what kind of automation can i deploy that will precipitate the particulates so that air can move (for cooling) and so that air won't bring grit (which is conductive)?
Have you considered a two-step process using water in the first step to remove particulates (water spray perhaps?) and then an industrial air-drier in the second step? Alternatively, have you considered air liquifiers like those used in mining (Draegerman suits) which produce very cold liquid air? The idea would be to spray the liquid air inside the data center rather than blowing in the gaseous form. Of course, I don't know if the economics of this work out, although there are people working on increasing the efficiency of air liquification so there is quite a bit of price variation between older methods and newer ones. --Michael Dillon