Diesel Auto Ignition Pressure 2

[Brent Boisvenue]

I'm designing a fuel distribution system for a mine with fuel piping going down a 600 m (~2000 ft) mine shaft and I'm trying to find some relevant literature on diesel auto ignition PRESSURES. I'm finding lots of information on diesel ignition pressures in internal combustion engines, but mainly regarding transient properties and ignition delays related to pressures.

My application is very simple. I need to figure out how much static pressure in a pipe would bring about a risk of the diesel fluid igniting. I've seen 80 psi, but I have nothing to substantiate it.

Any petroleum engineers out there with some pointers?

Thanks!

 

[LittleInch]

I've never really got into free flow, but you also need to check the Froude number to see if your free channel flow stays as a free channel flow at that velocity. My guess is that it doesn't unless you're dribbling this into a large pipe. What sort of liquid volume fraction are you getting?

The trick with static is to allow sufficient time for the charge to slowly dissipate and make sure everything is connected very well to the same earth. And don't allow any projecting metal or conductive element to come within a spark distance of the liquid surface. The issue is usually one of a manual dipstick or projecting level instruments.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Brent Boisvenue]

On a 2" sch. 40 pipe, I'm getting less than 20% fill based on area at 4 L/s (~63 gpm). However, this is based on the Manning equations and they're specific to water flows. They do not account for other fluids (ie. viscosity, density...)

 

[LittleInch]

That should be ok, but check out the Froude number.

Also at some point the liquid will be stationary in a vertical velocity sense as if you imagine a 4 litre (one gallon) bucket every second, there's no way you can pour that into a pipe and get open channel flow until it reaches terminal velocity ( you had 30m/sec which sounds a little high, but it's a lot more than it will be at the start). There's lots and lots of info on this wrt gutter pipes and down pipes where by you can only get so much into the vertical pipe before it seals, then transitions into open channel flow.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Brent Boisvenue]

we will be discharging into the fill pipe from flow control valves, so we have full control of flow. We won't be flooding the pipe.

Regarding the Freud number, I'm not sure what it really tells me other than whether flow is turbulent or critical. I don't have a firm understanding on how it affects any of the flow parameters. The Manning equation seems to be independent of the Freud number.