At 07:58 PM 06/05/2002, The Silent Observer wrote: >Condensation is also a problem with SCUBA tanks; if they're allowed to >drain off faster than the normal rate of breathing consumption there can >be enough cooling effect to condense liquid water in the tank and >promote corrosion. The analogy in the rocket would be condensation in >the pressurant tank.
I'm not too concerned about water in the pressurant per se - that's a well known problem. What interests me is what effects we can expect from high pressure and very fast blowdown. I'm specifically thinking about ice in the lines. We saw this once before, when we did a procedures check after a major mod of the static test hardware and associated checklist. When we got to the firing section of the checklist, we tested the emergency vent valve. It worked fine for a while, but around 200 psi it began to sputter. Now how on Earth does a vent valve sputter? We're just dumping nitrogen. So I waited for it to drop to 60 psi, which is what I put in my bicycle tires, and stuck my hand in the nitrogen stream. It was cold. Well below freezing. OK... It stopped for a second, than started back up suddenly, as it had been doing. Only this time, when it started back up, it stung the hell out of my hand. Hit my knuckle with something hard enough to leave a white mark that persisted for several minutes. What the heck? There's nothing in there but nitrogen and a little bit of water. What hit me? ...Oh! "Hey guys. This sputtering is going to be normal during an emergency vent. And don't stick your hand in the gas stream; there's ice in it." That was with many cc of water in the tank, but we were only coming down from 450 psi or so. For the new system, we're looking at 4500 regulated to 1000 blowing down to ambient in a few seconds. -R -- No electrons were harmed in the creation of this message PETE - People for the Ethical Treatment of Electrons Randall Clague [EMAIL PROTECTED] _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
