Fuel Transfer Rate

[Wcmille]

Given a tank, T0, which is full, of volume Vo, and number of tanks, T1, T2, T3, and T4... Tn, which are all empty and same size, Vi:

How long does it tank for T0 to empty, assuming it can (e.g. its Vo < Vi * n)?

[bewing]

Heh. Well phrased question. But I think the answer is messy. It takes a constant time -- very near 18 seconds (I think) to fill one tank of any size from any number of tanks of any number of other sizes. It takes N times that long to fill N tanks. So, if it can fill the other tanks, it will take 18*n, no matter how you try to arrange things.

If V0 < Vi * n, then the answer is 18 * n * (V0 / Vi * n) = 18 * V0 / Vi -- which may be longer or shorter than 18 seconds, depending on the ratio.

 

 

Edited December 27, 2016 by bewing

[Wcmille]

That's interesting that its constant. So what does this imply about a filling strategy? It appears to mean that you want to supply from the smallest possible tank when in a hurry?

[FancyMouse]

It means you'll deal with the biggest tank as much as possible.

The small tanks on my station/base are purely for LFO balancing reasons. Other than that, I'm always using the biggest tank for both directions

[bewing]

Well, it actually kinda means that there is no possible strategy. You want to fill your tank? It'll take 18 seconds. You're in a hurry? It'll take 18 seconds. (If you've seen the right Richard Pryor routine, you'll recognize "I don't give a sh1t, it'll be $500.")

[FancyMouse]

Well not really. If you have refueling mission - you'll be better off to refuel to big tanks. If you don't refuel the target tank to full, it'll take less than 18 seconds. And that motivates everything to go through that big tank.

[bewing]

That's true. If your desire is to just xfer 2000 units of fuel, then the bigger the tank, the better -- because it'll be a smaller fraction of a full tank.

[Superfluous J]

The real question is, who thought a constant time regardless of tank size was a good idea?