in solution? Perhaps some cleaning of flux after brazing/soldering with something with a low boiling point? I guess I am dating myself when I say we used to clean up flux on PCBs with freon, eh?

[Ls7corvete]

Any reason to suspect that? Where did you get it.

Ebay, maybe the wrong flourinert or something similar substituted?

If your stuff is indeed what you think it is, I'd hazard a thought that perhaps something in your fill method has resulted in a low pressure, effectively lowering the boiling point. What method did you use to fill the device? I'd bet maybe you did something with boiling to force vapor to remove the air, and were left with a low pressure in the system when sealed and cooled.

Open system, actualy the block is at the bottom so it has the pressure of the fluid on top of that.

Its generaly one bubble that grows after a couple mins if I keep the heat down. Seconds if I run OCed and FAH. Once it starts to overheat the block gets to around 100c and its truely boiling then.

I doubt contamination would affect it, I rinsed the loop with alcohol and allowed it to dry for ~24 hours, if there is contamination we are talking 1-2 drops in 400ml of liquid.

I am considering sending off a letter to the seller to try and verify the identity of this stuff.