Fluid throughput problem

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waduk
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Fluid throughput problem

Post by waduk » Sun May 19, 2019 4:08 am

I can't figure out what's wrong with this, i'm playing [0.17.41] to be clear.

My standard layout :
34 boilers, 68 Steam Engines, produce exactly what it should be, a 61.2 MW.
Image

And i want to build a bigger (or longer layout), for solid fuel.
And it will use a shared input water pipe, and it shouldn't be a problem since wiki says the pipe max rate is 12000 unit/s.
I don't use nowhere near that.

As a test, the exact layout above is changed where the pipe input is being joined first and spread (below pic):
Image
Problem was, as you can see there's bottle neck, the electric output is drop.
The whole setup is less than 30 pipes long (before split), based on https://wiki.factorio.com/Fluid_system#Pipelines, it can sustain 1112 unit /s.
A 34 steam engine (one side) only need 1020 unit/s.

So i add 1 pump before split, it doesn't fix.
Image

What baffled me is this, i use two pump AFTER split, it doesn't help either.
After the pump, it's only 17 Boiler (17 pipes?), it should sustain 1200 u/s based on wiki.
Does the boiler is counted as several pipes ? Then how come the original layout (the top most picture) workout just fine ?
I'm lost, plz send help.
Image

Zavian
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Re: Fluid throughput problem

Post by Zavian » Sun May 19, 2019 4:48 am

Not sure what wiki page you got that information from. An "offshore pump" (ie the pump you are using to supply water) can supply 1200 water per second which is enough for 20 boilers. https://wiki.factorio.com/Offshore_pump . As far as I'm aware that hasn't changed since 0.15.

The standard pump could pump 12000 fluid/second in 0.16, but it only achieved that rate tank/pump to tank/pump. Once you add normal pipes, the pipes restrict the flow rate. In 0.16 seven pipe segments was enough to reduce flow rate to around 1500/s. Fluid throughput table for 0.16 https://stable.wiki.factorio.com/Fluid_system . (You need to expand the table to see it).

I haven't seen updated fluid flow figures for 0.17 (the wiki still has the old figures), but the fluid algorithm changes in 0.17 mean pumps no longer achieve 12000/s even tank to tank. viewtopic.php?f=58&t=67037&p=421396#p409433

waduk
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Re: Fluid throughput problem

Post by waduk » Sun May 19, 2019 5:19 am

I know about offshore pump is outputting 1200 u/s, thus only support 10 boilers, 20 steam engine (20*30 unit/s)

My 34 boilers, 68 steam engine is not a common ratio, but it's not random number that i use, it's the max what yellow belt can support if using coal.
From factoriocheatsheet.com, the formula goes :

Code: Select all

Boilers supported by belt of fuel = Belt Throughput(i/s) * Fuel Energy(MJ) / 1.8MJ
15*4/1.8 = 33.333 boilers -> round up to 34

But as you can see i don't put 34 boiler/68 Steam engine in a row, i separate it on different side.
Feeding each side with 1 offshore pump.
It's more than they need; since each side only use 1020 u/s.

The problem as i mention is when joining and spread the pipe, it doesn't hold, even after i account the distance (by adding pump); with wiki reference.
I'm aware of that pump getting slower in 0.17.7+ on that post, but it says the throughput upper bound is 7133 u/s and the lower bound is 5500 u/s.
Both case should be more than enough for my simple setup to be feed, since i only need 2040 u/s at max.

Thus i'm baffled why this simple setup doesn't work.
At the moment i just workaround the problem by direct feeding in my bigger layout (for max solid fuel in yellow belt, 100 boiler/200 steam;180 MW),
No join/split pipes for time being
But i'm still curious, without knowing what is wrong, there's no way i know what limit i should workaround, giving trouble for different layout (chemical, refining, coal liquefaction, etc)
So it's a wild guesswork 😢

Loewchen
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Re: Fluid throughput problem

Post by Loewchen » Sun May 19, 2019 10:11 am

Pumps can only pump fluid that reaches them. Forcing the water of both offshore pumps through the single long pipe reduces the pressure so much that the upper pump drains its input completely liming throughput way lower than what it could pump.

Reduce the length of the horizontal connection by moving the whole setup to the right like it is shown in the bottom of the screenshot and have dedicated pipes for both offshore pumps instead of merging them.

astroshak
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Re: Fluid throughput problem

Post by astroshak » Sun May 19, 2019 12:10 pm

Although the coal does not support it, the Offshore Pump can supply enough water for 20 boilers. So I tend to do 1/20/40 arrays on both sides of a yellow belt (I replace the coal on it with solid fuel when I get there). Thing is - each 1/20/40 is fed by its own Offshore Pump (the ‘1’ in the 1/20/40).

You are limiting your throughput to 1200/sec total by combining the two offshore pump outputs into one set of underground pipes. You may as well remove one Offshore Pump with that setup!

To fix it, keep the water supplies on either side of the belt separate. You have two Offshore Pumps, have each one feed the boilers on its own side of the belt.

waduk
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Re: Fluid throughput problem

Post by waduk » Sun May 19, 2019 3:34 pm

I figure out what went wrong. This shared pipes setup is working, it's a matter of throughput flow rate drop due pipe distance.

So for those who happen to read this late:

I need 2040 u/s of water.
It will be provided using a shared pipe from 2 offshore pump, each with 1200 u/s giving me a total 2400 u/s.
It should be more than enough.

Now, this is where i misread the wiki.

A pipe throughput will drop due distance.
In my case, i need to ensure least 2040 u/s BEFORE it get split.

Based on the wiki (that i already link in the first post) :
https://wiki.factorio.com/Fluid_system#Pipelines
At 3 pipes between pump, the flowrate is already at 2250 u/s.

In short, i need to ensure there are pump between 3 pipes.
And voila, the new setup works just fine.

2 out of three people in this thread keep saying this is not the good ratio or whatever, you miss my point and i already said so in the first post.
This is a simple test to figured out the mechanics of pipes.

Basically i'm trying to figure out the pipes behavior like belts, where you can join and divide, where's and how the limit works.
Thus if i can't figure out this simple setup, there's no way i can build a much bigger liquid based production.

That's all.

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Re: Fluid throughput problem

Post by astroshak » Sun May 19, 2019 10:24 pm

Pipes do not behave like belts. They behave, basically, like magic. It has to do with the order they are placed, and possibly other oddball factors.

If you are able to get your 2040/sec through a single pipe, good for you. You should not be able to, it should be capped at 1200/sec ... but good for you.

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